Baja

My engine has been misbehaving, badly, for quite some time. I have lost quite a bit of power and torque, a LOT in the low end, mileage is sinking. The engine revs higher than it used to, and is quieter in the freeway. I have had it checked to the Nth degree, but no real difinitive "this is what is wrong" has been given to me. Getting a good mechanic has been a real hassle, if you have a good one wherever you are, buy him dinner, he deserves it. Anyway, I believe that the timing gear has slipped on its shaft, and continues to do. If I pull off the cover (and I will kill the KDP) how will I know what to look for? How can I measure the slippage, what are the benchmarks? Please help!!!! This problem has been driving me crazy. Thanks

infidel

If you want to check the timing you may as well bump it up as you are already most of the way there. You won't be able to see if it has slipped by removing the cover and the cover doesn't need to be removed to do the timing.
As far as I'm concerned the only way to do the timing is described here
http://dodgeram.info/tsb/1994/18-10-94a.htm

Baja

I will be bumping the timing when I get into it, and probably bigger delivery valves as well. I know that the pump timing can be changed by working on the pump itself, no need to mess with the cover. Either I was not clear in my description, or my terms were incorrect, I'll try again. I have been told that the timing gear can slip on its shaft. If the nut holding it on either works loose, or if it was not put on very tight in the first place, it can allow the gear to change its position relative to the shaft. I understand that the shaft is not splined or has any key to it. Sort of like putting your finger in your fist and rotating your finger. I am not positive this is my problem, but I would like to check it out, as I have eliminated so many other possibilities. I am wondering just how to do the check. Maybe I am all wrong about all this, (been given incorrect advice) but this is something I have been told about, and I am trying to do some research. My pump timing has been checked @12.5, stock. Thanks.

kerryneb

The timing gear is tapered and mounted on the tapered injection pump shaft. Checking it is done by measuring the injenction pump's lift (with a dial indicator) relative to engine TDC. timing can be adjusted by removing the oil fill tube, the timing cover does not need to be removed. Having said that, it doesn't seem very likely that timing would slip, although not impossible. More likely problems causing loss of power would include plugged fuel or air filter, lift pump failing, air in fuel, overflow valve sticking, plugged cat converter, or turbo and or wastegate operation. Hmmm, i just noticed it says you're running on WVO? Has the source changed? I'm thinking more along the lines of plugged filter,or the strainer screen in the settling bowl, or viscosity too high... what about the fuel heater.

Baja

The engine has been doing a slow death. The first items checked were the filters, all of them, no go. Lift pump checked, putting out 34psi, compression @ 350+, new overflow valve, no cat to plug, can still hit 30+# of boost. I DO have air in the fuel, and have replaced ALL the lines with marine grade line. I replaced the valve at the bottom of the water separator, and the "o" rings on the hand primer in the lift pump, removed and replaced the screen in the preheater. I still have air. The problem started before I put in the WVO system, and the WVO seems to make no difference in performance. I have plenty of heat for it, I have made very certain of that. I is now it is getting to the point where I cannot drive except for slow speeds on city streets. If I wind out the engine in any gear, it will starve for fuel and quit altogether. This starvation is new. I know that I have been pulling air for some time, as I have some clear filters in line. When the mechanic, who has turned out to be the worst person in the world put it in the WVO system saw it, he told me not to worry about it, it is normal. I am starting to believe that the air, starting slowly a long time ago, started the loss, but now is getting to the point where the engine simply cannot get enough fuel to run. I am not afraid to go into the IP, it is just that I want to be certain, because once I open it up, I will be out 2000.00$. I would rather not have to spend the money if possible. Thanks for all of your help.

kerryneb

most likely air is the problem then...there's probably a hose leaking air (very common problem), a restriction in a line filter or screen, or cracked steel line (crack could be inside tank even). when i took my lift pump off to replace it, i got on the wrong place on the steel line connection and twisted it all up. pressurize the fuel tank with 3-4 psi air, look for leaks, and/or try running while pressurized. you could also run a hose from a container of fuel to the lift pump to help eliminate possible sources of leaks. use brake parts cleaner to clean/dry leaks to help locate the spot. doubtful your injection pump is the problem.

