Won't rev when flooring. Revs fine when accelerating gently!
#1
Junior Member
Thread Starter
Won't rev when flooring. Revs fine when accelerating gently!
Hi guys. I have a 1993 JDM FD. Trying to figure out what the problem is.
Basically, if you step on the gas immediately, it won't rev past 2000rpm. It's like a rev limiter. If you gently accelerate, it's revs all the way to about 5000rpm, and then won't rev beyond that.
Same story when driving. Seems load dependent. When accelerating gently, it's nice and smooth until 5000rpm. Steeping on it makes the car buck at whatever rpm. Like shifting to 5th at 10mph.
I'm also getting a strong fuel smell from under the hood.
What could this be?
Basically, if you step on the gas immediately, it won't rev past 2000rpm. It's like a rev limiter. If you gently accelerate, it's revs all the way to about 5000rpm, and then won't rev beyond that.
Same story when driving. Seems load dependent. When accelerating gently, it's nice and smooth until 5000rpm. Steeping on it makes the car buck at whatever rpm. Like shifting to 5th at 10mph.
I'm also getting a strong fuel smell from under the hood.
What could this be?
#2
Urban Combat Vet
iTrader: (16)
Sounds like something triggered “limp mode” in the ECU. It’s what the name suggests, when the ECU senses a critical system isn’t working, it will not let timing advance and will cut fuel if the boost sensor doesn’t see vacuum at the manifold.
On NADM models it generates a CEL and codes can be pulled. Not sure how it’s done on a JDM model. Someone else will have to chime in.
On NADM models it generates a CEL and codes can be pulled. Not sure how it’s done on a JDM model. Someone else will have to chime in.
#3
Rotary Freak
iTrader: (1)
The JDM cars have the same/similar diagnostic port under the hood, just no check engine light.
https://www.rx7club.com/3rd-generati...jdm-fd-664425/
https://www.rx7club.com/3rd-generati...jdm-fd-664425/
#4
Urban Combat Vet
iTrader: (16)
Check Engine Light Codes
Not all codes will cause Limp mode. And I don’t think JDMs have all of those on the NADM cars.
Probably the most common in my experience are any one of the three associated with the Metering Oil Pump (MOP)
Not all codes will cause Limp mode. And I don’t think JDMs have all of those on the NADM cars.
Probably the most common in my experience are any one of the three associated with the Metering Oil Pump (MOP)
#5
RX-7 Bad Ass
iTrader: (55)
It's either limp mode or something wrong with the secondary injectors. Had a friend with a bad secondary (it tested as open circuit) and it had similar behavior.
Dale
Dale
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#8
Junior Member
Thread Starter
Thanks a lot for the response guys!
I thought limp mode is Rpm dependent. Not load. When I'm driving the car, if I press the accelerator pedal hard, the car bucks back and forth violently. But if I press it gently, it's nice and smooth. Can limp mode do that?
I do not have a Power FC
I thought limp mode is Rpm dependent. Not load. When I'm driving the car, if I press the accelerator pedal hard, the car bucks back and forth violently. But if I press it gently, it's nice and smooth. Can limp mode do that?
I do not have a Power FC
#10
Urban Combat Vet
iTrader: (16)
Thanks a lot for the response guys!
I thought limp mode is Rpm dependent. Not load. When I'm driving the car, if I press the accelerator pedal hard, the car bucks back and forth violently. But if I press it gently, it's nice and smooth. Can limp mode do that?
I do not have a Power FC
I thought limp mode is Rpm dependent. Not load. When I'm driving the car, if I press the accelerator pedal hard, the car bucks back and forth violently. But if I press it gently, it's nice and smooth. Can limp mode do that?
I do not have a Power FC
A PFC will certainly get you out of limp, but it doesn’t cure what caused the factory ECU to trigger it. That critical system is still not working or working properly. So it still needs to be addressed.
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c0rbin9 (09-12-20)
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