AdmiralSenn (Adam S.) #3416 "Christine" Megasquirt conversion

As I approach finally getting 3416 rolling again, I'll be documenting things here, particularly my settings and some of the things I've done differently and most especially as they pertain to converting using an original manifold. Hopefully this will be a lot more coherent than my prior attempts.

For startings, I'm using a dual fuel rail system (each rail on its own ports on the fuel regulator), 29.5 lb/hr high impedance injectors on two alternating banks, on a 3.0L odd-fire block with custom headers, lightened flyhweel, MSD coil and wires with plugs gapped to .05". I will also be setting up Megasquirt to control ignition next year, and once that's dialed in I'll be controlling a nitrous oxide injection system through MS's auxiliary outputs.

Cool. The ignition is a lot easier than fuel. The hard part is actually biting the bullet and putting that tack weld on the centrifugal advance inside the distributor! I think there is a lot of optimization that can be done with the advance table. Mine is set to pretty much mimic the actions of the vacuum and mechanical advances of the stock engine with the exception that I get the advance in quicker. So far no knocking, so I think I'm ok. I may experiment with a knock sensor to "push the envelope", but not yet.

Next step is to get position sensors (hall) on both cam and crank so that MS can control the spark for each cylinder (via coil on plug or coil pack) and get rid of the distributor all together. Now THAT would be sick. Being oddfire we don't have the option of going wasted spark. Since our ignition events are not equally spaced, the MS unit needs sufficient information to know when we are TDC on #1 to get the timing right.

Yeah, full COP would be awesome.

Unfortunately I still have to track down the culprit behind my RPM issue. Not sure if it's my RPM source or the board or what, but TunerStudio insists that I'm running at either 1500 rpm or 0 pretty much constantly. It seems to work great once I get it revved up above that point though. I'm going to investigate the VR input trim pots first.

Stupid question: Wouldn't switching to coil negative input (grey/slate wire) interfere with ignition control later? I can't wrap my head around the idea of MS both controlling that coil trigger and reading RPM off of it. I'm only asking because I wonder if the problem isn't my tap into the VR sensor.

I'm going to try to get in the garage and fiddle with the computer to see if I can shut down the RPM problem. Once I get my rear fascia back I can start tuning in earnest, as long as I have daylight and empty roads handy. I'd rather not be stuck waiting while I tackle this new issue.

I can post ballpark req_fuel and idle pulsewidths as soon as this problem is fixed.

The pulse trigger and the coil pulses should have the same timings. So technically the MS should be using that signal for RPM. But you should use the white/slate wire to read RPM and not the + side of the coil. You can read the RPM of either but the - side would have more voltage swing.

Adam, Bitsyncmaster (Dave) was really helpful when I was having issues getting my spark control up and running. We need to get him into this camp and developing the next evolution of ignition control or other cool things for us!
:relative:

I need to do a little remembering of how/why mine is setup the way it is, but my immediate recollection is that I go from VR straight into MS. No slate/white wire. Let me go back and check on things before you take that as gospel.

*sigh*

I suspect that either somebody is slipping something into my food, or someone is screwing with my car in between work sessions.

I went and checked out the car again today. First thing I found, the VR pots were turned about six turns clockwise - I always ran them fully disengaged counterclockwise and then MAYBE half a turn in. Fixed that and it made a marked improvement - TunerStudio now reports accurate RPMs and the car starts far more easily. So I guess I don't have to modify my input circuit after all, which is good.

Second thing I noticed, my tune was based on MS2Extra 2.1.0.... which came out before I even got the laptop that I use for tuning. How I managed to download a version of the software that's two years out of date is beyond me. Now running 3.1.1 and it's running great.

Currently running at ~1.3-1.5 pulsewidth at idle. If it wasn't hunting and seeking I could get it to idle at ~500 RPM no sweat, maybe lower - it will randomly decide to oscillate up and down and at that low of a speed it takes it too slow to keep running. Req_fuel 10.8 at the moment and AFRs in the 13-15 range - again depending on oscillations. Prior to the code update the same settings were yielding something more like a 9 or 8 AFR.

