joecitizennn

I have had 944s for years, but I am new to the 951. I recently had a short in the number 2 injector wire, and at the same time the car stopped revving past 1500 rpm. I fixed the injector wire and the car runs very smoothly now, but still I have the same problem with a rev limit of 1500 rpm. The problem may be totally unrelated to the injector wire shorting.

If you unplug the throttle position sensor the car will rev and drive down the road fine, but with a high idle speed when sitting still. Plug the TPS back in and the idle drops to normal, but the car again has a rev limit of 1500 RPM. What is the problem?

minho78

TPS

reno808

TPS is the problem

joecitizennn

Yeah, that is what I was thinking. My car was flashing a 3-3 trouble code, and if you unplugged the TPS it flashed a 4-1 then a 3-3 which points to the TPS. Thanks for the input. Where is the best place to get a TPS or can they be repaired?

minho78

I got mine from Pelican, but you can getthem from most vendors.

joecitizennn

It was a micro-switch inside the TPS. The switch told the computer when the throttle was shut. Inside a pin holding a spring broke and the switch was stuck on. When the switch is on and the engne revvs the computer thinks the throttle is still closed and as a safety feature is rev limited to 1600 rpm. I fixed the switch and it works very well.

quinnfiske

Thanks for the detailed update. It is always helpful when people post the solution to their problems. I don't recall anyone else disassembling a TPS and figuring out how it works. Good info.

Bomber

I have the same 1500 rpm problem, but a little different situation. Yesterday was a nice sunny day so I decided to exercise the 951. It's been at least a couple months since I started the car, and the battery was dead as a doornail. I charged it for a while, then jumped it and it started right up. Took everything off the battery to confirm it was charging, which it was. Got ready to move the car and that's when I discovered the rev limit issue. Got the car over to the work area and thinking maybe it's a low battery thing, put the charger back on to fully charge the battery. I decided to clean the battery posts during this time and noticed a healthy flash on one of the terminals. I'm guessing this is something unrelated, so we'll just set that to the side for now and get back to the rev limit issue. So, I come find this post about the issue and eventhough I had already replaced the TPS over the summer, I unhooked it and started the car. I still have the rev issue with the TPS unhooked. My question is, where else should I look for the problem if it is not the battery or connections, and it's not the TPS?

I replaced the TPS this summer because of some surging on accel/decel issues. I also had an issue with low idle(400ish) with a cold start that went away once the car was warm. This issue still exists as well. Any chance these things are related?

gt37vgt

could be the a short in the loom of the TPS .. so the ecu still sees the Throttle closed micro switch as closed ..
throttle closed +over 1500 rpm =injector cut

Bri Bro

While you are in there, I would recommend that you rebuild the throttle body. I did two and both units were shot, they take a far amount of cycling over the years. Here is the kit:http://www.arnnworx.com/catalog/inde...index&cPath=66

Ronin-951

DME Cold Idle Temp. Switch. Located under intake manifold runner #4 [front of engine]

Bomber

I looked at a schematic to see how the sensor or the harness related to things but that got me no where. I think I found the sensor you're talking about(blue?), though I couldn't find it in the PET unless it's 059 131 951a. I'll try jumping it and see if that changes the cold idle. Thanks for the tip. For the tps harness, I think I'll see if I can figure out which wires they are at the DME connector and check it unplugged on both ends for continuity. After that, who knows..

JFreeman

My car had the same cold idle problem, when i started it cold she would barely idle, but once it warmed up everything was fine. I drove it like this for a while, not really thinking much of it. One day i decided to fix the low idle problem (only when cold). Everything i tried wouldn't work, long story short my tps was out of adjustment. With the engine off, crack the throttle cam by hand, you should hear the tps "click" just off idle. I dunno if this could be your cold idle problem, but just my 2 cents

adrian1

I cleaned the resistor bar on the tps with an eraser and it seemed to temporarily work.

Bomber

Ok, I should be able to get a couple hours on the 951 today. Haven't done anything since my last post except unhook the TPS. It makes no difference at all. The car still doesn't rev above 1500. Also, I think the TPS is adjusted correctly re: the "click". I've got the DME/KLR out and I want to unhook the TPS harness both ends and continuity check the wires. As far as I can tell, the wires shouldn't have any continuity between them, only with the componants. Electrical issues aren't my fav..