If You Had the Choice - New Nozzles or New Injectors?

[retmil46]

I'm beginning to suspect that the persistent "WHACK-WHACK-WHACK" (like someone is hitting the side of the engine with a ball peen hammer) at idle and under 1500 rpm when moving, is injector nailing. That, and the way the beast now constantly misfires when started cold iron, from the time the glow plugs cut out until the engine is warmed up.

I stopped by O'Reillys on Saturday, picked up a filter and Mobil 1 5W40 synthetic, to change at the first opportunity, in an effort to rule out lifter noise. I'm going to wait until after this effort to make a decision on the injectors.

The nozzles appear to be Bosch remans, installed by the PO. A five part P/N on the side, and below that "REMAN FOR MB". The upper and lower parts of the injectors look to be original, quite well oxidized (ie, rust).

If it comes down to pulling the injectors, and you had the cash and the choice, which would be the preferred route -

1 - A new set of Bosio nozzles from DG, having the present injectors rebuilt, pop tested, and balanced.

2 - A new set of complete injectors, such as from Colorado Biodiesel, using new Bosch nozzles

[Hit Man X]

Current Bosch nozzles are garbage as I understand. Go with what works.

You're getting rebuilt in either case...

[dieseldiehard]

Have you checked the delivery valve seals (on the IP)? They tend to create nailing at idle where the rubber o rings are leaking. Its a lot cheaper fix than cleaning and calibrating the nozzles. The torque sequence is a bit odd but other than that and the fact that you need to remove the injector lines to get at them.
I would suspect that first then have the injectors pop tested if the noise persists.

[sixto]

Have you isolated the noise to an injector by loosening each injector line with the engine idling?

Have you discounted a worn serpentine belt shock? When the Heim ends get loose the shock can make scary noises.

Sixto
93 300SD

[retmil46]

Originally Posted by dieseldiehard

Have you checked the delivery valve seals (on the IP)? They tend to create nailing at idle where the rubber o rings are leaking. Its a lot cheaper fix than cleaning and calibrating the nozzles. The torque sequence is a bit odd but other than that and the fact that you need to remove the injector lines to get at them.
I would suspect that first then have the injectors pop tested if the noise persists.

Replaced the o-rings and copper seals 2K miles ago, due to fuel leak from #1 and #2 delivery valves. Checked here for info and have a copy of the FSM on the computer, used the torque/loosen/torque/loosen/torque to higher value procedure. Left the hard lines loose at the injectors, and cranked the engine over a few seconds at a time until I had fuel coming out at all injectors, then torqued the hard lines to the FSM value. All hard lines have new OEM line clips or are rubber hose/tystrapped to the brackets. No evidence of leakage at the IP or at the injectors.

[retmil46]

Originally Posted by sixto

Have you isolated the noise to an injector by loosening each injector line with the engine idling?

Have you discounted a worn serpentine belt shock? When the Heim ends get loose the shock can make scary noises.

Haven't had the time to do that yet. I've used a NAPA stethoscope and haven't been able to isolate anything by that method. If I have time this Sunday (my one day off this weekend) I'm going to try that method, and also changing out the 15W40 dino oil for Mobil 1 5W40 synthetic in an attempt to rule out lifter noise.

Haven't ruled out the belt shock, or any other possible causes yet. Even though I have the funds available to change out the injectors, I want to rule out all the simple fixes first. Besides changing the engine oil over to synthetic, I have a spare Permacool 2 micron fuel filter/water sep setup that I'm rigging up on the beast, to rule out water/junk in the fuel, also IF it comes down to pulling the injectors to keep from trashing the new nozzles/injectors with the same junk. On the '05 Jeep diesel, I ended up with 2 clogged fuel filters in the first 6 months due to the crappy fuel they have locally. Added one of the Permacool filters to it, drain it down about once a month, and always end up getting water and chunkies, even from the high volume full fledged truck stops.

The "WHACK" noise is loud enough that it echoes off the trees along the driveway, can be easily heard even with the windows rolled up, and have had people that have been next to me in traffic or in the parking lot at work comment about how loud/obnoxious it sounds.

One thing to note - the noise is quite distinct when the hood is up with it idling, and you're standing directly BEHIND the car.

[winmutt]

What happened here?

[derherr65]

Maybe someone WHACKED him?

[WINGAS]

Well then, he wouldnt be typing would he!?

I was quoted $75/ea for NEW injectors from the dealer. I have a good diesel pro here ( who specialty is farm machinery) who is rebuilding them. I got the nozzles from MBz, will pick them up tomorrow.

Had one where the pintel was sticking out, and another that didn't test well. so 2 of 6 were bad. Same symptoms, the ball peen hammer in the side of the block deal. Car ran surprising well at speed, but same cold start noise you have.

Bosio nozzles dont really impress me, I went with stock. My tech will find any bad nozzles if MBz sells me one.

If you have a good diesel tech, have them rebuiold them. If not, injectors at $75/ea isnt so bad. In my calculus, I DON'T ASSUME new parts are 100% , so I figured I wanted them "wet tested" before they went back in the motor anyway. So I chose the rebuilding route.

[winmutt]

75 is fantastic for new injectors. I finally scored down at the pull a part and I have 5 soaking in mozola right now. I dont have the parts I need to pop test yet so I am going to gamble and try a random re-assembled one in my car until the pop tester gets here. Cant be any worse than what I have going on now.