I have a 89 MAF TPI setup that I installed in my 88 camaro using a L98 from a 91 Trans AM GTA. The TPI unit itself is from the 91 and I am using the 89 Iroc chip to delete the 9th injector.

The problem is that I am running rich and the computer is not throwing any codes. I replaced the TPS and set the voltage to 0.54. I checked and replaced other stuff and nothing seems to work. I also get idle surging. I have no vaccum leaks and fuel pressure is around 41 psi. I did the A B jumper thing and confirmed that the ECM is entering closed loop mode. It also says I am running rich when in the diagnostic mode. Spark plug, cap, rotor, wires, etc.. are all new. Also engine runs smoothly when you get on the gas, but runs rough at idle due to being rich.

I read somewhere online that running headers can cause the regular O2 sensor to run too cool and cause problems. I also switched from the single cat exhaust system, to the dual cat system from the 91. TA I got the engine from. It was suggested to switch from the 1 wire sensor to the 3 wire heated element 02 sensor. And I figured I might as well get a wide band one while I am at it. However, I don't know where to find one. I checked Summit Racing and Rock Auto already. Where can I find one for a decent price? I have to order it online and they have to be able to ship to a post office box, because I am on a military base in Japan.

 

If it is going into closed loop then the O2 sensor is hot enough and working properly

Correct but if it is too cold engine won't go Closed Loop

Expensive WB O2 is used for tuning with a gauge or software on a laptop

 

I thought that the temp sensor is what sent it into closed loop mode? And that the O2 sensor controlled the Air/Fuel mixture while in that mode. If it's not the 02 sensor, then what else should I look for? I am running out of parts to change.

 

The O2 sensor needs to heat up to go to closed loop. Re-locating it to the collector may not heat it up enough.

The temp sensor in the intake manifold will cause a rich condition if it is faulty and there is no code for that.

 

How did you get around VATS?

How many in. of vacuum is it pulling when measured on the upper intake?

Have you checked your timing with a light?

I had this problem with my setup (very similar hybrid of carious years of parts) at first and found it was due to incorrect vacuum routing.

 

I had VATS disabled in the Chip. I am running one of those aftermarket adapters. Smog and EGR are also disabled as well.

Vaccum seems strong to my finger, but I don't have a guage to check it. I did the starter spay around the intake and runners to make sure I didn't have any leaks. And putting my hand over the intake will stall the car. Everything seems ok.

Timing has already been set with a light to 0, with the advance wire unplugged per the instructions in my Chiltons manual.

Do you have a diagram of the proper vaccum routing? I have been looking everywhere to find something on it.

 

I thought I read somewhere that it's supposed to be timed to 8* BTDC instead of zero with the advance unplugged... If someone confirms that maybe it will help?

 

My chiltons said to refer to the emissions sticker under the hood. The sticker said to set it to 0 with advance unplugged.

 

I don't have a diagram...

FPR to rear of upper plenum (PS) of course, and brake booster to rear of upper plenum (DS). PCV on PS valve cover to upper port on TB, charcoal canister to lower port. Vacuum ball and HVAC to rear of upper plenum (PS) with check valve, DS PCV to lower intake. I find the logic of the PCV to be non-traditional for some reason. The EGR solenoid has two lines, but since you don't have that you just need the smaller line from the charcoal canister to go to the bottom of the TB on the DS.

I could be wrong, but this is what works on mine so far.

 

Code 14
This code is set when the CTS voltage is low, typically close to 0 volts. The only things that causes this is a shorted sensor or the yellow wire to the sensor is shorted to a ground. Failure of a CTS will affect the functions of the fuel delivery, ignition timing, cooling fan, TCC and the idle control.

Code 15
This code is for a open CTS sensor or open yellow wire to the sensor. When the ECM sees more than 4.8V on this wire, it assumes that this is an open circuit. This problem will also cause the problems mentioned above for a code 14.

 

Progress on this?

 

I made a mistake in the timing. I discovered that the hood originally came from a TBI car. That is why it said the timing should be 0. It should be set at 6.

 

I found a nice 3 wire 02 sensor on ebay from TPI Parts. It even comes with the adapter to plug into the stock wiring and run the power to it. It is not wideband, but it will work fine for what i need it for.

eBay item #360307478412 GM 3 Wire Heated Oxygen O2 Sensor w/ Harness TPI LT1

http://cgi.ebay.com/ws/eBayISAPI.dll...m=360307478412

 

The car is running much better now. It still surges if you punch the throttle and then let off too quiclky. If you ease off the throttle, it doesn't surge.

I did find a couple of problems in the vacuum routing. I had hooked up the purge canister wrong. I also had 2 PCV valves installed by mistake. Those problems have been corrected, but there wasn't any change. Overall the engine runs fine. It is only at idle that the problem occurs. But it is at least managable now. It isn't running as rich as it was before either. I don't smell gas anymore, and it isn't trying to stall out even when it surges.

 

I recently purchased a OBD1 USB cable. I got it from
Cable: http://www.aldlcable.com/
Software: http://winaldl.joby.se/



Using the cable and software on my laptop, I was able to get a good set of readings on my ECM. I can feel the car having a misfire, but all the ECM data says everything is within normal operating levels. It was running rich, but I lowered the TPS voltage down to 0.51 and that worked pretty good (I actually found out I can go as low as 0.42 before throwing a code). The only thing I noticed, is that it is randomly throwing a code 42 every once in a while. So I might have traced the problem to a faulty distributor or ignition module. Anybody had this kind of trouble before?

Here is the info I found on code 42

CODE 42

Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system. During cranking, the timing is controlled by the ignition module and the ECM grounds the EST line. It expects to see no activity on this line at this time. When the ECM enters EST mode, it applies +5 volts to the BYPASS line and expects to see voltage variations on the EST line.
Reasons for the ECM to set Code 42:
? System in BYPASS mode (i.e. EST line supposedly grounded) but activity sensed on EST line
? System in EST mode (i.e. BYPASS line driven with +5 volts) but no activity seen on the EST line

Possible causes include:
1. BYPASS line is open or grounded
2. EST line is open or grounded
3. Poor connections between ignition module and ECM
4. Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise
5. Faulty or incorrect ignition module
6. Faulty ECMBottom of Form


FIX for GM obd1 with code 42:
Remove the distributor assembly and replace the following:
Pick up coil
Ignition module