My garage light just went out again so I'm done for the night. I definitely have an exhaust leak so maybe Thursday I'll pop off the header and muffler and see if I can bend them back into shape - the muffler end is slightly ovaled out so the car sounds vaguely lawnmower esque.

I do think that the car is overall still running a bit rich and/or needs yet another set of spark plugs. I was running it at ~19 degrees advance (whatever the maximum is with no advance) and after the update I can get it to run decently at ~13-15 but it's SO MUCH HAPPIER at the higher end that I don't like to leave it that way.

What are you guys running for your idle advance?

And yes, the more of Dave's brain that we have access to, the better. Having a wizard is never a bad thing.

It sounds like you should be rejoicing not sighing! Your injectors are so large (29.5 versus my 19 pound/hr) that I wonder if you aren't doing yourself a disservice with the terribly small pulsewidth. Bigger isn't always better; it's how you use them.
:devil:
We'll keep working on Dave (Bitsyncmaster) and get him over to this (unstated whether the light or dark side) of the force. He would truly appreciate the hardware and software flexibility of Megasquirt and I could see him having a field day with it.

I'd forgotten that you were advance controlling as well. Yes, those VR pots are important! Check my advance tables in my project thread. I'm fairly happy with it, but God only knows if it could be optimized. I followed the philosophy of the stock design, vacuum advance going up and then decaying, mechanical advance continuously increasing to a maximum of 37 total degrees. I try to get it all in by 2000 rpm if I recall.

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Originally Posted by AdmiralSenn

For startings, I'm using a dual fuel rail system (each rail on its own ports on the fuel regulator), 29.5 lb/hr high impedance injectors on two alternating banks, on a 3.0L odd-fire block with custom headers, lightened flyhweel, MSD coil and wires with plugs gapped to .05". I will also be setting up Megasquirt to control ignition next year, and once that's dialed in I'll be controlling a nitrous oxide injection system through MS's auxiliary outputs.

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Are you using the engine from the 3.0L PRV?

I have one of these sitting around, and am very interested in doing the swap.

Perhaps we can bring back the "3.0 swap and support" thread?

--buddy

I have 24 lb/hr high impedance injectors. At idle, I have pulsewidths around 3.5-4, an AFR around 14 once warmed up, and MAP at ~35.

Mike et al: I'm not sure where the ~1.5 pulse width in my previous post came from... looking at one of my logs it is CLEARLY idling quite happily at ~3.3-3.5 (lowest at 2.7), MAP at ~36, lowest at 33, six squirts alternating. I'm not sure what happened with my brain there. I could just be tired. The old tune ran in the 1.5 range and it never did very well, maybe my memory got mixed up. Shouldn't happen at age 24, but... I guess it's a good thing the lights went out when they did.

Owen, I'm not yet doing ignition control, just fiddling with the mechanical dizzy still. I'll be doing that map after fuel makes some kind of sense. Either way the advance numbers should be somewhat similar. And I know these injectors are huge, but I'm planning to use them on the nitrous oxide re-installation and then later on my supercharged build if/when I can afford that project. They're on the upper end of sanity for sure but they WILL let me drive it adequately.

nullset (buddy?), it's actually a very bizarre motor... PO did a lot of work to squeeze 3.0L pistons and rods into a factory odd-fire bottom end. I think this is the only one like it; if it ever blows up I'm just going to drop in a later 3.0 and be done with it. I don't know much about it because I didn't build the motor. I do think the 3.0L thread should make a comeback although I won't be any help with it, unfortunately.

I thought my hunting issue might be the fuel overrun settings but that's actually turned off in this tune, so I'm just going to have to keep hammering at it. I'll take a log of it if I can't figure it out and post it (tuning laptop's battery just died). The log I have shows very clear sine wave patterns of RPM, MAP, PW and AFR taking huge swings simultaneously. I'm not running any sort of idle air controller yet either so that's definitely not the issue.

