Another Megasquirt conversion: VIN00910

[ramblinmike]

So I've been lurking on here for years and watching you all convert to EFI and never quite getting up the nerve to do it myself. In December I was able to do some side work and, well, that money went into me converting my car from K-Jet to EFI.

The hardware side of the conversion is done: I sourced a Z7U manifold and injector rails and was able to make an adapter plate to mount a throttle body off of a Jeep 4.0. The Jeep throttle body allows me to use the integral TPS and IAC that were not part of the Z7U throttle body that came with the manifold.

Since I had no idea how crazy I was going to get with this thing in the future, I bought a MS3X with the relay board for this conversion.

I have everything installed and plumbed and, as far as I can tell, the wiring completed for the new sensors, injectors, etc. My current goal is to get fuel-only running first before I do anything with running spark control, as you guys have all mentioned that fuel-only is the easiest way to go. Since I'm a complete noob, I took your advice.

I followed the guide opethmike posted and used the settings he suggested in his writeup for the initial settings in TunerStudio. The car started right off but immediately started missing like crazy and running extremely rich. The sync loss counter started counting up quickly before resetting to 0 and starting over while the sync "light" at the bottom of the gauge screen flashes from green to red constantly. The 'Engine RPM' gauge flashes red repeatedly with the displayed rpm quite literally going from 10,000+ rpm to 0. It shows what I guess are 'normal' rpm readings while the starter is cranking. It only goes crazy after the engine starts.

I have the ignition currently set for 'basic trigger', as the car doesn't start at all when this setting is changed to 'fuel only'. I started with connecting the "tach" terminal on the relay board to the white/slate wire in the connector for the old rpm relay. After seeing all of the sync issues, I moved it to the white/slate at the old idle controller connection behind the driver's seat. I have not tried connecting it directly to the - terminal on the coil, but I know I read someone on this forum had issues with that placement. I've read so much today that I don't remember whose thread that was on.

The MS3X and the LC-2 wideband are both grounded together at the same place behind the passenger seat at the bulkhead ground. There is an 8AWG wire connecting the battery to this bulkhead connector and the engine block. The MS3X constant 12+ is wired to the battery directly and the LC-2 is wired as it showed in its instruction manual with a relay connected to the battery +. The trigger wires for both the MS3X and the LC-2 relay are connected to the green wire at the old rpm relay connector.

I've read several threads about sync issues, but mine seem much more severe than what I've read on other's posts. I have things grounded together like others suggested. I've been running an Accel coil for the past 15 years with it wired to receive a full 12V, but I swapped the original coil back in and moved the wires around at the resistor to their original positions without any effect.

I guess I should say that the car was running before I took it apart. :) As far as I know there wasn't any ignition-related issues. I had done the coil swap long ago on the suggestion of a local club member right after I bought the car.

Where would you guys start? Is there something from tuner studio I should post here? I played around a little with capturing a log file showing the things its doing if that would help.

Thanks in advance!

Mike

[powerline84]

So I run spark trigger direct from negative coil . When I first started my car I was getting the same sink loss symptoms you got. Then Fabombjoy was nice enough to let me know that the megasquirt ecu is not shipped set up for negative coil input. So you have to take your ECU apart and move some jumpers/switches. Let me see if I can find the pics from me doing it based off his help.

[powerline84]

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I believe these are the spots I changed. Get into the hardware manual for ms3 (Google it it's free should pop up) and go the the part about setting up the ECU . I'll see if I can find more info and hopefully Fabombjoy will chime in.

[powerline84]

Ok for my setup (negative coil input ).

You need to have
jp1 on 2-3,
j1 on 1-2.
Xg1-xg2 connected

That is referenced in the pic above.

If you are running negative spark and haven't touched your ECU I guarantee it's wrong and that's your problem. Go negative coil direct. Make the changes to your ECU board. Pat and I have that setup and my car starts almost instantly. No sync loss

[ramblinmike]

Holy smokes. I didn't know there was a different jumper setting for negative coil input.

I'll do that and post back. Thank you.

[powerline84]

Me either it was one of the many mistakes I made In the road to EFI lol

[FABombjoy]

There were definitely issues with using the VR pickup on the distributor. Some MS board revisions were better than others and it sounds like an in-line resistor was needed.

This approach was only taken if you wanted to run full programmed ignition from Megasquirt, removed & locked out the distributor advance mechanisms. TBH I'm not sure that the few minor gains you get from MS ignition control are worth the extra work on a non-turbo car. Idle advance control is probably the largest benefit. You're still only as accurate timing-wise as the VR pickup can be which is 12 events per 720 degrees of crank rotation.

Negative trigger for fuel-only though will work for you once the jumper & settings are correct.

