So I can NOT get my car to idle...?? I've searched endless hours, adjusted many things MANY times. This is becoming SUPER frustrating as I've been trying to get this thing to idle correctly probably for over a year now to no avail. Sorry for the downer but I am just SUPER bummed out over this.

The car is a 1987 TurboII. I'd like to start from the beginning, as if it's my first time messing with her.

As I'm typing this she's idling nicely 5ft away from me at around 950. If I rev the engine, upon deceleration she backfires and drops to about 6-700, shakey (sometimes more then once) until catching herself and steadying out at 950ish again.

This is probably the best I've had her in awhile.

 

The backfiring could be related to the TPS or a valve in the ACV which is designed to prevent backfiring.

 

Satch, my buddy has ALLDATA and one of their techs said the same thing. However, my air pump has been removed and my ACV blocked off.

Also my TPS will not allow me to adjust below 1.3 ohms....??

And my BAC valve has NO screw adjuster.

As per ALLDATA tech I am going to check AFM and accompaning hoses visually for working condition, cracks, loose connections, etc... Also that Air Bypass Valve isn't stuck open & is working correctly. He also asked me to locate the EGR. And report back.

 

The BAC not having the adjustment screw is puzzling. I guess you could have an NA BAC, which if so, you would want to get the one designed for the car. Your TPS also might be problematic. If you try adjusting it by voltage it should read 1 volt at idle, engine completely warmed, and the range of the TPS would be 1 volt at idle to 4.5 volts or so at full throttle (TPS button fully extended). And the range should be smooth w/no erratic bumps (you would need an analog meter to check this).

 

OMG. Well upon patiently checking everything mentioned above I found the wire clip on the green plug off the back of the water pump to be missing & the plug itself not seated properly, if not at all.

I really hope it turns out to be this simple. Fingers crossed as I put everything back together.

 

Satch, I must not of refreshed and caught your last post before posting.

I've read in searching past posts someone mention the NA BAC's did not have a adjustment screw and also Jspec's did not have it as well. I'm not sure how true that is actually is.

The car is a 87 TurboII w a 1990 motor but everything else (as far as I can tell 87).

So should a 1987 TurboII US spec have BAC adjustment....?? I can look through my parts stash to see if I have one to swap out.

 

The water thermosensor is an important sensor and the Green/White wire should read between 2 to 3 volts at the ECU (pin 2I) w/the engine cold, key to on, and close to .5 volts fully warmed, key to on.

The US BAC version would definitely have the adjustment screw.

 

When you say check voltage @ the TPS, I would do so with the TPS plugs connected, fully warmed up and car on...? (Not running since intercooler is off). Using the Black & Green...?? (just like the FC3S ohm test)...???

 

Connected. Green/Red wire. But the engine needs to be completely warmed. You could press downward on the rear throttle linkage to simulate a fully warmed engine when in a bind.

 

I finally had some time to tinker again. As stated before / above, the green plug off the back of the water pump was not plugged in. I made sure she's plugged in REALLY good now and I almost feel as if everything has gotten worse.

There is another plug under the green plug (also back of water pump) w two wires coming off of it...?? Search says aux fan...?? Although not sure how true that is. My aux fan runs @ the moment as soon the key/ignition is put to on..?? I found the nearest plug that fit and fan still stayed running constant. Again not even sure if I'm on the right track here so I disconnected.

Any input would be greatly appreciated as ALLDATA is closed for the holiday weekend, (figures as the weekend is when I have time to tinker).

TPS at least now will adjust DEAD ON using ohms @ 1.00 from Green/red to Black/red as factory manual says.

However, car is still surging and idle will not go under 1k.

Satch, I tried checking pin 21 like you said but the factory manual does not show a pin 21...?? Nor do I see any #'s on the plugs / ECU. I'm attaching a pic of my manual.

Edit: ahhhhh pin 2i Water thermo sensor. Got it.

 

Pin 2I should read 2 to 3 volts w/key to on and cold and .5 volts or so fully warmed up.

You also have a screw near the boost sensor which is used to dial in the proper fuel mixture. Should be more rich than lean (R is for rich and L stands for lean on the mounting element of the screw. The initial set coupler should be jumperd if you change the position of the fuel mixture screw and the engine should be completely warm before the screw is turned (screw position is rather limited to how much you can turn the screw in either direction. A little more than 180 degrees total).

The plug for the auxiliary fan is for the temp sensor at the thermostat housing. It has but one Green/black wire. If you have a 2 wire plug it is for something else. What are the wire colors for the plug?

 

Pin 2i (center plug off ECU, center pin / 5 pins in from either end, top row, green w white stripe red dash) reads .32v running @ idle warm. Re-checked again after an hour rest and she reads .44v warm @ idle. I'll do a cold check later and report back.

Idle is hanging around 1100. When restarting warm she stumbled from 1200 - 400 ish at least 5-6 times before smoothing out. I test drove w the jumper / inital coupler still in... Is that bad...?? Oooooops

 

Yeah you should not leave the initial coupler jumpered. The primary plate should be opened by about the thickness of a fingernail (exact measurement provided in the FSM). You might also want to check the timing as the CAS migh be a bit off. And the throttle stop screw might be in need of a small adjustment (changes the position of the primary throttle plate). And the thermowax could also be causing a higher than normal idle.

 

Well, I finally tested pin 2i cold and she's @ 2.39V.

Started her up (DEAD COLD, sitting for a day, 74* temp out, NO inital set coupler connected by accident this time...)

Two cranks to start and right to 12-1400ish for a sec or two and then a STUMBLE to 4-500ish (where the motor shakes as if she has bad motor mounts) and then steady at 1100 since, while I type this.

I can still hear a stumble ish every now and then but nothing serious 1100 - 1050.

I'm def getting closer.

I'm off to check timing again. Prob the 20th time in the past 3 months. It's always spot on, (unless I'm doing it wrong).

I added the pic bc I'm wondering if I have the right computer in there...?? I changed the computer the very first week of owning the car and still have the old one.

The old / original computer was a N333 as well as the original BAC N333 w adjust screw (both are not on car atm)

 

Timing:

Yellow mark is DEAD on the pin w timing light dial @ 0 and pick up connected L1 right off the plug boot.
Red mark is DEAD on the pin w timing light dial @ 0 and pick up connected T1 right off plug boot.

Can the throttle stop screw just be adjusted w out coupler jumping or any other hidden sorcery...???

 

Your ECU's are both for S4 turbos so they should both work. You should jumper the coupler always when setting the idle as far as I know. You could instead unplug the BAC electrical plug.

 

As far as timing, when on the stock ECU don't you have to jump a diagnostic connector to get it to 5* before using the light? It's been a while but I remember something along those lines.

 

I don't know either and that is EXACTLY why I say "IF" I am even doing it right. It seems there is always some sort of hidden trick to do anything w this car.

SATCH...!! I THANK YOU BIG TIME for taking the time to help me out...!!! I took her for a spin last night... The weather was kinda chilly and the car feels AWESOME...!! It's the best it's ever felt since I've owned her...!!! No stumbling, no shaking, nice idle. You are the MAN...!!!

 

That's good now garage the car and don't drive it.