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Thread: MAF cause engine to not start?
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08-29-2015 #1
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MAF cause engine to not start?
Will my missing MAF sensor cause ls2 to not start? I have good grounds, fuel pump cycles, throttle moves with the pedal. I have no spark at the plugs.
Should the MIL light light up when the key is put to ignition for a sec or two ?
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08-29-2015 #2
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Typically, the engine will start and idle without the MAF Sensor, but will stumble when the throttle is opened. Of you have no spark, I'd look at the cam or crank sensors first. If the ECM doesn't have a cam position signal it won't fire the coils. The MIL should come on when the key is turned on for bulb check.
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08-29-2015 #3
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Also make sure that the ECU is getting power from a source that is hot during cranking.
Andrew1970 GTO Version 3.0
1967 Cougar build
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Dr. EFI
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"You were the gun, your voice was the trigger, your bravery was the barrel, your eyes were the bullets." ~ Her
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09-01-2015 #4
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Thanks, how can I tell if I'm getting a cam and crank signal? Can I check voltage somewhere?
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09-01-2015 #5
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When I worked at the dealership, we just plugged in the scan tool, and looked to see if there was an rpm signal when cranking. Do you have access to a scan tool?
Clint
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09-01-2015 #6
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I can probably get one. Looking at it deeper it looks like when I was trying to get oil pressure in the motor I didn't have enough grounds hooked up and the starter used the harness main ground through the computer. My main ground wire at the computer (bk-red wire) looks like it got hot. Hoping I didn't fry the ECU! Anyway to check?
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09-01-2015 #7
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Again, scanner. If it commucates with the ECU, then it's not fried.
Originally Posted by jlay
1970 GTO Version 3.0
1967 Cougar build
GM High-Tech Performance feature
My YouTube Channel Please Subscribe!
Instagram @projectgattago
Dr. EFI
I deliver what EFI promises.
Remote Holley EFI tuning.
Please get in touch if I can be of service.
"You were the gun, your voice was the trigger, your bravery was the barrel, your eyes were the bullets." ~ Her
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09-04-2015 #8
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Didn't get a scanner yet but, I checked and I am getting a crank signal back to the ECM. It is ranging ~8-9 volts. Only weird thing that is occurring now is the fuel pump is running constantly. I am getting ~6.5 volts from the ECM to the fuel pump relay? The other day when I was messing with it I was getting a MIL light, now nothing.
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