grantmac

I've got an NA S4 engine in my car. I've got everything hooked-up except for the wires on the "cut list" and a few that I've confirmed are emissions only (I've got no cats). I've been trying to get it to spark while I wait for my new fuel pump but I've had no luck. What imputs exactly does the ECU need for it to run the engine. I've been checking continuity with my volt meter and voltages at the ECU plugs with the key on and I haven't found any problems, it just won't spark! Unfortunately many of the voltages are listed with the car idling or whatnot and I'm not sure what the story is. I'm getting nothing on both leading and trailing, both coils are getting 12V and the signal voltage is correct according to the FSM. If anyone has been where I am now then could they please chime in. Failing this I was wondering if the ecu will still inject fuel if I run it without the spark and use my 12A distributer.
Grant

P.S. Megasquirt would have been so much easier in hind-sight

grantmac

BUMP!!!!!!!!!!!! My ECU is throwing a CAS code (code 01) but my CAS is hooked-up, all the wiring has continuity and the CAS is showing the correct resistance (150 Ohms). I'm really starting to consider just giving-up on the stock computer, it's just that it's been done so many times I really hate to fail where others succeed.
Grant

H4Inf

I think MegaSquirt will give a lot more back to you, much more configurable and you'll be able to easily monitor it with a laptop.

I don't know anything about the stock ECU because I never had one hehe...

grantmac

Yeah I just ordered the megasquirt, seems like I might make the money it cost me back by selling a few of the stock EFI bits too. I'm also looking forward to being able to lean it out a bunch and ditch the AFM.
Grant

Jeff20B

iTrader: (13)

Ditching the AFM is very nice.

H4Inf

Cheers to that

grantmac

Should be good for at least 10-15HP from what I hear. I'm hoping for about 160RWHP with my full exhaust and the MS. I'm just gonna run 2GDFLIS for now with stock triling coil, until I venture into the spark control world.
Grant

Rotererer

what does losing the AFM do?

H4Inf

I believe the AFM provides quite an air-flow restriction.

steve84GS TII

The AFM is used to meter the air going into the engine so the ECU can determine how much fuel to deliver.This is called metered air EFI,mass air EFI is a similar system.These types of EFI are good for guys doing mods because they can compensate for things like headers,intake,exhaust systems,even porting to a degree.As long as you stay within the air flow meter's abilities,you can safely make more HP.The downside is that the air meters tend to be a bit restrictive as they lay smack in the middle of the airflow.Its a neccesary evil however since thats how they measure the airflow.
The standalone EFI systems and EFI systems on cars like Hondas and older Chevys are called speed density EFI.They have all the needed info about airflow pre-programmed into the ECU so they dont need an AFM.They moniter RPM,manifold pressure and throttle position to guess how much air is going into the engine,then deliver the fuel based on what their pre-programmed fuel map tells them.This setup is very simple,cheap and reliable.The downside is that the ECU has no way to know if youve increased airflow into the engine with headers,TB,intake,ect.So you will run lean and possibly pop the engine if you do mods without a dyno session and re-burn of the fuel maps(this is what happens to so many FD guys).
The S4 AFM isnt the best,but it can flow enough air to make a decent amount of power over stock.I wouldnt write it off yet,keep looking at the wiring setup and sensors for an answer.Be sure you have power to the ECU input and the 2 big black/white wires that power up all the solenoids and injectors.These come directly off the FC main relay and are powered on when you turn the key/ECU on.Also,be sure the 10 or so wires on the left side harness are correct.These wires run the coils,CAS and ECU power,which is in the direct area of your problem.Most of the other wires that you dont need on the left harness are for AC,PS,mileage sensors,voltage load and other crap you dont need for a S4 to FB engine swap.