MAF erratic
Thread Starter
Teching In
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MAF erratic I was wondering if someone could help me with a tune no issue that I have. I went yesterday to have a tune put on my 69 Camaro. I put an LS2 out of a 05 corvette with a Tremec 6 speed. The only mods are LT headers 3” exhaust, CAI, and a Fast 92mm intake everything else is stock. The car ran just fine until I installed the Fast intake and now I was getting lean bank 1 and 2 codes which I get considering the tune was stock. Well I took it to get it tuned and the tuner says at WOT the MAF is stable but at deceleration and idle the MAF goes erratic and acts like it’s at WOT and dumps fuel in causing the car to run rough and want to die. Replaced the MAF and still the same. Ground? AIT? Vacuum leak? I did install a oil/ air separator with braided lines (for looks) could that be my vacuum leak? Any help would be great
Thread Starter
Teching In
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My CAI starts in the corner of the passe
nger front fender. My filter is connected right o my MAF then the CAI tube goes right to my TB. There is one port in the middle of the tube that connects to my passenger cable cover . I removed the little rubber vacuum line that goes from the manifold to the valley cover and used hard line to -8 AN fitting so I can run braided line to my air/oil separator. Would a vacuum leak there effect my MAF and cause it to go erratic? Not sure how because it is after the MAF so how can it have any effect on the MAF? Or can it?
nger front fender. My filter is connected right o my MAF then the CAI tube goes right to my TB. There is one port in the middle of the tube that connects to my passenger cable cover . I removed the little rubber vacuum line that goes from the manifold to the valley cover and used hard line to -8 AN fitting so I can run braided line to my air/oil separator. Would a vacuum leak there effect my MAF and cause it to go erratic? Not sure how because it is after the MAF so how can it have any effect on the MAF? Or can it?
TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
Has the filter always been directly connected to the MAF? Usually that's not a good way to do it. The MAF should have a straight path a few inches before AND after the MAF for proper function.
Thread Starter
Teching In
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Yeah that’s how it’s always been but I built the rest of the air box and cover for the CAI when I put the manifold on. When I made the CAI cover to keep the hot engine air out I cut a 4 inch hole in the bottom of the inner fender well and installed a tube to get good cold air in from the lower bumper area when driving. I don’t know if that would cause it but I wouldn’t think it would
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
Yeah come to think of it, some MAF's are installed right off the filter box. As long as it's calibrated that way it's OK.
But to repeat my previous question- do you know your MAF is good? Have you/can you test(ed) it?
But to repeat my previous question- do you know your MAF is good? Have you/can you test(ed) it?
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Thread Starter
Teching In
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Erratic It’s a DBW I will have to get the graph from the tuner but he showed me the MAF value would show even across the spectrum when it was ok then it would jump high then drop then go high again like it was seeing WOT and it would surge and want to die because the PCM would throw fuel to the engine because it thinks we are at WOT. Please understand I am just getting into this EFI stuff so I am learning, this is way different than a Holley Dominator and a distributor. What I am being told is what I am asking you guys because they pulled my car off the dyno and said bring it back when it’s fixed.
Thread Starter
Teching In
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Erratic I ask him if he can tune it in SD and he said yes but it takes a lot longer and cost more.
Hey I have a question for you LS gurus could the MAF wiring cause the MAF to be erratic if it is lying on the lower radiator hose? The signal is by resistace I think right so if the wires are getting hot could it cause an erratic signal to the PCM?
Hey I have a question for you LS gurus could the MAF wiring cause the MAF to be erratic if it is lying on the lower radiator hose? The signal is by resistace I think right so if the wires are getting hot could it cause an erratic signal to the PCM?
Thread Starter
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My MAF sensor wiring was too long and lying on the radiator hose. I believe the MAF works of resistance so if the wiring is lying on the lower radiator hose after it gets hot could it make the MAF signal look erratic?
Launching!
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it shouldn't cost more for the "calibration" alone. only extra cost may be addition of independent IAT sensor if required.
SD means only the VE table is tuned. if the factory cal is edited in its dynamic format then both the MAF and VE need to be calibrated meaning more time.
SD means only the VE table is tuned. if the factory cal is edited in its dynamic format then both the MAF and VE need to be calibrated meaning more time.