im stumped on this one boys

lincolnlocker

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so i am trying to help a guy back home and when i came home this weekend i went to his house cuz everything that he was explaining to me over the phone wasnt adding up and all the basics where checked over.. this is one of 3 7.3s that i haven't been able to diagnose and help fix when putting my scanner on it out of i dont know how many over the years so it has me a little stressed out. prolly more then it should be.. lol...

history on truck
2000 sclb zf6 4x4. 186k on truck. he just had motor rebuilt and installed brand new alliant injectors(supposedly not reman but new) put 2500 miles on it and says it ran like a top then all of the sudden it started running like chit and would barley move under its own power. also has new 38r and a few sensors. prolly not motorcraft for most of them but that doesn't matter at this point i dont think anyway.. it does have a superchips flashpaq installed since it is a zf6 he didnt care what tuning he went with but just wanted a mild bump in power.

it will fog raw fuel out of the exhaust and if you try to rev it up it just flat out gets nastier and will fill a small shop with white raw fuel smoke in a few seconds when trying to rev it up while parked.. it will only rev to 1500rpm before it stumbles and misses and gets worse.. it wont pull its own ass up a small grade or driveway and has backfired extremely bad a time or two and continues to smoke worse while trying to drive..

i have ran every test and watched every parameter on every sensor and it all checks out. i Uninstalled the tuner and it actually made it worse and wouldn't even let it rev past idle without spitting and stumbling and fogging more smoke.

the only thing that i found is that icp will only climp to 1500-1600psi while trying to rev it up.. that is the only thing off.. but ipr dc is only at 7-8% at idle and 500ish icp and 11-15% at 1500psi while trying to rev it up.. so it really isnt that far off..

pulse width at idle while in stock mode was 3.6-3.8 millsec. im not sure but i thought that would be lower since some tuning is maxed out at just above 3 millsec except when its a cold start trying to warm the engine.. but even up to temp, it stayed there.. i ended up putting the tuning back in it and pw dropped to 3-3.2 ms and it did calm a little bit of the smoke and allowed it to rev to 1500rpm. (wouldn't do that in stock tune at all) ut still fogged


it flat out acts like it is over fueling or isnt getting any air at all.. i unplugged ebps and the rod didnt move so it souldnt be stuck closed. i even put a bar in there to move the rod and it still had spring pressure holding it open so that shouldnt be stuck..

im out of ideas...

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lincolnlocker

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wonder if throttle position sensor would cause this.. not sure if i can pick that up with my scanner but also, wouldn't there be a code for that?

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79jasper

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I think you can view throttle percentage or volts.
With these (besides faulty wiring, or idm) wouldn't the cps be the only thing that can cause a misfire?

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ghohouston

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I wonder if some trash got in the ipr? Doesn't look like a hpo leak by the duty cycle numbers. I also wonder with the hazing fuel smoke about the copper crush washers, and injectors being properly seated. Lots of possibilities.
 

superpsd

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Try unplugging one injector at a time to see if there is a change. I had one injector blowing white clouds. I feared crack nozzle but instead it turned out the core injector I used had good armature clearance but had been shimmed for poppet wear. They had not however shimmed the solenoid. There were marks from armature to solenoid contact. The upper seat I figured was not being sealed correctly. I swapped the body and was up and running again. Buzz test had passed in this situation. You need to figure out which bank is smoking. I was in my situation able to identify by firing off a few times with Spyder removed and found smoke rising out a intake plenum once shut down. I unplugged one at a time until smoke stopped and then realized that it was not likely a cracked nozzle or unseated copper washer.
 
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ja_cain

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Try and use an ir thermometer on the manifold to figure out which bank/cylinder is causing the raw fuel issue and then go from there. An ir camera would be killer for pinpointing things like this.

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heavydoc

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Ya what they said above a temp gun shooting the exhaust manifold close the head will show which are your problem areas, it will show abnormally cooler temps than the rest.

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DEEZUZ

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i def agree on maybe a compression washer is toast from not proper sealing..


take the fuel filter out, fill the housing, them turn engine over and watch for compression coming back. you may need to depress the valve in stand tube.

If this is the case, it may hydrolock so be careful
 

lincolnlocker

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I think you can view throttle percentage or volts.
With these (besides faulty wiring, or idm) wouldn't the cps be the only thing that can cause a misfire?

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3 different cps's and all read the same and pass cct. other then number 3 which is the normal for the recall style cps and number 8 due to being the LL injector.

I wonder if some trash got in the ipr? Doesn't look like a hpo leak by the duty cycle numbers. I also wonder with the hazing fuel smoke about the copper crush washers, and injectors being properly seated. Lots of possibilities.

this thing purrs like a kitten at idle and up to 1500rpm when the performance tune is in it. he had someone else scan it and said one of the cylinders failed which i think was number 3 so he pulled that bank and took them back to the place ge got them from and they said that they all checked out fine. no cut orings and no washer issues..

Try unplugging one injector at a time to see if there is a change. I had one injector blowing white clouds. I feared crack nozzle but instead it turned out the core injector I used had good armature clearance but had been shimmed for poppet wear. They had not however shimmed the solenoid. There were marks from armature to solenoid contact. The upper seat I figured was not being sealed correctly. I swapped the body and was up and running again. Buzz test had passed in this situation. You need to figure out which bank is smoking. I was in my situation able to identify by firing off a few times with Spyder removed and found smoke rising out a intake plenum once shut down. I unplugged one at a time until smoke stopped and then realized that it was not likely a cracked nozzle or unseated copper washer.

passes buzz test with authority like way loud and crisp, passes cct, passes visual with valve covers off watching each spout, i can monitor rotational velocity and the only ones that are at all off slightly are 3 and 8 due to what i said above. you give it an ever so slighty rch of throttle, and it is even across the board.

