Poor idle control and TPS sensor? - SRT Forums

z00 · 02-06-2008, 08:02 PM

The AEM EMS forums suggest:

Throttle configuration: In the calibration file, adjust the TPS min and max voltages manually rather than using the setup wizard. Set the TPS settings in such a way that the throttle readings NEVER reach 0% or 100% (even with variances caused by engine bay temperature and on/off status). This will save you from many headaches with throttle based trims.

I tried it and the idle control got better. Particularly the "Ign vs Idle RPM" trim started working. The problem is the TPS value would pulse constantly. Anyone else try this and get it to work?

duster360 · 02-06-2008, 09:49 PM

Rule #4 of programming EFI: Know when to think outside the black box.

Not all drivability problems or on your case idle problems, have thier causes and/or solutions inside the EMS.
Ask yourself this: If you had a stock pcm, would you want to reprogram it or replace it, if the the engine idle wierd? probably not.

The only thing that would cause the TPS value to pulse at idle is a change in voltage from the TPS sensor. So either the throttle is actually moving (doubtfull) or the TPS sensor and or its wiring is a little buggered up. I'll bet the wiring connector is a little messed up. Probe the TPS connector with a multimeter to varify its voltage ouput is eratic.

z00 · 02-07-2008, 07:16 AM

Tried looking at it on a multi meter. Reads nice and steady there. It's happening so fast you can only see it when logging with the EMS. If I use the wizard to setup the throttle I always get a nice steady reading, but it does let the reading go to zero and that results in the TPS based trims not working. This a well known bug in the AEM EMS. I belive the SRT4 TPS has a natural osolation below a certain voltage. The stock PCM knows this. The AEM EMS wizard also compensates for this, but still allows the reading to drop to zero. If you don't belive this please try it on an SRT4. I'm hoping someone has alraedy solved this problem and will share the solution. Don't confuse this with me not getting a nice steady idle. I can do that butt he idle RPM will vary as weather conditions change because the trims never take effect. It is also very hard to get a steady idle below 1000 RPM without doing some big changes to the ignition table in the idle band. Normally the trims would automatically adjust for this.

tavenger5 · 02-12-2008, 10:25 PM

I would double check your wiring going to the TPS. Do you have any other electronics hooked up? Could be something grounding out as well.