Number 3 plug wet

[eric819]

Running through a problem where my number 3 plug is wet.... and by wet i mean drenched with gas....

All of the other plugs look great. Is so wet that its coming out the manifold, around the turbo, excessive smoking out the exhaust but gets worse when i rev it....

I have tried to swap plugs around, plug wires around, 1&4 coil with 2&3 between. Pulled the injectors out, did a home made clean and put them back in, in different spots.

I did a leak down kit and all cylinders are about the same.... did valve seals to rule that out.... Fuel pressure is right....

Save me from turning the car into a big bon fire.... lol

 

[G]

Injector is probably toast.

 

[eric819]

I have checked the injectors and they are opening and are not leaking when the car is powered off.

resistance is as it should, and they spray is decent. I moved the injectors out when i cleaned them and stayed on that one cylinder.

What would cause an injector to stay open like the ECU keeping it open?

 

[MellowVR4]

Is the switch hooked up on the throttle body? its just a 1 terminal switch..

 

[EfiniX]

Quoting G:
Injector is probably toast.



You are on borrowed time if this is the case. I got my Galant with a failed injector that the PO had driven on for lord knows how long. I wasn't getting a good mist on injection and as a result, a had my #3 run lean and run hot. it ended up fusing the plug to the head and cooking the piston and cylinder.

1 rebuilt motor later....

 

[eric819]

Single wire on throttle body is hooked up.

Car was not like that when i got it. It has not been driven like this, started after letting it sit over the winter.

Just trying to fix it before it causes any serious engine damage

 

[eric819]

looks like the ecu may of had a crappy repair job.... thoughts?

 

[toybreaker]

A problem like this can be very frustrating to troubleshoot.

A calm, methodical approach will give the best results.



It could be a mechanical problem (stuck injector), or it could also be an electrical issue.

You've made some good tests, so now it's time to get more serious.

Lets start with the easy stuff and work towards the more complicated.


An injector can become internally contmintaed with varnish from sitting, and then when it's commanded to open, that varnish can lock the pintle in an open position. This condition will allow fuel to flow anytime the system is pressurised
I don;t believe this is your issue, as a mechanically stuck injector will transfer the problem to the new hole when you swap it's location

An injector can also get a shorted coil, and it will "fire" anytime power is applied.
I don;t believe this is your issue either, as it would also move to a new hole when you "doos~ey do" the injectors to a new hole.
Checking the resistance of the injectors would tell this tale.

Unplugging the injector resistor pack on the firewall would eliminate this possibility altogether


So, now it's time to dive a little deeper.

Power is on the injector 24/7, and the injector is "fired" by switching the ground side of th circuit on and off in the ecu.
A problem in the ecu driver circuit could cause your issue, (but I'd hate to fire an ecu at it and find the problem still exists.)

Breaking the system down into it'a individual components would be a good next step.


If you unplug the injector resistor on the firewall, and then all the injectors, and then unplug the ecu, the injector wiring harness runs will now be isolated.


Then, check the integrity of the harness

should be nothing, nada, nobody home from pin to pin in the injector housing, and there should also be nothing from either leg to ground.
finding any continuity during this phase means the harness has a pinch, or is chafed and allowing a bare wire to find ground.

 

[eric819]

Im going to run through those to make sure that none of those problems are here. Thanks for the feedback

In further investigation of the ECU, someone had done a terrible repair job. There are shorts between some of the capacitors, and an electrical engineer I work with is not confident that it could be repaired. So i got a nice looking one off ebay... lol

 

[eric819]

Swapped out the ECU today with one off a 1G. and the issue went away. Running alot smoother then it ever did since i bought it. seems to be mostly all fixed now

thanks for the help