Baja

I will do the container-to-lift-pump idea. I have pressurized the main tank a bunch of times to bleed the system after I have worked on it. I have not discovered any leaks, air or fuel, during any of those times. One of my in line filters, all of them are new and are there for observation purposes only, is before the lift pump. I would assume that if the air leak was somewhere in the tank, or lines from the tank to the pump, the lift pump would be sucking in the air, and I would be seeing bubbles in the filter.
I have also replaced the diaphram in the AFC, as it failed a vacuum test. I have checked the solenoid shutdown, and it is working fine.
The engine starts instantly, always has, it idles perfectly.
Just to make it interesting, I can change the return to either loop back through the IP, or go straight to the main tank. If I select to loop to the IP, there are no bubbles at all, and I can hold it at WOT with no miss or hesitation. If I select to return to the tank, bubbles will appear after about 10 seconds, in pulses, but not a huge amount. In this mode the engine will start to miss and quit after about 20 seconds. On the road, no matter where I have the return valve selected, the engine will starve even if there is no load on it.
Can air affect the engine RPM? The engine at WOT used to stop at 2800, now it is 3500. Can air cause a change in the torque curve, it used to pull hard at 1200, now it starts to pull at 1800.
Sometimes I wonder if I have two problems, timing and air.
So confused I can hardly see straight.

kerryneb

By selecting loop back to pump mode, seems that it would reduce the lift pump flow requirement. To me, it indicates a restriction on the suction side of the lift pump, and a small air leak. The 1200 vs 1800 rpm change might be afc adjustment or wastegate. The AFC operates on turbo PRESSURE and is opposed by a spring. Reducing the spring tension allows more fuel at lower boost therefore bringing on more power at lower rpm. CAUTION must be taken in making fuel adjustments... too much fuel for a given amount of air generates heat...hot enough to melt pistons, turbos and cause many expensive problems...that's why the first investment should be in a set of gauges. I know as a diesel is nearly out of fuel, the rpm increases...probably due to the governor trying to compensate for too little fuel, the effect lasts only a few seconds until the fuel is gone. Fuel delivery is proportional to both load and rpm, but LOAD has by far the largest effect on the amount of fuel delivered by the injection pump. therefore an engine at high idle (wot with no load) uses much less fuel than a truck driving down the road (higher load, lower rpm). The governor in the injection pump should limit rpm... if no other pump changes were made (for example governor spring changed) and your max rpm has gone from 2800 to 3500, sounds like you have a gov spring that has broken or something along that line. What gauges do you have, and what are they doing under the low power condition? Low exhaust temperature under load indicates more fuel is needed.

infidel

Don't know if this applies but is worth considering.
I've worked with designing hydraulic systems over the years, big no-no is a filter in the line in-between the tank and pump. What happens is the pressure differential across the filter causes air that is entrained in all types of fluids to be "sucked" out and become free air (bubbles). This doesn't happen with a pump ahead of the filter, only with a filter on the suction side.
Return fuel back to the pump equals less fuel flow through a suction side filter.
Kerry touched on this when thinking a restriction could be the cause.

Baja

I have a Carter electric pump before the lift pump, but it is easy to change the filters to clear temporary hose, and I will, if for anything else, to eliminate any possible problems. I have checked the pump for volume and air, and it seems to work fine. Question though, wouldn't the water separator act as a pressure differential and release entrapped air to become free air?
I have not touched the AFC, except to change the diaphram and to center the star wheel. I have not touched the wastegate, or spring, although they were on the suspect list for a while.
This slow death has been going on for, literally, years. I had the first mechanic look into the problem in May of 02! I first discovered air in the system after the crook of a mechanic installed the WVO. That was in April of 05, and he said the bubbles in the in-line filter was normal. Between those dates, I have checked, or have others check most everything but the pressure in the spare tire. It has been in the last two months has this problem reached critical proportions.
I do have gauges, but my EGT gauge is presently on the blink. I have not fixed it as I have more pressing problems to deal with. I will have to re-think my priorities.
I have not touched the IP or govenor spring, it is stock.
Kerry, it is interesting that you mention that a diesel will increase in RPM as it runs out of fuel. I have been in touch with DTR member, Ponci, who has been a big help, and we talked about RPM's and air. He said that the RPM's can increase due to the fuel being lean, which is what you say. I think that my engine acts like it is running out of fuel all the time. That is why it can hold a high RPM at WOT, standing still, but die on load. No fuel, no power, no fuel, no torque.
I will be getting a used lift pump and preheater for free, so I think I will install it. It can't hurt, and it is not too hard to do. I will put in some other clear hose sections for observation and report on everything later.
Right now, I want to thank all of you and Ponci for helping me, giving me new directions and hope, as I was very confused and bummed out. I will be leaving for Thanksgiving tomorrow, returning on Sunday. I plan on eating and drinking way too much, and riding my mountain bike way too much as compensation. I will pick this up on Sunday, until then, thanks, and have a great Thanksgiving.