Need help, more problem than I have knowledge $50 if you can solve it.

[keith42]

1999 trans am
390, turbo , 4L80e

Here's the issue I accelerate and at right around 5500 rpm the pcm does a reset with the swing of the gauges and the trip meter reset, also my wideband looses power and resets. It does the same thing everytime. totally stumped.cutout2.hpl

I attached a short datalog, frame 195 is where it does the reset, if you look at the afrs you can see how they drop down to 10 that's the wideband powering back up.

I'm thinking it's somewhere in the electrical, I datlogged the voltage and it does it everytime.

If someone knows what's causing this I will gladly paypal you $50. Worth every penny to get this resolve.

thank You

Also I recently installed 28" rear tires with 26" fronts so the abs, brake and tcs light are on.

[keith42]

cutout2.hpl

[Pekka_Perkeles]

Please remove MAP (SAE) from your Scanner Table Display. It will now spoil your MAP readings.

[Pekka_Perkeles]

Simple question: do you have any error codes when it does this? And remove also BARO sensor, you don't need that information..

Do you have a ported TB? I'm guessing your problems are related to Engine Diagnostics department. Unless there's something mechanical (including electrical stuff).

[DSteck]

I bet you have a loose or disconnected ground.

[Pekka_Perkeles]

I think Dsteck is the winner. As always.. :-)

[blownbluez06]

I bet you have a loose or disconnected ground.

^^^^ often the case^^^
I've also seen expanded retaining pins in fuse positions that show good when you touch them but drop when you lift off. Same with relay pins.

[keith42]

No error codes, no ported tb, checked grounds multiple times, pulled intake and checked grounds on the back of the head with multi meter. It does it every single time in the exact parameters.

[01SLPSSM6]

My first guess would have been checking grounds. I would check power and ground going the pcm and condition of terminals etc. The 99 model year trans am and camaros had problems with the trip meter reseting which was caused by low ambient temps and low voltage. I know it doesnt exactly pertain to your problem but maybe low voltage is a possible reason for it. Also, how do you have your wideband powered up? If you need schematics i can get you what you need.

[gagliano7]

Could the traction control or ABS be causing your problem with the bigger tires?

[keith42]

Could the traction control or ABS be causing your problem with the bigger tires?

I was thinking that, I pulled the abs/tcs fuses, disconnected the abs module and disconnected the wheel sensors. Didn't fix it.

[keith42]

My first guess would have been checking grounds. I would check power and ground going the pcm and condition of terminals etc. The 99 model year trans am and camaros had problems with the trip meter reseting which was caused by low ambient temps and low voltage. I know it doesnt exactly pertain to your problem but maybe low voltage is a possible reason for it. Also, how do you have your wideband powered up? If you need schematics i can get you what you need.

checked grounds, I have the wideband getting power from the fuse box inside the car. I attached a picture of the cover, I tapped power from the IGN

[keith42]

thanks for everyone's help. I just unplugged the wideband just to verify that it wasn't the issue and no change. The only thing I have done recently is install 2" taller drag radials, Could it be a TCS/ABS problem? I have the tcs/abs fuses pulled and disconnected the large connector from the abs module, also disconnected the wheel sensors.

[flame]

Check the ignition switch on the steering column

[01SLPSSM6]

So after looking at a schematic I noticed that the gauge fuse and the ign terminal are tied together in the fuse block. That pink wire from the gauge and ign terminal also sends power to the Instrument panel cluster. I would be leaning toward an ignition switch like flame mentioned

[01SLPSSM6]

Being powered up on the same circuit would probably explain why the wideband and IPC are losing power. I would also connect your wideband straight off the battery, that's what ive always been told is the best way to have on hooked up.

[keith42]

thanks, installed a new ignition switch today, haven't had a chance to test yet. I really appreciate everyone's help

[keith42]

no the ignition switch didn't fix it.

[keith42]

getting really bummed out that I can't get this figured out.

[flame]

Trace the power feeds to the ignition switch there has to be a bad connection loss of voltage in there somewhere