Fuel Injector not firing - I think

[shopartsnw]

One of the local club members just bought a stock 91+. The car was running great until he pulled the #4 plug wire to check for oil. Lots of oil in the plug wells. After he checked the car started missing and running rough. We thought it was from the oil contamination, so we did a full upper 60k. Everything looks good now, but the car still has a loss of power and feels like it is only running on 5 cylinders.

I took my mechanics stethescope and listened to each injector. I can hear nice clicking from each injector except #6. #6 is quiet. I figured it was a dead/clogged injector. We swapped the injector, and I still cannot hear any clicking of the injector. I now think it has a wiring issue. The injector does have power to it (red wire). I am trying to troubleshoot the injector wiring for the other wire, and I am a bit stumped.

Any suggestions?

Thanks

 

[yamahaSHO]

I'd try a new injector harness and work from there. Also, another way to check the injectors is to ground each injector (one at a time with the intake off) and watch for flow (non-red wire). You'll also have to jump the pump to stay on which is easily done up front with the diagnostic plugs.

 

[shopartsnw]

I will give the injector test a try.

Thanks for the tip.

- Mike

 

[dpsutphin]

If you haven't already done this, follow the wiring from the injector as far as you can looking for even the slightest break in the insualtion. Look especially close where the wires touch anything metal, like against the intake. Use a good quality electrical tape to cover anthing suspicious.

I had almost the same exact problem, and that is all it turned out to be, one very small bare spot that was shorting out, not allowing the injector to fire.

 

[AREA 91]

I know you said you did the upper 60K, but did you replace the plug wires? If not, that's your problem. If you did, than I think your on the right path with chasing the injector. I Always prefer the K.I.S.S. method.
KEEP IT SIMPLE STUPID!