[Ron Vogel]

I get electrical gremlins occassionaly, and it's the hardest thing for me to diagnose. I keep throwing a TPS sensor low voltage, and occassionaly a MAF sensor low voltage. I think they are both related somehow. When the TPS problem happens, my shifting gets very erratic. With the MAF one, the car will cut out. Both problems come up the most during cold or damp mornings, and usually will go away after a good warm-up. It has to be a short, but I can't find it. I originally pulled off my TPSE (no help), replaced the MAF and TPS connectors (no help), replaced the TPS (no help). I have a Casper's volt booster (it hooks to the TPS), and that's coming off next, but talking to Justin at Casper's..says the TPS just feeds through the unit, and shouldn't be causing it. It's been happening for a few months now, but getting worse since the weather's getting colder. Anybody have some other ideas on this?

 

[johnt]

Ron,

Separate the MAF and TPS connectors and look to see if the weather-pak gasketing material is intact. You may also try taking a hair drier to the open connections. I don't remember for sure, but they might both be on the same fuse. Also, check the wiring on your O2 sensor harness and the connector. I know for a fact that the O2 sensor is on the same fuse as the MAF.

John

 

[Ron Vogel]

Yeah, this is the kicker...I already replaced the weatherpak's on the 02, MAF, and TPS. I had a problem with the 02 connector last winter, replacing it solved the problem. The MAF connector/connector to the mini-afc laid on the crossover during some maintanace and melted a little. On the way home from a race in June the car started the MAF code. So I replaced both weatherpak's there, also trimmed back the harness wires a few inches until I found un corroded wire. It mad the car run very well, but then started happening again over the last few weeks.

A bit of history...My TCS has not been working for over 2 years. I checked every wire in the harness to try and fix it, but still throw a code for torque management request circuit. It hasn't affected anything other than the TCS, so I gave up and just dealt with it. During my inspection of the problem, I pulled off the PCM connectors and found some corrosion. In fact, one of the pins was pretty badly corroded to the point there wasn't much left of it. My last resort would be to replace the PCM, but this may also be the root of the problem.

 

[Ron Vogel]

I think it's fixed...mini-afc may have took a crap. I dropped it down 1% and the car died. It was running too rich, and only 1% difference made the car stall. Took it out of the loop, trims pegged at 16.4, car idles better than it has in a long time.

 

[johnt]

Ron,

I'm glad your car is running better, but I'm confused. You say that your trims are now pegged at 16.4%? How is that good?

Your AFC probably died due to the heat from the crossover. I hope people see this and take some precautions to protect their wiring/electronics that hang out under the TB from the intense heat near the crossover.

John

 

[Ron Vogel]

I doubt it's from heat. I'm really nuts about heat propigation under the hood. My exhaust crossover and manifolds are Jet-hot coated, thermal wrapped, and covered with fiberglass, and wrapped over that with foil tape. You can grab them and rev the motor up after 3 hours of driving and they feel slightly warm (actually it's wrapped that way all the way to the mufflers). Having the trims pegged is obvoiusly not good, but better that chugging along too rich like it has been. I have been running it at 107% on the mini-afc. I'll just take it easy on the revs until I get the fueling corrected.

 

[Ron Vogel]

Well, the MAF is now OK with the Mini-afc gone, but I'm still getting the TPS code. It may be 2 seperate problems. I TT Casper's. and it looks like the MAF and TPS are seperate wiring paths, unless they share a ground in the PCM. Car ran great all day yesterday until I took a left turn on my way home from work, and 4th gear was gone. Shifted it into 2nd, and it hooked. Idled like crap and didn't want to shift into the next gear from a stop unless I let off the gas. I tapped it when I got home and the TPS went out again, reset the codes, checked the TPS voltage again, and was A-ok. Took it out for a drive, and it shifted perfect again. Up until a couple of weeks ago I thought my trans was on it's way out, but I'm pretty positive that the shifting problem is directly related to the TPS, and it's just electrical.