1JZ problem...
#1
1JZ problem...
ok, i have a 1j in my sc w/ about 70k mi.... so here is my problem.
Whenever i'm driving (sometimes) when i start moving in 1st gear the car will feel like its studdering, like that feeling of fuel cut at highboost... when the car just jerks but this is at low boost and low rpm also sometimes my RPM drops to about 500 or less. and my voltage drops but then my voltage rises back up. Alternator is fine; when i drive my battery goes up to 13.6+. i thought i was losing fuel or my fpr was malfunctioning, but its set right on.. and the vacuum line to it was fine. also checked all my vaccuum lines and all is good no leaks or cracks. i changed my sparkplugs about a month ago. so now my next thought is my fuel pump, but nothing wrong there, its functioning.. i bought a fuel filter, so im going to try that and hope that fixes it...
PLEASE ANY INPUT WOULD BE HELPFUL!
thanks in advance
--jeriel
Whenever i'm driving (sometimes) when i start moving in 1st gear the car will feel like its studdering, like that feeling of fuel cut at highboost... when the car just jerks but this is at low boost and low rpm also sometimes my RPM drops to about 500 or less. and my voltage drops but then my voltage rises back up. Alternator is fine; when i drive my battery goes up to 13.6+. i thought i was losing fuel or my fpr was malfunctioning, but its set right on.. and the vacuum line to it was fine. also checked all my vaccuum lines and all is good no leaks or cracks. i changed my sparkplugs about a month ago. so now my next thought is my fuel pump, but nothing wrong there, its functioning.. i bought a fuel filter, so im going to try that and hope that fixes it...
PLEASE ANY INPUT WOULD BE HELPFUL!
thanks in advance
--jeriel
#2
Lexus Test Driver
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hmmm, get the walbro 255 fuel pump....check your injectors, when i was doing my single swap, my car would idle weird, die down and then fly right back up, it was my injectors, injector 4 was stuck open, flooding my car with fuel.......check it out
#7
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You remove the back seats, remove the driver side panel, and youll see the pump ecu. Then cut the thick wire (yellow I think), and the red????, and splice them together.
Someone help me with the wire colors.
Someone help me with the wire colors.
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#8
Lexus Champion
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Stuttering at full boost
I might as well chime in on your thread as our problems may be related. I read something about fuel cut at high boost.
I too have a 1JZ with about the same amount of mileage. There used to be a time when I could boost up to 15psi on stock twins, no problem. As of late, I can only boost to ~12psi. Anything higher results in a stuttering of the engine. It almost sounds like it's coughing. When I dial the boost back, it runs perfectly fine up to about 12psi. I'm running a walbro 255lph with 440CC (may be 550CC) injectors.
Any idea?
Steve
I too have a 1JZ with about the same amount of mileage. There used to be a time when I could boost up to 15psi on stock twins, no problem. As of late, I can only boost to ~12psi. Anything higher results in a stuttering of the engine. It almost sounds like it's coughing. When I dial the boost back, it runs perfectly fine up to about 12psi. I'm running a walbro 255lph with 440CC (may be 550CC) injectors.
Any idea?
Steve
#11
I might as well chime in on your thread as our problems may be related. I read something about fuel cut at high boost.
I too have a 1JZ with about the same amount of mileage. There used to be a time when I could boost up to 15psi on stock twins, no problem. As of late, I can only boost to ~12psi. Anything higher results in a stuttering of the engine. It almost sounds like it's coughing. When I dial the boost back, it runs perfectly fine up to about 12psi. I'm running a walbro 255lph with 440CC (may be 550CC) injectors.
Any idea?
Steve
I too have a 1JZ with about the same amount of mileage. There used to be a time when I could boost up to 15psi on stock twins, no problem. As of late, I can only boost to ~12psi. Anything higher results in a stuttering of the engine. It almost sounds like it's coughing. When I dial the boost back, it runs perfectly fine up to about 12psi. I'm running a walbro 255lph with 440CC (may be 550CC) injectors.
Any idea?
Steve
Check your plugs....Also check the gap. whats happening is the spark is being blown out either by 1, too high of a gap, or 2, fouling of plugs. just get yourself a set of the cheapie ngk's and youll be boosting back to 15 psi guarenteed.
#12
ok, i have a 1j in my sc w/ about 70k mi.... so here is my problem.
Whenever i'm driving (sometimes) when i start moving in 1st gear the car will feel like its studdering, like that feeling of fuel cut at highboost... when the car just jerks but this is at low boost and low rpm also sometimes my RPM drops to about 500 or less. and my voltage drops but then my voltage rises back up. Alternator is fine; when i drive my battery goes up to 13.6+. i thought i was losing fuel or my fpr was malfunctioning, but its set right on.. and the vacuum line to it was fine. also checked all my vaccuum lines and all is good no leaks or cracks. i changed my sparkplugs about a month ago. so now my next thought is my fuel pump, but nothing wrong there, its functioning.. i bought a fuel filter, so im going to try that and hope that fixes it...
PLEASE ANY INPUT WOULD BE HELPFUL!
thanks in advance
--jeriel
Whenever i'm driving (sometimes) when i start moving in 1st gear the car will feel like its studdering, like that feeling of fuel cut at highboost... when the car just jerks but this is at low boost and low rpm also sometimes my RPM drops to about 500 or less. and my voltage drops but then my voltage rises back up. Alternator is fine; when i drive my battery goes up to 13.6+. i thought i was losing fuel or my fpr was malfunctioning, but its set right on.. and the vacuum line to it was fine. also checked all my vaccuum lines and all is good no leaks or cracks. i changed my sparkplugs about a month ago. so now my next thought is my fuel pump, but nothing wrong there, its functioning.. i bought a fuel filter, so im going to try that and hope that fixes it...
PLEASE ANY INPUT WOULD BE HELPFUL!
thanks in advance
--jeriel
#13
Basically the symptoms happen whenever it wants to. Alot of times it happens at low rpm in 1st gear. and about 20% throttle... or sometimes when im cruising on the frwy at about 75 at about 20% throttle or less the car tends to jerk... one time i actually felt the car studder when i went over the little reflectors on the frwy, could this be the ECU? or something major electrical?
#14
I might as well chime in on your thread as our problems may be related. I read something about fuel cut at high boost.
I too have a 1JZ with about the same amount of mileage. There used to be a time when I could boost up to 15psi on stock twins, no problem. As of late, I can only boost to ~12psi. Anything higher results in a stuttering of the engine. It almost sounds like it's coughing. When I dial the boost back, it runs perfectly fine up to about 12psi. I'm running a walbro 255lph with 440CC (may be 550CC) injectors.
Any idea?
Steve
I too have a 1JZ with about the same amount of mileage. There used to be a time when I could boost up to 15psi on stock twins, no problem. As of late, I can only boost to ~12psi. Anything higher results in a stuttering of the engine. It almost sounds like it's coughing. When I dial the boost back, it runs perfectly fine up to about 12psi. I'm running a walbro 255lph with 440CC (may be 550CC) injectors.
Any idea?
Steve
oh yea i would say change ur plugs, my car used to studder at high rpm and boost and i changed my plugs also my broken coil pack connectors and it was great again.
also btw, is anyone down to help me change out my injectors to my 440s? im thinking maybe the injector is stuck open or sumthing... please. help =) .. free food and drinks