O4 379 MBN 24234 C15 Cat Poor fuel and power

Sounds like you have a failed headgasket at number four cylinder. If the injector did not repair the white smoke on start up and the valve set is ok, remove all the injectors and use a rubber tip air blower and pressureize number four cylinder, you may find it will blow out number five hole. Very common problem on 6nz and mbn.

 

We did that already. The cylinder holds pressure. I think its something electronical since it ran perfect right after i put that injector in. Is that a possibility? It is a blue smoke. The truck doesnt use any water and it has good power

 

I agree. W9 475acert,13spd,3:36 rears and 6.5 with no mods yet pulling a van. So to say u cant get fuel mileage with a hood just dont what they are talking about.

 

Wish I could PM. Anyway, since you have the no-go gauge for the overhead and can do your own work, swap #3 and #4 and do another cancel test. My bet is the new injector is junk (one out of ten ReMans fail OEM Cat specs, not to mention tip drip, etc., and the come back rate for all general Lucas types [basically all big truck that isn't Piezo] is one in fourty). See if the miss follows...

 

I already swapped them too. And its still number four that is missing. I did the bottle test on it also so i dont believe it is the head gasket

 

It's not a head gasket... Have you watched everything move and checked running clearances down to Jake pistons and pins? I find electronic hard to swallow if it ran good for ten minutes before pukin again. I spose you ohmed out the wires to the ECM too, so if it popped a switch in the ECM it prolly won't show, unless someone knows a way to read command + pulse, which I don't think even the new ones show anyway. So swapping ECM's from a different truck (of the same arrangement) would show that for a "bench" test.

 

Have you done a solenoid test with Cat ET? does it pass and can you hear the solenoind click? If the ecm swap does not repair the miss, It you will have to look closer at the headgasket. The engine does not have to build pressure to have the fire ring failed. The newer cylinder heads have cut outs between the cylinders, the fire ring fails and the compression in the cylinder pushes up in to the cut out space. This lowers the compression in that cylinder. Could be an upper ring broken, lowers compression also.

 

Some more info would be good, are you positive its blue smoke? blue smoke is oil smoke usually. has it had any other work recently? how may miles on it?
I assume when you say you did a cutout test you mean you cut out cyinder 4 and could not hear the engine note change as Cat ET will not do an automated cutout test for you with the engine below 69 degrees C. Beware of this method as injector quality has been a bit of a problem with Cat lately, often you can get a rough idle and a miss on a cylinder even with a new injector because that injector is weaker than the others but not actually faulty (according to Cat, not to me). Another way to test the injector is to cut out the other five and see if the engine will run on one alone (if it wont do this at idle on any cylinder bump the rpm up untill it will), an injector that is weak and not firing with the others at idle will pick up when its loaded up. BTW dont try increaseing rpm will the engine is only running on one, very bad for engine.
If it will run on all the other cylinders individually but not on number 4, assuming your sure that injector is firing (you said no miss under load, runs fine when warm, etc). then you have a compression issue with cylinder 4. however this should give white smoke not blue, which is why this doesn't make sense, no electrical fault I can think of will cause blue smoke either.
Blue smoke may be from worn rings and liners.

 

Thought I might elborate on Cat injector quality issues, not sure if you guys already knew about this but for those who dont....
For about the last 18 months when you fitted a set of reman cat injector in a C15 (10R0957) usually the engine will miss on at least one cylinder at idle (not joking thats how many bad ones I've seen), under load the engines fine. they found that their delivery valve springs, the one in the tip of the injector, were faulty causing some injectors to have a higher than desired pop off pressure. This basically means that at idle when the engine is trying inject the minimum amout of fuel the solenoid was not being turned on long enough for the pressure inside the injector to overcome the delivery valve spring pressure, therefore no injection and a misfire. Cat now knows about the fault and have updated the injectors, a 10R0957 is updated to 10R8501.

 

I bought the truck on 2-16-09. It now has 681,000 miles on it. It ran fine when i bought it. But once it went on its first trip it started missing. The thing i dont understand is why it ran perfect for 5 minuets after i put that new injector in. Its like the computer had sensed i put a different injector in after i shut the engine off. The smoke is like the smoke from a old 92 series detroit. Or a truck that has leaky injectors but never clears up till it gets warm. I was reading about a 11 digit trim code on here. What is that exactly?