Charlie C

I have this 93 ram 4x with 97k on it. This past weekend I towed my 7K boat and at that time I thought that I was having to shift down going up the hills before I should have but the truck was running fine just seemed weak.

Today I took the truck out for a drive of about 10 miles and coming back home is when the problem really started.

When I let off of the throttle the engine would run real rough (actually shook the truck) and acted like it was going to die. Raise the RPMs up and the engine would smooth out.

It has been about a year since I changed the fuel filter so that is one thing I will do this week end. The other thing that I did that may have affected the engine and maybe the fuel filter, if the filter is the problem, is my fuel is getting low and I filled the truck up. The fuel tank that I fill from has a fuel filter/water trap on it. I think that would have taken care of any contamination though.

I am a real novice with diesels so any suggestions/thoughts would be appreciated.

sooty

dosent the water separator have a valve to drain it? replace all filters to judge current problem, usually filter fails under load, repost conditions after service.

Charlie C

I picked up the fuel filter today, will install it tomorrow and see what happens.

Thanks for the reply Sooty.

wannadiesel

A new lift pump would be the next step.

Charlie C

I changed the fuel filter with no change. So I guess that the lift pump will be the next change as Wanna suggests.

Charlie C

I got a new lift pump this afternoon so it will be installed in the morning when it is cool out side.

If the lift pump is bad is there any chance that diesel fuel got into the crank case?
I also purchased oil and a new oil filter and plan on changing them just in case. The oil and filter is way cheaper than a new engine.

ofcmarc

Only if the diaphragm ruptured or got a hole in it.

Charlie C

After 4 hours and a qt. of blood I got the lift pump, oil and oil filter changed. Started the truck up with high hopes but they were soon crushed. The truck still will not run right.
It will just barely run at idle, the tac indicates about 500rpm.

I now understand why I never had any interest in working on autos. Every thing is stuck in a small space and when the factory stamped out the parts they did not debure them so everything has a sharp edge just waiting to cut you into little pieces of meat.

Any how I am open to any more ideas.

I think I will send it to the shop and let them work on it but I still would like to have some idea of what is wrong.

wannadiesel

Air leak in the fuel system is pretty much your only other possibility other than a bad injection pump. Lightly pressurize the fuel tank (air nozzle wrapped in a shop rag) and look for seepage at all the connections. On the suction side, a leak will just pull in air along with the fuel from the tank and the truck will not run right.

Charlie C

Thanks Wanna for your reply. I did not get a chance to try the air pressure idea today. I certainly hope it is not the injection pump as I understand they are $$$.

Charlie C

It looks like a new injection pump is in store for the truck. At the same time I am going to have the valves adjusted and new injectors put in.

At one time a few years ago I would have attempted to do this myself but not any more, it just too much for this old boy to attempt.

jesussaves

did you bleed all the air out when changing the filter and lift pump? I highly doubt the injection pump would go out with that few of miles.

Charlie C

Yes, I did.
I have the truck at a shop that I believe will give me good advice. After the shop tested things he believes that it is the injection pump.

jimbo486

How about a bad injector or injectors? Doesn't seem like they'd go out with so little miles on them but always something to consider. Even though it's idling around 500RPM, it could be multiple injectors gone bad. Does it smoke any when idling? Crack the fitting at each injector. If the idle doesn't change any then you've found a bad injector. Just other/free things to check before spending a ton of money. Also, a good habit I've picked up is changing the fuel filter at every other oil change. May not be that necessary but just something I like to do so that I know things stay fresh.

Charlie C

Jim, I did not expressly check for smoke but if there was it was not a great amount.
I did ask the guy if it could be injectors and was told that there was that possibility of a injector gone bad.

One thing about this thread every thing that you guys point out or ask me is adding to my diesel education.