If I were to try EFI, I think I would get compleat 3.0 even fire and work on it mounted on a test stand. It's such a big project it is at the end of my to do list.

I've been thinking about another project for quite some time but have to keep this also on the back burner. That is a new ignition ECU that lets you adjust ignition timing on the fly. So you would set your ignition timeing at 20 deg. and it would delay each fire to let you adjust it to any value less the 20.

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Owen, I'm not yet doing ignition control, just fiddling with the mechanical dizzy still. I'll be doing that map after fuel makes some kind of sense. Either way the advance numbers should be somewhat similar.

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I'm curious as to why you are fiddling with VR pots therefore :8ball:

Are you taking your RPM signal from the coil (-) gray/white wire or from the VR signal wire directly out of the dizzy? If you are already taking the VR signal (which it sounds like you must be since you said it "made a marked improvement" to the running of the car, you are mere nanoseconds from running full EFI & spark control! Tack down those weights, disconnect the vacuum hose and run the advance table.

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Originally Posted by nullset

Are you using the engine from the 3.0L PRV?

I have one of these sitting around, and am very interested in doing the swap.

Perhaps we can bring back the "3.0 swap and support" thread?

--buddy

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Why don't you bite the bullet and start such a thread as if it were an EFI conversion? Just name it something like "Nullset's 3.0L PRV conversion". It doesn't have to be a real project, but who knows, it may turn into one!

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Originally Posted by Spittybug

I'm curious as to why you are fiddling with VR pots therefore :8ball:

Are you taking your RPM signal from the coil (-) gray/white wire or from the VR signal wire directly out of the dizzy? If you are already taking the VR signal (which it sounds like you must be since you said it "made a marked improvement" to the running of the car, you are mere nanoseconds from running full EFI & spark control! Tack down those weights, disconnect the vacuum hose and run the advance table.

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I apologize for sort of highjacking this thread, but since I plan on spark control AFTER I get fueling going, I'd like to understand how this works a little better.

So the weights get tacked down, the vacuum hose disconnected. So the MS ECU gets the tach signal straight from the VR wire so I understand how it knows what the RPMs are.

What I'm not understanding is how MS actually controls the timing at this point. How is it actually telling the system when to fire?

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Originally Posted by opethmike

I apologize for sort of highjacking this thread, but since I plan on spark control AFTER I get fueling going, I'd like to understand how this works a little better.

So the weights get tacked down, the vacuum hose disconnected. So the MS ECU gets the tach signal straight from the VR wire so I understand how it knows what the RPMs are.

What I'm not understanding is how MS actually controls the timing at this point. How is it actually telling the system when to fire?

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In MS you have an advance table in which you tell it what degree of advance at what RPM/load combo. Just like the VR signal from the dizzy tells the ignition controller when to send coil pulse, it does the same for MS who sends the signal to the coil instead. As part of the MS build there was the choice to build the input circuits: Hall/optical or VR. Usually you just build both and choose with jumpers. Later in the build you had a choice to build the high current ignition driver circuit to drive a single coil. This basically does what the stock ignition box does but with the added ability to play with the timing digitally, rather than letting vacuum and centrifugal forces do it. If one wished to drive multiple coils then there are a few additional circuits that must be built on the board, but it isn't too bad. The problem lies in the fact that we are odd fire and therefore must provide the logic module with information on both the cam and crank positions so that it knows when we're on the power stroke. In a "wasted spark" setup (even fire only), we can just tell the unit to send spark at every TDC event. Half of the time it is sparking in a cylinder that has exhaust valves open, but who cares; hence the term wasted spark. On an even fire engine, there is a cylinder that is on its power stroke at the same time, but not for us odd fires. I'll see if we can add more info in the EFI documentation sticky.

I believe MS actually just grounds the coil to fire it at the appropriate point. Pin 36 on the DB37, just tap it into the white/slate wire.

