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markmurfie
Well-Known Member
Have you tried adding a bottle of iso-heet and running the fuel tank very low before refilling?
Red bottle, not the yellow.
Red bottle, not the yellow.
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fast306stang
Well-Known Member
I know it's been 2 years but did this problem just start suddenly or did it start out slowly and get worse? Any chance it's got anything to do with the tune? I'm just spitballing, I know nothing about tunes but just want to throw out some ideas...
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Torinate
Well-Known Member
- Thread starter
- #20
Yea, it was a gradual thing. At first I had the off idle thing every now and again but it has progressed to over half the time. Quite frustrating.
It could be the tune. Not ruling anything out. I can't seem to see anything in the logs and i've had all the smart guys in the forum have a look as well. It's very difficult to see anything that's going wrong. A lot of what i'm doing to rule things out is also so if I go back to the tuner to have a look I don't waste anyone's time to do these things then. I will have some concrete information that will hopefully help them help me.
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ZXMustang
Well-Known Member
Are you seeing the misfires in a log or feeling them and the engine stumbling?? I see cylinder misfires all the time randomly on all cylinders while logging my 22GT. Runs perfectly and makes great power. But you will see misfires in the log at various times. You always will, but you shouldnt feel those.
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Torinate
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- Thread starter
- #24
I didn't think they looked bad. No octane boost in those miles. I did use Royal Purple injector cleaner as well as Techron in those miles. No hard pulls - babied the car really. They're actually quite tan coloured up close - but not orange as MMT would make them. Could be from the cleaners though.
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Torinate
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- Thread starter
- #26
The misfires are occurring 99% at idle. In all of the logs i've taken, i've only seen one where the misfire occurred under load. They do not occur during warm up either. Once the engine is at temp and goes into closed loop, I will see the misfires. It's not that the car is running poorly other than when I step on the gas and there is that lag hesitation before anything happens. I press the gas maybe 1/2 pedal and instead of jumping forward, I have the delayed reaction before it decides to go. I can hear the idle misfire pops through the exhaust randomly and they completely coincide with the mode 6 date registering a misfire. On occasion with throttle closed closed on deceleration I will get a sort of backfire from the exhaust. It will pop louder ONCE. Not a constant but it will backfire and then continue on as normal. Not a typical backfire "bang", but sort of a halfway one with respect to noise volume. Quite audible but not gun shot loud. Again, nothing registering a CEL and i'm not sure i've ever caught it on a log. This does not occur often, but it does occur.
It's frustrating as I know there is an issue so I don't want to beat on it in case of hurting it when I know there's an issue. But, there's nothing I can see that pinpoints what the issue is.
There's the 2 separate issues. One is the idle hesitation and the 2nd is the idle misfires. I'm making the assumption the misfires and the backfire are the same issue. I'm hoping if I can solve one of them it may point me to the issue with the other.
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Torinate
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- Thread starter
- #27
Yes. I see the black colouring, but it's not actually soot. It doesn't wipe away and there's nothing on the rag when wiping. The porcelain is a light tan colour. Maybe it's the pic. I'll post up my old plugs for comparison. They had about 8-9k miles. These are what I replaced when initially in an attempt to correct the misfires.
Cory S
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I’m thinking tune related. PCM initiates closed loop between 6 and 90 seconds depending on upstream O2 and calculated ECT temp.
So it sounds like you are only seeing/feeling/hearing these misfire pops as the Air/fuel mixture settles at Stoich. During open loop warmup (6-90 seconds) the fuel mixture is enriched and you say it’s much smoother running with no popping or misfires right?
So it sounds like you are only seeing/feeling/hearing these misfire pops as the Air/fuel mixture settles at Stoich. During open loop warmup (6-90 seconds) the fuel mixture is enriched and you say it’s much smoother running with no popping or misfires right?
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Torinate
Well-Known Member
- Thread starter
- #30
Correct.
Nothing during open loop warm up. That is one of my plans to get with the tuner and go over it. I know they will likely say check this or check that, do a compression test etc… doing / done that so I’m prepared. I have no qualms for paying for a tune again, as long as that’s the fix.
I truly wish I could tune myself, but these are a little beyond my ability to turn carburetor screws or play with a few different settings on my extender.
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