I have an 1991 7.3. I just put new injectors in it, and a new return line kit from a good diesel injection shop. I am also running 50% used oil. After I had completed installing injectors and return line kit, I washed the engine out. I cleaned up my shop, and came back to start it about 30 mins after washing engine. The engine had already been fired since installing the injectors. The glow plugs were all immersed in water so I didn't use them, and the truck didn't start. I went and grabbed a can of brake clean and sprayed a bit in the intake. I cranked it over and it started up and ran at 650 rpm with a horrible loud knocking noise from 1 or 2 cylinders. The knocking noise lasted for 2-3 seconds. Now I have a vibration at 2000 rpms and above, could have I bent a rod or broke the crank? I didnt use the glows to start the engine since the last time I had washed my engine out, all my glow plugs shorted out and blew out, due to being immersed in water. Thanks.
Engine issues
- Thread starter BigDiesel
- Start date
the glow plugs can handle being immersed in water.
how much water did you pour down the "v" of the motor?
have you checked your oil yet?
was the motor warm when you hit it with water?
more info please.
how much water did you pour down the "v" of the motor?
have you checked your oil yet?
was the motor warm when you hit it with water?
more info please.
You either have a bad injector, or you sucked in water and bent a rod. A compression test will tell you which one it is. That and/or pop test the injectors. You shouldn't have worried about not using the glow plugs. It is impossible for the water to cause an electrical short that would damage the plugs. If you think something like this happened in the past, it is more likely a fluke.
icanfixall
Official GMM hand model
When you "washed the engine" did you cover the intake or just wash off the air filter lid along with the motor? The top of the air filter lid has a factory rubber sealer gasket under the wing nut. If yours is gone so is your motor. Water will leak into the intake past the wing nut and cause a hydrolock. Sorry for some bad news... If all this was covered then you may just have some dirt messing up an injector. It doesn't take much dirt to ruin an injector. Just how dirty was the top of the motor before you worked on it and why didn't you clean it "before" working on it....
I had the air hat and filter installed on the engine when I washed it. The engine was slightly warm, and had come off high idle. The engine was clean before I started to work on it but I had spilled some diesel in the valley so I had to clean it out. I had cranked the motor before adding brake clean and it didn't turn hard.
kas83
Full Access Member
The horrible knocking noise is from the brake clean burning uncontrollably, similar to ether. That, in itself, could've busted a pre-cup, broken a ring land in the piston, or I've even heard of glowplugs snapping because of the violent explosion.
How long did you let it crank before deciding to aid it in starting? These things will fire after about 20 seconds of cranking at about 50* temp without glowplugs, or at least all of mine have.
How long did you let it crank before deciding to aid it in starting? These things will fire after about 20 seconds of cranking at about 50* temp without glowplugs, or at least all of mine have.
I had cranked it for about 10 seconds with no fire, so I tried brake clean and it fired quickly. I had about 50% used oil in the fuel so its harder to start then with 100% diesel. I had started it with another brand of brake clean in the summer with no big knock noises but this brand knocked like I had used ether.
punkmechanic
diesel tech
I would crack the lines one at a time with it running to isolate the cylinder that is knocking, then pull that injector and check the pattern and pressure. if the pattern is good then check compression and pull another injector to see its pressure. much more than 50 psi (agnem? correct me if that number is off) difference and you could have issues with uneven idle/vibration.
punk
punk
Brianedwardss
Registered User
Well I've been thru this before, go recheck for a leaking return line or leaking copper washer. Seems like everytime I replace the injectors on my idi's, I've got wierd vibrations or leaks for a week before things start working the way they're supposed to. I'm hesitant to say hydrolock/water damage if you indeed cranked it for ten seconds before adding brake clean to the intake. How 'bad' is the vibration..?
Well I just did a compression test and all cylinders were between 400-450 except for the pass rear cylinder. On that cylinder the gauge goes up to 250 then to 0 over and over again. I also did crack the injection lines and that cylinder did cause a skip when I cracked it.
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