LML No Start New Pump

[exira]

2011 Duramax

So bought a truck off auction and someone had started to dig into it.
Someone pulled the regulator off the top of the injection pump so i got a new one, put it together, still no start. will start off ether, but then die due to no fuel.
Installed a new injection pump from GM, now the truck will start, but only with ether. shut it off and crank to start right away, nothing, 500psi max pressure cranking, 65 psi KOEO Starts and idles smooth. while driving it is a little under powered and says it is cleaning dpf. kicks engine code for low rail pressure. has one bad injector according to balance rates, i do not have an injector on hand so i capped it off and still no start.

Does the ecm need reflashed/programmed after pump install? probably not.
I do sometime here buzzing from the regulator on top of the pump with the key on, and it wont stop unitl i pull ecm relay.

going to do a bottle test and see how much it is returning next, just thought it was wierd that the fpr buzzed sometimes.
Is there a fuel return valve that could go bad on these also to cause not start

Sorry so long but looking for some insight

 

[duramaxzak]

The LML injection pumps are timed to the cam. Maybe it's out of time?
http://www.duramaxdiesels.com/forum/showthread.php?t=56149

 

[LWATSON]

Ether may have destroyed the engine?

 

[duramaxzak]

Ether may have destroyed the engine?

Duramax + Ether = BOOM!!!!

 

[duramaxdiesel]

Duramax + Ether = BOOM!!!!

I keep hearing that but the honest truth is that I put 15 cans, yes, 15 cans through my LB7 when my injectors went out to start it every time. Other than one backfire through the intake she still runs perfect. Installed my new injectors and she's still going strong at 500,000Km

But I wouldn't advise doing this. From what I've read, if the injection pumps ( CP4.2 ) goes out on the LML's, it contaminates the entire fuel system and it all has to be changed out.

Nick

 

[exira]

I know ether isnt the best thing on them and have used ether on 100s of trucks with no problem, thanks being said
i know the 11 lmls had problems with the pumps, and i did put the updated pump on it.

ANYONE WANNA GUESS HOW MUCH THE PUMP WAS THRU GM? you might be as surprised as i was?

I got it timed to the cam, just checked return, but cranking 10 seconds got me id say 30 ml which isnt right, the #3 injector reads 10 or so on the balance and 2 shows 3ish. the rest are +1-2. So, ima flush the system, pull injectors and get them checked and should be done with it.

Thanks for the quick replies!

 

[Taylor-34]

Why you holding out in the price lol.. Bought my '11 lml used so I need to go through the whole thjng and try and see if/what was done to the truck.. Bought it off the lot so I couldn't ask the precious owner but he was a salesman for CAT so it didn't see too much abuse from what I can tell.. No hitch in bed pull behind hitch has zero scratches from towing but you never know..

 

[DIESELMAFIAPER.LB7]

I keep hearing that but the honest truth is that I put 15 cans, yes, 15 cans through my LB7 when my injectors went out to start it every time. Other than one backfire through the intake she still runs perfect. Installed my new injectors and she's still going strong at 500,000Km

But I wouldn't advise doing this. From what I've read, if the injection pumps ( CP4.2 ) goes out on the LML's, it contaminates the entire fuel system and it all has to be changed out.

Nick

X2 the cp4 will take out the rest the fuel system

 

[02greysixer]

X2 the cp4 will take out the rest the fuel system

yep. injectors probably had a lot of metal pushed through them. Now they are returning to much fuel causing hard start and low rail codes. cap off a few more injectors and you'll probably see more rail pressure during cranking.

Sent from my SAMSUNG-SGH-I337 using Tapatalk

 

[exira]

The injection pump was only $535! Crazy huh!:thumb:

 

[Taylor-34]

The injection pump was only $535! Crazy huh!:thumb:

Hmm that does seem surprising for a GM part.. Think I'll do some preventative maintenance

 

[exira]

I would def upgrade the pump if running the older style cp4 and not under warranty

 

[Jberryhill]

2011 lml runs w starter fluid but won't crank without it

h&s mini max
3" straight pipe
175,000 miles
Got the truck at auction, said it was a run and drive…. ya about that, it cranks with stater fluid, and yes iv read all the no no on that. I drove it home from jackson ms, to memphis TN. Changed fuel filter and still no start. Smooth idle, it does roll coal pretty good but that programmer is pretty dirty anyway. Reading only 1.0 KSI on the H&s rail pressure and was throwing the low rail pressure code as well. If my pump was bad i would think it wouldn't run? I purchased to resale so it would be great to not do injectors and entire fuel system out of warranty….. HELP!

 

[02greysixer]

Fuel supply issue? Either a restriction or filter head issue? I'd definitely rule that out first. Normally when those pumps go it's catastrophic and they build no pressure at all. What's your rp during cranking? Will it start if you pump the filter primer?

 

[Jberryhill]

It won't start after priming it, and iv heard the pump could internally be leaking down. Im just trying to rule out why it runs fine, but looses prime. I can shut it off and try to crank and it won't even right after it has run.
And i havnt chacked rpm while cranking

 

[onebaddmaxxx]

Working at gm, an lbz pump with the regulator is only $556!

 

[Big Block 88]

Looses prime I would check for leaks externally first before suspecting internal leakage. Pressurize the fuel system

 

[HeavyDuty204]

I know ether isnt the best thing on them and have used ether on 100s of trucks with no problem, thanks being said
i know the 11 lmls had problems with the pumps, and i did put the updated pump on it.

ANYONE WANNA GUESS HOW MUCH THE PUMP WAS THRU GM? you might be as surprised as i was?

I got it timed to the cam, just checked return, but cranking 10 seconds got me id say 30 ml which isnt right, the #3 injector reads 10 or so on the balance and 2 shows 3ish. the rest are +1-2. So, ima flush the system, pull injectors and get them checked and should be done with it.

Thanks for the quick replies!

I would def upgrade the pump if running the older style cp4 and not under warranty

I would never put another CP4 back in while not on warranty, I'd be hard pressed to put another one in while on warranty, too unreliable. CP3 conversion and have some peace of mind.