Try and use an ir thermometer on the manifold to figure out which bank/cylinder is causing the raw fuel issue and then go from there. An ir camera would be killer for pinpointing things like this.

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if everything i mentioned above is spot on, how would one cylinder not act up and be noticed on my scanner? it is a smooth running engine till it gets that throttle input...

i def agree on maybe a compression washer is toast from not proper sealing..


take the fuel filter out, fill the housing, them turn engine over and watch for compression coming back. you may need to depress the valve in stand tube.

If this is the case, it may hydrolock so be careful

gutted the stand pipe when i had him change the filter..

this truck starts amazing like there isnt a dam thing wrong, then within seconds, starts hazing like its trying to warm in the winter.. but all sensors are reading correctly.. so i dont see how its thinking its -20° outside..

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co04cobra

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Didn't read through every response, but I'd pull all 8 injectors back out. What is fuel psi at idle and under load?
 

redneck1

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Agree with everything so far, good advice. Another thing is your fuel tank and pickup tube, have you checked it? Something could be in the tank that sloshes and partially plugs the pickup. Get rid of the duck bill of you take out the sender.

Does he run good quality fuel? Water in injectors never helps either. Definitely an interesting one.

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lincolnlocker

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Didn't read through every response, but I'd pull all 8 injectors back out. What is fuel psi at idle and under load?
why take them out? 60psi and 60psi
Agree with everything so far, good advice. Another thing is your fuel tank and pickup tube, have you checked it? Something could be in the tank that sloshes and partially plugs the pickup. Get rid of the duck bill of you take out the sender.

Does he run good quality fuel? Water in injectors never helps either. Definitely an interesting one.

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fuel pressure is fine.
Find out what the pulse width is on a good running truck

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no doubt. i didnt have time to check my 01 as im heading back to new york now..

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co04cobra

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Pull them back out bc a copper washer failure or not completly seated is the most likely area to have a raw fuel problem. That and all the nozzles should be cleaned and inspected throughly.

While you are there might as well run a base compression test also. A valve problem can also have some of the symptoms you describe.
 

lincolnlocker

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Pull them back out bc a copper washer failure or not completly seated is the most likely area to have a raw fuel problem. That and all the nozzles should be cleaned and inspected throughly.

While you are there might as well run a base compression test also. A valve problem can also have some of the symptoms you describe.
all brand new and even pulled the passenger bank and took them back to the place he got them for inspection and put new orings on them.. but again, why would it pass all tests unless every single injector was leaking evenly? cct and rotational velocity pass... barely a whisp of smoke comes out of oil fill cap from fresh rebuild and i mean barely.. have to look close and put a shop towel over it to see anything..

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redneck1

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How's the intake sound? Any weird popping through the intake? Co04cobra is on it with the valve issue. Bent pushrod, valve not seating, loose rocker arm, lifter failure, you'll get enough air to idle certain rpm, but with rpm it starts acting up. Pull the injectors, do a compression test, if good, send in the injectors. Could be an internal oring. Sounds like you're down the rabbit hole anyways..

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79jasper

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On another forum, a guy posted about similar issues.
So far he's found at least one broken push rod.

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mandkole

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its hard to see the command for 3.5ms of fuel at idle as a valve train issue. Fuel pressure is a possibility-- pressure in the bowl, but not at the injector? I'd look at sensors with parameters way out of range, a PCM that's gone sideways, a chip/programmer issue, etc. It appears to be temp or fluid heat related.. has it been on AE yet?
 

lincolnlocker

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How's the intake sound? Any weird popping through the intake? Co04cobra is on it with the valve issue. Bent pushrod, valve not seating, loose rocker arm, lifter failure, you'll get enough air to idle certain rpm, but with rpm it starts acting up. Pull the injectors, do a compression test, if good, send in the injectors. Could be an internal oring. Sounds like you're down the rabbit hole anyways..

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nothing bent. idles smooth as glass if one was bemt that bad it would show up on cct or rotational velocity..
On another forum, a guy posted about similar issues.
So far he's found at least one broken push rod.

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i have bent 8 pushrods in my dually. this is no where near anything like those have been.. and again, that would show up on tests..
its hard to see the command for 3.5ms of fuel at idle as a valve train issue. Fuel pressure is a possibility-- pressure in the bowl, but not at the injector? I'd look at sensors with parameters way out of range, a PCM that's gone sideways, a chip/programmer issue, etc. It appears to be temp or fluid heat related.. has it been on AE yet?
my op explains that i have watched and looked at every sensor and that with the tuner on it, it actually runs better.. lol. no idea why but it does. has les pw at idle bit still at 3-3.2ms. i have an otc genesis scanner and can monitor everything ae can.

im leaning against pcm..

again, it ran like a top for 2500 miles after a fresh rebuild then all of a sudden started acting up..

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lincolnlocker

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i gotta get his code for the pcm and im hoping someone on here might have one cuz that is about all he can do at this point..

the way it was acting is spot on with the cps but that checks out. even put in one of my motorcraft cps's to verify cuz he didnt know what one was in it. it was a big head like the black original but it wasnt black so i was certian it was a dime store cps. both read the same..

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