Haltech EMS - Won't rev above 2,200rpm?
11-28-2008, 12:43 AM
#16
Nordschleife Master
Thread Starter
Latest update:
It Revs up above 2k and runs decently up above 2k. However ... anything within 1 or 200 rpm of 2k and it runs terribly (popping, missing, etc...). Looking at the timing light, it seems to miss every once in a while (does this at idle and at a steady 2500rpm). However, it does sound smooth despite the timing light. I am guessing it's missing on the waste spark, which seems strange.
If I hold it at 2500rpm and let off the gas, it lets out a big exhaust backfire (big fireball), probably indicating that fuel is good but ignition is no good. Revving from 1000rpm to 1900rpm it is smooth.
Timing shows good at idle and 2500rpm.
Here's a link to the coil I'm using (with factory plug wires, indicated to be OK by MSD):
http://store.summitracing.com/partde...0&autoview=sku . At this point it does seem like an ignition issue ... plugs are new copper Bosch plugs @ the original gap of roughly 0.025". A/F is between 12 and 15. It starts to get poppy anything above 15.
It seems really weird since it runs poorly ONLY at +/- 100 rpm of 2100rpm. Everywhere else it runs OK. It needs tuning of course, but this 2000rpm issue really doesnt not seem like tuning. The maps are smooth through that range (I will post them on saturday).
I have been checking ignition timing with a timing light on the cam up until today. Today I decided to double check it to the crank, it matches up there also.
As always ... I appreciate any help
thanks,
Adrial
It Revs up above 2k and runs decently up above 2k. However ... anything within 1 or 200 rpm of 2k and it runs terribly (popping, missing, etc...). Looking at the timing light, it seems to miss every once in a while (does this at idle and at a steady 2500rpm). However, it does sound smooth despite the timing light. I am guessing it's missing on the waste spark, which seems strange.
If I hold it at 2500rpm and let off the gas, it lets out a big exhaust backfire (big fireball), probably indicating that fuel is good but ignition is no good. Revving from 1000rpm to 1900rpm it is smooth.
Timing shows good at idle and 2500rpm.
Here's a link to the coil I'm using (with factory plug wires, indicated to be OK by MSD):
http://store.summitracing.com/partde...0&autoview=sku . At this point it does seem like an ignition issue ... plugs are new copper Bosch plugs @ the original gap of roughly 0.025". A/F is between 12 and 15. It starts to get poppy anything above 15.
It seems really weird since it runs poorly ONLY at +/- 100 rpm of 2100rpm. Everywhere else it runs OK. It needs tuning of course, but this 2000rpm issue really doesnt not seem like tuning. The maps are smooth through that range (I will post them on saturday).
I have been checking ignition timing with a timing light on the cam up until today. Today I decided to double check it to the crank, it matches up there also.
As always ... I appreciate any help
thanks,
Adrial
12-03-2008, 01:40 PM
#17
Burning Brakes
Join Date: Feb 2002
Location: Edmonton
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Adrial, it is very odd that you have good running everywhere except around the 2000rpm point. To me this would indicate something is happening that interferes with the coil signal for one or more cylinder events around that rpm. Can you put a shield like a coax cable shield around your sensor wires just to try to eliminate any interference? Do you have a different sensor to try?
