Pump replacement time??

[Subzilla]

Hi Doc,
I bought my '83 6.2 about 7 years ago with 130k miles and have put about another 100k on it without touching the injection pump and injectors. It appears the injection pump was replaced before I purchased the vehicle but I really don't know it's history. It starts great but idles a little rougher than it use to. The thing I've noticed in the last couple of months is the uphill climbing power seems to be dropping off epecially with any load. Even without a load, I'm having to downshift more than I use to and I'm still have trouble maintaining a constant speed. How do I know when it's time to replace these components and do you think that's my problem? I just replaced my fuel filters before you suggest that!

[britannic]

Has the timing chain ever been checked or replaced? Dual idler gears are recommended if you can afford it - the difference is night and day. My symptoms were similar to yours despite a new pump and injectors, turns out my chain (which could be heard rattling like crazy) had over an inch of slack and the cam was retarded to the point the engine was starved of air at lower rpms until the turbo compensated.

Generally, a recommended guildeline is to replace the injectors at 50-75K and the pump around 100-125K, but some have reported much higher mileages for these components without problems.

[CleviteKid]

Britannic is correct on the guidelines, but as he suggested "Your Mileage May Vary."

One test to isolate the cause of your symptoms is to add one quart of non-detergent 30 weight motor oil to your fuel tank when you have about 8 to 10 gallons of diesel left. If your engine peps up and responds, that indicates your injection pump is about shot, but the higher viscosity fuel allowed it to generate higher pressures.

Dr. Lee :cool:

[Subzilla]

I'll try the motor oil trick and measure the chain slack. I'm really amazed the IP and injectors have lasted so long. Maybe it's because I've used the Stanadyne fuel treatment since I purchased the vehicle. When the pump does die, is it a slow, painfull death with loss of power or a sudden thing that could leave me strandard somewhere? Thanks for the advice.

[britannic]

Slow and painful seems to be the way these pumps exit, but of course there's always the possibility of a part failure that can bring on sudden death - I always believe prevention is better than cure...