Owen, I agree that I'm close, but I lack the ability to tack anything down since I don't have access to any sort of welding equipment. I'm also super reluctant to do anything to my distributor without a spare handy - having gone without driving Christine for more than a year as it is, I don't want to risk a longer wait just as I'm about to get her on the road again. Removing that last ECU is on my to-do list, especially since I need the ability to retard ignition once I start playing with the nitrous. Find me a broken distributor to have welded and I'll do it tomorrow! :cool:

I have no idea why the VR pots were that far out of adjustment as I don't normally touch them - I just figured I'd make sure this time and lo and behold, they were all screwy.

And I'm still happily taking my VR signal off the distributor directly. I think I might have been the first person to try that, actually...

Appreciate the education, Owen. So, for example, on my car if I wanted to go ignition control, I would tack down the distributor weights, get the tach input straight from the VR wire, set the appropriate settings in Tuner studio.

And to get MS to then tell the coil when to fire I run a wire(s) from the ECU (in my case, relay board) to the ignition coil....?

Adam & Mike;
Yes, the MS is just a switched ground from the coil. (same net effect, right? All we are doing is controlling when to break the primary circuit so that the induced voltage goes high on the secondary coil... thus a spark that gets distributed)

Rather than tacking, perhaps something so deliciously low tech and reversible as a couple of twisty ties to secure the arms in place? Hell, just wrap thread around them! Remember, all you need to do is stop the arms from swinging outwards with centrifugal force.

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I think I might have been the first person to try that, actually...

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I'm taking signal straight from VR, so sorry, you aren't unique!

Mike, Pin #36 goes straight to your coil (or just tap it into the slate/white which goes to the coil). MS does the rest so long as it is getting the VR signal from the dizzy and you have the right parameters set (see my .msq in my project).

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Originally Posted by Spittybug

Adam & Mike;
Yes, the MS is just a switched ground from the coil. (same net effect, right? All we are doing is controlling when to break the primary circuit so that the induced voltage goes high on the secondary coil... thus a spark that gets distributed)

Rather than tacking, perhaps something so deliciously low tech and reversible as a couple of twisty ties to secure the arms in place? Hell, just wrap thread around them! Remember, all you need to do is stop the arms from swinging outwards with centrifugal force.

I'm taking signal straight from VR, so sorry, you aren't unique!

Mike, Pin #36 goes straight to your coil (or just tap it into the slate/white which goes to the coil). MS does the rest so long as it is getting the VR signal from the dizzy and you have the right parameters set (see my .msq in my project).

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Starting to make more sense. Right now, I run a shielded wire from the tach wiring port on the relay board to the negative post of the coil. So, for ignition control, I would have to remove the shielded wire from the negative post of the coil and instead tap it into the gray/slate wire, correct?

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Originally Posted by opethmike

Starting to make more sense. Right now, I run a shielded wire from the tach wiring port on the relay board to the negative post of the coil. So, for ignition control, I would have to remove the shielded wire from the negative post of the coil and instead tap it into the gray/slate wire, correct?

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Not exactly. The shielded wire is your tach input. Gray/slate is the same wire as coil negative. For full spark control you'd tap the shielded wire into your VR wires from the distributor, and run pin 36 to the gray/slate (or direct to the coil).

Owen, I know you're running VR too. I just remember feeling like I was nuts, being the only one who did it that way. It was so long ago, though, I don't really remember. I vaguely remember advising somebody on it during their conversion, maybe it was yours - it was on the .com site.

Anyway, it doesn't matter who came up with it, I don't know why I even mentioned it. >_<

Any piercing insights into my hunting problem? I'll log on from the laptop shortly and upload the log.

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Originally Posted by AdmiralSenn

Not exactly. The shielded wire is your tach input. Gray/slate is the same wire as coil negative. For full spark control you'd tap the shielded wire into your VR wires from the distributor, and run pin 36 to the gray/slate (or direct to the coil).

