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View Full Version : GM 6.2L Diesel Losing Prime


Liamfm
Jul 26, 2007, 08:59 AM
Hi,
I've got an 85 Suburban, 6.2l Diesel. I'm losing prime after sitting for extended (10+ hrs) of time. I see no fuel leaks.

I have replaced:
Fuel Tank
Sending unit
Fuel Pump (with electric)
Fuel line from tank to filter
Fuel Filter and housing

When I go out in the morning the return line from the IP is empty. Not bubbled... completely empty. The truck will fire right up but then stall 1-2 seconds later. The return line will still be empty.

After that I have to crank for about 30 seconds to get it to fire up. Once it's going I have no problems and I can shut it off and restart it all day long with no problems.

The only line that hasn't been replaced on the inlet side is the one from the filter to the inlet of the IP. It's a PITA to get to, so if there are other things to try first, that's what I want to do.

Thoughts?
Thanks

Liam

svizzini
Aug 3, 2007, 05:21 PM
Hi,
I've got an 85 Suburban, 6.2l Diesel. I'm loosing prime after sitting for extended (10+ hrs) of time. I see no fuel leaks.

I have replaced:
Fuel Tank
Sending unit
Fuel Pump (with electric)
Fuel line from tank to filter
Fuel Filter and housing

When I go out in the morning the return line from the IP is empty. Not bubbled... completely empty. The truck will fire right up but then stall 1-2 seconds later. The return line will still be empty.

After that I have to crank for about 30 seconds to get it to fire up. Once it's going I have no problems and I can shut it off and restart it all day long with no problems.

The only line that hasn't been replaced on the inlet side is the one from the filter to the inlet of the IP. It's a PITA to get to, so if there are other things to try first, that's what I want to do.

Thoughts?
Thanks

Liam
On mine, the only time I had a problem losing prime is when the o-ring on the fuel filter wasn't seated perfectly. No leaks. Just losing prime. BTW, aren't there two filters? Primary and secondary?