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post #1 of 5 (permalink) Old 01-12-2013, 11:28 AM Thread Starter
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lt1 help

new block,heads done ,but after testing the 2 rear cylenders on the passenger side arnt working.Used one of those test lights you plug into the injectors and nothing,unpluged the injectors while the motor was running and theres no change.followed the wires and cant find any breaks,HELP,HELP,HELP
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post #2 of 5 (permalink) Old 01-12-2013, 03:57 PM
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u checked with a noid light ? and what was results
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post #3 of 5 (permalink) Old 01-12-2013, 04:26 PM
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i feel your pain; wiring is a bitch

first thing is run the car and check for constant power to those injectors, with your test light grounded to the block (NOT the other injector wire). you should have 12 volts at the pink wire @ those injectors with ignition on.

see, the injector power system on your car has two runs of pink wire. that's why there's two injector fuses. i find it incredibly unlikely that both of them would lose power, since you are failing injectors 6 and 8. injectors 6 and 8 are on different power circuits.

but just check for peace of mind.

if you DO have power there (which im pretty damn sure you will), there are three possibilities:

damaged GROUND (actually signal) wire between injector and pcm (yellow/black and blue/white). the ecm grounds each injector to fire it. run the car and test light from battery + to those wires on the injector. don't use too big of a test light.

to test further, remove the RED connector from your ecm, then look at this:

grab a paper clip for the ecm plug, and check for continuity (use an ohm meter) @ the pins for #6 and #8 injectors back to the injector wires themselves. if you're confused about which pin is which, open the back of the connector carefully. there are numbers stamped in there for each pin.

inspect the pins themselves while you have the ecm connector off. they might have been pushed back into the plug somehow.

if that fails, you need to repair that wiring. de-pinning things from the ecm is stupid easy. remove the red part, pull up on the tab, pull the pin. if you need spare ecm pins, gm can sell them to you.

only other reason is the opti. it's possible but unlikely that damage or crud on the optical encoder wheel would screw with only those two cylinders. that would almost certianly throw a code, though...
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post #4 of 5 (permalink) Old 01-17-2013, 03:25 PM Thread Starter
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Stevo ,i did like u said with checking 4 constant power,its there,,,,the ground side is the same on all 8,WORKING.....STILL HAVING SAME PROBLEMS,I;M GONN PULL THE PLUGS AGANI AND B SURE THEY R GITTIN FIRE AND GET BACK TO YOU.....thanks
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post #5 of 5 (permalink) Old 01-17-2013, 05:25 PM Thread Starter
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STEVO,,Thanks alot ,i got under the car andswitched the 6 and 8 wires and BOOM she's runnin great now.....Lesson learned ,Dont trust a friend ...thanks for your help cause he got paid and waz to shitty of a person not only to do the job right but follow up on his on work..I WILL PASS IT ON TO ANYONE I HEAR HE IS DOING WORK FOR AND FUTURE WORK I HEAR HE WILL B DOING...this Forum is great ,hope i can help someone in the future with what i've learned from it
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