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
Plugged fuel injector?
Bill in MD
'88 Alfa Milano Verde x 2
'77 Fiat Spider
'88 Alfa Milano Verde x 2
'77 Fiat Spider
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.
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.
1986-GTV6
1989-75 Twinspark very sadly sold-remarkable sedan !
2014 Audi Q5 3.0l TDI - torque MONSTER
1989-75 Twinspark very sadly sold-remarkable sedan !
2014 Audi Q5 3.0l TDI - torque MONSTER
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
Thanks, and stay tuned.
Bill in Maryland
Bill in MD
'88 Alfa Milano Verde x 2
'77 Fiat Spider
'88 Alfa Milano Verde x 2
'77 Fiat Spider
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.
1986-GTV6
1989-75 Twinspark very sadly sold-remarkable sedan !
2014 Audi Q5 3.0l TDI - torque MONSTER
1989-75 Twinspark very sadly sold-remarkable sedan !
2014 Audi Q5 3.0l TDI - torque MONSTER
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.
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.
Bill in MD
'88 Alfa Milano Verde x 2
'77 Fiat Spider
'88 Alfa Milano Verde x 2
'77 Fiat Spider