Spittybug - Designs for converting stock setup to EFI

[elfking]

Looks great, very tempting! Thanks for doing all the leg work!

[nkemp]

Bump...

So how are things a year later? How do they run and what are your opinions of the converion?

[Spittybug]

You'll need to hear it from TexasTwister and Lazabby (Ian and Shannon) themselves, but I believe both are very pleased and would never go back........ Got another we are about to do.

[lazabby]

Mechanically everything is great. I need to do somew fine tuning with the preogram as I know it could run better. We've talked about trying to hire a dyno shop one Saturday so we can spend time trying to dial in the best numbers. We may do that once the third person finishes his comversion.

[nkemp]

I think the bottom line question is related to how much EFI differs from CIS be it a positive change or negative. So how does performance and operation differ from stock?

[Spittybug]

Performance wise, it's stock or better. How much better is up to your willingness to tinker with tables to optimize the timing and fueling. In my case I eliminated some significant weight when I went to a different manifold.

Reliability wise, it has no more K-jet related issues (which pile up with age).

Cost wise, after the initial conversion, no more K-jet expenses or mechanic costs to fix them.

Convenience wise, I like playing with a laptop in the cool of the cabin rather than turning wrenches.....

[nkemp]

Convenience wise, I like playing with a laptop in the cool of the cabin rather than turning wrenches.....

It's 90F, 90% RH, help from 10,000 of my closest mosquito friends and I'm leaning over a hot engine wondering why I don't tackle these jobs when it's 20F outside. The laptop alone may be the driving factor for me.

[Spittybug]

It's 90F, 90% RH, help from 10,000 of my closest mosquito friends and I'm leaning over a hot engine wondering why I don't tackle these jobs when it's 20F outside. The laptop alone may be the driving factor for me.

90* would be welcome. I quit looking at 100* which is a pretty regular occurrence here in Houston. Let's not even discuss the humidity. On a positive note, bugs are not bad. I don't know if it's too freeeekin hot for them or if the comprehensive spraying programs that the neighborhoods partake in does the trick.....

[Spittybug]

Just enabled (long overdue) another feature of Megasquirt. Several of the inputs is configurable as to when it goes to ground. The easiest one to connect to is the f-idle wire (if you are running a 4 wire stepper IAC valve this isn't used), but there are others. This circuit goes to ground if certain parameters are met, which are set up in the Tuner Studio. I have connected a Radio Shack buzzer to +12V and ground it through the f-idle wire. The parameters I have set up are either coolant temp >220* or AFR >19. The AFR warning may be temporary once I'm convinced I have my fueling table adjusted to the point where I never go too lean. For now however, it provides a nice quick buzz for me while driving so that I can note the circumstances and adjust my table accordingly. The coolant temp is a no-brainer for our cars. Rather than rely on fan fails and hope to see gauge reading before it's too late, I'd like a warning! The current code only allows 2 conditions, but rumor is that it will accommodate more in future versions.

Neat safety feature.

If you want something more substantial to be driven (fans coming on or whatever), all you have to do is add a relay.

[lazabby]

I wanted to revive an old thread to put in information for future records. We had a problem with the Megasquirt 3.57 board. The 3.0 board worked great in the Deloreans but not the 3.57 board. after several months of trying to fix the issue DYIAutoTune finally figured out what to do to fix it. They made changed to my board. Here is an email from Matt with DYIAutoTune:

"The main difference between the V3.0 and V3.57 is the input impedance -
it's higher on the V3.0. I have shipped this one with three
resistor-on-a-wire jumpers to let you change the impedance. The one I
think will be the best bet is a 15K with green leads, and I have put
that in your ECU. There is also a red 10K and a blue 20K - use the red
one if it won't sync at low RPM, or the blue if it's having high RPM
problems but low RPM is fine."

This was the change he made in my box. I've been running ok but haven't pushed the car to the red line. When I took my car in to the dyno shop, there was sync loss (?) at very high RPM so I plan to swap the green lead with the blue one to see if that makes a difference.