Forum Replies Created
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Quoted From college man:
I posted wrong on the traction control (sorry) I was thinking limited slip differential. I googled how traction control works.it has everything to do
with abs. if your light is on that maybe the issue with the traction control and the rpm bounceEric said they are linked together. When the abs light goes on, the traction light does as well. Traction control is only active when the computer detects the wheels are slipping, there not slipping doing over 40mph. And my brakes arent locking up while I am cruising, so ABS isnt active either.
So update on the problem, I put my car in 2nd gear, was travelling about 50km/hr (about 30MPH) and I had the same problem. I dont know what this could mean? any ideas. I dont think the car would try to lock up the TCC in 2nd would it?
Quoted From dreamer2355:
I don’t have a smart phone unfortunately.
Hopefully we get our own chat feature on these forms soon.
I know a few of use talk using a instant messenger program while browsing the forums.
Still a great idea though.
Yea, the forum I frequent for my car (grandprixforums) has a chat. Its pretty useful, if you need a quick question answered.
Got a video of what is happening, it turns out that brake input has no effect on the problem.
Quoted From dreamer2355:
Out of curiosity, what is the ABS light on for?
Im not too sure, my traction control light is on aswell, but it doesnt really worry me, I dont have a need for either. Its probably a pinched wire or a broken sensor somewhere.
Quoted From dreamer2355:
I would have those codes checked as they may have some information that my correlate to the fluctuating RPM’s.
I believe most Autozone’s can scan domestic ABS codes now.
When the RPM’s begin to fluctuate, if you gently depress the accelerator pedal, does the vehicle pickup and coast in that problem RPM range if that makes sense?
I get what you mean, and I’m not to sure, i lightly press the throttle at the end of the video if that answers your question.
Quoted From college man:
do you have a egr valve? if that is passing it would make the idle surge. if its mechanical push on the diaphragm.see if its hard to move.
The EGR is unplugged, the problem stays whether its plugged in or not. I have the PCM tuned so I dont get a CEL for it.
Quoted From college man:
I just went to grand prix forum. according to other people with your symptoms they disconnected the battery to reset the computer and the problem went away.
you say you have the engine or trans tuned? try the reset or return the tune to stock and see if problem goes away. also I don’t know about having the egr
disconnected.does’t sound good.I’m actually a member over there. Ill try to reset the battery again and see what happens. I have the PCM (powertrain control module) tuned by a tuner who specializes in tuning 3800 series engines.
And I have the egr disconnected because all it is for is emmisions and I don’t want exhaust gas to be cycled back through the intake manifold.
So, I unplugged the battery and put the stock PCM back in. The car is still doing it. Im running out of ideas, I checked the TCC fuse to see if it was out, but its good. I plugged the EGR back in, no change. Any other suggestions?
Quoted From Beefy:
Actually, EGR is also used to cool combustion temperatures to no only reduce NOx (emissions), but also prevent pinging, or pre-detonation. Just saying it’s not ONLY emissions related.
Oh, ok, I was misinformed then, thats what I was told. I have it plugged back in now anyway.
Quoted From EricTheCarGuy:
After reading through this thread I would guess it has something to do with a slipping transmission more than anything as I can’t really think of much else that would cause an rpm fluctuation like that as you cruse. You might try resetting it as suggested as that is an easy thing to try but if the problem still exists I might turn my search to the transmission. If memory serves that is a difficult transmission to check the fluid in as I don’t think it has a dipstick which means you have to jack up all 4 wheels so that it is level and remove the inspection plug as the engine is running to check the fluid level.
The dipstick is actually pretty easily accessible, the fluid is at the proper level and its kind of a pinkish red. I think I’m going to go back to ignition (faulty coil pack maybe?idk), Im completely lost.
Quoted From college man:
if the tps sensor is showing zero while driving. then I would say thats a problem. usually it shows a 0-100 its a percentage of how open the throttle
body is. sounds like you need a new tps.good luck and keep us posted.I meant it shows 0 when the problem is happening. It will show numbers when I actually press the throttle.
Quoted From Beefy:
Does you scan tool read in volts or percent throttle angle? If it is volts, and reads 0.0 with no throttle input, then you may have a problem with it. If it’s percentage, I still seem to remember there being a slight angle at closed throttle, like in the single digits. I’ll dig my scan tool out and test my car tomorrow if you haven’t got a better response before then.
I believe it reads percentage, this is from the owners manual : TPS Throttle Position Sensor In some vehicles, a closed throttle will read 0 and full throttle will read 100. Other vehicles will have a higher value than 0 for a closed throttle and a full throttle value less than 100.
This is the scangauge I have : http://www.scangauge.com/products/scangaugeii/
If it helps determine the problem, I could get a video of some parameters as the RPM’s are bouncing?
Quoted From dreamer2355:
I would just use a DVOM and sweep test the TPS. Find a wiring diagram and probe the GRND ad SGN RTN.
And you have no pending codes correct or any freeze frame data?
No pending codes, and I will go do a sweep test asap.