Need Fuel Help

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frozenbob - 06 Mar 2006 14:52 GMT

Hi Guys
Have an 86 4 cyl with 5 speed. Just did some engine work and now have a
fuel problem. Fuel is getting up to the injector but injector is not
openning. Not sure if it is electrical or not. Is 12V just fed to the
injector solenoid? What other sensors or switches have to be made
before the injector will get power. How can I jump them out to confirm
operation of the injector.
Thanks in advance for your help
Bob

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Phil Randolph - 06 Mar 2006 15:46 GMT

I know it's very basic but did you check the infector fuse? I'm not sure
on the 4 cyl but on the 6's 12V+ is always to the injector and the ECM
provides the ground when it receives pulses from the ignition.

> Hi Guys
> Have an 86 4 cyl with 5 speed. Just did some engine work and now have a
[quoted text clipped - 5 lines]
> Thanks in advance for your help
> Bob

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R W Hughes - 06 Mar 2006 16:05 GMT

> Hi Guys
> Have an 86 4 cyl with 5 speed. Just did some engine work and now have a
[quoted text clipped - 5 lines]
> Thanks in advance for your help
> Bob

The injector is fed 12v and grounded by the ecm. But, the ecm will not
fire the injector until it sees spark signals from the ignition system.
Be sure you have this, does your tach read 300-400rpm while cranking?
0rpm is a sure indicator of ignition failure.

The injector is fed 12v through a fuse by the red (at the injector) wire
when the ignition is on. The ecm provides a ground to turn the injector
on through the blue wire. You should be able to see the 12v on the red
wire and a lower pulsating voltage on the blue wire while cranking if
you do have spark.

Signature

Robert W. Hughes (Bob)
BackYard Engineering
29:40.237N, 95:28.726W or perhaps 30:55.265N, 95:20.590W
Houston, Texas "The city with too much Oxygen"
rwhughe@oplink.net

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