#90258, "Horrible idle, bucking, and wont rev past 4000rpm?"
Im having an ongoing problem with car. It is boosted but the issue is not boost related because when I unhooked my IC piping it still went on.
The idle issue is weird, sometimes it idles perfect but other times it idles at like 600 rpm. It will shut off from time to time but other times its like the problem is barely there.
When im crusing in 3rd or 4th and i step on it a little it bucks like crazy, and i have let off because its so strong im afraid i might break something.
To follow up with everything, the revs will not got higher than 4000 rpm. I dont know what the hell this is, i just changed my plugs and wires. I put in NGK bkr7e's and MSD wires. I checked my coil and the resistances are in spec. My SAFC is wired correctly as well. Injectors where replaced last year with Accel 400cc's, it has a HAHN fuel pump, and all new steel braided fuel lines. The car is equiped with a Vortech FMU and a split second. The only thing that strikes me odd is the car came with a FPR installed along with the FMU (i bought it boosted). If i try to just jack up the fuel pressure to bypass the FPR the idle just gets worse.
The only problem i know of is an exhaust leak I have between the manifold and turbo which will be fixed soon, but an exhaust leak wouldnt cause problems like this. The car seems to run pretty hot too, but EGT's stay pretty low. My throttle body is clean but it was dirty as hell before i cleaned it out. My friend said when he was driving behind me said my car would let out white smoke sometimes when I really step on the gas. I ran it on my G-tech yesterday and came out with a 18 second 1/4 mile, so you guys can imagine how much this problem sucks.
I had a post on the bogging in the turbo forum, but since i found its not boost related i opted to move it in here and add some info. I have searched and searched and still not found any solution. Any help or imput would be appreciated.
#90673, "RE: Horrible idle, bucking, and wont rev past 4000rpm?" In response to Reply # 4
Okay this car is starting to piss me off.
Heres what I have done so far...
New Plugs/Wires New MAP Sensor New Throttle Position Sensor Missing Link Fixed All Exhaust leaks.
The reason that i replaced the TPS is that if i unplug it, i can SOMETIMES get it to rev up to redline a few times before it stalls, but the new one did nothing for me. Im going to order the Auterra scan tool shit for my laptop to see if im shooting any trouble codes. Otherwise i dont know.... other than replacing all the wiring, i dont know what else i can do with this car now?
#90675, "RE: Horrible idle, bucking, and wont rev past 4000rpm?" In response to Reply # 5
Was the replacement map sensor brand new? I'd say go to the junkyard and grab a couple of them. Many dodge/chrystler vehicles have the same one. If that doesn't work, trace the sensor wires back to the ECU in search of a bad connection.
#90679, "RE: Horrible idle, bucking, and wont rev past 4000rpm?" In response to Reply # 6
I had this problem, and guys he keeps saying it's not boost related. Try replacing your coolant temp sensor. If that goes bad it thinks your car is -240degrees and screws up all kinds of shit. This happened to me and I spent 2 weeks replacing every sensor on my engine other than that one. Once I replaced that it was fine.
#90684, "RE: Horrible idle, bucking, and wont rev past 4000rpm?" In response to Reply # 7
Originally posted by a_miller_76 I had this problem, and guys he keeps saying it's not boost related. Try replacing your coolant temp sensor. If that goes bad it thinks your car is -240degrees and screws up all kinds of shit. This happened to me and I spent 2 weeks replacing every sensor on my engine other than that one. Once I replaced that it was fine.
I think you are onto something here my man, since whenever i drive the car lately the coolant temp gauge has been at just a tiny bit under the middle point.
I'll go ahead and try that. I'm sure the Auterra scan tool will throw up the code right away for what it is, its in transit now so i should have it by wednesday or so.
#90712, "RE: Horrible idle, bucking, and wont rev past 4000rpm?" In response to Reply # 11
Originally posted by sike Does it ever rev past 4000rpm? MAP SENSOR OR MAP SENSOR WIRES!!@#$
Rarely it will. If i shut the car off and turn it back on and step on it right away, then it will go past for a second or two.
Also i tried going very very easy on the throttle and it climbed up to like 5000 but once i punched it there it bogged back down.
If i unplug the TPS and step on it right away (timing it is really critical for it to work) i can rev freely all the way to redline as long as i dont let rev's drop back to like 2k. Then it just stalls and wont rev higher than idle if i start it back up.
I'm considering the wires too tho, thats going to be the next thing to check out after the coolant sensor.
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