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Discussion Starter · #1 ·
Cruising speed-
Check engine light comes on and engine backfires several times and sometimes dies completely, others times it sputters and backfires and then smooths out (light goes out)- tried reading malfunction codes with scanner and it would not connect- sometimes the engine will restart immediately and other times it will take a while- once restarted it will run fine for anywhere from a minute to several hours- seems to run longer at higher speeds as opposed to stop and go-
fuel pressure was fine during all of this-
appears to be something in the timing circuit, as if it loses where #1 is-
Thanks, Dave

1986 GN
 

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9 Posts
Discussion Starter · #4 ·
Scan tool would not read ecm codes- shorted out the aldl connector and read blink code- reads code 41, cam sensor malfunction or ecm malfunction-
ordered new ecm and will replace cam sensor, check wiring-

Thanks All
Dave
 

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KILRV6, Chris Fasulo
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54 Posts
If the cam sensor was bad the car will not start. Once the engine is running you can unplug the cam sensor and the engine will stay running but will switch the injectors to bath fire instead of sequential. However if you shut the engine off and do not plug the sensor back in it will not restart. You will get a check engine light if you unplug it. Also it is not just a matter of replacing it if it is bad. It needs to set up correctly or the engine will not start. It can also be set up 180 degrees out of phase. Clear the codes and reread them after the check engine light comes on. If the car is starting the sensor is not bad. As was mentioned it could be a bad MAF. With the car idling rap on the MAF with a screwdriver handle. If the engine stumbles and dies it is a bad MAF. If not I think you are correct that the ECM is bad. I went through the same issues many years ago.
 

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If the cam sensor was bad the car will not start. Once the engine is running you can unplug the cam sensor and the engine will stay running but will switch the injectors to bath fire instead of sequential. However if you shut the engine off and do not plug the sensor back in it will not restart. You will get a check engine light if you unplug it. Also it is not just a matter of replacing it if it is bad. It needs to set up correctly or the engine will not start. It can also be set up 180 degrees out of phase. Clear the codes and reread them after the check engine light comes on. If the car is starting the sensor is not bad. As was mentioned it could be a bad MAF. With the car idling rap on the MAF with a screwdriver handle. If the engine stumbles and dies it is a bad MAF. If not I think you are correct that the ECM is bad. I went through the same issues many years ago.
You can try tapping on the MAF but I've heard that is not the best test. You could tap on it and the car still runs the same....but the MAF is still bad. If possible, try swapping it with a known good one.
 
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