By Tony K
Rig has been running great, but now there seems to be an issue with the injection pump. Getting some pretty loud ticking that is rpm related and hearing what may best be described as gear meshing.
So you know just what type of diesel I am dealing with, my 1982 wagon has a 3B, the electronic diesel injection control (edic) has been removed and replaced with a manual glow plug control and a shutdown cable. The shutdown cable sits right where the edic control rod was in the run position. Lest you think the cable is part of the problem, removing the cable end doesn’t change whats happening with the engine. Here is a brief synopsis of what I have found and what has been done so far.
1. Started hearing loud ticking at all speeds. Sounds like a valve tick but adjusted the valves and no change.
2. Constant pulsation in #1 and #2 fuel lines when you touch them while running. Can also be felt in the soft line off the stock fuel filter that feeds the injection pump. Lines have been bled and I am not finding additional air.
Injectors were pulled and pop tested and they were all good around 1700psi with a good pattern. Switching them around made no change in the pulsation of #1 and #2 fuel lines.
3. What sounds like gears meshing (sort of like a whirring sound?) can be heard while driving down the road. Not coming from the gear boxes! Gets louder and faster when you step on the pedal with the gearbox in nuetral. Never did this before. Definately coming from the left side of the engine.
4. Rig idles and accelerates as always. No change in fuel consumption. No black, blue or white smoke at any time with the exception of high rpm on a hill in 3rd, a bit of black but I would expect that.
5. Diaphram is OK. Pull the line and the idle takes off. Also holds vacuum with my hand pump.
6. Fuel filters have been changed. No change to symptoms.
7. Air has been bled from filter screw, injection pump and injectors several times. No additional air found with follow up bleeding.
8. Rubber section of Fuel return hose has been changed and tightened.
9. I have never messed with the timing of the pump. Nor have I moved the fuel control screw.
The only thing that seems to eliminate all the new sounds, ticking and the gears meshing sound, is while down shifting. Letting the rig coast down hill with the rig in gear all the sounds go away as the rig slows down. Step on the clutch and the sounds come right back.
This also has some of the diesel mechs at work puzzled (I work in a diesel boatyard but not as a mech)
About the pulsations, they are also present in the soft hose that feeds the pump from the stock filter but not in the hose from the lift pump to the filter. The hard lines to #1 and #2 have always had a bit of pulsation since I have had it. One of the mechs said the pulsations are common in Yanmars. So this part of the problem wasn’t my main concern. Also leaving a finger on the injection line you can feel a momentary pause in the pulsations when you let off the throttle.
What seems to be gear meshing to me did get quieter when I did what the mechs at work frequently do on boat engines. I pretty much filled my Racor (the pre-filter) with Stanadyne and let the rig idle for 20 minutes. This has noticably reduced the meshing/gear sound. It seems there is not enough lubricity in todays low sulphur diesel fuel. The remainder of the Stanadyne double dosed the fuel in the tank.
Part of the diagnosis problem is that all brands of diesels tend to make there own sounds, with no two alike. I have worked around Detroits, Yanmars, Hino’s, Cummins, Volvo’s, Westerbekes, Kubota, Luggers, Perkins, Cats, John Deere’s, Ford Lehmans and who knows how many others and they all sound different. Some of them sound like they are going to come apart at idle when they are cold.
One of the longtime mechs who I have a lot of respect for said I could spend a bunch of money chasing the problem and may not find it. He suspects the pump but since it runs fine even with the noise I may need to live with it. At this point I don’t want to spend several hundred dollars to get the pump tested. But it may come to that. He also said that if a customer came in with the same problem he would suggest they live with it as everything has been done short of pulling the pump to isolate the problem.
Could the ticking be related to the timing gear, yes. But using a stethyscope on the block always sends me toward the injection pump. I need to learn how to set the timing, maybe that is effecting things as well. Never has been adjusted since I have owned it.
After this adventure I am now a firm believer in Stanadyne. Somewhere I saw that you can also use 2 stroke oil but I don’t know the ratio. These things were built when diesel was formulated quite differently, primarily it had a lot more what the mechanics call lubricity (mostly from the sulphur that they have taken out of diesel in the US). From now on I will be using something to put it back, probably Stanadyne.
As for progress the pump seems to be almost back to normal, still a little ticking but nothing ridiculous that I can’t live with. Surprising considering all I have done is lots of bleeding of air and putting in a significant dose of fuel additive.
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Interesting turn of events with my injection pump/noise issue’s. Had to make a hard run down the freeway for about an hour to pick up one of the kids. Took the mellow way home and lo and behold the noises pretty much stopped. Some of the ticking is still there but as a whole the level of noise has come down. The sound that seemed like gears meshing is gone too.
Can’t say for sure if it was the Stanadyne, the fuel I just added, the 2700 rpm for almost an hour or possibly oil in the speedo cable that got hot enough to thin out and not bind the cable (turns out this was contributing to some of the noise, might have been what sounded like gears meshing), Also some of the noise/vibration was transmitted through the stop cable (which is new since I removed the Edic set up recently)
Also found the old thread about pulling the drain in the injector housing and got about a tablespoon of oil out. Thanks Lostmarbles for that thread.
Still going to change the diaphragm as who knows how old it is.
Interesting the things I keep learning.
Finally got the diaphragm changed out and it may have solved some of the fuel line pulsations, or at least they have been drastically reduced. I won’t go into the diaphragm change as I wrote it up in another article here on the site, so check that out if you are interested. Did find a bunch of oil on the wrong side of the housing which is a bit of a mystery and unfortunately no drain on that side.
