Technical 1980 Main Four Fuel Injectors Not Firing On Computer

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Technical 1980 Main Four Fuel Injectors Not Firing On Computer

recycledjack

New member
Joined
Jul 18, 2012
Messages
5

Hi I’m a new member on the forum. I’ve had a 1980 fiat 124 spider for about 30years. It’s the car I plan to drivecross country in when I retire, but I’ve not yet retired. Its mostly been in storage in the last 30years and may have been driven a thousand miles. It ran well about two years ago but now willnot run continually. I’ve had experiencewith the injectors as I’ve owned VWs with L-Jetronic system before.

The engine will run forever at fast idle if the 5thinjector is connected to positive power.

The engine will also run on four or maybe less of the maininjectors if everything is hooked up (with or without the fifth injectorconnected as normal) and if the main injector ground wire is removed from thecomputer and ground out the four injectors going tick tick tick tick to theground. This completes the groundfunction of the computer and the car will run until you get tired of doing this.

I’ve opened up and cleaned off anything I could find in theECM, but I haven’t really done much more than this. I’m guessing the “relay” or whatever iswithin the computer that produces the intermitted grounding is notworking. I would appreciate any input soI can move onto the next step with blowing up the computer.

Thanks,

Jack Finn
 

argtv6

New member
Joined
Dec 11, 2010
Messages
2
Hi I’m a new member on the forum. I’ve had a 1980 fiat 124 spider for about 30years. It’s the car I plan to drivecross country in when I retire, but I’ve not yet retired. Its mostly been in storage in the last 30years and may have been driven a thousand miles. It ran well about two years ago but now willnot run continually. I’ve had experiencewith the injectors as I’ve owned VWs with L-Jetronic system before.

The engine will run forever at fast idle if the 5thinjector is connected to positive power.

The engine will also run on four or maybe less of the maininjectors if everything is hooked up (with or without the fifth injectorconnected as normal) and if the main injector ground wire is removed from thecomputer and ground out the four injectors going tick tick tick tick to theground. This completes the groundfunction of the computer and the car will run until you get tired of doing this.

I’ve opened up and cleaned off anything I could find in theECM, but I haven’t really done much more than this. I’m guessing the “relay” or whatever iswithin the computer that produces the intermitted grounding is notworking. I would appreciate any input soI can move onto the next step with blowing up the computer.

Thanks,

Jack Finn
Hi Jack,
I wonder if you had ever solved this problem?
I presently have a 124 at the garage that will only run on any combination of 3 cylinders. Once the remaining wire is connected it will not start and if done while the engine is running, it will turn off.
I have access to another L-Jetronic spider which runs perfectly with the problem car's ecu, relay set and air flow meter.
The resistance of all 4 injectors is the same and I've checked all the supplies and ground connections as well as most of the wiring.
Thanks
Ralph
 
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