The only downside of coil negative is it can be susceptible to solenoid / relay / coil noise if you're missing filter capacitors (from the cooling fans, AC fan, AC clutch, things like that).
It probably won't cause any issues running but you would see it as a strange once-sample spike in RPM w/ creates a brief rich spike in fueling.

Once your MS box is set up for coil negative, any of the white/slate RPM wires that sprawl throughout the car will work fine as your RPM pick-up point.

[AdmiralSenn]

My experience was the opposite of most - I had terrible noise problems with everything I tried, until I switched to VR input running off the distributor pickup, and tuned it using the on-board adjusting pots. I used shielded wire for the inputs with one pin being attached to the shield and one to the core, and IIRC the shield was attached to the sensor ground on the board and the core to the VR in pin (don't quote me on that it's been several years). This setup ended up with a nearly perfect VR input and I never had ignition trigger issues again. Bonus points that it can be run straight off the existing pickup wire in the relay area so one less wire to run.

[Bitsyncmaster]

My idle ECU can provide a cleaned up ignition signal that a few users have used but most people going MS end up removing the idle ECU.

[ramblinmike]

Well, I need to thank powerline84 because his suggestion worked!

I was able to get the car started tonight without a single sync error in TunerStudio!


https://youtu.be/m_Pp-PnyJBo
https://youtu.be/m_Pp-PnyJBo

I was able to get the car to 'run' immediately after making the jumper changes powerline84 suggested, but it would not idle on its own. After much reading and tinkering with settings I was able to get it to idle fairly smoothly at 1500rpm as in the video. I was pretty happy at that point, so I spent the rest of the evening texting everyone and sharing that video! :)

I had some of that plastic wire loom wrap here at the house, so I wrapped what I could:
63253

I've been doing some reading about getting the idle to lower where it should. I have it set to idle at 700, so I don't know if I have the IAC wired incorrectly. As far as I can tell the idle stop screw on the throttle body lets the butterfly completely close. I have the distributor solenoid wired to ground to fidle on the relay board and I followed the suggestion in opethmike's writeup to have the ecu ground the solenoid when I'm just off idle.

I want to get the rest of the harness wrapped and get something figured out for the air filter before I drive it, but the lack of any sync issues and the engine running made me pretty happy today.

Thanks for the replies!

Edit: the YouTube link didn't work so I just pasted it in the body of the post.

[powerline84]

"Well, I need to thank powerline84 because his suggestion worked!"

Glad I could help. Just paying it forward from all the guys who helped me.

[Josh]

I must bring this up again as it continually baffles me.
Why are people buying MS3x boxes to run fuel only batch firing setups. It is such a waste of a MS3

[Delorean Industries]

I must bring this up again as it continually baffles me.
Why are people buying MS3x boxes to run fuel only batch firing setups. It is such a waste of a MS3

I get the feeling it is more of a "testing the waters" thing with a few toes in. Gives room for improvement down the road. In most cases the installer gets it running fuel only and then updates it from there. I could be wrong and it might be a case of people just copying what others buy with no intention of further updates.

[FABombjoy]

It does make certain things easier. A base MS2/3 runs short of inputs & outputs. 3X gives you these options more readily without repurposing status LEDs or other solder solutions most people probably wouldn't be comfortable with:

-VSS input
-AC control (1 in and 1 out)
-Check engine light

A companion BCM would probably better suit these goals, but I don't think any such thing exists yet.

[powerline84]

I plan on expanding mine. I am not staying fuel only
There's your answer lol.

[ramblinmike]

I get the feeling it is more of a "testing the waters" thing with a few toes in. Gives room for improvement down the road. In most cases the installer gets it running fuel only and then updates it from there.

This is the correct answer. I've already moved the cooling fans and a/c control to the MS and rigged up an output to use the Lambda light as a "check engine" light.

I bought the MS3X because of the expandability it offers. I can do anything I want to in the future without much headache. It has already completely changed the car in a positive way. I'm enjoying learning as I go. I haven't had this much fun in the garage in, well, a very long time.

[Josh]

This is the correct answer. I've already moved the cooling fans and a/c control to the MS and rigged up an output to use the Lambda light as a "check engine" light.

I bought the MS3X because of the expandability it offers. I can do anything I want to in the future without much headache. It has already completely changed the car in a positive way. I'm enjoying learning as I go. I haven't had this much fun in the garage in, well, a very long time.

I have the radiator fans, ac control, and fuel table switching setup with just a microsquirt :)

[ramblinmike]

I have the radiator fans, ac control, and fuel table switching setup with just a microsquirt :)

That's awesome! I have no idea what I'm doing, so I went with what I thought would be easiest for me to use. I'm hoping to go ignition here before too long, hopefully with EDIS or something similar.

