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Old 07-08-2013, 11:32 PM
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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.

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
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Old 07-08-2013, 11:55 PM
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only changes to the car is I installed taller rear tires 28" rear and 26" front so the abs, brake and tcs lights are on.
Old 07-09-2013, 01:08 AM
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Check all of you grounds on the block and heads before you go any further. Tug on them lightly to verify they are strong I have seen these cars many times break a ground wire inside the insulation where it is not visible but will stretch like spaghetti when you lightly tug on it. Then grab the harness with the engine running in the area where it crosses over the top of the air box to the passenger side valve cover wrench and stretch and pull in the drip loop area I have also seen them break various sensor and power wires in the insulation in the same manner as above in this area. Last but not least double check your pcm connectors to make sure they are clean and snug. Look for wires burned against headers and or hot side turbo piping. Check the battery cables to make sure they are tight and all of the block to body body to frame grounds.
Old 07-09-2013, 04:49 AM
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is the battery secure? or is it flopping around
hitting the a\c line?
Old 07-09-2013, 07:56 AM
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01WS6 did that many times, I've had the intake manifold off 3x.
sreve battery is secure.

I would have something similar when I forgot to turn off the tcs,
Old 07-09-2013, 06:37 PM
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Did you check the grounds on the drivers and passenger side of the block?
Old 07-09-2013, 09:03 PM
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Originally Posted by 01WS6/tamu
Did you check the grounds on the drivers and passenger side of the block?
Yes sure did.
Old 07-09-2013, 09:06 PM
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Alternator going out? Not keeping the battery charged and loosing power causing the cluster to sweep. Check what voltage its cranking out.
Old 07-09-2013, 09:08 PM
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nope, checked, installed a truck alternator. Only sweeps in boost at around 5500rpm.
Old 07-11-2013, 12:56 PM
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Lets play shots in the dark on the internet. lol - your log file scares me for a turbo car anyway but

ok, if it happens every time at 5500 and your voltage is dipping out - and you've changed the alternator...

what I see is a voltage drop @ about 4400 - you have too many things running on the scanner to spot when it actually drops. So things to check-

The grommet on the back of the alternator that covers the + positive terminal from possibly grounding out as the engine starts to Rev up @ 4400 u can see it makes 13.3V right before it startrs to dip. So next I would check things that are requiring an increased draw at this point. Recheck the voltage at the coils, their connections and grounds AGAIN. Check the fuel pumps wiring, I would be inclined to assume that the pump has insufficient power or grounding.

It really has to be a bad wire somewhere- loose connection on the pump or something silly like that. Not knowing everything about the car makes this kinda thing hard.

Does the car have AC? maybe the alternator belt is slipping once you pass the stock AC clutch disengaging value of 4,294, . Are there signs of belt wear or slippage showing? Possibly check the tension and idler pulley, maybe the whole system is getting too tight under that kind of load.

P.S.
Wtf is with your fuel trims being 6% different side to side. I hope your wide band is on the driver side of the motor, or this issue wont be your last.
Old 07-11-2013, 02:11 PM
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Buffjoey the fuel trims is something new with pcm resets.

I'll check the fuel pump wiring and grounds, no A/C thanks for the input. I've been running Trick 114 in the car.
Old 07-11-2013, 08:55 PM
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Check the battery cable connection at the power distribution center on the drivers side wheel well. I've seen that terminal get loose and or burn out of the PDC. You can run a 8 gauge jumper from the battery to the PDC as a process of elimination.

Drop the panel under the column and make sure someone in the past did not put in a alarm that interupts the pink ign wire coming out of the ign switch.
Old 07-11-2013, 09:50 PM
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Originally Posted by 01WS6/tamu
Check the battery cable connection at the power distribution center on the drivers side wheel well. I've seen that terminal get loose and or burn out of the PDC. You can run a 8 gauge jumper from the battery to the PDC as a process of elimination.

Drop the panel under the column and make sure someone in the past did not put in a alarm that interupts the pink ign wire coming out of the ign switch.
I just added a jumper today, and checked the wiring yesterday under the column when I installed a new ignition switch. Thanks for the suggestions.
Old 07-11-2013, 09:54 PM
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You could always get real ghetto and run a set of jumper cables from the battery to the alternator and from the batter ground to the engine block. If that doesn't change anything run the jumper cable to the alternator / battery , and the other to battery+ and power + distribution on the passenger side.
Old 07-11-2013, 10:58 PM
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Have you tried removing the Alt wires and making a pull? Does this happen in every gear?
Old 07-11-2013, 11:19 PM
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Originally Posted by BuffJoeyD
You could always get real ghetto and run a set of jumper cables from the battery to the alternator and from the batter ground to the engine block. If that doesn't change anything run the jumper cable to the alternator / battery , and the other to battery+ and power + distribution on the passenger side.
Don't laugh I've done that many many times chasing gremlins like he's chasing.



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