Base Timing Adjustment retarding at higher revs.

[KeithMac]

Hello all, I've been working on the car this morning and part of it was to set the base timing with 1st gen CAS setup.

Brown plug grounded, logger disconnected, strobe on lead 1 etc.

At idle the car shows 10dbtdc which is over factory spec by 5 degrees but since runnng meth mix this is benificial to me.

At 3500 rpm the timing retarded to 5 degrees!, surely this is well outside the limit and I can only assume at 7000rpm it will be even worse (couldn't rev that high to check).

So has anyone else reved the car up during base timing adjustment and checked the timing is still locked out at 5 degrees or are my findings normal?. Surely the commanded timing from the ECU will be miles out at higher revs.

I have the option of adding advance back in with the Emanage Ultimate to compensate but would like to hear if anyone else has encountered this issue first of all.

Cheers, Keith.

[DocWalt]

I wonder if it's something that the ECU simply compensates for internally when it's not in the base timing adjustment mode... but free bump!

[RealMcCoy]

I wouldn't consider it an issue... I think the idle switch needs to be closed to enter base timing mode. Base timing mode is simply a preset point on a line, and not the lowest point the ECU is capable of.

If I were trying to accomplish that task, I'd compare data readings to actual timing while in normal operation.

[KeithMac]

Yeh I've been told there is a finite delay in the transistors in ecu/ ptu and delay from the coils discharging, so it makes sense that timing will retard at higher revs if the ecu is fixed.

Probably why the manual stilulates idle speed to do the adjustment?.

Posted in Gregs post to see if there is compensation built into the timing strategy in the ecu (would have thought so!).

[napkinthief]

did you resolve this? as with my chrome ecu on stock tune and injectors, at about 50% throttle/4000rpm, its locking timing at 5* are you getting any knock when this happens? mine locks the knock at 8 or 9 and stays there until I restart the engine

[anyonebutme]

did you resolve this? as with my chrome ecu on stock tune and injectors, at about 50% throttle/4000rpm, its locking timing at 5* are you getting any knock when this happens? mine locks the knock at 8 or 9 and stays there until I restart the engine

That's a knock sensor fault. When the sensor fails or the ecu doesn't see a signal from the knock circuit it locks the knock at like 9 and retards the timing to protect the engine.