I think the lift pump on my 94 Cummins 5.9 is going bad. My old mechanic said three years ago that he thought it was weak. Lately, I habe to crank the engine over 2-3 times to get it started. It runs great all day after that.

Is the lift pump in the gas tank on this engine? Should I have a mechanic do it or can I do it myself?

Thanks,
Rick

Have you noticed that the engine idle is a bit low? I had the same issue about starting, I had to depress the throttle slightly to get it to fire, turned out it was the idle stop that was to low and over time it had worn to the point that the governor was in the fuel cutoff area. Since setting up the idle stop a bit, I don't have to depress the throttle at start and it fires right away.

If it is the "lift" pump it is located on the engine, passengers side, near the bell housing. There is no pump in the tank.

Hey Ed,

Thanks for the reply. I have not noticed that the engine is idling too slowly but I will try your suggestion tomorrow.

Rick

To be clear,you don't have to floor it, just move it a bit off idle position.

The former owner complained about the starting issue when I bought my Barth, it finally got so bad that the engine would stall sometimes when shifting into reverse, until then I had no clue as to what ws causing the hard starting issues. Hope yours is as simple as mine. It was not easy to adjust, idle stop is hard to get to with all the throttle linkages etc.

quote:

Originally posted by Richard_Muise:
Should I have a mechanic do it or can I do it myself?

The lift pump is easy to access and you should be able to do this one yourself.

Hey Bill,

I did what Ed suggested and the engine started almost instantly. I hope that means that the lift pump is OK. Now that this is under control, do you have any advice on my post about changing the heater core? It look like it's impossible to get at.

Looking forward to meeting you at Goodwin's Barth gathering.

Rick

Hey Ed,

I started it twice doing what you suggested and it started almost instantly. It idles around 500 rpm in neutral. Does that sound ok?

Thanks for your help.

Rick

No, 500 RPM is to low. It should be around 700 RPM at idle when hot in neutral. I got mine just a bit high at 800 RPM but it is ok as it is coming down abit after I set it. I have to be careful on mine because with the MD3060 transmission, if the idle is to high, it will not shift into gear.

Of course you do not have to reset the idle, just remember to depress the throttle slightly at start-up, BUT eventually, you may have the same problem stalling the engine when shifting into gear or changing from forward to reverse gears.

Also if to high, you will require a bit more brake pressure at a light in gear.

The idle stop screw will only require a 1/4 to 1/2 turn to bring up, doesn't take much.

Just a word of warning about the lift pump on the 5.9 Cummins, check the pressure at the filter case. It should be about 10-15 pounds at idle.
My son just bought a 1999 Dodge P/U with the 5.9 and they have a lot of failures, according to the forums. A weak lift pump will lead to injector pump failure ($1000 to $1500). He installed a pump which was mounted off the engine as recommended by the forums for about $200. The lift pump on the P/U was only about one year old and only held about 4-5 lbs at idle.
This is a long long story and maybe it only applies to P/U's but I thought all you RV owners should be aware.