1G ECU Problems

[Laserfreak]

Hi,just sign up and I was wondering if anybody would know were the sensor ground is located in the ecu for a 1991, Plymouth Laser,have two ecu’s one when I plug in with key on,didn’t light up,so I figure bad sensor ground and other ecu plug in,get constant light cel on ,not turning off,means code stored,but need to buy code reader,

 

[shinzon]

Hi,just sign up and I was wondering if anybody would know were the sensor ground is located in the ecu for a 1991, Plymouth Laser,have two ecu’s one when I plug in with key on,didn’t light up,so I figure bad sensor ground and other ecu plug in,get constant light cel on ,not turning off,means code stored,but need to buy code reader,

What didn't light up with the first ECU? The check engine light when you first turned the car on? What sensor ground? Do you mean the ECU ground? Grounds are listed in the 90-91 electrical manual:

https://www.scribd.com/doc/15602873/90-91el

I'm not as familiar with 1gs as I am with 2gs, but if I'm not mistaken, ground #7 on page 8-5 is the main ECU ground.

You don't need a code scanner to read codes on a 1g, just a cheap analog volt meter:

Jason...here's a quick guide to a simple test and link to code list:
http://vfaq.com/mods/wayback/BradBauer/electrical/code.html

An awesome amount of FAQ answered:
http://vfaq.com/index-main.html

 

[steve]

More likely capacitor leakage problems with both ECU's, have you opened them up yet? If so take pictures and post them.

Here's a easy way to read the codes or check for the ECU heartbeat. http://www.dsmtuners.com/threads/1g-code-reader-cel-code-reader.319844

1G ECU pinout http://www.dsmlink.com/images/forums/1GECUPinout.pdf

Shows that the sensor ground is pin 17 and the ECU ground is pins 101 and 106.

1G ECU Wiring diagram (MPI Circuit) http://www.dsmlink.com/images/forums/1GECUMFI.pdf
Shows that the ECU is grounded to the chassis at ground #7 which is on the right hand center console support passenger side.

 

[boostjunkie92]

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