pushrod36

I have a 2000 LS1/T56 in a 1968 GTO. As my title says, the engine will not idle without throttle application. I hooked up HP tuners, and there are a couple things that seem strange. It is not showing a value for air amount feedback, with no pedal application it reads 5 deg throttle, and it thinks it is in D4 (PCM is original so I am not sure if this is normal) while it is actually in neutral. Meanwhile a lot of things seem OK: ignition advance is at about 20deg, injector pulsewidth is 3-4msec, and IAT and water temp are OK.

Does anyone have advice as to what I could look at? Currently the car has its stock tune, so I am curious if something is hooked up wrong or a bad wire is causing issues.

Thanks in advance!

pushrod36

...also, it is running rich. I have checked fuel pressure and it is OK (~58psi).

pushrod36

I know this is old, but I still have not been able to solve the problem...

...bump

Old Geezer

iTrader: (3)

Post the tune, a data log or 2, and see what the HPT users can see.....

robbyredneck

iTrader: (1)

put some data up. i am sure you have changed the intake plumbing etc. were gonna need a scan and a tune at least. are you sure no leaks were introduced during the swap? also do you have a wideband?

macca_779

TPS reset might be a good start. Are you using a known good base tune?

mike171562

iTrader: (4)

Having a similar problem here, could it be that since your TPS sensor is showing the peddle is slightly depressed, your PCM closing the IAC a little because it thinks your not at idle?

I would reset your TPS by unplugging it with the key on for a few seconds.

My TPS sweeps up and down fine, but at idle with no pressure on the peddle it jumps from 0 to .39% back and forth, im not sure if this is normal.

pushrod36

Thanks for the thoughts so far everyone. Here are some log files that we took. I think they are all pretty short, but hopefully something useful in there. I do not have a copy of HP Tuners, so I can't look at them myself.

I do recall that the TPS sensor would not read 0 at any point. I think it kept bottoming out at 4, so the TPS reset could help.

The thing that drives me crazy about all of this is that regardless of anything else the O2 sensors are reading rich, and injector pulse is not getting smaller. It doesn't make any sense to me.

Again, thanks for all of your thoughts/help/advice. I'll get this thing beat yet!

mike171562

iTrader: (4)

I would start with a TPS reset, your PCM is thinking you have your foot on the peddle when you don't

2xLS1

iTrader: (25)

With KOEO measure the voltage between the blue wire on the TPS and ground. Have you messed with the stop screw on the TB? You might mention if everything on the 00 LS1/T56 combo is completely stock for not. You also need to post the tune that is in it. It sure gets tiring constantly having to ask for this kind of information.

pushrod36

I have a 228R cam with 112lsa. Edelbrock A-body swap headers. Everything else is stock.

We made some small changes to the VE table, but nothing else was changed. I will get the calibration posted this weekend.

I have not touched the throttle stop screw. Also, I assume that KOEO means to put the key in the run/on position, so please correct me if I am mistaken.

mike171562

iTrader: (4)

Have you checked your IAC motor to make sure it is opening and closing like it should?

When I replaced mine, I took it out and the spindle had opened so much it had separated from the motor part.

pushrod36

The calibration file is on my friend's computer. I should have it sometime this weekend.

I checked the IAC. It was pretty well seperated, but I was able to push it back in (hopefully that didn't break it). I have not tried to start since then.

I'll be checking the TPS and IAC stuff this weekend (had to charge the battery after winter). Updates on Monday.

Have a nice weekend, everyone!