Owen, I know you're running VR too. I just remember feeling like I was nuts, being the only one who did it that way. It was so long ago, though, I don't really remember. I vaguely remember advising somebody on it during their conversion, maybe it was yours - it was on the .com site.

Anyway, it doesn't matter who came up with it, I don't know why I even mentioned it. >_<

Any piercing insights into my hunting problem? I'll log on from the laptop shortly and upload the log.

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Okay, so I would have to add another wire; thanks! And that was me you advised on it :)

So the pin 36 talk was confusing me a bit, as I am running the relay board. I just looked it up; that corresponds to an igntion output port on the relay board. So in this case, once I have fueling going and tuned in the spring, I think I will go ahead with spark. Don't have a welder though, so will need to find someone to tack down the weights for me. Plus, I'd get to learn how to install a distributor.

Adam, I'll look at your files when you post. I have found it to be critical that all the cells sitting in the idle area be very close to one another on VE and advance (AFR too if you have given it authority). If there is any discrepancies you start creating oscillations as it gets more fuel, RPM goes up, moves to a different cell, etc...... lock 'em all down if in doubt. The optimizer is the biggest culprit for changing them. I exclude all my idle cells when tuning with autotune.

Friggin' finally... 97Kb is not much room for a datalog!

You'll see the oscillations clearly in this log, they start immediately after a restart. Note that I did NOT touch the throttle and have not adjusted anything at all except for initial req_fuel and other absolute necessities prior to starting - I hadn't even opened the VE table except to make sure it looked vaguely sane.

MSL: http://www.mediafire.com/?uno278cf9mg0unn
MSQ: http://www.mediafire.com/?1o93imb2xgcrs6z

It's very possible the VE table is totally off since I haven't dialed it in yet, but I'm honestly not sure exactly what to adjust there because when it idled on this table without oscillating, it idled REALLY nicely. :shrug:

I haven't even started tuning on this file since it's brand new as of yesterday. Autotune and the optimizer have never even seen this table.

It did this before on the old code too, but it was somewhat more violent when it did.

Also, I hadn't even considered just tying the distributor arms down... maybe I will experiment with that tomorrow night if I have time - I do have plenty of ways to secure them nice and tightly. Have you uploaded your advance maps yet? I'm 100% lost on ignition control so far so I will definitely need your settings to start with, and will probably leave them as is for a good long while. What did you set the base timing at (i.e. without MS advancing or retarding what would your timing be)?

EDIT: Yes, I see how much variation there is now. Not sure if I should tinker with the bins or not. I'm shooting to idle at 850-900 RPM.

Your file shows you are using a narrow band 02 sensor. (Basic menu, EGO control). True or is that just one of those oddities about MS where some of the menu items change back? Try disabling any AFR authority until you get the hunt resolved. Try making your advance as consistent as possible too.

Your VE values in the block between 40% and 1100rpm varies between 26 and 39. I would believe that to give you some oscillation as it will constantly be getting different fueling. I only vary mine by a few, say ~4 over the same range. I also set my table up to give me very fine control; 10-35% 5% increments, 40-100% in 10% increments. The RPM axis goes: 500,700,900,1100,1300,1500,2000,2500,3000,3500,400 0,4500,5000. Remember, these are just "points on a line" so Megasquirt interpolates between them and past 5000. By doing this I can be fine tuning the idle area where little changes make a meaningful difference to the engine, and have "close enough" in those areas that the optimizer is going to play with and that only has transient hits as the car accelerates or decelerates through them.

Yeah, I have an LC-1. TS just decided to ignore the wideband settings I configured for some reason.

I didn't realize that I forgot to disable EGO control... it's been too long since I did some of this.

I guess I should take my vacuum advance off completely for now then, and monkey with the VE table. Apparently the generated table isn't even REMOTELY close to making sense. I'll just open up DARCOM's and compare values.

