Diesel mechanic shop recommendations

[Doubleggregg]

Looking for a shop that is willing to help diagnose a check engine light on my 2002 duramax.

I get a p1093 code when towing a decent load 8K+ under load. Like going up a hill. I do not tow a lot with it but when we tow a 36’ travel trailer to and from ocotillo wells from Temecula I get the code usually at the grade on the s2 right after the borrego turn off and then coming home I get it going up the same grade.

This last weekend I got it closer to Temecula going up one of the smaller grades outside Temecula.

I read alot about it and the forums say loss of power / limp mode when it comes in well I’m not a diesel know it all and it really doesn’t seem like I lose power I mean I’m just chuggin along 2200-2500 rpm 45-55 mph and the code comes on I see it flash, I read the code and clear it.

I have been daily driving it for the last 3k miles and the light hasn’t come on. Last time I saw was it a year ago during our annual Super Bowl weekend trip just like this past weekend.

I’ve had a local shop The Truck Shop in Temecula try to figure it out paid them 2 hour of diagnostic fees for them to drive it around and no light. We’ve changed the fuel filter, I just want a reputable mechanic to throw some advise and maybe offer some diagnostics and see if we can figure it out. Anyone in the Temecula area worth trying besides the truck shop?

Gregg

 

[Klever]

Try this Gregg:
The P1093 is low rail pressure during power enrichment. Could be restricted fuel lines-[check at the driver's side of the Allsion.] Also possible FPRV is weak [common on a LLY engine] That can be checked with "Bottle Test"--- Here is some info on the "Bottle Test".

On the drivers side fuel rail-- to the back and next to the Turbo, you will see a "U"
shaped 3/8 hose-- remove the hose from the fuel rail-- and plug the hose.

Now attach a 3/8 hose to the fuel rail nipple, and stick the end in a bottle. Now drive the truck hard-- with several wide open runs-- if there is any fuel in the bottle the FPRV [fuel pressure relief valve] is leaking main pressure from the fuel system.

The FPRV is a plug looking part that screws in the back of the driver's fuel rail. Many just increase the pressure with a couple #4 washers, to help hold the pressure. Others use a "Race" plug [not recommended] available from supporting vendors.

Also this: GM's 6.6L Duramax diesel engines were not equipped with an external diesel fuel lift pump. Instead, they relied only on the scavenging ability of the Bosch CP3 high-pressure fuel injection pump

 

[Doubleggregg]

Try this Gregg:
The P1093 is low rail pressure during power enrichment. Could be restricted fuel lines-[check at the driver's side of the Allsion.] Also possible FPRV is weak [common on a LLY engine] That can be checked with "Bottle Test"--- Here is some info on the "Bottle Test".

On the drivers side fuel rail-- to the back and next to the Turbo, you will see a "U"
shaped 3/8 hose-- remove the hose from the fuel rail-- and plug the hose.

Now attach a 3/8 hose to the fuel rail nipple, and stick the end in a bottle. Now drive the truck hard-- with several wide open runs-- if there is any fuel in the bottle the FPRV [fuel pressure relief valve] is leaking main pressure from the fuel system.

The FPRV is a plug looking part that screws in the back of the driver's fuel rail. Many just increase the pressure with a couple #4 washers, to help hold the pressure. Others use a "Race" plug [not recommended] available from supporting vendors.

Also this: GM's 6.6L Duramax diesel engines were not equipped with an external diesel fuel lift pump. Instead, they relied only on the scavenging ability of the Bosch CP3 high-pressure fuel injection pump

I saw that thread when I googled. Thought about trying it but I’m also not an engine guy and I hate working on shit that I am not familiar with.

If all else fails and I can’t find a mechanic to talent have help diagnose I’ll start there first I guess.

Gregg