missfiring wont idle or rev out clean, ideas from a pro
01-03-12, 01:19 AM
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missfiring wont idle or rev out clean, ideas from a pro
i would never normally post this up but this has myself and a few others completely clueless to our problem, my tuner is MIA on holidays. if you can offer some more ideas of things to check it would be much appreciated.
quick rundown.
13b s4 motor (gen 2 to you guys)
s475 turbo
very large cooler
custom plenum
nitrous in primarys(although irrelevant to my problem)
4x2200cc bosch injectors at the same height in LIM all fuel through 2nd port. program for firing on alternating rotor faces
aeromotive regulator
- 8 lines throughout
e85
autronic sm4
m&W cdi
bosh HEC coils (yes they work)
car has made with this EXACT SETUP 800hp+ engine dyno a few weeks ago, all we did was hook up power and earth and its now back in the car and will not run properly, took it for a little test drive and not just a belly full of fuel or oil to clear out. so we began, THE CHECKLIST
the problem sounds much like fouled plugs/retard ignition
-change plugs to hotter set
-check all earths for everything sand paint off and re done
-test plug leads
-swap plug lead 1 by 1
-test spark will jump from leads 1 inch air gap very strong
-check power for ECU and CDI
-test resistance for ECU and CDI grounding
-perform M&W coil test as per manual testing one at a time
-test manual grounding CDI inputs to fire plugs
-check piping for blockages
-check for vacum leaks
-checked timing - matches to laptop datalog
-unbolt crank sensor while car running to adv./retard ignition, no improvement
-CDI is mounted in front bumper of car - extend loom away from coils and any other wiring around to the computer
-SM4 showing no log errors from computer
-check vac lines
-run new vac line to ecu
-compression test - all good
failing electrical we look to fueling
-change fuel - possible stale
-check filters
-test injector pulses with node light
-test injector grounding correct and powering correct
-remove injector - flow bench and ultrasonic clean - all withing 4cc/min
-check injector plugs
-check fuel rails for obstruction
-check rising rate FPR
and i think there is more i have forgotten!
we have an event starting in 2 days and we just need this thing done, if you have any suggestions or ideas please post up we are not even sure were to look now.
cheers
quick rundown.
13b s4 motor (gen 2 to you guys)
s475 turbo
very large cooler
custom plenum
nitrous in primarys(although irrelevant to my problem)
4x2200cc bosch injectors at the same height in LIM all fuel through 2nd port. program for firing on alternating rotor faces
aeromotive regulator
- 8 lines throughout
e85
autronic sm4
m&W cdi
bosh HEC coils (yes they work)
car has made with this EXACT SETUP 800hp+ engine dyno a few weeks ago, all we did was hook up power and earth and its now back in the car and will not run properly, took it for a little test drive and not just a belly full of fuel or oil to clear out. so we began, THE CHECKLIST
the problem sounds much like fouled plugs/retard ignition
-change plugs to hotter set
-check all earths for everything sand paint off and re done
-test plug leads
-swap plug lead 1 by 1
-test spark will jump from leads 1 inch air gap very strong
-check power for ECU and CDI
-test resistance for ECU and CDI grounding
-perform M&W coil test as per manual testing one at a time
-test manual grounding CDI inputs to fire plugs
-check piping for blockages
-check for vacum leaks
-checked timing - matches to laptop datalog
-unbolt crank sensor while car running to adv./retard ignition, no improvement
-CDI is mounted in front bumper of car - extend loom away from coils and any other wiring around to the computer
-SM4 showing no log errors from computer
-check vac lines
-run new vac line to ecu
-compression test - all good
failing electrical we look to fueling
-change fuel - possible stale
-check filters
-test injector pulses with node light
-test injector grounding correct and powering correct
-remove injector - flow bench and ultrasonic clean - all withing 4cc/min
-check injector plugs
-check fuel rails for obstruction
-check rising rate FPR
and i think there is more i have forgotten!
we have an event starting in 2 days and we just need this thing done, if you have any suggestions or ideas please post up we are not even sure were to look now.
cheers
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