I'm not really sure what I should do with the RPM bins. I'd really like to define the upper limits of the engine's range so that when I start playing with the nitrous oxide system it doesn't have to guess at proper fueling - blowing up this motor is not on my to-do list. Granted that it's a wet system with extra fuel injected anyway, but even so. I'll probably bump up the 500 bin to closer to my idle speed rather than sacrifice the top end. I think that's what I did on my pre-fire tune and it idled just fine.

I now have a bunch of work to do tomorrow outside the DMC world so I may not get back to this until Saturday or so.

EDIT: Owen, thanks for posting your VE table. I was able to get a good sense of some sane VE numbers from looking at it. The advance table will be coming in handy very soon, too.

Some solid progress tonight, although I'm chickening out before I start tinkering with the ignition system. I'm just on the edge of "I'm sure that fuel smell is nothing dangerous" levels of tiredness. Figured I'd stop before something really dumb happens.

Part of the reason I keep asking impossibly dumb questions about basic tuning is that I got REALLY lucky on my first ever tune. I got a pretty much rock solid idle my first try and the generated VE table didn't need much tuning, so I never really got very far into the fundamentals of setting this stuff up correctly. But I'm learning!

I flattened out the VE table to the mid-30's range by trial and error and adjusted the bottom two RPM bins to something that makes a little more sense - 700 and 900 RPM. This smoothed out the idle hunt completely. I also dropped the upper third of the table down by about 10% and smoothed it into the rest, which should keep things a little more sane. I was seeing VEs in the 80-90 range at about 3000 RPM and ~60% load. Not quite normal even for a modded engine.

After tweaking the map until I was satisfied, I started to disconnect the vacuum advance and accidentally pulled the hose off the butterflies instead of the T junction I put in. Grumbling, I pulled the throttle/w pipe assembly off and found a leaking water pump pipe (apparently I didn't quite tighten that clamp as much as I thought) and a crumpled, slightly blackened W pipe gasket on the plenum that feeds the passenger side. I need to get some proper meaty gasket material and replace it, but fixing the huge vacuum leak on this side toned down my idle popping and stumbling significantly.

It's always something simple. I am optimistic that replacing those gaskets with something squishier and thicker will almost completely resolve the instability of my idle. The "popping" I thought was an exhaust leak was actually a misfire - I could feel the gap in the exhaust stream with my hand.

See my "solididle" log for tonight's results. It stays almost perfectly still on a single VE intersection. The RPM still fluctuates a bit but it's more "normal" vibrations (probably the vacuum leak) rather than that sickening sine wave pattern. The engine is also WAY quieter now, which is good - I'm at about 80% of the quality of idle I had on my previous tune now.

Also, in a fit of scientific curiosity, I decided to find the absolute lowest speed my engine will run at. See "stupidlowidle".

A few things on this attempt. First of all I was able to get the engine down in the 370-400 RPM range (again I'm on the OEM manifold). It was actually reasonably smooth considering that it was running so slowly. However, I had to OPEN the throttles significantly to accomplish this (and adjust the distributor excruciatingly slowly), and look at the MAP readings compared to my regular idle. From playing with that it's pretty clear that this is a horribly inefficient engine speed to run at, and required a lot of fiddling to get it to operate. The alternator is basically not doing anything at this point. The log is too short to show it clearly but the voltage was dropping noticeably. This should be obvious to anyone who knows how an alternator works but I figured I'd mention it anyway just in case.

Normally I wouldn't even bother to share these findings, but I recall some discussion on the .com site (I think it was in one of the many carb threads, not sure) of the disadvantages of the stock manifold and/or the smoothness of the idle at lower engine speeds. I think this shows pretty clearly how bad of an idea this is - certainly from a fuel efficiency standpoint and probably from an emissions standpoint as well. There's a reason the factory bumped us up to 900 RPM!

Anyway. From playing with the engine all night I think I'm basically ready to start road tuning. Even with acceleration enrichment turned off I can rev the engine pretty hard and it barely murmurs - prior to these fixes it would hesitate for half a second before screaming ahead. I was unable to get the engine to stall or behave strangely otherwise despite anything I tried, so the open road shouldn't pose much of a problem now.

