Lmm rail psi trouble

[JakeBrakeIH]

I have a friends truck with the same symptoms. 2010 LMM with 10,000 miles on it. Lift pump, deleted fuel filter, race plug, ported rail filttings and even stock tune it drops way low on rail pressure(26k command/16k actual). Air dog keeps plenty of fuel pressure. Ramped up rail pressure with the DVT tab and held rail pressure great. Could it be a regulator???

 

[Bonestock]

I have a friends truck with the same symptoms. 2010 LMM with 10,000 miles on it. Lift pump, deleted fuel filter, race plug, ported rail filttings and even stock tune it drops way low on rail pressure(26k command/16k actual). Air dog keeps plenty of fuel pressure. Ramped up rail pressure with the DVT tab and held rail pressure great. Could it be a regulator???

In your case maybe but when mine gets ramped up very little change happens.

 

[Bonestock]

I have a friends truck with the same symptoms. 2010 LMM with 10,000 miles on it. Lift pump, deleted fuel filter, race plug, ported rail filttings and even stock tune it drops way low on rail pressure(26k command/16k actual). Air dog keeps plenty of fuel pressure. Ramped up rail pressure with the DVT tab and held rail pressure great. Could it be a regulator???

In your case maybe but when my friends gets ramped up very little change happens.

 

[JD Dave]

Bottle test it, takes 5 min and then you know. I just put a zip lock bag around the hose and use electrical tape to attach it to the hose. My race valve wasn't tight enough and I was having a similiar problem as this. The hard starting does make it look like it's a problem elsewhere though. The bottle test is the cheapest place to start.

 

[Bonestock]

Well I tested fass psi @ filter head and 10.5 psi. I am going to put dye in fuel system and use blacklight to see if there are any hair line cracks in the filter head. Also I will get this thing bottle tested. If there is an injector with a high return rate how do you diagnose which injector it is? Do you need a tech 2 cause I am not familiar of any test with EFI that will do this? Hopefully it is just the race plug not tight enough.

 

[Harbin_22]

Return test is a manual type test only.

 

[Bonestock]

Is there any way to tell which injector is returning too much fuel? Use dvt tool to cut an injector and test return?

 

[Bobo]

Also the DVT for LMM's doesn't work half the time. A lot of times, it might change something for a split second and then go back to where it is supposed to be. You will need to look back at the log to see if it actually upped the rail psi. But you should hear it rattling like crazy if it does ramp up rail

You can watch the log while you use the DVT.

Is there any way to tell which injector is returning too much fuel? Use dvt tool to cut an injector and test return?

Pull all the return lines of the injectors and make a mess.....:rofl:
I'd yank all 8 injectors, send them out to be tested, and get the ones replaced that fail the injector test. That's your best bet.

 

[MaxPowerLB7]

Probably bottle test one bank at a time. Then if one bank is high test them individually.

 

[Harbin_22]

You can watch the log while you use the DVT.

I know how to use it, I was saying that on my LMM, sometimes the DVT tools just dont work. Sometimes they do. I was saying to check the log while you have the DVT ramped up because it might not actually be working.

The idle DVT sometimes will kinda bump the idle for a second then go back to normal, even though I still have it raised. Same for RP and vane position.

Pretty much just saying be sure to check that it actaully took the command and dont just assume that it did

 

[Bobo]

You will need to look back at the log to see if it actually upped the rail psi. But you should hear it rattling like crazy if it does ramp up rail

I know how to use it

Wow....
You knowing how to use it isn't making your explanation very clear. I stated that he is able to watch it real time....just to make sure he watches it while he is using DVT controls. Calm down a little! No need to get worked up about it.


Edit- I deleted the video this is a PG13 site Kat

 

[EFI Support]

Also the DVT for LMM's doesn't work half the time. A lot of times, it might change something for a split second and then go back to where it is supposed to be. You will need to look back at the log to see if it actually upped the rail psi. But you should hear it rattling like crazy if it does ramp up rail

There have been some changes made to DVT's in the latest release candidate software http://forum.efilive.com/showthread.php?21842-EFILive-RC-1-(March-01-2013)

Cheers
Cindy

 

[03Tommy]

Here is one for the gurus. I have a buddy with an 09' lmm. He is getting reduced engine power on the dic. His truck has a dsp5 tune , fass hd-150 and a 5" diamond eye exhaust system. I logged the truck on a test drive for rail psi. When demanding 26k it actual rail is 17k. Just for shits & grins I loaded the stock tune in & it did the same thing 26k commanded & 17k actual. I then took an injector balance test & all were perfect. I then used the dvt tool to ramp up rail psi. I was able to get a little rattle out of the injectors but not much change when commanding 160 mpa max. I am damn sure you can kill a running engine ramping up rail if it has a good cp3. Any ideas before the cp3 comes out?

I sent you a PM, this wouldnt be the first truck to have this issue.

 

[LWATSON]

This was mentioned earlier in this thread, but Ive seen an LB7 behave like this. Hard to start, loss of power with stock tune and it didnt throw any codes. Balance rates were high so the injectors were replaced, and there was no change. Ended up being the CP3.

 

[Harbin_22]

Wow....
You knowing how to use it isn't making your explanation very clear. I stated that he is able to watch it real time....just to make sure he watches it while he is using DVT controls. Calm down a little! No need to get worked up about it.


Edit- I deleted the video this is a PG13 site Kat

I was not worked up over anything. I guess when I said he needed to look back at the log, I should have said go back to the data screen and see if the RP followed the command. Thanks for trying to make me sound wrong, really appreciate it.

 

[Harbin_22]

This was mentioned earlier in this thread, but Ive seen an LB7 behave like this. Hard to start, loss of power with stock tune and it didnt throw any codes. Balance rates were high so the injectors were replaced, and there was no change. Ended up being the CP3.

Damn that sucks. High dollar repair.

 

[LWATSON]

Yea it is, its a shame cp3's arent easier to swap out, you could get a loaner from some one just for a test.

 

[Bonestock]

This one wound up being high injector return rates.

 

[Andrewslmm7]

My lmm did the same thing and the rail plug I had killed my cp3 put a stroker pump in it an a shim kit 2200$ later no more rail pressure and mine was running at like 12.5 wot