.Help! Car stutters/ bucks at 4000 rpm's

[dmj]

Took my car out yesterday to go to the Doctor and the car won't go past 4000 rpm's.feels like a loss of spark or fuel starvation.As soon as I get off the gas the car runs fine. I replaced the spark plug wires,but no change the car will rev past 4000 rpm if it is not under load Note.just installed new turbo ,injectors ,Evo mas And stage 3 chip from Keydiver. Excellent job Jeff .The car starts and idles better now than before the upgrade.Garfield recommended I swap out the transistor first. Anybody with other ideas or solutions?

 

Becuase you have a spare one. If that doesn't work then change the plugs & see what happens.

 

Sounds like bad plugs to me, but a logger would definitely help you see what is going on.

 

[ktmrider]

Talk to SleepinGVR4 in PA, he was having the exact same problem but has not updated anything recently.
Last suggestion for his problem was to check the Stutterbox wiring ( assuming you have this function in your chip ). Lots of people wire them up wrong which can cause the symptoms you describe.

 

does the car have a boost leak, because mine was ding that and we boost leaked tested it and it was hitting 1 lb.

 

[Nate]

Yes, double check the stutterbox wiring. Specifically, make sure that you CUT pin 103 and not tap into it. You need the contact closure from the lower clutch switch being depressed to complete that ground curcuit.

 

Quote:
Yes, double check the stutterbox wiring. Specifically, make sure that you CUT pin 103 and not tap into it. You need the contact closure from the lower clutch switch being depressed to complete that ground circuit.


Actually its pin #104, but he said he can free rev it past 4000 without load, so I wrote the stutterbox off as the issue. To be sure though, just reconnect the black ground wire to pin #104 that you cut off, which forces the ECU to use only the MAIN rev limiter.

 

[dmj]

Problem solved. Boost leak at intercooler pipe and 90 degree elbow.it was not clamped tight enough and pipe was slowly working its way out.rechecked all the pipes and hoses made sure everything was nice and tight now the car runs great.Time to turn up the boost . Thanks for the input guys. /ubbthreads/images/graemlins/grin.gif