MAP turbo kit idle issue
#1
Newbie
Thread Starter
MAP turbo kit idle issue
So I recently installed a MAP v-band turbo kit with a Precision 5858 ball bearing turbo. I also installed a walbro 400lph fuel pump and ID1300cc injectors. Stock block and stock cams, currently running on 93. The car went to get tuned but my tuner had to leave me with a conservative map because of what seems to be a misfire. Under load, there is no evidence of it, it's only having trouble at idle. It idles steady and every few seconds, the rpms dip a bit and I hear a small "puff" from the the exhaust like it stutters. It does this at somewhat random intervals and I can't figure out the cause, no engine codes. I boost leak checked it and that's clear, as well as replaced the spark plugs. So at this point, I'm thinking it's fuel system related, either bad fuel pressure or a clogged injector. Any thoughts on this? Any other things that could be causing this? Is it actually a misfire? Maybe too much injector? So many questions, would appreciate any input.
#2
EvoM Guru
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What do the AFR's do when it does this?
#4
Evolved Member
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If I were you I wouldn't run it until you figure out what it is. I blew my engine because of an injector related problem that gave symptoms very similar to yours. Can you pull the injectors to see if theres any clogs? Also when you installed the pump did you use corrugated tubing?
#5
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If I were you I wouldn't run it until you figure out what it is. I blew my engine because of an injector related problem that gave symptoms very similar to yours. Can you pull the injectors to see if theres any clogs? Also when you installed the pump did you use corrugated tubing?
#7
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#8
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I'll look for that. Just replaced the spark plugs, all were the same OEM gap. Should they be adjusted to a different gap than OEM?
#9
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Yup, did this along with the boost leak tests. Checked the manifold nuts and v band clamps for the turbo to manifold and downpipe to turbo. Let the car run and felt for any leaks, nothing.
#10
EvoM Guru
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Sparkplug gap should be .020". But that will effect WOT way before it effects idle.
#11
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WOT runs sooth, but understandably, my tuner was concerned about pushing the car with it misfiring at idle. If it were to start running lean and misfire on the dyno, it could've caused some damage. So unfortunately I'm stuck with a light tune and not driving the car until I can diagnose and fix the issue.
#12
EvoM Guru
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I suspect your misfire is being caused my something like bad idle settings. An ignition system related misfire, or even fuel system would only become worse with load. If AFR's are normal at idle, I would look into what the MAF is doing (log MAF Hz, make sure its smooth, and not jumping around), and if could also be one of the idle settings.
Who is the tuner? His response to the issue makes me think you need to find a new tuner.
Who is the tuner? His response to the issue makes me think you need to find a new tuner.
#13
Newbie
Thread Starter
I suspect your misfire is being caused my something like bad idle settings. An ignition system related misfire, or even fuel system would only become worse with load. If AFR's are normal at idle, I would look into what the MAF is doing (log MAF Hz, make sure its smooth, and not jumping around), and if could also be one of the idle settings.
Who is the tuner? His response to the issue makes me think you need to find a new tuner.
Who is the tuner? His response to the issue makes me think you need to find a new tuner.
#14
EvoM Guru
iTrader: (1)
Did you do a rewire when you installed in the walbro 400?
#15
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