Sc300 Backfiring On Idle Rough Idle NO CEL!
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Intermediate
Joined: Jul 2011
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From: New York
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 278
Likes: 0
From: New York
idk it was on due to grounds but now cleared also could it be rotor from the distributor or my fuel pump i need solid answers remember it only back fires on idle which means no load
https://www.clublexus.com/forums/per...le-timing.html
GL
revving it up can hide alot of symptoms, but that doesn't mean you don't have the same problem when the motor is loaded. the motor is just a lot more sensitive when its idling to fluctuations. I wouldn't even rev it hard until you fix the issue unless you want to risk breaking something.
its not hard to check the cap and rotor, take it off the cap and inspect it or just replace it if its old and you are unsure. If the edge of the rotor looks very rounded off, or the cap has gouge marks on the 6 pins, where some have alot less material than others, you are probably in need of a new cap and rotor.
When one of them is done, you loose spark on 1-6 cylinders pretty randomly. also when the rotor and cap goes its just a matter of time before all those sparks jumping around the inside of the distributor kill the cam and crank sensors in the base.
From that video there is no way the car can rev properly like that, it sounds like more of a bad knock than a backfire. From the video it sounds like you are not getting spark on all 6, possibly some cylinders are washing down with fuel which slows the motor down and then you get that sound in the video. It could also be an injector or something. you will have to try and pin point it a little more or give us some more info, keep us updated it doesn't sound like a leak to me anymore, cause right after start it idles down just fine, it just can't keep the rythym its either fuel or spark on this one.
*edit* just read you said you changed the cap. if you didn't change the rotor you should, you always replace those 2 together.
also the 12v fuel mod won't affect your idle, the fuel pressure regulator returns the excess fuel back to the tank. It may be noisier than stock but shouldn't change the way the motor runs under normal conditions.
its not hard to check the cap and rotor, take it off the cap and inspect it or just replace it if its old and you are unsure. If the edge of the rotor looks very rounded off, or the cap has gouge marks on the 6 pins, where some have alot less material than others, you are probably in need of a new cap and rotor.
When one of them is done, you loose spark on 1-6 cylinders pretty randomly. also when the rotor and cap goes its just a matter of time before all those sparks jumping around the inside of the distributor kill the cam and crank sensors in the base.
From that video there is no way the car can rev properly like that, it sounds like more of a bad knock than a backfire. From the video it sounds like you are not getting spark on all 6, possibly some cylinders are washing down with fuel which slows the motor down and then you get that sound in the video. It could also be an injector or something. you will have to try and pin point it a little more or give us some more info, keep us updated it doesn't sound like a leak to me anymore, cause right after start it idles down just fine, it just can't keep the rythym its either fuel or spark on this one.
*edit* just read you said you changed the cap. if you didn't change the rotor you should, you always replace those 2 together.
also the 12v fuel mod won't affect your idle, the fuel pressure regulator returns the excess fuel back to the tank. It may be noisier than stock but shouldn't change the way the motor runs under normal conditions.
Last edited by Ali SC3; Apr 5, 2013 at 08:50 AM.
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 278
Likes: 0
From: New York
revving it up can hide alot of symptoms, but that doesn't mean you don't have the same problem when the motor is loaded. the motor is just a lot more sensitive when its idling to fluctuations. I wouldn't even rev it hard until you fix the issue unless you want to risk breaking something.
its not hard to check the cap and rotor, take it off the cap and inspect it or just replace it if its old and you are unsure. If the edge of the rotor looks very rounded off, or the cap has gouge marks on the 6 pins, where some have alot less material than others, you are probably in need of a new cap and rotor.
When one of them is done, you loose spark on 1-6 cylinders pretty randomly. also when the rotor and cap goes its just a matter of time before all those sparks jumping around the inside of the distributor kill the cam and crank sensors in the base.
From that video there is no way the car can rev properly like that, it sounds like more of a bad knock than a backfire. From the video it sounds like you are not getting spark on all 6, possibly some cylinders are washing down with fuel which slows the motor down and then you get that sound in the video. It could also be an injector or something. you will have to try and pin point it a little more or give us some more info, keep us updated it doesn't sound like a leak to me anymore, cause right after start it idles down just fine, it just can't keep the rythym its either fuel or spark on this one.
*edit* just read you said you changed the cap. if you didn't change the rotor you should, you always replace those 2 together.
also the 12v fuel mod won't affect your idle, the fuel pressure regulator returns the excess fuel back to the tank. It may be noisier than stock but shouldn't change the way the motor runs under normal conditions.
its not hard to check the cap and rotor, take it off the cap and inspect it or just replace it if its old and you are unsure. If the edge of the rotor looks very rounded off, or the cap has gouge marks on the 6 pins, where some have alot less material than others, you are probably in need of a new cap and rotor.
When one of them is done, you loose spark on 1-6 cylinders pretty randomly. also when the rotor and cap goes its just a matter of time before all those sparks jumping around the inside of the distributor kill the cam and crank sensors in the base.
From that video there is no way the car can rev properly like that, it sounds like more of a bad knock than a backfire. From the video it sounds like you are not getting spark on all 6, possibly some cylinders are washing down with fuel which slows the motor down and then you get that sound in the video. It could also be an injector or something. you will have to try and pin point it a little more or give us some more info, keep us updated it doesn't sound like a leak to me anymore, cause right after start it idles down just fine, it just can't keep the rythym its either fuel or spark on this one.
*edit* just read you said you changed the cap. if you didn't change the rotor you should, you always replace those 2 together.
also the 12v fuel mod won't affect your idle, the fuel pressure regulator returns the excess fuel back to the tank. It may be noisier than stock but shouldn't change the way the motor runs under normal conditions.
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 278
Likes: 0
From: New York
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