Lml no start after regulator removal

[clrussell]

How’s about some tech again? First off I’m out of practice, haven’t played with diesels in 5 years minus the last 6 Months and now I’m back as a manager.

Truck rolled in the shop last week, tech does brake work etc. test drives all good to go. Says check engine light is on so I call the customer and see if he wants diag, customer says yup fix it I need it 100%

So he diags it, fuel pressure regulator performance code.. look up flow chart, give it to him, he runs return test- bad #2 regulator. Cool, I get one from Gm and give it to him to put on.

Since then the truck hasn’t ran. Will only build 180psi of rail, has fuel everywhere it should have fuel.

Even swapped the old regulator back in to see what was up. Same deal crank no start no fuel pressure.

I have verified no flow out of the return line cranking on the #2 regulator, all the plugs in are in the correct spot. Also put air pressure to return of injectors while Cranking, that did give me 300psi of rail pressure.

I can’t really dedicate time during the day to get much accomplished, holiday has put it on the after hour back burner. Running a 18 employee shop and taking care of customers puts me at a time limit I can spend under the hood.

Just looking for insite I can use or give to the tech.

Also merry Christmas guys

 

[Ron Nielson]

The truck thinks the problem is the circuit for the #2 regulator. What check on the circuit was done? If you're satisfied with that, there must be another problem yet to be discovered.

The attachment is specifically for my 2008 LMM, but the problem is similar for the LML also.

 

[2004LB7]

Just be aware that the LML's injectors need some back pressure on the return line to operate correctly wear as the LMM doesn't

 

[JoshH]

What was the code prior to the repair? Were there any symptoms of a problem other than the code? Does it have any codes now that it isn't starting?

 

[gmduramax]

There’s a harness in front of the motor that if disconnected it won’t close the regulator. I don’t remember exactly where I’d have to go check. Doesn’t hurt to make sure because I missed it once

 

[clrussell]

p0191 frps performance

 

[Ron Nielson]

See here: https://oregonfuelinjection.com/ser...ics-repair/chevy-gmc-diesel-diagnostics/#07.5 There are some specifics o check for P0191. You probably already know all of this, but it's a goo review if nothing else.

 

[1FastBrick]

p0191 frps performance

Looks like you got the " F***ing Real Piece of Sh** " code...

 

[JoshH]

See here: https://oregonfuelinjection.com/ser...ics-repair/chevy-gmc-diesel-diagnostics/#07.5 There are some specifics o check for P0191. You probably already know all of this, but it's a goo review if nothing else.

LMM and LML fuel systems are very different. The diagnostics won't share much in common.

 

[Ron Nielson]

Josh - you read the link but don't think it is correct/ or ?? Maybe you are just making an additional statement?

 

[JoshH]

Josh - you read the link but don't think it is correct/ or ?? Maybe you are just making an additional statement?

I clicked the link and saw it said 07.5-10. I didn't scroll up to see it has information for other year trucks too.

 

[LBZ]

I clicked the link and saw it said 07.5-10. I didn't scroll up to see it has information for other year trucks too.

I did see this part. I believe it is relevant to the lml. Mentions it could be either regulator.

 

[clrussell]

Got tired of messing with it. Put a new pump on it and it runs. Guess it either took a shit in the shop or trash in it.

 

[1FastBrick]

Got tired of messing with it. Put a new pump on it and it runs. Guess it either took a shit in the shop or trash in it.

How many Miles were on this fine piece of equipment?

 

[clrussell]

220k Factory pump as far as we know. Well
Used truck, service truck to a logging company

 

[TheBac]

Sometimes it just happens. Glad you got it sorted, Corbin.

 

[clrussell]

Sometimes it just happens. Glad you got it sorted, Corbin.

Yup.