As some of you know i have been having some noise problems under load. And after reading through various posts here about the troubles with overflow valves, i decided to look at mine as i have been hearing that annoying ticking sound. The valve is differant than the ones i have seen pictured here, If i am looking at the correct thing. It appears to be a 1 piece sealed assembly on the common rail system. I manually restricted the return line with a clamp untill the engine started clattering bad at idle, then backed the clamp off slightly to where the engine sounded smooth. put it on the road under a load and all i can say is WOW. Very little clattering, and i mean very little. engine sounds like it did when new. I know this is a temporary fix. but i beleive i have found that it is a low pressure problem. What i dont know is what else besides that valve determines pressure or if i am indeed looking at that valve as i havent been able to find any pics of the pump on a 2003. I dont think the dealer will be any help as they have allready said i have no problem. ( they did not run a fuel pressure test). I dont think it would be wise to tell them about the manuel restriction fix. any help or confirmation of my findings would be very much appreciated.

 

I am guessing that you have the valve, although I don't know about the too-many valve engines. The spring gets weak in the overfow, and allows too much fuel to return and so there isn't enough to feed the injectors...layman's explanation.

 

Im gonna try to upload a picture of a pump like mine with the suspected overflow valve circled in red.

 

I couldnt resist the temptation. That little ball looking thing in the center of that valve is apparently a pressure plug. I put a little socket over it and gave it a good tap, seating it an 1/8 inch lower in the hole and apparently tightening the spring in the process. removed my homemade restriction device from the line and tried it out. There is now a pleasant little growl when you first touch the throttle, then pure smooth acceleration. Very little clatter. No high RPM load clatter anymore. At 65mph i can kick it down into passing gear and feel solid acceleration. Goes back to high gear at 75mph and still good solid acceleration to 115mph. The only annoying thing is now at idle in gear there is a slight fuel knock again. Intermittant tho. so it is liveable i guess. Mileage seems to be about the same. I have only driven 30 miles since taking a hammer to it. I am not going to make any more adjustments to the valve untill i know where i can get a replacement if needed. In fact, no more adjustments to anything for awhile. I think i may be pushing my luck at this point. I have not heard that ticking sound since the adjustment. I did not think i had lost any power prior to this. But i can now tell i most definatly had. If it gives me any problems i will let you guys know.

 

INsidIOUS,
I had similiar noises as you have. Here is what I did to resolve them.

Had some rocker arm noise. Went thru all the valve lash adjustments and set them to nominal or less.(Several were on the high side of nominal, but still within specs)

This took care of A LOT of noise I was having. But I still had a loud tick at idle and low rpm. This had to be related to fueling. I dosed up the fuel tank with Power Service and took a 300 mile trip. No change. I double dosed the fuel tank with Power Service and after about 30 miles did several WOT starts from dead stop to 100mph.

No more ticking!!

Conclusion was that the ticking was from a dirty injector. The combination of Power Service as cleaner and high fuel rail pressure from the WOT starts and speed runs cleaned everything up.

 

INsIdious,

Where did you find a road around Tish to get up to115 MPH?

 

I set my valves and cleaned the fuel system, Both of which helped. I am keeping my fingers crossed this latest fix is where i want it to be. Im not going to declare victory just yet. Ill wait untill thursday when i hook up my 5ver and head to the lake.
It sounded awesome this morning when i took my daughter to school. so far so good. I wonder what type of driving is the hardest on those valves?? And i do think i will invest in a decent set of guages, so i can monitor things a little better from now on. Can anyone recommend a good vendor at a good price for some pillar mounted gauges?? and shhhh... I hope none of my local troopers visit this forum. What they dont see wont hurt em is how i see it. lol

 

INsidious,

After looking at the picture again of your high pressure fuel pump, I realize what the problem is....where is the red dust that is supposed to cover everything??!!

That engine is entirely too clean!!!

 

actually SBishop, I borrowed that photo off the net. I havent got brave enough to try and take a picture on my own. My camera seems to only take a picture thats about 1 meg in size. But you may be right after all. My engine is that clean. I wash and wax it regularly. I hate a greasy mess under the hood. Ahh the smell of wax and diesel