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bmacf · Post by **bmacf** » Sun Jun 18, 2006 3:28 pm

Hey everyone, I think I have a plugged fuel injector or a dead injector. A couple weeks ago the engine started misfiring. I thought it was spark, but all the plugs seem to be firing as determined by a timing light. I've replaced the plugs, thinking that they were fouled. After a trip of driving around, all the plugs but one have carbon on them. The #1 plug looks like I just pulled it out of the box. Oh, one other thing, I have one of those laser infrared temperature thingies - indeed #1 exhaust header is a tepid 100 deg. F while all the others are much hotter.

So, I think the #1 injector is plugged or dead. I put a long screwdriver on it (kinda tough to do) and I hear ticking, but that could be the valves for all I know. Are there any other things I can do to figure out what's going on with #1 without ripping out the injectors?

Thanks,
Bill

Murray · Post by **Murray** » Sun Jun 18, 2006 4:07 pm

Bill there are three things you can try.
First disconnect the electrical plug to the injector while the engine is running.If there is a change in engine speed and smoothness then this indicates that the injector was in fact doing something.
Secondly you can attach a test "Noid" to the injector wiring to visually ascertain if the injector is receiving a signal to fire from the ECU.You can make one of these with an led and a resistor.There are instructions on how to do this in the Cardisc tech bulletin section,unfortunately I don't have access to mine so I can't give you the value for the resistor.
Thirdly (or maybe firstly) the injector grounds must be good in order for them to work.The grounds are grouped together on one of the bolts at the rear of the passenger-side valve cover.

bmacf · Post by **bmacf** » Sun Jun 18, 2006 4:35 pm

Ooh, all good ideas. And I forgot that I bought a set of noid lights a while back. Thanks for the suggestions.

Bill in Maryland

sh0rtlife · Post by **sh0rtlife** » Sun Jun 18, 2006 8:10 pm

you can also swap the injector to another location to verify that its not a problem in the rail

bmacf · Post by **bmacf** » Mon Jun 19, 2006 4:26 pm

Thanks for the reminder on the noid lights. I plugged it into the #1 connector and it didn't flash. I plugged it into #4 and it flashed. At the #1 connector, the common lead had a low impedance connection to ground, so it's time to trace the signal wire back to the ECU.

Thanks, and stay tuned.
Bill in Maryland

Murray · Post by **Murray** » Mon Jun 19, 2006 4:36 pm

Bill step #1 is to closely inspect the terminals inside the Bosch connector on the injector.The female terminals sometimes work loose inside the connector body and fail to make contact with the male injector terminal.

bmacf · Post by **bmacf** » Mon Jun 19, 2006 5:22 pm

Hmm, I think I'm ok there from what I saw, but very good point. The noid light has really long leads that penetrate inside there.

Actually, you know what, I get a solid 12V, which means it's connected to something. I wish I had an oscilloscope to see what signal it's actually getting on #1.

OK, I'll check the connector again.

Thanks,
Bill in Maryland.

Plugged fuel injector?