rwsduc

I've been fighting with some ongoing performance issues on my 92 auto coupe that I have addressed in the Tech/Perf section but still haven't been able to resolve my problems. I'm ready to drop the cash on a scanner or software and just wanted to find out which will do the best job for me. First of all, I want to replace my throttle position sensor and would like to know if TTS' Datamaster software or an Auto Xray EZ-scan 5000 can initiate the "TPS learn procedure". Also, I'm hoping that the Datamaster software can help me isolate my acceleration and performance problems to either a malfunctioning optispark or otherwise. The ECM is only storing codes 22 & 32, but after reading the (seemingly countless) symptoms of a failing opti, I can't help but wonder if that is the source of all my troubles. Any thoughts and comments would be greatly appreciated.

65Z01

My understanding with the post '90 ECMs is that you only need to replace the TPS and start the engine for it to "learn".

The code 32 is due to a problem in the EGR system; there is a diagnostic method on my site that may help.

I use an old style AutoXray for ECM data analysis and like it's portability, though it does not allow downloading of data to my PC.

To reset your ECM simply open the connector in the large Orn wire near the battery for a minute or so. This resets the ECM without losing your radio and clock presets.

dan6712cc

The car has to be hooked up to a Tech II to learn the TPS procedure only if it has a new TPS, thats what my 94 service manual says. I had to do this a few months ago, a shop around here charged around $80 for it.

rwsduc

Dan6712cc, just wondering if you went to a dealer or an independent shop? The Helm manual for my 92 calls for using a Tech 1 to perform the learn procedure. Maybe the Tech II is the next generation scanner for OBD II cars? Anyway, did your car run better after dropping $80 on the procedure? I'd be willing to pay that amount with a smile on my face right now if that's all it took to straighten mine out.

Nathan Plemons

There may be a TPS learn procedure but it is not needed. The LT1 TPS is "self zeroing." This means that as long as your TPS is within a certain voltage range when you turn the key "on" it reads this as 0 and then calibrates itself accordingly. The system works great with ONE catch. If your throttle body sticks and you turn the key ON with the blades ever so slightly open it will read this as 0. If while the car is running the blades get un-stuck and the reading goes below "0" it will cause some strange errors. In this case replacing the TPS won't do anything, it's the TB that is at fault.

I had this issue when I put on my Holley throttle body. It would hang slightly and allow this to happen. Some minor adjustments on the TB to eliminate the hang fixed the problem.

FYI Datamaster cannot command the car to do anything, it is for data logging only. It will tell you TPS voltage though so you can watch it as you play with it. I've used it several times to make sure that the TPS voltage is within spec.

Timmy!

I think the only thing that Datamaster can do is clear out all of the trouble codes, other than that it's for datalogging only.

dan6712cc

Right it will self zero but from what I understand it has to learn the ASR functions, thats what the relearn procedure does on a Tech II. It has to know how much to reduce throttle, etc for the ASR to work right.

Rwsduc, I went to an independant shop, it was a little cheaper than the dealer. A Tech I or II will work, the II is just the newer version.

Nathan Plemons

Hmm, never messed with it. Next time I'm at my friend's work I'll just have him plug in his tech 2 and run the proceedure and see what happens. I always drive with my ASR off though, so it's never been a problem

Tom Piper

It's my understanding that the "TPS Learn" is needed for the TPS buffer (this buffer, or amplifier, is located beside the washer fluid bottle on my '92). This "learning" is only needed for an ASR (traction control) event and the ABS/ASR computer, and it has nothing to do with the zeroing of the TPS by the ECM. The zeroing of the TPS is done automatically on each startup by the ECM.

I know the Tech-1 can cause it to "re-learn", and I imagine the Tech-2 can also. But, I know no other way to cause the "re-learn."
Keep in mind, this learning will only affect ASR.

Tom Piper