nfld85GS

iTrader: (2)

I just finished putting in an S4 13B with the stock ECU N326. I was able to get the engine starting tonight, but won't keep running on anything other than starting fluid. I know I have a bad secondary injector which I will be replacing tomorrow. Here are the questions that I have and hopefully someone will know the answers!

1. Do I need to have the circuit opening relay since my pump is running on a switch? Looking at the wiring diagram, it controls the fuel pump and tells it when to run.

2. Does the door on the MAF open with vacuum? I have it wired as follows: BR/W to pin 2A on ECU and connecting to Throttle sensor, Variable resistor, ATP sensor, and boost sensor; G/L to pin 2E on ECU; G/O to pin 2J on ECU; BR/B to pin 2C, Throttle sensor, Variable Resistor, ATP sensor, Water Thermo sensor, Air intake temp sensor, and boost sensor; B to ground. What supplies power to the air flow meter? Does it come from the ECU?

3. Would a not working secondary injector cause it to not keep running?

4. My brain keeps getting fried looking at the wiring.

Any help would be appreciated as to how to keep it running! I'm so close...

Thanks!

nfld85GS

iTrader: (2)

I spent a looks more time on it this morning. I checked all the voltages on the ecu and they were all looking ok according to the fsm. The only two were the starter switch (pin 3b) and inhibitor switch (pin 3d). I picked up two more primary injectors and a igniter pack and coils for the leading since one wasnt putting out a constant spark. Any ideas where to go next would be helpful. Thanks!

j_tso

iTrader: (2)

You do need the circuit opening relay unless you have the pump wired to activate with ON switch on the ignition switch. It's usually a good idea to keep it so that the pump will shut off in case of accident.

Confirm the pump is running, if it won't stay running without starter fluid, I don't think it's getting fuel. It runs on the primary injectors most of the time, bad secondary injectors will give you stumbles when you try to accelerate quickly.

nfld85GS

iTrader: (2)

I hooked up the COR but when cranking the pump did not run. So I re wired it to only go on ON.
So this will probably be a dumb question but what tells the ecu to keep the injectors going? I'm assuming the the starter wire connected to 3b tells when it is cranking bit what takes over when it starts?

85rotarypower

IIRC, when I did this swap in my 82 about 4 years ago, there wasn't much wiring to do if your using a stock harness. Not knowing what you have for a harness or parts, I will try to answer your question.

The component needed to tell the injectors when to fire is the crank angle sensor (CAS). If this sensor is not working right, the car won't even start. Being you have spark, I'm willing to bet its a problem elsewhere. I don't think there is any real exotic wiring besides the CAS when it comes to getting the spark and injectors working.

First thing to check is if the injectors are even firing. Pull the fuel rail bolts out and remove the assembly with injectors and fuel lines attached from the engine. Leave everything else attached to the rail and zip tie the injectors to the fuel rail in a way they are held tightly to the rail. Crank over the engine and check for fuel squirting from the injectors. BE VERY CAREFUL TO KEEP SPARK AND OPEN FLAME AWAY FROM THE INJECTORS, AND POINT THEM AWAY FROM YOU OR ANYTHING YOU DON'T WANT FUEL ON!!!! The injectors should not be dripping fluid all the time, or have a constant stream coming from them. You will want to perform this check on the primaries.

If that checks out, have a look at your air intake. Make sure there are no obstructions and all electronic peices are hooked up. Check the flapper in the MAF is not seized up or anything to that effect. Even without the MAF, the engine should run, so you can actually remove that if you want.

Thats about as far as my knowledge goes on the fuel injected engine. I never got my S4 FI swap going strong as the engine turned out to be toast, super low compression. I did however get it running and stay running without too much issue.

nfld85GS

iTrader: (2)

Well a quick update: i have managed to keep working on the car in the extreme heat and have managed to get the engine running! Now i am in the process of fine tuning all the sensors. I got the TPS right at 1v when at operating temp. I also used the variable resistor to make it run more lean since my eyes were burning after a few minutes. Now the backfiring has stopped but it won't rev above 3500. My next task is to check the secondaries to see if they are firing or not. I'm assuming not. I also have a few vacuum leaks which correct gaskets will take care of. Thanks for all the advice! Couldn't have gotten this far without the forum.

^^I had to fix the flapper on the MAF since it was stuck shut. The main problem was that one of my primary injectors was not working. CAS works great and have good spark in the plugs.

Sgt.Stinkfist

iTrader: (6)

if you unplug the boost sensor, the secondaries will come on around 3500rpm, regardless of load. you could probably just rev the engine with 1 hand and grab one of the secondary injectors to see if it starts clicking.

i recently finished a similar swap 2 months ago and am still smoothing out the bugs. making a hybrid of wiring between S2 chassis and S4 EFI was definately one of the more fun parts im about 200 miles away from considering the breakin on the motor done... then i have the blessing to rev it passed 6k