I'm having more fun with this thing than I can put into words. I've been driving the car at every opportunity for any pathetic reason I can muster. Josh, you should know that your LS4/Subaru conversion was what pushed me over the edge to start this MegaSquirt thing to begin with.

I stopped making excuses for what was annoying me about the car and decided to change it for the better. :)

[ramblinmike]

I'm wanting to go ignition control next, and I'd like to try and lose the distributor all together when I do this. In preparation, I got a PRV distributor off of eBay to play with.
63679

After some disassembly and cleaning
63678

What have you guys done for a cam signal? I've seen the optical conversions in another thread but I don't think I need anything with that kind of resolution. From what I've read I think I can get by with a single tooth setup and a trigger wheel on the crank pulley. Does anyone have pictures with what they've done for a single tooth setup using the stock distributor? I've read descriptions about what has been done but I was wondering if anyone had some pics they'd care to share. Thanks, appreciate the help so far!

[FABombjoy]

Gutted distributor and riveted / jbwelded (hell yeah jbweld) a single tooth on to the original pole piece.

63685

The single tooth metal was an old pinball machine bracket. I tried to use as many old pinball machine parts as possible during my conversion LOL

More pics (https://lukesandel.com/zpm/Auto/DeLorean/2017---EFI-conversion/CMP---Camshaft-Position-Sensor/)

[Bitsyncmaster]

Gutted distributor and riveted / jbwelded (hell yeah jbweld) a single tooth on to the original pole piece.

63685

The single tooth metal was an old pinball machine bracket. I tried to use as many old pinball machine parts as possible during my conversion LOL

More pics (https://lukesandel.com/zpm/Auto/DeLorean/2017---EFI-conversion/CMP---Camshaft-Position-Sensor/)

It may work with one pulse on the distributor so you get a reference of which stroke your on for #1 cylinder but it's going to take some fancy software to keep track of when all cylinders need to fire. Your crank sensor needs a lot of teeth to know RPM quickly and when to fire the other cylinders.

[FABombjoy]

That's exactly how it works when in conjunction with a crank wheel. The cam signal is only polled once to obtain full RPM sync.

If you tried to run fuel only on this setup it would be pretty sloppy. Ignition control would probably be very entertaining from a distance.

[ramblinmike]

Gutted distributor and riveted / jbwelded (hell yeah jbweld) a single tooth on to the original pole piece.

63685

The single tooth metal was an old pinball machine bracket. I tried to use as many old pinball machine parts as possible during my conversion LOL

More pics (https://lukesandel.com/zpm/Auto/DeLorean/2017---EFI-conversion/CMP---Camshaft-Position-Sensor/)
Thanks for the pics. I've read about the "half-moon" shape used on the cam sensors and see you've used the same. What is the advantage of the half-moon shape rather than a single tooth passing? That's actually one of the things I'm confused about. Should the arm be in a half-moon or just a single 'tooth'?

I've seen cam synchronizers on some vehicles use the half moon:
63692

...and some that use a single 'tooth':
63693


The way you attached it under the original 'trigger' pins is similar to what I was seeing in my head, but I was going in the direction of using the plate at the bottom where the weights attach.

Thanks!

Mike

[FABombjoy]

I'm sure there are a lot of ways to go about this, I just picked one that made sense at the time.

I still have the advance mechanism intact. In a crank+cam signal setup you don't have to clobber the mechanical advance.

Because the advance weights are still there, if the tooth is mounted to the shaft, it's expected position relative to the crank wheel might change.

Normally the tooth is only read at startup and it probably would always appear in a fixed position. But if you ever have a crank sync error, depending on your RPM a small tooth might miss the sampling window. It was easier to make a half-moon shape and set Megasquirt to look for cam tooth right in the middle of the range.

Probably in an OEM computer situation, a full predictable half-moon would net you a faster full sync?

[ramblinmike]

I'm sure there are a lot of ways to go about this, I just picked one that made sense at the time.

I still have the advance mechanism intact. In a crank+cam signal setup you don't have to clobber the mechanical advance.

Because the advance weights are still there, if the tooth is mounted to the shaft, it's expected position relative to the crank wheel might change.

Normally the tooth is only read at startup and it probably would always appear in a fixed position. But if you ever have a crank sync error, depending on your RPM a small tooth might miss the sampling window. It was easier to make a half-moon shape and set Megasquirt to look for cam tooth right in the middle of the range.

Probably in an OEM computer situation, a full predictable half-moon would net you a faster full sync?

I think I'm going I'm going to remove the advance mechanism and trim the shaft to let me make some kind of cap to fit over the distributor housing. The way you described it makes sense. I'm going to build it with the half-moon and see how that goes.

The quarantine is double-edged sword. I'm getting tons of time to do some pretty major stuff around the house but I'm not able to go out to get stuff for the car. :(

I appreciate the help!

Mike