Help!!!
Help!!! Ok...so I've been chasing a problem thats been happening with my car for quite some time now. It started awhile back breaking up in 3rd and 4th WOT but didn't do it all the time....I took the car off the road for awhile to put the TH400 in and now it's doing it in 2nd and 3rd. It seems to only happen between 5100 and 5500 and clears up after that. I have changed the coil packs, spark plugs, wires, and injectors. I have turned the motor over with the valve covers off and it doesn't seem to be a valve train issue, but I'm no expert. I really don't have the financial backing to leave it at a shop currently. When I log the car with HPT it shows no abnormailities in the log. Everything seems to run fine. I've tried both adding and removing timing, as well as richining the AFR in that RPM range. I hope some one can point me in the right direction. Also it doesn't seem to be the crank sensor being I had a Modis on the car and that can't even narrow it down. Hopefulyl someone can chime in and help me out....
-Dave
-Dave
well 2-3 on the th400 would be almost an identical senereo as 3-4 on the t56.
Have you logged the A/F ratio? Sounds like it could be a fuel pump issue. Adding timing wouldnt change where the fuel pump maxes out. Could also... however unlikely be a tune/computer issue. I have one sitting on my desk that would (for no reason at all) think it had knock and would retard at a certain KPA. Only happen when that particular KPA was reached. So funky things do happen w/ comps. Are the O2's fluctuationg quickly?
What mods do you have? It could be anything from a maf issue, to a map sensor, to the tune, to an intake leak (un-metered air getting in), fuel pump, O2 sensor... Did you check the wiring on the passanger side to see if anything is getting cooked? (follow it down the engine bay from the top of the motor down past the headers.)
Have you logged the A/F ratio? Sounds like it could be a fuel pump issue. Adding timing wouldnt change where the fuel pump maxes out. Could also... however unlikely be a tune/computer issue. I have one sitting on my desk that would (for no reason at all) think it had knock and would retard at a certain KPA. Only happen when that particular KPA was reached. So funky things do happen w/ comps. Are the O2's fluctuationg quickly?
What mods do you have? It could be anything from a maf issue, to a map sensor, to the tune, to an intake leak (un-metered air getting in), fuel pump, O2 sensor... Did you check the wiring on the passanger side to see if anything is getting cooked? (follow it down the engine bay from the top of the motor down past the headers.)
Well I took the car out last night and did some test passes...The car seems to have stopped breaking up in second and no just seems to do it in third. While I was logging the car I can't seem to find any abnormalities in the log at all...my wideband took a crap on the way out last night so my AFR log isn't complete but I checked my mV readings on the factory O2's and they seemed to be in check. As for the MAF I am currently running a speed density tune, and yes I had this problem when it was still a MAF car. How would I be able to check if my fuel pump is maxes? My stock injectors are only at 85% duty cycle. The stocker should be able to keep up with my 28.8lb/hr guys...as for mods it's a bolt on car with a FAST 92/92 set up.
-Dave
-Dave
