Hi Guys,

I have been following your posts for a few months now and would like to say thanks for all the information and great tips. I have learned alot in the short time that I have owned my 6.5 thanks to this group. I have recently run into a problem that I can't seem to figure out.

I have encountered the dreaded "miss/stumble" under a load or at highway speeds. I read a post awhile back about the EGR valve so I have it blocked off and the problem still persists. I have been reading about the LP/OPS problems so I decided to check it out today. I opened the bleed valve with engine running and no fuel came out, engine stalled. I hooked the LP up to an extra 12v battery I had and the pump started running -- fuel pumping out the bleed valve. (the LP sure made alot of noise and vibration when it did start running) I used a lightbulb type tester and checked the LP plug and leads with the engine running and I did have power but the light was weak and seemed to pulse with the engine. When I plug the LP back in with the engine running it doesn't run. Could this be a sign of a failing pump or a problem with my OPS and/or relay? Does the LP require a certain amount of amperage to operate? I'm a little stumped at moment because I have power to the LP with the engine running but it won't pump unless I hook it up to the battery. If one of you sharp-(trouble)shooters out there could point me in the right direction I would surely appreciate it! Thanks!!

P.S. -- This is my first time posting, sorry in advance for any errors that I made while trying to figure out how it works.

Sounds like you found the problem well enough by yourself. Good Job. I'd bet the OPS is shot. Replace that OPS and think about installing a relay around it for longer life.

OH BTW
WELCOME
):h

You're describing classic Oil Pressure Switch failure - replace it, and you're good to go.

Engine block, behind and to driver-side rear of fuel filter.

Sometimes you will also need to loosen the glow plug relay too to get to the ops.

Sounds like you found the problem well enough by yourself. Good Job. I'd bet the OPS is shot. Replace that OPS and think about installing a relay around it for longer life.

OH BTW
WELCOME
):hI had my OPS start going in the fall the truck 9 years old with 175,000 miles I though, heck thats not bad life out of $33 part that takes about half hour to change. In my simply way of thinking it would be more headache to add the relay than just to change the OPS. Now if I had several OPS crap out in short order I would add the relay. But, I'm just a simple minded clutz.

BTW it takes a deep well socket or a OPS socket to change the thing out, I got one for $9 from the parts store.

Well Sounds like you had better luck then most others here I guess.

I had my OPS start going in the fall the truck 9 years old with 175,000 miles I though, heck thats not bad life out of $33 part that takes about half hour to change. In my simply way of thinking it would be more headache to add the relay than just to change the OPS. Now if I had several OPS crap out in short order I would add the relay. But, I'm just a simple minded clutz.

BTW it takes a deep well socket or a OPS socket to change the thing out, I got one for $9 from the parts store.Mine went out with about 182K miles on it or so , and I was happy about the life span too. The lift pump went at the same time too, but Napa's life time pump only made it a year before needing to be swapped out. :mad:

Carey

Well, I managed to get the OPS replaced yesterday evening. I did some test driving with my enclosed snowmobile trailer and it ran like a champ. No more "miss/stumble", thanks to everybody for their input!

Well, I managed to get the OPS replaced yesterday evening. I did some test driving with my enclosed snowmobile trailer and it ran like a champ. No more "miss/stumble", thanks to everybody for their input!
:cool2:

does the lift pump from Napa (Carter) have a warranty like some of their other products?



Mine went out with about 182K miles on it or so , and I was happy about the life span too. The lift pump went at the same time too, but Napa's life time pump only made it a year before nedding to be swapped out. :mad:

Carey

does the lift pump from Napa (Carter) have a warranty like some of their other products?
Yes it has a lifetime warrenty:cool: , but I still hope to get more than a year out of one.

Carey

thats good to know. i even think i still have the box.

whats the part number on that lift pump?

Carter lift pumps

napa--NFPP74143
advance auto--P74143