Flooding out

[Mikephenix]

Throwing my two cents in. This sounds like a stuck injector. When the symptoms arise, take a test light connected to battery positive. With a t-pin, one by one, backprobe the injector control wires. Touch the t-pin with your incandescent test light. If one lights, you've found your dead short. This eliminates the guessing game and proves once and for all you have a short. Another way of conducting the same test if you don't have a test light, would be to unplug each pigtail with the key on. Touch both female pins with a DVM set to volts DC. If you read 12 volts on any pigtail, that pigtail has a short on the control wire.

Any other ideas short of yanking the whole harness out?

Was it acting up as you were testing it? The only way to have fuel pouring out of the tailpipe is a stuck injector or injectors.

No they were consistent and all read the same... I've heard flat spots on the cam will do this as well, any thoughts?

 

[ItchyDong]

I don’t see how your Jeep would run fine sometimes with flat spots on the cam. Did you wiggle the piss out of the harness while doing it? You’re checking for an intermittent short. You have to simulate vibration while doing it. This is why I like the test light method. You’ll be able to see the light flicker out of the corner of your eye without having to stay fixed on the meter.

If I were there, we’d hook up the o scope and look at injector wave forms one by one. This is 100% what needs to be done. But most people don’t have a scope in the box.

 

[Wranglerfix]

We are now rebuilding harnesses…that’s how bad the issues are.

 

[mrblaine]

Was it acting up as you were testing it? The only way to have fuel pouring out of the tailpipe is a stuck injector or injectors.

Any time we run into an issue like this, we come at it from the direction of what we would do it we wanted to make something happen. In this case, if we have known good injectors and we wanted to dump some fuel out the tail pipe, what would we do.

We know a whole bunch of what it isn't. I'm struggling to come up with a what it is.

 

[Mikephenix]

I don’t see how your Jeep would run fine sometimes with flat spots on the cam. Did you wiggle the piss out of the harness while doing it? You’re checking for an intermittent short. You have to simulate vibration while doing it. This is why I like the test light method. You’ll be able to see the light flicker out of the corner of your eye without having to stay fixed on the meter.

If I were there, we’d hook up the o scope and look at injector wave forms one by one. This is 100% what needs to be done. But most people don’t have a scope in the box.

Looks like I'm going to take it to a shop then thanks

 

[ItchyDong]

Looks like I'm going to take it to a shop then thanks

Let us know what they find. Make sure to take it to a true diagnostician. Not someone who's going to throw more parts at it. Fuel delivery is a simple circuit. Either your PCM is commanding injectors to stay on for long periods of time (which is BS, plus you've thrown a few PCM's at it with the same results), your injectors are sticking open (highly unlikely because the problem existed before and after new injectors), or the injector control wire is shorted to ground (very likely.) To diagnose this, they need to troubleshoot this WHILE IT'S ACTING UP. This could easily be caught in the act with a current ramp reading with an oscope. But again, only when it's acting up.

If you wanted to be a redneck about it, you could cut the control wires one by one at the injector pigtails and somewhere at the close to the PCM and splice in or overlay all new control wires.

 

[Mikephenix]

Let us know what they find. Make sure to take it to a true diagnostician. Not someone who's going to throw more parts at it. Fuel delivery is a simple circuit. Either your PCM is commanding injectors to stay on for long periods of time (which is BS, plus you've thrown a few PCM's at it with the same results), your injectors are sticking open (highly unlikely because the problem existed before and after new injectors), or the injector control wire is shorted to ground (very likely.) To diagnose this, they need to troubleshoot this WHILE IT'S ACTING UP. This could easily be caught in the act with a current ramp reading with an oscope. But again, only when it's acting up.

If you wanted to be a redneck about it, you could cut the control wires one by one at the injector pigtails and somewhere at the close to the PCM and splice in or overlay all new control wires.

I will thanks! Do you know of a good mechanic in Arizona?

 

[ItchyDong]

I don't, sir. I'm over in Bama.

 

[Mikephenix]

So after another month and a half at a shop we finally found the problem. No oscop could find a problem. New opda and all factory sensors replaced again still didn't fix it.... Bad fuel simply drained the tank and added new fuel 30 minutes of run time and poof problem solved. Hope this helps someone!

 

[Old_Crow]

So after another month and a half at a shop we finally found the problem. No oscop could find a problem. New opda and all factory sensors replaced again still didn't fix it.... Bad fuel simply drained the tank and added new fuel 30 minutes of run time and poof problem solved. Hope this helps someone!

I just went through this with my Jeep. I had a 5 gallon can of what I thought was good gas hanging around. I dumped it in the tank and the Jeep, which had been running fine to that point, started running like crap within a minute. Fortunately, I realized what I'd done and went straight for the drop the tank, clean it, flush the lines and fresh gas. Back to normal now.

 

[SkylinesSuck]

So after another month and a half at a shop we finally found the problem. No oscop could find a problem. New opda and all factory sensors replaced again still didn't fix it.... Bad fuel simply drained the tank and added new fuel 30 minutes of run time and poof problem solved. Hope this helps someone!

Bad gas was making it intermittently run pig rich at idle? Color me skeptical.

 

[Mikephenix]

Bad gas was making it intermittently run pig rich at idle? Color me skeptical.

Yes. The 02s were saying it was running lean. So computer compensated as soon as I touch the throttle to add more fuel which would flood it out and puke gas out the tail pipe.

 

[SkylinesSuck]

Okay, I hope it stays fixed for ya

 

[Jerry Bransford]

Yes. The 02s were saying it was running lean. So computer compensated as soon as I touch the throttle to add more fuel which would flood it out and puke gas out the tail pipe.

Color me skeptical too. I'd believe a bad O2 sensor.