G60 - 5700rpm stumble - Help

[Trakx 0]

so i still have the high rpm stumble. It seems it starts consistently at 5700 rpm (can be seen on power grahp)

it seems like misfire. it does not pop.

 

found this the other day:

"almost sound like an electrical failure (key cylinder, ecu relay, fuel pump relay,ISV short circuit).

sounds like the ecu is rebooting; but since you've replaced that already you must start looking upstream

you know there was a guy on here with his keychain it would rattle at 5700rpm (out of gear) and misfire rapidly as the key cylinder hit a harmonic that caused power to cut on/off and reboot the ecu acting like a rpm cut. weirdest isht we've ever seen. don't rule anything out"

dont seem to be my problem

 

I've already changed ecu relay, fuel pump relay, distributor including hall sensor, cap and rotor, sparkplugs and wires, blue coolant sensor, co pot, knock sensor, injectors, injector loom and FPR.

Missing is ignition coil, fuel pump, ignition switch and alternator.

Already tested wire loom for continuity/resistance. All seem ok.

Also tested for voltage at high rpm and no problem.

 

Any ideas?

[Supercharged 2]

This sounds very much like the ECU / Map sensor dragging the timing back... what boost are you getting at that RPM?

[Trakx 0]

its independent of boost (my g60 is now turbo, have a Profec B so i can change boost)

[Trakx 0]

Some more data

 

Gtech performance logs (diferent curves correspond to diferent boost. higher = 1 bar boost)

 

Innovate lc-1 and lma-3 logs (rpm-black, injectors duty cycle-green, boost-blue, afr-purple and g meter- yellow line)

 

In the second pic its clear the stumble at 6000 rpm - g meter-yellow line goes up and than down again - which means the car had a certain accelaration (the lower the yellow line means more accelaration) than it was reduced and then it got up again

[Supercharged 2]

Are you still running the Digi ECU mate? - if so it looks very like the Map sensor as above as they only work to 1 Barr.

 

You need to get hold of an ECU from a Rallye - 1.5 Barr Map sensor.

[dirtytorque 0]

sounds like your bumping up on the rev limiter to me.

[Yandards 0]

sounds like your bumping up on the rev limiter to me.

 

Me too, you will get a massive drop off at 5800 rpm as that is where a stock digi ECU will open the ISV up to return boost pressure for gradual introduction into the rev limit of 6250rpm.

[Trakx 0]

I dont have a ISV. From the log we can see that boost is not going down and fuel seem ok.

 

If its a rev limiter than it must be retarding time, but from what i know the ecu doesnt do that.

From my knowledge the rpm limit is less boost and less 5700rpm to fuel cut at 6300.

 

Anyone has any info on ECU retarding time ?

[dirtytorque 0]

i would imagine there is a soft cut( retart timing )and then a hard cut(fuel cut) at some point later,..

[Yandards 0]

I dont have a ISV. From the log we can see that boost is not going down and fuel seem ok.

 

If its a rev limiter than it must be retarding time, but from what i know the ecu doesnt do that.

From my knowledge the rpm limit is less boost and less 5700rpm to fuel cut at 6300.

 

Anyone has any info on ECU retarding time ?

 

Soft cut is 5600 rpm and hard cut is 6200 rpm, whilst it is not documented that the timing is pulled back between these two values it would not suprise me if the default digi map does this.

[dirtytorque 0]

Soft cut is 5600 rpm.

 

 

ughh....

 

early. :)

[Yandards 0]

Soft cut is 5600 rpm.

 

 

ughh....

 

early. :)

 

That's a gradual introduction to rev limit cut, at 5600 rpm the ISV bleeds boost back to return. Best bet is change at about 5200 on a G60 on standard management then.