TPS
 

Hate to sound stupid but every day and I mean every day is a learning experence with my 90Roadster. Id like it to run a couple of weeks with no issues. Well again it's at the garage. To start off several weeks ago it was running rich (previous post). I brought it to my mechanic and they replaced a bad fuel pump, fuel filter, fuel injectors, cleaned crap out of the fuel tank and lines. It ran fine for a day or so the it went back for bucking at starts and when I hit the highway. The changed the fuel filter and the fuel pump again. Again, it bucks or is sluggish like it wasn't getting fuel at times. Oh still smelled rich. Well it has been in the shop since Tuesday and now he is saying that there is no voltage to the TPS. He says that the computer might be bad and is trying to find a used one to check it with. Does anyone know what computer this is and is this what could be causing my rich smell and sluggish starts and highway sputters? I'm so ready to put this car up for sale.

RE: TPS
 

Why did they choose to replace the pump? Could it not be heard doin' it's priming thing when the key was turned on?

Did he test the ground from the TPS to the frame?

Taking a 'no voltage situation' all the way to the ECM is quite a leap...

RE: TPS
 

ECM supplies a 5v reference to the TPS. The TPS is a variable resistor that should be set at .5v at idle to about 4.5v at full throttle. Does he mean there is no 5v reference? If so, you can check the rest of your sensors, particularly coolant sensor, manifold air temp sensor for the same 5v reference. If they have the 5v reference, then the problem does not lie with the ECM, but an open circuit to the TPS. If the TPS has the 5v reference, then search for open circuit to TPS since the ECM also supplies a sensor ground. The TPS has 3 wires to it, 5v reference, sensor ground, and signal return. Hopes this helps.

RE: TPS
 

Mech259, there was little fuel pressure on the rails and he traced it back to a bad fuel filter and crap in the lines. He actually took metal crap out of the fuel tank. He replaced the fuel pump, cleaned the lines, replaced the fuel filter and the adjustable pressure regulator and threw a new set of injectors in. I saw on other posting that there should be .54v at idle then up to 4.5v at full throttle. This is all a learning curve for me and I appreciate all the help. I'll mention the voltage to the other sensors as well when I talk to him on Monday. The car does run well except for the sluugish starts and at times on the highway. What I do notice though is the rich smell at stop lights etc. Also Mech259 at this time I do not have an Engine Service light being displayed. I guess that's a good thing. Again, thanks...

RE: TPS
 

...running rich, and now the fuel delivery system is new.

So now the fuel is getting to the fire better. Is it now burning even richer?

???

I'm guessin' there's not a fuel delivery issue; rather a burn issue.

RE: TPS
 

Is it possible that if I don not have volatage that just the TPS switch id bad?

RE: TPS
 

I'm sure it's possible.

BUT, if you have no voltage at the switch, you have no way at the moment of knowing if the TPS is bad or not. You must first find out if indeed there is no voltage at the TPS.

Do you have a ohmmeter/multi-meter? If not, get one. Nowadays you have to have one for your auto, your pc, lawnmower, toaster, toothbrush, etc., ...

RE: TPS
 

If you had no voltage to tps, it would go into a limp in mode and would hesitate and not perform hardly at all, also would most likely have a CE light on.