High reference voltage to sensors
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High reference voltage to sensors
Car engine is stalling. The MAP sensor is receiving 5 volt with switch on and engine off, but with engine on this voltage increases to 6.5 volt.This causes high voltage from signal wire of MAP sensor to ECM, causing increased fuel supply to manifold. This causes engine to stall.
Joined: Dec 2004
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From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Joined: Dec 2004
Posts: 16,771
Likes: 1,001
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: High reference voltage to sensors
I’m assuming you have a 730 ecm and might have a code 33.
there is a step showing 1v or less if higher possible bad ecm.
http://www.chevythunder.com/map_code_33.htm
there is a step showing 1v or less if higher possible bad ecm.
http://www.chevythunder.com/map_code_33.htm
Thread Starter
Junior Member
Joined: Sep 2018
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Re: High reference voltage to sensors
I think there is problem with the alternator rectfier, which may be sending some AC currrent when the alternator is running. This may be the cause of ECM erratic respone in the form of higher fluctuating reference volatge in the MAP sensor when the engine is running. But when engine is off the reference voltage comes back to normal 5 volt range. Pl see if this can also be one possibility...
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Mar 31, 2001 08:32 AM