Ignition problem on 1991 beretta

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moulte
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Ignition problem on 1991 beretta

Postby moulte » Sun Mar 01, 2015 10:21 am

Hello everyone !

I'm an happy owner of a 1991 chevy beretta 2,3L GTZ manual transmission.
Since one month my engine to start it's cranking but doesn't start, i checked my spark plugs,my coils, and my crankshaft sensor.

I've finally checked supply voltage on the ignition module and i read only 2,2 volt when the key switch is on.
According to my haynes wirediagram the ecm supplies the 12V to the ignition module do you think it's him who has a failure or is there something else i'm missing ?

Thanks for help !



SuperLbody
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Re: Ignition problem on 1991 beretta

Postby SuperLbody » Mon Mar 02, 2015 12:21 am

If it's only getting 2.2 volts, than yes it's the ignition module. Replace with an AC Delco unit, not cheap crap and you'll be fine.



moulte
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Re: Ignition problem on 1991 beretta

Postby moulte » Mon Mar 02, 2015 2:44 am

Thanks for the reply.

Actually i was thinking in replacing the ECM, because i get the 2.2V when the plug is diconnected.

the only diagnotic code i get is "12 No distributor reference pulse (diagnostic test active)"



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Rettax3
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Re: Ignition problem on 1991 beretta

Postby Rettax3 » Thu Mar 05, 2015 11:15 pm

I have a Haynes around here someplace too, but it should be showing the same thing as my Chilton's manual. The ECM does NOT supply the ignition module with power -that should come from fuse #1, which ALSO supplies voltage to the ECM. So, they are on the same circuit, but the power does not come FROM the ECM. Check that fuse, and the supply voltage through that. No reason yet to suspect the ECM... No reason yet to suspect the ICM either, just because it isn't working with only 2,2 volts -it shouldn't be able to run on that anyway. Good luck, keep us updated, and welcome to the site! Where are you from?


1989 Super Charged 3800 Series II (First)Six-Speed Conversion GTU
1990 Turbo 3.4 Five-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 Five-Speed Indy GTi (Rebuild Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 3400 Top-End Auto OD Z-26

SuperLbody
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Re: Ignition problem on 1991 beretta

Postby SuperLbody » Fri Mar 06, 2015 11:15 am

moulte wrote:Thanks for the reply.

Actually i was thinking in replacing the ECM, because i get the 2.2V when the plug is diconnected.

the only diagnotic code i get is "12 No distributor reference pulse (diagnostic test active)"


Ahhhh, now the picture is clearer. That would mean your ICM isn't getting a signal to fire properly. That would indicate your crankshaft position sensor isn't working or the reluctor wheel is messed up. I know you mentioned looking at the crank sensor but I would start there again by testing the continuity and resistance of the sensor. Than move on to the reluctor wheel to see if it's damaged.



moulte
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Re: Ignition problem on 1991 beretta

Postby moulte » Wed Mar 11, 2015 2:55 pm

I'm from France :)

Thanks for the information about the supply voltage of ICM, you're right, my reading of the diagram was bad. However, my 15A fuse is good.
I don't understand how can it be possible that my ECM receive 12V (i havn't checked but other system works great) and my ICM receive 2.2V if they are on the same wire ?

I've checked the AC output voltage from crankshaft sensor when cranking and it' seems good. I'll check for it resistance also, thanks for the advice.

Next step is trying to shunt the 12V directly to the ICM supply pin and pray...



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Rettax3
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Re: Ignition problem on 1991 beretta

Postby Rettax3 » Sat Mar 28, 2015 1:06 pm

If the ECM is getting 12 volts from fuse #1, but the ICM on the same circuit is getting 2 volts, probably the wiring is damaged. I would shunt 12v directly to ICM too (fused though). Good luck!


1989 Super Charged 3800 Series II (First)Six-Speed Conversion GTU
1990 Turbo 3.4 Five-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 Five-Speed Indy GTi (Rebuild Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 3400 Top-End Auto OD Z-26


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