99 Diesel Suburban

Anyone work on a 99 6.5 Diesel Suburban? I talked with a guy today who bought one new. It has had 3 dealer installed Injection pumps in its life and is inop again. Only 114K, 4WD, LT. Could it be a lift pump instead? This truck needs to live at my house but only if it will be happy and run.

ever change a fuel filter before?

The 6.5 tends to have problems with both the injector pump and lift pump. Do a google search and sit back and read. Other than that they are pretty reliable. Of course 3 pumps in 114K is pretty bad.

Check for metal filings inside the pump. There is a TSB on failed pumps, need to be inspected for metal, if any is found, complete fuel system needs to be dropped and flushed.

Also check that the lift pump works properly and that the PMD on the side of the pump is good. A lot of failed PMDs are misdiagnosed as bad high pressure pumps. A bad lift pump will burn out a good high pressure pump, but you would need the lift pump working to install a new pump and get it primed so I am guessing it works, at least marginally.

There are a lot of cheap junk parts out there for the 6.5, buy whatever you need from an authorized Stanadyne selling diesel injection service shop, not Ebay, not the stealer, not the local truck shop.

The guy is a lifetime GM emplyoyee. It has fresh rubber and clearly has been well kept. It has had filters on time and the one in it now has like 2k miles . I completely appreciate the advice.Will start at the PMD. Looked at Ebay and will now look for a Stanadyne dealer in the area.

93gsxturbo wrote: Also check that the lift pump works properly and that the PMD on the side of the pump is good. A lot of failed PMDs are misdiagnosed as bad high pressure pumps. A bad lift pump will burn out a good high pressure pump, but you would need the lift pump working to install a new pump and get it primed so I am guessing it works, at least marginally. There are a lot of cheap junk parts out there for the 6.5, buy whatever you need from an authorized Stanadyne selling diesel injection service shop, not Ebay, not the stealer, not the local truck shop.

Having learned a lot about the 6.5TD fuel system on my old WVO powered Suburban, I agree with all of this. When I bought mine, it was barely driveable. Replaced the failed lift pump and it drove great, lift pump never failed after that. Not long after, failed the PMD while towing down in California, quality Stanadyne part never failed after that. Not long after, failed a pump timing sensor on another long drive down in California. Put in a cheap rebuilt unit and had to replace it two more times before it would actually work...wished I had just dropped the cash and got a Stanadyne part in the end, wasn't worth the money saved to do that job two extra times and have a month of downtime.

Bryce

Probably not what you want to hear, but I looked into 6.5 Suburbans, and what I read scared the crap out of me. In my opinion, a diesel is supposed to be more reliable and more powerful than the gasser option. Not sure the 6.5 fulfills either of these requirements.

I bought an Excursion with a 7.3 PSD and haven't regretted it once.

And getting better fuel mileage. I do love the 7.3 Excursion but could probably buy three or four Diesel Subs for what one of those is bringing.

Get the Suburban and down the road you can do a Duramax swap, no more 6.5 problems. Or you can go really grassroots and swap in an old International/Ford 7.3L IDI (pre-powerstroke). No computer to deal with, plenty of turbo kits available, cheap to buy.