427 L92 a4 GTO issue

[10secvette]

First I would mention the car runs very hot; too hot. Second, are you sure all of the grounds are properly tightened? Besides the low timing at idle (-10.0 at times) and cruise (5.0 at hwy speed), there are times when some of the PIDS flat line which almost would seem there is no signal (or very weak) coming from the sensors causing erroneous readings. I would also check the battery voltage and alternator output under load.

I agree, the car ran hotter than normal. The -10' of timimng only shows up when TC is off, in gear and on the brakes. I just watched the scan from start to finish, I did not see the pids flatline until the engine was shut down towards the end and I left the scanner on. I just checked all of the grounds per memory and the shop manual. All are secure and tight. I did another leakdown today. All cyliners are at 10% or below. I'm borrowing a Tech2 on Monday and see what the hell is happening with some of the other modules.

[joecar]

Some ideas:
- log the pids whose names start with EST_ (electronic spark timing).
- look at some tables like B5105, B5107.

[DrkPhx]

Sorry I should be more specific. Whenever the timing drops to -10 at idle and 5 at cruising speed, both O2's show 0.00v. It may be nothing, but I've never seen that before.

[10secvette]

Sorry I should be more specific. Whenever the timing drops to -10 at idle and 5 at cruising speed, both O2's show 0.00v. It may be nothing, but I've never seen that before.

Cool, thanks!!

[DrkPhx]

The -10' of timimng only shows up when TC is off, in gear and on the brakes.

But what about when it suddenly drops to 5.0 degrees at hwy speed at frames 8942-9002 and again from 14159-14203? Oddly enough the timing jumps up to 39-40 degrees then drops to 5.0.

[10secvette]

But what about when it suddenly drops to 5.0 degrees at hwy speed at frames 8942-9002 and again from 14159-14203? Oddly enough the timing jumps up to 39-40 degrees then drops to 5.0.

New ecm should be here anyday. The tune has been reviewed by a few people and nobody has been able to find anything screwy with it. It's been tech2'd and no codes or anything showing up malfunctioning. I'm lost, so I ordered a new ecm to start eliminating things. Wish me luck.

[DrkPhx]

New ecm should be here anyday. The tune has been reviewed by a few people and nobody has been able to find anything screwy with it. It's been tech2'd and no codes or anything showing up malfunctioning. I'm lost, so I ordered a new ecm to start eliminating things. Wish me luck.

Rarely is a new ECM needed, but you never know it could be the problem. I would try a full reprogram (not just a flash) of the old ECM before you swap computers as a last ditch effort. Keep us posted.

[10secvette]

Rarely is a new ECM needed, but you never know it could be the problem. I would try a full reprogram (not just a flash) of the old ECM before you swap computers as a last ditch effort. Keep us posted.

Thanks, that was tried early on. I hate to just start throwing parts at it, but it's been two months and I need to do something to try and fix this lump in my garage.

[Stealth97]

You checked compression and leakdown in all 8 holes?

Compression tells you if a ring is fried. Leakdown tells you if valves are fried or not opening/closing

This is a new motor, right? Is it possible a valvespring broke? I'd pull the valve covers just to give it a look see. Easy thing to do (well, on my truck anyway).

I'm wondering why it layed down at half track. Layed down on a shift too I assume? Overrevved?

Is it possible that a valve came in contact with a piston at high RPM (valve float) and now all your valves are bent, leading to no compression?

Just trying to be of assistance. May not be EFI related, but hard parts related.

Please let us know what you find! I am very very interested to know.

Eric / Stealth

[10secvette]

You checked compression and leakdown in all 8 holes?

Compression tells you if a ring is fried. Leakdown tells you if valves are fried or not opening/closing

This is a new motor, right? Is it possible a valvespring broke? I'd pull the valve covers just to give it a look see. Easy thing to do (well, on my truck anyway).

I'm wondering why it layed down at half track. Layed down on a shift too I assume? Overrevved?

Is it possible that a valve came in contact with a piston at high RPM (valve float) and now all your valves are bent, leading to no compression?

Just trying to be of assistance. May not be EFI related, but hard parts related.

Please let us know what you find! I am very very interested to know.

Eric / Stealth

It's not mechanical, all of the above checked and ruled out.