1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

injectors not pulsing

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Old Jun 19, 2007 | 04:53 PM
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bugman1973's Avatar
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From: clarksville tn
injectors not pulsing

We went in to this swap blind my son and i are spent on the injectior ar still not working. we swaped 12a-13b 1985. if any can help us please do so far we have done a lot of stuff but no fuel. the fuel is in the rail if appears that all the wireing is hooked up. 12 v all over the place when my son gets off work i will have him do pics of the ecu and engine area. at this point just to hear it start wound be great. thanks to all
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Old Jun 19, 2007 | 05:15 PM
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Blake's Avatar
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Originally Posted by bugman1973
We went in to this swap blind my son and i are spent on the injectior ar still not working. we swaped 12a-13b 1985. if any can help us please do so far we have done a lot of stuff but no fuel. the fuel is in the rail if appears that all the wireing is hooked up. 12 v all over the place when my son gets off work i will have him do pics of the ecu and engine area. at this point just to hear it start wound be great. thanks to all
Do you have Factory Service Manual? If not, I highly recommend one. Anyway, the first thing to check is fuel pressure to the injectors. Presuming it is good, then you need to check +12v to the injectors. If that is good, then it is a question of the ECU not sending a signal (injectors fire when the ECU grounds the injector). In that case, the first thing I'd look for is no coil signal (-), telling the ECU that the engine is turning over. Many other possibilities, but that's where I would start.
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Old Jun 19, 2007 | 08:27 PM
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From: Peoria, IL
If the 85 injectors work like the second gen (which I would guess they do), you should have 12V to one side of each injector. Then you will get a pulse on the other side (as the ecu opens the circuit to ground). If you are not seeing pulses, the injectors can't work. If they are not working, check the signal from the coil, check the grounds at the ecu, you should have zero V.

Check the factory manual for the pin numbers at the ecu to tell you which ones are the ground. Find out where the ground wire(s) are for the fuel injection system and make sure they are connected well.
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