Alright first of all I have an 88' Iroc that I'm rebuilding, but on a budget due to me being in college. It originally had TBI. Well I yanked all that and am in the process of finishing my 355 build. I'm wanting to use a carb intake converted to EFI since i had the intake laying around. I have a 4bbl dry flow throttle body something like force efi's.

1. Can I use a speed density engine harness and computer from a 90-92 F-body to control this setup? I think I can but can't find any information on it, most people go stand alone. But I can't afford it. I'm searching for a harness right now, but before buying one i want to know that it will work.

2. Also what's the best method of tuning the car IF i can use this ecu and harness?

Any suggestions or ideas welcome.

 

Shouldn't be a problem if the Force TB you have uses a GM-style TPS and IAC. If not, you'll have a few additional challenges.

Also just FYI it doesn't take much effort to convert a TPI MAF harness into a SD harness. Other than rearranging the ECM connectors, it's only about five wires difference between the two. Just mentioning that in case you see a deal on an '86-'89 MAF harness.

IMHO, the best method is an emulator and a wideband O2 sensor. If your budget doesn't allow for those right now, you're limited to more traditional methods. There's plenty of information over in the DIY-PROM forum.

HTH,

 

its not an acutal force efi throttle body but it does take the gm tps. it does not have a provision for an iac but they said it could be machined easily. I'll get some pictures see what you think also thanks for the help i see MAF harnesses all day cheap, I may just snag one of those.

 

here's what I'm starting out with

 

TPS is the big hurdle; gotta have one of those. So, that's one problem out of the way.

I suppose you could run without an IAC by setting the minimum air high enough. It'd be rather crude, and the idle speed would end up being a lot higher than necessary, but it would run.

You might take a stroll through a junkyard, and look at various styles of IAC housings. You might find something that can be adapted to feed either into the TB housing, or onto the manifold itself.

There's been some good threads on single-plane EFI over on the DIY PROM forum. Might want to search for those, if you haven't found them already.

BTW, I'd probably lean towards a single plane manifold rather than a dual plane. So, if you're going to end up having to spend a significant amount to pay someone to add the injector bungs, it might be worth shopping around to see if you can find a deal on a used single plane manifold first. If you're modifying it yourself, then no big deal, since you can always upgrade later on.

Anyway, it sounds like a fun project! Good luck!

 

i just came across the megasquirt system. Would that be worth it? Or should i stay with a stock SD system? The car will be driven often and I'm also thinking of some kind of forced induction. More than likely turbocharging but i have alot to learn about that first.

 

Its hard to see from the top left photo but i think your throttle body is machined for an lti later model tps . If it is youll need a harness with the correct connectors on it. Holley sells an IAC adaptor that threads into a 3/8 inch threaded hole and uses its own mini air filter for sucking the air through. Its listed in their DFI catalog.

 

i have no idea what the tps is from the beretta one i have works upside down lol here's a better picture by the way thanks for the info on the iac i'm still trying to figure it out

 

Heres a picture of holleys IAC adapter its on page 21 of their DFI catalog.