TPS Issues (I think)

[Jaysz28]

Well I thought I had my rpm issue narrowed down to a bad TPS. So I replaced it to no avail. The car will stop revving at like at 4k or so. TPS reads .56Xv at idle, and idles perfect. Shut the car off, and rotate the throttle by hand and watch the TPS voltage move normally from .56 to 4.20v Is this right? Helms says it should read 5v at WOT. This is the 3rd TB and 3rd TPS I've put on it. I also have a new throttle cable, so I am running out of ideas.
The weirdest part of all this is that once I hit 4k and the car stops revving, I can let off of it some and feather back down on the pedal and it will pull hard to 6k.
Any ideas?

[WS6 VERT]

Whens the last time you put a fuel filter on this car? I know it sounds silly, but the Vortec engines are very sensitive to fuel filter issues. I never kept a filter in the TPI long enough to find out what a plugged filter will do, but its worth a shot.

[Jaysz28]

Filter was replaced about 3k or 4k miles ago. It did this before and after.

I checked the wife's formy TPS and it reads 4.30v at WOT and it doesn't have this problem.

Fuel pressure is whatever I set it at. For right now it is 45 psi with the vacuum off. I checked and it doesn't fall off or anything at WOT.

Meanrob suggested that I look at the timing. I beleive it is set at 0 degrees. Last time I had it on a scantool it was pulling about 12 degrees of timing out of it at wot and picking up about 20 something knock counts on startup.

Does that help or confuse?

O2 counts have been monitored and with the FP @ 45 psi, the O2 counts are at 700, I got it up to 850 with no change.....

help

[irocbsa]

I had my disty out this weekend and when I got everything bavk together the motor wouldn't pull past 3000. Ends up I had the timing off by about 6 degrees. Maybe MeanRob is right for once. :D

[Kat]

<--- Jaysz28

timing is set at 6 degrees BTDC. Verified with a timing light. Timing doesn't seem to affect this problem.

using a scantool, the computer is pulling out between 12 and 14 degrees of timing when this is happening. Also, Knock Counts are around 20 just revving it in neutral. Tonight the car started running lean, so..... going to swap out the ECM for another and see what happends.....

[WS6 VERT]

Whoa, whats going on???? :confused:

[Kat]

Originally posted by NOTaGTA:
Whoa, whats going on???? :confused: what are you confused by B? Its Jaysz28 hanging out at Kats house and I am too lazy to log him off of his own computer.....

Any ideas? Or do you need more info?

[RobP]

post-mortem fuel pump?
lean condition can only be a few things. How about that CTS? That can seriously mess up the ecm. Just tossing ideas.

[Kat]

CTS is reading fine. Car wouldn't go into closed loop all of a sudden. I am hoping it is a fluke. I just drove 5 hrs straight on the hwy to Kats and all was fine. Go to the parts store and on the way back it hits lean and what not. Knock counts are confusing as well. I have no clue what is acceptable and what isn't.

I had a total of 590 knock counts in about 4 hrs. Just confused.

Glad you got your car sorted out finally! Hope mine follows suit.

[RobP]

I don't think you should collect but a few knock counts. Usually when you start the car up. Definate lean condition or the knock sensor is whacked and sending false counts and retarding timing. But remember, I'm the guy who struggles to figure out what is wrong with his own car. I'm just tossing ideas.