g60 hesitation at high rpm

[wormy 0]

Hi folks!

(I'll start by excusing any bad english that might be here :pale: )

 

My car have developed some kind of "hesitation" at high rpm's. Typically 4k+.

It doesn't happen all the time, but relatively often. It still pulls decently, but not as good as it's supposed to.

It might just be for 2 seconds or so, and then be all good, or it might be there untill I change gear.

I still got full boost while this happens..

 

The car is a '91 G60 with a TEC 2rs g-lader that has been ported even more. Running a 68mm pulley. Rebuilt 8 months ago.

The charger/boost is not the problem, as it's pulling 0.9-0.95 bar from approximately 3k rpm, and staying there up the revs. :norty:

Autotech stage 3 :roll: + ISV-reroute and low-temp rad-switch + thermostat.

 

I've recently changed:

3.5mm x 1m ECU-vacuum hose.

Fuel Pump (old one suicided..)

Fuel Filter

Rotor

Distribuitor cap

Plug leads

Plugs (Bosch w6dp)

De-cat'ed the car (as the old one almost broke in 2...)

 

 

I've done a comp test. Not "good as new", but within specc, and relativly close numbers.

I've tested the BTS, both by unplugging it at idle and ohm'ing it - it's fine.

Ohm'd the injectors as the Bentley Manual suggests, they're within specc.

Co-pot is set to 500ohm (was last time I check anyway..)

Timing was set to 6btdc two months ago, then double-checked a while later.

The vacuum in the MFA is ~550 at idle, but I haven't checked for any vacuum leaks other then that. (Should I?)

 

Might the oxygen sensor cause this? I know I probably should change it, but being a student, I can't afford to change as many things as I'd like...

Any input appreciated.

[dirtytorque 0]

just leaves the coil really from your list above..

[wormy 0]

Could a failing alternator be the cause of this?

Noticed today that with the stereo and the lights on, I had 13.2v on the battery.

Without anything on I had 13.9v..

 

I've already replaced the wire from the alternator to the starter, so I'm not loosing any power from the alternator to the battery.

The brushes looks kinda new too. The alternator have been making some weird noises the last months, so it might be failing and causing all this? :confused4:

[wormy 0]

I learned something today. Allways double check everything. Or in my case; tripple-check.

It was the damn timing that already had been checked a little while ago.. Changed from 3-4 to ~8 btdc. :censored:

Just fyi if anyone wondered.

[Album56 0]

Glad you were able to sort it out but how had the timing changed? Was the distributor not clamped tightly. Confused as to how this can happen

[wormy 0]

Really wondering about the same myself. Maybe it wasn't completly tight, and got bumped into while fiddling around in the engine bay... :s