Hi all, I'm new to the 6 liter forum and I'm having fun catching up on all the bugs n fixes on these engines. They do have way more than their fair share.

I have a friend with an 05 that appears to have the earlier problem with it's HPOP. The oil gauge drops to zero when it's hot idling below 700 rpm. Just to get it out of the way, I replaced the oil switch. I'm going to run it for a while tomorrow and see if it still does it. It acted fine backing it out of the shop tonight. It has 198k on it and has an injector (or 2 according to the dealer) on their way out, but some Stanadyne has smoothed it out some. I'm not sure what all has been done to it over the years, but after reading in here for a while I can see where a guy could loose his shirt pretty fast in there if he has to take the motor apart.

 

When you say the oil pressure drops to zero, i'm assuming you mean the one in the gauge cluster? That would be your LPO system. There is no gauge, factory anyways, for the HPO system. Not sure maybe your reading HPO through the OBDII port. Just want to clairify that we are talking about the HPO side of the system. if you truly had zero oil psi on the High pressure side the truck would not run, as that is what runs your injectors. Is this what's happening? Truck warms up then dies? Didn't really see a question in your post. So I figure I would just cover all the basics.

 

It's just the dash gauge falling off at idle. It's been doing it for a couple weeks. I had heard about the earlier HPOP's popping a ball and causing a similar problem, but I hear an 05 shouldn't have the problem. I did notice the valve cover says 04 on it while I was changing the switch. How can I tell which pump this one has?

 

im not real sure what your talking about as far as witch pump. Someone else will have to help you on that one. If im understanding you correctly, the truck doesn't die when the gauge falls off? Is that correct? If so then the problem is on the LPO side. As the HPO side of the system runs the injectors and if you had no pressure on that side of the system then the truck would die. not real sure where to hook up a gauge on the LPO side to verify the problem, but that would be my next step. Just to eliminate any posible electrical problems. Then you may need to take a look at your LPOP gears.

 

Your factory gauge is the low press. side and it feeds the high press. side. If you had 0 low press. oil then the hpop would not be getting oil and the truck would not run. If the truck is running the odds are that you have a gauge or sending unit problem.

 

Yeah, it does stay running so it must be getting some oil up there. I'll run it hard for a while this morning after changing the oil pressure switch and we'll see how it does at the stoplights. Thanks for all the replies, guys!!

 

We ran it all over today and never saw the gauge fall off. I'm hoping the switch fixed it. We'll let the owner drive it around for a few days and see if it's actually cured.

 

Sounds good. Let us know how it turns out