I remembered that it followed firing order, but it was not shutting off the injectors. It made me wonder if there was an electrical problem. He also told me that for some reason he unplugged the cp3 and the engine raced toward redline and he shut it off. I've pulled the regulator and it just goes to max rail and gets noisy. Never heard of it acting like a runaway. I used the DVT to command 26k and it just made powerstroke noise last night, lol. Maybe the 12mm exergy acts differently unplugged? I wasn't about to dick with it. haha
buddy's LMM is hurt
- Thread starter N2BRK
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can you flash a stock tune back in? you are correct in that when you pull the reg, it should only get noisy. if its racing off, for some reason pulse width is increasing as rail pressure increases OR you have a few wires shorting to power on the injector/s
If you have one or more leaking injectors the upping the rail pressure will make it worse. It may be leaking enough at that pressure to ramp the rpms up.
Turning them off may not stop a leaking injector
What about pulling all of the glow plugs disabling the injectors and cranking it over and see if you get any diesel coming out?
Turning them off may not stop a leaking injector
What about pulling all of the glow plugs disabling the injectors and cranking it over and see if you get any diesel coming out?
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As they say "sh*t can happen". If they were replaced I would agree that it is unlikely. With just doing work to the truck and the problem not going away with new injectors BUT going away when all power/grounds are removed from the injector I am thinking that there are some wiring issues going on and something got pinched where it shouldn't.
If I recall correctly doesn't the ECM alternate ground to the injector to fire it on LMM? If so, if the ground side of the harness got damaged it would cause the injector to stay wide open when plugged in and also explain why as pressure goes up RPM starts to climb since it is at 100% open and the added pressure increases injected fuel quantity. I'm spit-balling here, it makes sense in my mind but that's making an assumption that ground is switched to inject fuel.
That is how they work, yes. And shorting the injector ground could cause weird things to happen.
You should be able to measure it with an ohm meter. It is also possible the solenoid shorted to the injector body. Had that happen several times on my LB7
Is it possible that you got the pigtails got swapped with another injector?
You should be able to measure it with an ohm meter. It is also possible the solenoid shorted to the injector body. Had that happen several times on my LB7
Is it possible that you got the pigtails got swapped with another injector?
So heres what id do.
Dont start the thing, let it sit for some time, dont even do a compression test yet. unplug each injector pigtail so it wont start, pull #5 glow plug and wad up a paper towel. Have your buddy hold the towel close to the hole (dont cover it unless you wanna watch him jump :roflmao
and crank it over. see what gets all over the towel (smell it). id be curious if its coolant or fuel. Then crank the thing over a few times to see if what is being sprayed out continues or stops.
From there, id do your compression test on all 8 and record each. i dont feel a leak down will give you much info here unless you want to be sure its not a hung valve. Then id start looking at electrical. ohm testing, voltage testing wires, etc. You may be shorting out each new injector as 2004lb7 suggested can happen so ohm it as well.
that should give you a heck of a start and atleast some process of elimination from what we have all talked about here.
Dont start the thing, let it sit for some time, dont even do a compression test yet. unplug each injector pigtail so it wont start, pull #5 glow plug and wad up a paper towel. Have your buddy hold the towel close to the hole (dont cover it unless you wanna watch him jump :roflmao
and crank it over. see what gets all over the towel (smell it). id be curious if its coolant or fuel. Then crank the thing over a few times to see if what is being sprayed out continues or stops. From there, id do your compression test on all 8 and record each. i dont feel a leak down will give you much info here unless you want to be sure its not a hung valve. Then id start looking at electrical. ohm testing, voltage testing wires, etc. You may be shorting out each new injector as 2004lb7 suggested can happen so ohm it as well.
that should give you a heck of a start and atleast some process of elimination from what we have all talked about here.
Bent pushrod should definitely hurt compression. It caused 0 compression on my lb7 and a +15 balance rate from my injector. It definitely sounds electrical to me since it hasn’t changed with multiple injectors and the other strange stuff going on. James nailed it on the head with his recommendation of diagnosis
I can remember which it was on mine. Either way, wouldnt it being hung open hurt compression regardless? Mine was completely hung open. Not sure what happened.
Edit: that was a legit question. If I’m wrong please correct me.
Also mmmmmmm ziti
I think you’re thinking a bent valve. If a pushrod was bent or broken the valve would stay closed.
This is what happened on my truck push rod was bent to the point the valves were hung open all the time
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I do Mr. Mom stuff well. Lol