I'm making a junkyard run tomorrow and will be keeping my eyes peeled for a proper idle motor. If the Volvos that I usually scavenge from are still there I should be able to set up idle control by Sunday.

Looking much better. A couple of points to consider;

• Your TPS is showing 14 at idle, so I think you need to calibrate. It should be zero. Probably occurred when you cracked the butterflies.
• Running too low an RPM not only hurts your alternator, but oil pump too!!! You need to stick with >700 in my opinion.
• The ranges on your MAPdot and TPSdot are pretty narrow and that's good. It will help you when you get to acceleration enhancement. My TPSdot is still kind of noisy (interference on wires or unclean 5v supply, I need to diagnose more...) and this means I have to have a higher threshold or I get random acceleration boost.

Keep in mind when you autotune it that you should drive reasonably and not hop on it. Otherwise it will try and give you fuel values that are too high (and should be accommodated via acceleration enhancement).

I'm off to see my daughter at OU this weekend and see us whip up on A&M. I'll take the laptop with me and check on your progress!

Well, my TPS is disconnected as the sensor itself is actually dead. I just set the flood clear threshold to 100% and ignore it. Similarly the thresholds for mapDOT and tpsDOT are set high enough to entirely disable AE, and the balance for that is set to 100% MAP.

This will change when I get the TPS sensor replaced, so I'll have to put in settings that actually make sense...

And yeah, I forgot about the oil pump being affected. Like I said, it's an AWFUL idea and I'm not really sure why anyone ever advocated it as a good thing.

As soon as I get my bumper back I'll take it out on a back road and update this thread. I am REALLY looking forward to driving her again!

Zoom zoom...

Drove her around today. She's actually pretty well set for power, though there's an alarming rattle on hard acceleration - sounds like I'm in too high of a gear, even in first. It could almost pass for engine knock but I can't imagine that I'm seeing that with the way I have my advance set up. (Yeah yeah, I probably shouldn't have accelerated hard the first time out.... >_> sue me)

A few days of doodling and tuning and I'll start my ignition control project. Still have to grab and install an idle motor too. Currently idling right around 1000-1100 RPM but I'd like it to be lower off the throttle.

I've decided to stick with the stock idle speed motor. I have a GM IAC + the housing block for that diyautotune sells, if you're interested. PM if you'd like, and we can work out a deal.

New issues have cropped up (Non-EFI related) that have kept me from doing any real work on the car, but I am driving it around. Now that the spark plugs have cleaned themselves up a bit I can finally start fine tuning.

I have purchased the PWM IAC kit and the BIP373 coil driver kit so I'll be going full idle and ignition control soon (currently my "idle control" is the throttle stop screw).

I have also found that adding a check valve to the output line of the fuel system completely obviates the need for the fuel accumulator, so if you don't have a check valve built into your fuel pump, the Aeromotive one on ebay (Aeromotive #15106) works beautifully.

My accumulator died shortly after the engine fire, so I've been having to prime the pump multiple times to start the car. Last night I started the car and ran it for about a minute. This morning it started right away on the first rotation, just like it used to. So anyone doing a conversion with a bad accumulator, just leave it in there and save yourself the money and hassle. Since I'm using AN -6 lines and fittings it took about two minutes to install. It won't hold fuel pressure but it will keep the lines full; the difference between 45 psi being held in the lines and pressurizing lines already filled is negligible.

We're doing the finishing touches on converting my car to EFI. It appears that my accumulator is bad too. I'm wondering if I should install the check valve also.

I would. It's not perfect - it doesn't hold full pressure - but I found that it drastically reduces the amount of time needed to start the car. Instead of priming 3-5 times and cranking over two or three times, it takes anywhere from 1/4 to 1 1/2 rotations of the motor to start now. That delay has more to do with my ignition and fuel settings, though; I suspect that when I get spark control I can reduce the average time to 1/2 of a rotation.

