Craze8

Hello one and all I have an 87 turbo with a street port, I bought the car and it had a few vacuum leaks, with the vacuum leak it idled at 12.5:1. I spent time fixing the various leaks, adjusted the idle to 800 (since once the leaks were gone it did not want to idle at all, just above 400rpm) adjusted the tps to be 1k ohms with the engine warm. After this my AFRs went to 11.5 to high 10s. Noteably, all emissions related parts are deleted except for the vapor canister. The OMP is deleted and fuel of course is premixed. I have tried jumping the set connector and using the adjuster on the passanger fender to lean the idle out. Seems to have no effect what so ever.


Charging concern, at idle the alternator only puts out 12.5 volts, increase RPMs (Above 2k rpms) and it puts out enough voltage to charge the vehicle and operate everything normally. Seen this before I did anything to the car to start with, Has my alt failed or is there something else that I need to look into? And is there an easy way to tell if its an S4/S5/FD alternator?

diabolical1

iTrader: (3)

i will assume since you didn't mention anything that this is still on the OEM ECU? is the BAC still in place?

for you alternator, i would double-check and make sure that there's no underdrive pulleys in the mix. also check and make sure all wiring is intact and connections are tight. if it's all factory pulleys and worse comes to worst, have it tested.

you may want to post a photo of it if you're unsure what alternator you have.

Aaron Cake

iTrader: (1)

Sounds a bit like the previous owner hacked the car.

First, make absolutely sure that every vacuum leak is solved. You'll never get a decent idle if there are leaks.

Confirm you have stock primary injectors installed and if there are any questions about their condition (really, I'd recommend this anyway) have them cleaned and tested by an injection shop.

You'll need to start from scratch when setting the idle. Use the hard idle stop screw to set the idle at about 900 RPM. Then follow the instructions in the Haynes/FSM to set the base timing. Then set the idle as per the Haynes/FSM. You may have to chase the idle around a few times in order to get it to stabilize.

If the car is missing the BAC valve, reinstall it.

As for the alternator, make sure the two wire connector at the back is connected. If it is, replace the alternator as the voltage regulator is failing.

satch

iTrader: (1)

An S4 has a two wire plug in the rear where the B/W wire receives power w/key to on. The other models receives constant voltage on this Black/White wire.

Craze8

Yes, the BAC is inplace and intact. I initially attempted to use it to get the cars idle back up. When it wouldn't come up I adjusted the hardstop screw and then adjusted the tps to match. I know without it connected (As I found out the connector to it was broken and had to repair it) It wouldn't want to idle or to stabilize an idle when coming to a stop once the leaks were stopped. I checked its operation by applying 12v and ground to make sure the plunger inside still operated. It does and I even cleaned the plunger area with carb cleaner.

As for checking for leaks, I've now been all around the intake and along all the vacuum lines with ether/carb cleaner to ensure all the leaks were gone. The main leak it had, was the injector bleed was not hooked up under the intake, the vacuum line was just laying there. I replaced it with a new line and checked all the other hoses and there routing.

Injectors, I will have to pull the intercooler back up tomorrow after work to see which injectors are actually in the car. Is there an easy identification of them? I know it has a walboro 255 in the tank, but it shouldn't make it run THAT rich at idle.

At cruise and under WOT the fuel trims are where I would expect them to be 14.7-15.8 and 11.5-12.5

ECU- I was told it was on a stock ecu. I will double check tomorrow.

Alternator- I've found n3a1 18 300r on the alternator itself. Still has the double pulley on it. Google search shows it to be an FD alternator. The pig tail to the back of it has been spliced. I will check the wiring to it using the different diagrams found here in the second gen FAQ section to make sure it was done correctly

Craze8

Worked on the car today checking things over. It is on the stock ECU and stock injectors, (Tan primary and secondary) most likely explains my rich condition at idle? If my thoughts are wrong here please let me know, considering port work makes the cars act like a large cam are in them with a lop at idle the stock ecu can't control fuel properly at idle.

Also, double checked for vacuum leaks to verify there were none. No vacuum leaks present.

Alternator- It is an FD alternator, the wiring patch that was done to make it a plug and play was done poorly, repaired the wiring and now the alternator starts charging the car at 900 rpms compared to nearly 2000 rpms.

Thanks for the advice so far.