Well, I finally got my buddy to throw his computer on my truck and came up with the 0605 - PCM READ FAILURE, and a P0470 Backpressure Circuit Failure. I have had an ongoing trouble with my truck I have posted here numerous times, however never had the chance to throw a real computer on it. I have a DP Tuner and 4" dual Exhaust and an aftermarket clutch. I seem to run out of power when I stand on it and push about 120kmh in 6th gear around 2300RPM, eventually this turns into a bad miss and the truck will barely do 50kmh, especially on hills. Someone suggested that the IPR could be toast, is there a way to test this? I have replaced the lift pump as it appeard to be weak. This problem is increasingly worse with a load behind it, but has been intermitant in the past.

We did the Contribution test - passed
Injector tests - passed

Does anyone know what the HPOP pressure should be at an idle? I saw about 475PSI with my buddies computer, is this correct? When I hit the throttle in neutral it went up to around 800psi.

Anyone have any idea what could be going on here?

Please help! I don't know what to do anymore.

Thanks,

 

I believe you want about 600 at idle, and anywhere from 2200 to 3000 at WOT. I would at a minimum try IPR orings. Where the power tapers off in the upper RPM's.......that's running out of high pressure oil. Worst case, new HPOP and IPR. But I'd start with a $15 set of orings on the IPR.

 

Would that have anything to do with my codes? (Someone else told me to do the IPR as well). Any idea where in Canada to get the kit? Is it a dealer thing? 600 @ Idle eh? Would it also cause the odd hard start when its cold?

 

Need to know the IPR % at idle at 475psi. What oil and how long since oil change?
Your description sounds like a truck I fixed recently. Turned out to be algae in the tank. It would run out of fuel on long hard runs. The screen on the pick up tube was sucked in and the small filters in the mixing chamber in the tank were plugged. Easiest way to be sure is with a pressure gauge hooked to the filter housing.

 

ICP at idle looks normal. Are you sure your fuel pump is not going out? Bad filter? I would think 1211 would be what you would see at higher rpms given your symptoms if you have a good fuel pump and filters.

EDIT: OK, kevin is saying about the same thing here.

 

I just replaced the Lift Pump, filter is clean, had the tank out already to check for blockage on pickup, looked good.

What do you mean 1211 (of what) @ higher RPMS?

What about the Codes? Anything there?

Also didn't make note of the IPR% at idle, didn't think it was too important... Can go back soon though... But, I would prefer to try something first... Sounds like the O-Ring Kit is the first cheap thing to try.

TENN, your quote of my description says "Look here Fix this", did you add that? What exactly is that?

I appreciate your guys help, keep the suggestions coming please.

Oh ya, someone else asked about oil change, brand new 100% Synthetic oil about 200kms on it.

 

If the ICP was low enough to run bad it would set a code. The filters in the mixing chamber in the tank can't be seen unless you take it apart.

 

I mean clear those and make sure they do not come back. If they do, they have to be fixed. P1211 is the oil pressure above/below desired pressure code that is usually set when the oil pressure that drives the injectors is too low and the truck stumbles at higher throttle demand. I doubt Orings will fix any of this as the IPR will either leak or not. It will be sluggish if clogged but Orings do not repair this. A replacement or servicing may, but the Oings simply come with the kit.

 

This is what Kevin and Mike are talking about.


Did you make sure these screens were clean, or did they look like this?

 

Thanks Chris! I never think to take pics at work. I think this is where the problem is. If it was hpo related it would set a 1211 code before it ever got low enough to cause a miss. When it runs out of fuel the power will start dropping off then start missing.

 

I did have another couple of codes last year that never came back, one was Turbo Boost Pressure too low, and Injector 5 failure (or something like that). Those codes never came back. As far as the pickup in the Tank, when I had the Tank out, my pickup doesn't look like that, mine is a Pedistal like pickup with a screen on the bottom, I think it was black. The reason I looked in there was because I felt it was a fuel issue too. If it was HPOP failure, would there be a code? Before I pulled the tank with the old lift pump, I turned the key on, and watched in the filter bowl to see how quick it filled, and it was just barely rolling off the side of the inlet. When I replaced the pump, it filled so quick I could barely get the key off in time, so I figured I had fixed the problem. (This was done after pulling the tank and checking the pickup.

So, next step - Clear Codes
Purchase rebulit kit for IPR
???

Thanks,

 

If I missed these filters when I took the pickup out (Mine didn't look like the ones in the photo)...Could this cause an intermittant problem? IE. This problem has come and go for quite some time until now where it just runs out of POOP @ about 120kms and 2200rpm on the highway. Before this, it would be fine up hill down hill all over the map for ever, and then all of a sudden it would kick in and haunt me for a while then go away.

Thanks,

 

Yes this can cause an intermittent issue, especially under heave load, or high speeds. Did your fuel pick up look like this?


Those filter screens are in the white part.

 

That is exactly it. I didn't take apart the white part. I guess I should pull the tank again and check those now. Can the problem be intermittant? Is there a MOD for it? Or is it just take em out and fix em?
What about the exhause back pressure code? Could that be caused by lack of fuel?
What about the PCM Code? What would cause that?

Thanks for your patience, I have been beating my head against a wall for some time now on this one.

 

Yes this can be an intermittent issue since the fuel pump pumps more fuel than the motor typically uses. As long as there is enough fuel making it to the bowl, or back through the FPR into the tank, then there is no fuel starvation issue. Under load, the lack of fuel in can cause problems. Yes there is a way to get rid of this design. Here's a link with the instructions and pics of what to do. Welcome to guzzle's In-tank Hutch Mod Web Page

The common issue with the exhaust back pressure can be fixed like this Welcome to guzzle's Exhaust Backpressure Sensor Cleaning Maintenance Web Page