6.5 Diesel problem(s) (ugh!!!)

(Pardon me for cross-posting to the Tahoe forum, but since a Suburban is very similar to one I thought others may have had similar problems and/or results.)

I have a 1997 Chevrolet Suburban with a 6.5 liter turbo diesel engine with 235k miles on it. Lately I've been having problems with it dying-out on me, especially when I pick the kids up at school or on the way home from church. Examples over the past two months:

1) Hard to start. But once it starts, which is most of the time, it will idle for up to 20 seconds then just die on me. Other times it will run fine for up to 20 miles, then start "surging" on me in traffic, then it will completely die at a traffic light. Sometimes then I have to restart it several times, only to have it die on me as I push on the pedal... then it will run fine again. (the transmission runs fine, so I believe its not the problem).

I've had a mechanic student over here trying to help but its costing me a lot to find this problem! The first thing replaced was the fuel filter, which came out black and utterly filthy! ...I felt so happy to think that such a simple thing could fix my truck....but the next day I learned my problem was not solved!...Next he replaced a relay switch under the hood (located on the driver's side of the engine). The first thing I noticed is that the turbo once again began to work, but the darned vehicle started acting up again the very next day....Then a couple weeks later he decides its the in-line fuel pump/regulator thingie, and its replaced (Its the pump under the truck, along the frame rail, directly below the driver's seat).....But I'm still having a problem! The ignition wire to the alternator? good connection there. Same goes for the battery cable terminals and the grounds..

A few miserable days passed and I replaced the fuel cap at the recommendation of a neighbor...problem not fixed.... Today I checked for any cracks in the fuel line but didn't see or feel any. I've even checked the fuel relay fuse inside the fuse box. Anyone have suggestions?

I hope its not the injector pump which costs over 1k. It's a bit too expensive to buy right now. Thanks ahead of time for any help!

I had the same problem with my suburban about a year ago. Unfortunatley, it turned out to be the injection pump. The hard starting and stalling is caused by a bad pump mounted driver (PMD). the module is mounted to the side of the pump and is regularly affected by the extreme heat of the engine. The jerking of the vehicle while driving in my case was the optical sensor inside the injection pump. While the PMD can be easily replaced by a mechanic, the optical sensor can not. For a TEMPORARY fix, reach underneath the front of the intake manifold where the turbo inlet is , and disconnect the plug on the very top of the injection pump. This should stop the jerking. This is only meant to be temporary, and done only long enough for you to get to a mechanic.

<snip>The first thing replaced was the fuel filter, which came out black and utterly filthy! ...I felt so happy to think that such a simple thing could fix my truck....but the next day I learned my problem was not solved!

Pull out the "new" fuel filter and check if it's still clean. If not, you've got junk in your fuel tank. This can cause problems for the fuel lift pump (along the frame rail, directly below the driver's seat), the fuel injector pump ($$$) and the fuel injectors ($).

Does the Check Engine Soon lamp to the top left of the tachometer come on? If so, go to an AutoZone or similar auto parts store and have them read the (trouble) codes generated by the vehicle's computer -- there should be an ODBII plug under the steering wheel column for them to plug into. Have them read the codes and reset.

Start with that.

You should visit www.62-65-dieselpage.com. You could also call a few of their sponsoring diesel-related businesses and ask for their opinions. Helpful bunch.