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New here again, have a 7.3 that won’t cooperate. About 8 months ago, I replaced the injector o-rings with what I didn’t know was a bad batch. Went on a 200 mile drive and when I got back it was running rough again and wouldn’t start the next morning.
it had pumped a lot of oil back through the fuel system into the tank. Bad O-rings, I sent the 8 injectors away to be rebuilt, now to cut a long story short, not it has lost a little power, surges at idle, sometimes so bad it stalls at a stop light and sometimes the sea light comes on, then very hard to start, but this only happens when it reaches operating temp.
Now it throws no codes, and I’ve cleaned out the fuel tank and screens, blown out the lines, changed the oil, swapped off a great running truck the cps, ipr, hpop, fuel bowl, fuel pressure is good hot or cold,
bled out the air 100 times.
ipr values and cps psi and volts are perfect while running except go up and down with the idle. Does not blow any smoke on start up hot or cold, no big clouds on wot while driving. Oil comes out the injector exhausts while idling the way they should.
I’m just about to pull the engine and dump it in a hole🤬.
any thoughts?
cheers
Ok thanks for the reply, stock injectors, no tunes, done about 80 ish miles since injectors.
yes eBay guy “rebuilt” so probably not done then.
but ran fine before the oring incident.
also changed map sensor and vacuum hose, accelerator peddle sensor, did the unplug cps thing etc.
What controls the idle on these trucks? Also if I knock up just off idle, soon as I let off it drops back down and stalls.
The question would be what was done or not done during your injector rebuild it seems. Maybe the injectors aren't injecting the proper amount of fuel at idle. Possibly one of the injectors aren't even idling.
Checking the harness for the IPR and the ICP for worn or questionable insulation, never hurts. I suggest unwrapping the pigtails back a few inches. I had a bad IPR wire that haunted me for a while because I didn't dig deep enough into the harness.
Sorry for the delay, here’s an update, I ran the engine until the surging or hunting for idle started and then unplugged the icp and it idled fine. Plugged it back in and the up and down started.
the icp works because it works on another truck and also it gives readings on the scanner.
at cold idle it shows around 630psi and ipr 12.5%
hot idle (bad) it’s between 490 and 580 ish...ipr between 977 and 11.72%
rpm fluctuates between 560 and 775.
Air in the system?
Sorry for the delay, here’s an update, I ran the engine until the surging or hunting for idle started and then unplugged the icp and it idled fine. Plugged it back in and the up and down started.
the icp works because it works on another truck and also it gives readings on the scanner.
at cold idle it shows around 630psi and ipr 12.5%
hot idle (bad) it’s between 490 and 580 ish...ipr between 977 and 11.72%
rpm fluctuates between 560 and 775.
Air in the system?
Sounds like it's definitely linked to the ICP or it's pigtail. If you're sure the sensor is good then replace the the pigtail. I suggest soldered connections with heat shrink.
Sounds like it's definitely linked to the ICP or it's pigtail. If you're sure the sensor is good then replace the the pigtail. I suggest soldered connections with heat shrink.
Changed pigtail, no different.
I didn’t think it would since it only does it when hot and starts like you’re flicking a switch.
Sound electrical I know but I’m not so sure now.
Ok. Next thing to check is your IPR. Is the nut on the back of it tight? If it is, then when the truck is warm and the surging is apparent, hold a can of computer duster spray upside down and spray the electromagnet. The idea is to cool it. See if that resolves the surging. If so, that magnet needs replacing.
Subscribing, I also have similar problems as you but mine aren't nearly as drastic. Being that is only happening when the truck is hot , that definitely sounds like your ipr. Aside from replacing the ipr, ftn has some good info on cooling down the ipr to see if the problem persists. There have been a couple other threads on fte in the past several months that had the same symptoms and the ipr was to blame. It's best to test the ipr first before spending the coin. Let us know what you find out, good luck
It seems the fellas have you on a path to success, but I wanted to share another thread with you by ArmyLifer that was dealing with a similar condition as you are.
If you skip toward the end of that thread, you will see where he replaced his IPR, even though he had recently replaced the o-rings and his problems went away. I am not saying this is for sure, 100% your issue, but signs are pointing toward the IPR. You may have some other underlying problems, but the corrective actions you have taken thus far with the ICP and the anomalies you have told us about while the ICP is plugged in or unplugged are leading you down a path.
If you have a multimeter you can test the coil on the IPR for resistance.
Performing this check will not tell you if the IPR is working mechanically, but it will allow you to check one more box as not the problem.
jstihl is dealing with a similar issue, but we are starting to think his issue is an electrical gremlin, although the jury is still out on that.
