Weird problem under hard acceleration SOLVED

[aguiloco]

Hi, I am having a wierd problem with my ZE and after some days I cant figure out what is, maybe you can help me.

The issue is that when I try to accelerate hard the engine can not get RPMs up, it just starts to die like it has too much fuel or not nought air, but if I press the pedal slowly is driveable and revs up fine.

This happend without a reason, I parked the car after work and the next morning the problem started, only a few hours elapsed since the last good running.

I did this:

New spark plug wires and mint condition spark plugs.
Change fuel filter and clean the washable air filter.
Clean all the admission system, manifold, hoses, etc...
Tested the MAF with an ohmmeter and get good values.
Try to run without the TPS plugged (It worked years ago when I had a broken one)
It pass the diagnostics test, only EGR errors, like always.
Reset the timing belt, it was one tooth out place on the back camshaft.
Try to advance or retard the timing from 5 to 15 degrees.
Check for vacuum leaks.
Reset the ECU and made the tune-up again.
Try with the old K8 ECU.

None of that worked...

Any ideas???

I can record a video, I know my limited english could be difficult to understand, because is bad written...

[Inodoro Pereyra]

Get underneath the car, and disconnect the exhaust pipe, right in front of the catalytic converter, and try again. If that solves your problem, your catalytic converter is clogged.

En caso de que no hayas entendido algo, desconecta el tubo de escape, justo delante del convertidor catalitico. Si eso resuelve el problema, el CC esta tapado.
Recuerda que cuando arranques el coche con el escape desconectado, va a hacer mucho ruido, y si lo dejas funcionando por mas de 1 o 2 minutos, la luz del motor se va a encender en el tablero de instrumentos.

[aguiloco]

Get underneath the car, and disconnect the exhaust pipe, right in front of the catalytic converter, and try again. If that solves your problem, your catalytic converter is clogged.

En caso de que no hayas entendido algo, desconecta el tubo de escape, justo delante del convertidor catalitico. Si eso resuelve el problema, el CC esta tapado.
Recuerda que cuando arranques el coche con el escape desconectado, va a hacer mucho ruido, y si lo dejas funcionando por mas de 1 o 2 minutos, la luz del motor se va a encender en el tablero de instrumentos.

mmm... I dont think so...

[aguiloco]

Here is the video.

http://www.youtube.com/watch?v=B2Xf3FJV-u0" onclick="window.open(this.href);return false;

You can notice the difference between soft an hrd acceleration.

[_-Night-Shade-_]

I'll say vacuum leak.

[Muzzled]

try IAC. unplug the iac and see if it runs better. mine did the same thing but it would do it randomly.... and flood the engine at times. while driving.. mx3autozam (john) told me to unplug the iac and its running perfectly fine since. try it might solve your problem.

[_-Night-Shade-_]

try IAC. unplug the iac and see if it runs better. mine did the same thing but it would do it randomly.... and flood the engine at times. while driving.. mx3autozam (john) told me to unplug the iac and its running perfectly fine since. try it might solve your problem.

IAC doesn't really do much unless in idle.

[aguiloco]

I tried another MAF and checked the fuel presure, all fine.

Tomorrow I will try the IAC trick, will clean all contacts, reset the TPS and disconect the exhaust line after the headers, hope some of that works, I am running out of ideas...

[aguiloco]

Some new test done today, no results...

Cleaned all electrical conectors

Reset the TPS

Disconnected the IAC

Re-check for vacuum leaks (I need to put a gauge on it to check it perfect)

Removed exhaust, only headers plugged, the catalithyc converter is fine

Here is the video, maybe it helps:

http://www.youtube.com/watch?v=yYdhaexRBUQ" onclick="window.open(this.href);return false;

And that´s the intake vacuum:

http://www.youtube.com/watch?v=j2TyOThV_UE" onclick="window.open(this.href);return false;

Any other suggestion? this is getting more and more weird...

[aguiloco]

I found the problem! It was the ditributor, the coils has good resistance values but seems like the magnets, the capacitor or any other electric part was getting down the engine.

Thanks for the contributions.