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Originally Posted by AdmiralSenn

I would. It's not perfect - it doesn't hold full pressure - but I found that it drastically reduces the amount of time needed to start the car. Instead of priming 3-5 times and cranking over two or three times, it takes anywhere from 1/4 to 1 1/2 rotations of the motor to start now. That delay has more to do with my ignition and fuel settings, though; I suspect that when I get spark control I can reduce the average time to 1/2 of a rotation.

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I'm getting the MS unit tonight with the changes on it to do the full spark. I plan to plug it in and fire up the engine to see how it runs.

Raaarrghh, the thread lives!

Since I am sucking it up and paying the machine shop to do my cylinder heads, I am going to ask if they can make a sheet aluminum adapter from the stock throttle body to a 3" intake pipe.

Should I ask them what the costs would be to make multiples? If there is interest I am willing to have them do it but I will need to take some kind of down payment for each one. I will of course ask them about price per unit.

Adam, did you ever build a mock up of what you are going to have made? It's been a while, so perhaps a picture would remind some people? Essentially you want to totally remove all parts of the stock fuel system upstream of the throttle body (fuel distributor, mixing unit and airbox) so that you can get a nice compact air filter to fit in between the air runners, right? Or were you going to run a hose to the side pontoon and hide one in there?

Cool way to clean things up if you join the growing number of people that are converting to EFI using the stock manifold! Go for it!

Quote:

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Originally Posted by Spittybug

Adam, did you ever build a mock up of what you are going to have made? It's been a while, so perhaps a picture would remind some people? Essentially you want to totally remove all parts of the stock fuel system upstream of the throttle body (fuel distributor, mixing unit and airbox) so that you can get a nice compact air filter to fit in between the air runners, right? Or were you going to run a hose to the side pontoon and hide one in there?

Cool way to clean things up if you join the growing number of people that are converting to EFI using the stock manifold! Go for it!

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http://dmctalk.org/attachment.php?at...5&d=1339990701 from the middle of last year. Essentially I want to replace the flex hose with solid tubing and have it all bolt together nicely via an adapter to the stock throttle bodies.

You can see how ridiculous and unfinished the air cleaner system is in that picture (and the wiring and hoses and all - I am taking care of that as well). I want to make a sheet metal adapter from the throttle bodies to a 3" intake pipe, and then either keep the filter where it is between the plenums or move it forward of the engine and to one side so it pulls in somewhat colder air. I'm not really a fan of the 180 degree bend necessary for a pontoon mount, I'd rather move it forward and add a heat shield/box. Or do something like a K&N Apollo, with the filter mounted where it is and an intake hose that runs wherever I want it.

I've been slowly adding improvements to that setup, but I was never happy with the way it looked or the slapdash way it was connected together. It hasn't been an issue since the car's other problems keep taking it off the road, but I am trying to get the engine bay "done" with this rebuild. I am tired of being forced to take shortcuts due to budget constraints so I am making it a point to make each component a "forever" upgrade. No more "good enough".

I figure if the shop can make a few of these adapters it will solve one of the last barriers to entry for a budget EFI project. Not that my build is budget any more, but still.

Necro bump!

(The Admiral hasn't logged on since last August, but maybe other have experience here?)

I see the Aeromotive FPR is connected to vacuum which enables rising rate mode. I would have assumed this would make CL tuning - especially idle tuning - more difficult since FP will decrease as vacuum increases. Just wondering what the rationale was.

I'm going to talk to myself here just to admit that this turned out to be a real newb question. After reading a bit more I see the point of vac/boost referenced FPR is to maintain a (as close to as possible) linear pressure differential between MAP and FP.

My brain was in kjet mode which has no such compensation mechanism, which is why Kjet turbo leans out under boost - as MAP increases, the pressure differential decreases meaning less fuel flows from the injectors.

(/me puts thread back in the ground)