Ok guys here goes im workin with a 95 f450 powerstroke and all of a sudden today it felt like i dropped 1 cylinder but just so you know what ive done in the past 6 weeks is replaced all 8 injectors with new alliant power ones replaced both vc gaskets and all 4 under vc gaskets and 2 connectors that were burnt.. now also ive determined that it is running on seven cylinders cause if you unplug both passenger side vc gaskets the engine will die shortly after but if you unplug the 2 on the drivers side the engine will run rough but never die so that tells me that the problem is obviously on the driver side..so i ohm checked the injectors just to make sure there were no issues under the vc and all of them read 3.4 ohms... and from all that i can see the wiring seems ok and now im stuck!!!!! so after all the obvious was checked the only other thing would be idm right????? i mean i thought after reading all you guys very helpful information that i could be a 7.3 diesel mechanic lol... anyway what am i missing what do ya'll suggest now???? thanks for all the help

 

I do not think it is your IDM....I would pull back some insulation on the VCH and check the wire a few inches back....I know injectors can stick open,not sure if they can stick closed though

 

ok one more thing i forgot to mention i took a 24v test light and checked the center pin on each of the 4 connectors and on the driver side rear it didnt like as bright or blink as fast as the other 3 did so does this mean anything to anyone and i did pull back quite bit on the wires but didnt find any broke wires yet...

 

Is ther excessive smoke? A huge loss in power?How does it rev up? I had an idm problem recently I'll let you know if it compares. I'll check back in later.good luck

 

I think the center pin is supposed to be ground. If you have an intermittent connection there it could be your problem. Look for a bent pin, broken or loose wire, etc. Does it run rougher with only the driver's side front unplugged vs the driver's side rear? If your ground is gone on that plug you could be losing both cylinders fed by that plug.

 

That is an interesting troubleshooting technique. Yes the center pins on the plugs are ground return to the injectors. Each plug runs 2 injectors. On each bank these 2 ground wires are tied together somewhere in the wiring harness. The diagram suggests down by the fuel pump. With the information you supplied I would use a volt ohm meter and on the drivers side measure the resistance between both center pins. It should be close to (0) ohms.

 

ok guys problem fixed thanks for all your input.. ended up being a blown injector o ring which i guess caused the injector to loosen up the bolt was finger loose when i pulled the cover.

 

Glad you got it fixed

 

Glad you got it! Thanks for posting your fix. Green beans sent

 

I'm not sure an oring will do that.
Most likely a copper washer that gets toasted will cause the injector to loosen, and usually because the injector wasn't installed correctly in the first place.
Did you remove the injector to confirm it's an oring problem? If you did, was it the bottm (orange) oring? And if it was I'll bet that copper washer is gone.
It's VERY important that copper washer didn't go. Much more serious problems if it did...

 

ok jim you are right but initially i thought s was an idm or a wiring issue but after swapping idms and finding no nurnt wires i started it again and this time it was knocking and smoking so bad i couldnt see a building just 50ft away and i aleady knew smething was wrong on the driver side so i pulled the valve cover and discovered the injector loose so i pulled it and just like you said it was the orange oring split and swelled up so i replaced all the orings on that injector but like you said the copper washer was gone not on the injector or in the cylinder so now since you knew all that what does that mean?? i just thought i may have forgot to put it on whe i installed them 2 mos ago so i put a new one in put it ack together and runs perfect no miss no smoke and no knock....should i worry if that washer is in the motor or did it just vanish???

 

If you didn't find remains of the washer, then either you didn't put it in to begin with or it melted away. It's not the washer that's the big issue.

The problem is that the cylinder's combustion blew away that bottom oring and fuel was getting dumped into the cylinder all the time. Notice the entire bottom of the injector was pitch black from this. There's so much heat from all this fuel and improper combustion that it stresses the nozzle, to the point that it will most likely fail and send shrapnel into the motor. I've seen this over and over. Sometimes the small chunk gets pushed out the valve, past the turbo and all is good. Sometimes it gets beat into the piston and combined with the increased heat when it breaks blows a hole in the piston. Time then for a total motor strip down and major overhaul.

How long did it run like that with gobs of smoke and knocking?

Best thing to do in this situation is to replace the nozzle so you have no worries about it whatsoever. I can put a DIY Kit together if you want to tackle this one task yourself, I can replace the nozzle for you if you send that injector in, or you can take it to a local injector shop to have the one nozzle replaced.
Whatever you choose, since you purchased all new injectors, you really should have that nozzle replaced so you know they are all good.

 

it only carried on that way for about 25 min or so before I tore it down should I be worried

 

Were you driving it like that for 25 minutes? Was it just idleing?

It's going to have to be your call what you want to do with it. It's near impossible to say that 'You're good' or that 'The nozzle is shot.'
I tend to want to take action to take care of things to prevent major motor repair, but it's got to be your call. If it's a brand new injector/nozzle, and it only did it for a short while, not being driven, you might be OK. But don't take my word on it. And I'm not trying to sell you anything, just trying to prevent a lot more work. Like I said, you could also go to a local injector shop for the work, it's just something I'd consider doing.
Good luck.