R32 Gtr Tune Issues

[R324DR]

Issue: Car (R32 gtr) sometimes misses at idol. Before the engine reaches full operating temp it coughs/farts and jerks when lightly excellerating. Once full operating temp is reached the coughing and jerking is much less but it still misses on idol, back fires a lot, and pings on free rev and while in gear above 6000rpm.

Current Mods: Mines remap, steel wheeled/highflowed standard turbos, trust front pipes, trust cat back, pods, new spark plugs gapped to 8mm, adjustable cam gears, actuators set to 18psi.

Adjustable cam gears were tuned with old spark plugs (6deg advance on intake side and 3.5 retard on exhaust), which caused misfire close to redline but felt strong at low revs. i replaced my old spark plugs with 8mm platinums and issues started to develop after this. Car feels like it has lost low end torque and top end power

To me it seems that at low revs the tune is to rich, and at high revs far to lean. Tuning has been removed from the cam gears which hasnt made a difference.

Any help would be much appreciated.

[rob82]

Issue: Car (R32 gtr) sometimes misses at idol. Before the engine reaches full operating temp it coughs/farts and jerks when lightly excellerating. Once full operating temp is reached the coughing and jerking is much less but it still misses on idol, back fires a lot, and pings on free rev and while in gear above 6000rpm.

Current Mods: Mines remap, steel wheeled/highflowed standard turbos, trust front pipes, trust cat back, pods, new spark plugs gapped to 8mm, adjustable cam gears, actuators set to 18psi.

Adjustable cam gears were tuned with old spark plugs (6deg advance on intake side and 3.5 retard on exhaust), which caused misfire close to redline but felt strong at low revs. i replaced my old spark plugs with 8mm platinums and issues started to develop after this. Car feels like it has lost low end torque and top end power

To me it seems that at low revs the tune is to rich, and at high revs far to lean. Tuning has been removed from the cam gears which hasnt made a difference.

Any help would be much appreciated.

Did you recheck the base timing after moving the exhuast cam??

[rev210]

Perhaps a few things might be worth a look.

Was the Mines remap done with the modifications you now have or prior to them (turbos etc)?

If you got the car from japan with the Mines ecu and later added the turbos and other bits then you have your answer. A tune that is too lean for the new higher airflow and a missmatch for the mixture changes brought about by the cam timing.

If the ecu is tuned for jap fuel then the ignition curve might be a shade to aggressive for the 98 stuff.

Platinum plugs are lame. They cost too much and yours are perhaps now rooted. get some copper NGK BCPR's and gap them to 0.8mm, cost is small for testing in any case. Have a look at the plugs in there. Make a note of any differences between cylinders too in colour and marks.

Bung a wide band o2 in and check the AFR's.

other ideas include a partially blocked injector or two, a fuel pump on the way out, fuel filter issue.

Also, don't go demonstrating the 'pings' at 6,000rpm again, it's detonating long before you hear it and we don't want you to lose the motor.

[R324DR]

yes, base timing was checked. The cam gears and timing was done on a dyno.

thanks for your help guys.

Edited April 28, 2008 by R324DR