Can’t stop the smoke or knock

Hello all. So about a year ago I installed some injectors. I say injectors because they where not new injectors. They where pulled from a running engine and have been running great up until a few weeks ago. These are mileage unknown pulled from a running engine tested and cleaned injectors. And yes I know before it gets brought up and I get flamed.. Only new Bosch injectors are good and everything else is bad. I get that but that was not what I was wanting to spend on a 3000k mile truck I use to move equipment or bales once a month. So yes i took the less expensive route and it’s been running great until now. sounds like it has a cam. Real ruff loapy idle and heavy fuel smell.white smoke that’s thick. I thought one of my take out injectors went out. Ok for what they cost and what I got out of them it’s not a big deal. Pulled them all out had them tested. One came back way out of spec from the others. Sent it back to the company I bought them from they tested that one injector and said it was good. So I told them to ship me out another take out injector to replace that one. Got it put in and got the same problem still got white smoke, bad idle and what I assume is injector knock. Went injector by injector with rail cap and no matter what injector was capped the idle, knock or smoke never changed. I don’t have a gauge or anything to monitor rail pressure. But from what I’ve been reading on here low rail pressure would result in hard starting, correct ? You hit the key and it fires right up with the above listed symptoms. I’ve gone back and double triple checked injector torque, fuel tubes, lines etc etc. so other than injectors., that would fit the cause of these symptoms what else could have caused a sudden shift in running. I keep thinking injectors injectors injectors. The guys who tested them are a pretty respect business here and I wouldn’t think they would get bad results, but here again the people I bought them from said it was good. So I’m unsure what the standards for testing are at this point and who knows what on the side. I just keep thinking injectors. If the rail cap going one by one made no change it would have to be multiple injectors causing the issue correct ? Anything else I could be missing.. thanks yall

 

Pick up a couple more cap off tools. You can cap off three, but it is pretty hard on things. I would go every other cylinder on the firing order. We do it at school to show the students how the system can compensate for dead cylinders.

 

I thought about that. But That’s a lot of capping. And does not seem like it would work that well. You would need to cap off the bad injectors in a group to remove them from the equation right ? I’d have to just get lucky and by chance cap the correct ones. Even if I did every other I wouldn’t know if every other was bad or good because I’m testing three or two but the other two or thee not capped could be good or bad. Is my thinking right on that ? I was looking at some software that has the ability to a few tests. Like injector cut out. Since I’m not to familiar with diagnostics on this thing does the injector cut out test kill the signal to each injector solenoid as you go down the line testing. And if it does I’m assuming that injector is closed. Or does it command the injector to stay shut ? Could you do the same thing by removing the wires from each injector solenoid manually? But I’d still be in the same boat as rail capping multiple cylinders, just getting lucky on removing any correct combination of faulty injectors to stop the issue ?? If I haul it to a shop for diag I’m assuming they will be able to pin point it pretty fast with software ? I was hoping that it was just one injector since it was running good. I don’t know why one two or three would all decide to fail at once. I mean it could happen but I would think there would be some underlying cause that led up to it i would have noticed before it did the shake rattle and role number on me..

 

I thought about that also. I’m going to pull injectors out again and bore scope each cylinder and take a look see tonight.

 

Compression test while you are at it. Burned valve(s) would not generate blowby.

 

I didn’t have any blow before this happened it really just started the smoking and knocking rather quickly.
I ordered a compression tester on amazon just now. Do I just pull the fuel pumps relay out to keep from blowing fuel every where with the injectors out ?

 

I can try that. I still have not put the valve cover on. I didn’t want to button it all up until I knew it was running and I checked for leaks etc. I literally just put the injector in started it up and let it run for a few but was scared to let it run to long the way it sounded and the fact the issue did not go away with the out of spec injector replaced. then proceed to start capping off to try to isolate the issue.

 

Well i ran a compression test. # 1 cylinder had around 250 #3 was also around 250. All others where up around 350ish. Went ahead and pulled the head off to inspect the situation. That is one heavy heavy head. Got the head off expecting to find horrible things. Every piston look great. Every cylinder bore was clean with out scoring. I rotated each cylinder up and down to really inspect the bore. I can still see cross hatching on cylinder walls. I figured with the milage i had it was going to be carnage inside. Head looks great from a visual inspection i see no signs of valve damage or seating issues. I guess im going to pull the pan off and push those guys out and see whats going on. I was really surprised to see how clean the motor was. No real carbon build up and i didnt even have enough ridge on the cylinders to catch with my nail. I unsure why compression was so low in those 2 cylinders. I ran each cylinder twice to double check. With out any visual damage i was leaning towards valve but after pulling the valve out of the head on 1 and 3 to inspect they look fine. Mystery continues

 

Head gasket look ok?

 

Head gasket looks fine to.. no issues with it. I did notice that cylinder 1 and 3 have alot more piston movement inside the cylinder. If you bring each cylinder to the top and try to move the pistons side to side or front to back those two move around alot more inside the bore. Have not had a chance to get the pan off yet and go any further

 

I think im going to do an in frame and order new new injectors

 

It’s not easy to get the pan off in the truck, may as well pull it.

If you’re buying injectors and have the motor apart it’s a very good idea to get 03-04 pistons/injectors and a tune to go with it.

 

I can pull it also i just thought an in frame might be quicker. Looks like you got to pull the rad, intercooler, push aside the condenser and remove the radiator support. All very doable and probably not hard. I could change pistons ect but i really was trying to keep a budget. Ive been looking at some running pull outs with reasonable miles. Injectors, overhaul kit is getting just as close to what i can buy a take out for. Time wise a take out might be quicker. I have a 68gmc longhorn thats been aching for a Cummins swap. I just cant decide on what to do. Heck i cant even find an article on what injectors to buy. Everyone has horror stories it seems from no matter where they get them. alot of information to decipher both good and bad. This has been one of the best trucks ive ever bought. Since i drove it off the lot its really stuck with me. Hell its the only truck ive ever paid off and never traded in. Im torn on what to do. Thousands on a motor or just sell it as is.

 

How many miles and what shape is the truck in exactly? A 2WD is a total loss at this point and with injectors plus engine a 4X4 may be a total loss as well. Again how much is the truck worth and how much of the $15K engine and new injector cost can you cut corners on? You sure you got a bad engine?

BBi injectors have a reputation for being virgin new vs. "horror stories". Injectors are expensive and no shortage of "cheap" offered to help with the $pain$.