loping lb7 with no tune???check engine lit--help

[toddster911]

not sure if this is in the right place ...new here.

I have a lb7 with 62000miles 6 speed manual dually, injectors done by stealership. never an issue till now....try and follow this,

I ran the truck for 40 or so miles, no issues. stopped in my driveway for 20 or so minutes. started her back up and the check engine lit and a heavy loping was noticed..I don't have a tuner..bone stock.
Ran my obd2 scanner and no codes appeared, but check engine still lit.
Left her overnight and started up next moring all was normal...ran her for 30+miles..no more mil light and all was smooth.

got home, stopped her and started her up again 20 minutes later, and it all started again..mil light-no code and loping....don't understand?

ever happened to anyone?
thanks for all help!!!

 

[02bigstrokin]

any smoke while its loping? when was the last time you changed your fuel filter? theres a code if the light is on, you need to find a scanner that will read it.

 

[SmokeShow]

so it didn't do it after parking overnight but did do it while it was still warm but had been sitting for a few minutes? Hmmm. I'm sure one of these gurus can help you out. I'm not real sure.


Good luck

 

[Big Block 88]

I would say the stealership got you... I would check balance rates and coolant tank for oil.

 

[toddster911]

thanks for the responses,

no smoke during loping.
no oil in tank...maybe a small residue from when it needed the injectors changed 20k miles ago ...if I can call it that, not noticable really..but seems fine. (any tech method to check for sure?)
have not changed the fuel filter in a while, was planning on doing that this week as I though maybe it was clogged or got bad fuel with water or something??.

will look into a scanner that is up to date, and get back with a code.

 

[toddster911]

codes up.....

just started it up and ran well but mil light still on....then what seems to be once it is warmed up...loping started again and it ran rough...sounded like a powerjoke

ok buddy came over and we toyed with it a little...scaned with better scanner and

p0088 fuel pressure too high
p0089 fuel pressure performance
p0090 fuel pressure regulator

when we reset the dtc's it comes right back
can the fuel filter needing changed create this problem, or is it the fuel pressure regulator needing to be changed?

thanks

 

[Big Block 88]

regulator is needin help, I have seen an LB7 eat a CP3 pump aswell, I don't think that is to common.

 

[toddster911]

what are your thought's on lubimoly diesel purge in fuel filter and tank to loosen it up

also read some interesting info on adding atf fluid to tank to loosen and lube up the fpr and save it.....thoughts? anybody have good/bad experience with this?

or just change it up with an oregon fuel injection

 

[delong_1]

i have used about the twice reccomended concerntration of "diesel kleen" in a couple tanks of fuel and that cleared mine up, this was about 2 years ago and not a problem since.

if that doesnt work you can get a new regulator for pretty reasonable.

 

[Sledhead]

I heard a local dealer will spin a new fuel filter on with a bottle of stanadyne poured into it. I've had a bad FPR that caused the loping with no smoke.

 

[wes06dmax]

I have a friend with a 01 LB7 and he has the same problem but we think his fuel regulator hangs open sometimes his is little lope not nothing like a EFI Live lope take a programmer if you have one and clear the codes and retune it see if it doesnt stop

 

[2007 hd white]

Have you tried running some 2 stroke oil? It is supposed to return some

lubricity to the diesel after they changed to ultra low sulfur. I have a 2002

Lb7 and running about a pint and a half per tank. It made my Fpr run

smoother and it made the engine run quieter. You can buy the stuff at wally

world for about ten bucks a gallon, just make sure you get the tcw- 3 low

ash 2 stroke oil by super tech.

 

[x MadMAX DIESEL]

Maybe a bad connection with the fuel pressure sensor? That would cause a lope, maybe they had that unplugged while working on it?

 

[toddster911]

to help with a few questions that were asked. She is bone stock, injectors done a year ago and no problems since (only oil changes done a month ago....not used much) ...till now, no tuner or perf program's


ok threw some atf into the tank to help lube...seems to have run a little bit better,not smooth yet and less loping, and I have a little torque (nothing like it was) till 2000 rpm but then it de-fuel's or hits a cutoff , could that be a limp home style protection seeing my mil light is still on or is it too high pressure and it is choking out? even a stand still rev's will cut off at 2k?? my buddy wasn't around with his scanner to see if I could reset the error's .

thanks for alll your input it is very much appreciated, want my smooth runnin baby back.

 

[Sledhead]

I changed my fpr without pulling the cp3 with about a 3" T25 torx bit (1/4") and something like this. I'm pretty sure the A/C pump had to be temporarily relocated but not unsealed.

 

[toddster911]

update

Ok, so 2 nights ago I put some lubricating fluid into the tank and ran it. that same night it was alittle smoother but still on the ruff side, had the mil light so it would cut out at 2000rpm. but pulled well(not as usual) till that rpm
Stopped the truck and tried running it again the next day....back to ruff clackness and loping...no smoke out rear but stinks of diesel...like it was rich.

Spoke to a local diesel race/builder and said to start with a new fuel filter as these symptoms are also that of a clogged filter. did that primmer her back up....same thing loping and ruff

same codes come back up...0088-0089-0090 all fuel pressure based, too high and regulator.

I don't mind going into it and changing the pressure regulator...just need to know that it is that the problem

Those who changed thier regulator....were these the symptoms and codes?? did it lope and run ruff..no smoke? MOST of all did it happen one start to the next??

thanks for all the input...if it needs a regulator, that is what I will do...anything special about it other that the 25t torx and a bunch of molex plugs/piping and parts to remove? do I have to bleed the system? will I have coolant and diesel pour out everywhere?

cheers

 

[toddster911]

update 2

decided the fpr is probably bad...removed it tonight....noticed that in the 3-t25 torx screws, only 2 were as tight as everyone said...70foot lbs or so, the bottom one was much easier to remove...also mentioning that someone played in here before I PURCHASED THE TRUCK.

can a small leak due to a bad seal on the fpr cause a high pressure code??

there was no fuel in the valley but noticed the fpr is under pressure, when I removed it it sucked air in a little???

thanks for the help

also I read 3.5 in continuity on the fpr, it is stamped 3.2....could this be an issue? can you tell physically if the unit is defective?

 

[toddster911]

please refer to update here:

http://www.duramaxdiesels.com/forum/showthread.php?p=360342#post360342