Okay I've got something going on with my truck and I'm in need of ideas. My truck sounds different (more tinney rattle) in the top end, less power, less boost higher EGT's. I pulled the valve cover off and re-torqued everything. I was worried something vibrated loose. Everything was tight. I did start the truck while the valve cover was off, and I could hear what was I think was the injectors. Not sure what they are suppose to sound like?

I haven't changed a thing with any settings in the Quad tuning. I'm running the edge tune, (I can post them if anyone wants to look them over). Only thing that I found was the set screw on the boost elbow backed out and was gone. I replaced it (screwed all the in) built a "boost tester" pressurized the system, zero boost leaks. I'll add the data logs, the one in green is from January, red one is from yesterday. 

 

Today I adjusted the valves ( they were a little loose), while running the truck after the valve lash adjustment I noticed the fuel pressure was running between 12-13 psi at idle. I put a mechanical gauge on it and I've got a crazy surging going on. It will stay at 12ish - psi for a second or two, then surge up to 22ish, then drop back to 12ish again(I'll try and add a short video). I did the bucket test on the fass 150 everything is flowing great no surge, Next, I put everything back except pulled the fuel line off the vp44 and ran it into the fuel tank via main fill hose (used the key bump flowed great). Last, I powered the pump with a constant power source independent of the trucks electrical system flowed great no surge.  

 

What I need ideals with is I think I have possible two problems aggravating each other.

First is the loss of power, boost with higher EGT. I'm not sure on this one bc I haven't changed anything with the power out put in my tune. Just showed up along with the change in engine sound...

Re-recap: boost test= no leaks, replaced the boost elbow set screw(I found it missing), adjusted valves, no blow by, waste gate functioning normal with compressed air test.

 

Second is the fuel surging issue... It only seems to surge when the fuel lines are hooked up to the vp44. I'm wondering if there is a fuel return regulator or valve that's malfunctioning ?

Re-cap: Fass 150 bucket test= no surge, in-tank pick up used to feed the fass 150 and pressure line flowing into tank fill = no surge, out side power source = no surge, all the lines back in the places they came from(pick-up, pressure, return) truck running with out side power source= surge, same as test before truck power source= surge

Video file is to big, it won't let me upload it. I can email it to anyone that wants to take a look.

Thanks guys any input or ideas will help!!

post the video to you tube and the give the link here.

 

This is when I first installed the fass 150. I thought the petcock just needed to be close a little. I closed it and barely cracked it which helped the gauge bounce but the system is still surging. Is there some kind of pressure regulator that maintains constant pressure? 

Flow test moved the pressure line from the vp44 and stuck it in the tank fill. 

Any engine codes?

 

Which one of those gauges is right. One is bouncing from 30  to 40 psi and the other 16 20 psi.

Only code was p0500, the analog gauge I dropped once and it zeros at the 18psi mark on the gauge. The actual pressure is 12psi then surges up to 22psi. 

 

I'm going to replace the overflow valve on the return side and see if that helps.

 

But the truck is definitely down on power.  Not building as much boost, higher egts. 

I'm down to fuel issue which I can see on the gauge and possibly a sensor issue.... map, iat?

You aren't going to do anything for the gauge bounce with the overflow valve. That is not what it is there for. Looks like the ball and spring in the fass is worn out.

The fass is only 3 months old I've only put 800 miles on the truck. 

The video with the quadzilla screen is just afterm I installed it in December. It had a surge issue then also. I thought it was just my sensor being overly sensitive, so I barley cracked the petcock just before the sensor and took a lot of the bounce out of the gauge. Made more fuel pressure then.

 

Now making less fuel pressure, and still has the surge issue.  

It doesn't matter how old fass is, when I got mine brand new it had same issue they ended up sending me a new ball and spring that fixed the issue. You can try mortifying spring a little bit and see if it helps and if you do get a new one modify it right off the bat. Also if you don't have half inch lines all throughout the system you will have greater PSI swings but it will not be bouncing at steady idle that is caused by ball and spring.

Modified end goes towards the ball

51 minutes ago, Dieselfuture said:

It doesn't matter how old fass is, when I got mine brand new it had same issue they ended up sending me a new ball and spring that fixed the issue. You can try mortifying spring a little bit and see if it helps and if you do get a new one modify it right off the bat. Also if you don't have half inch lines all throughout the system you will have greater PSI swings but it will not be bouncing at steady idle that is caused by ball and spring.

Modified end goes towards the ball

 

 

What is different about the "new" ball and spring that Fass sent you and what came in the pump ?

 

 

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Yeah I called fass two days ago after finding a write up about the ball on this site. My ball was stuck in the end of my spring a little bit, which would account for the pressure loss. I tried the spring mod and it helped a little, but still had the surge going on. My ball had about a 1/8in, grove/imprint where it was contacting the pump side. Fass is sending me a new ball and spring. I also ordered a viton ball and spring from Vulcan just incase the problem comes back. 

Guessing my pump was one that sat on the shelf for a while before they shipped it. 

I have 1/2in push lock throughout the system. 

 

Just a little info for everyone Diesel auto power stressed to me not to go over 16psi to the vp44 bc it causes them to heat up shortening the life span of the electronic. 

10 minutes ago, 01dodge24v5.9 said:

Just a little info for everyone Diesel auto power stressed to me not to go over 16psi to the vp44 bc it causes them to heat up shortening the life span of the electronic

Like to hear a little more info from them on that. I have been feeding mine between 15 and 19 psi with normal cruising pressure at 17 psi for 7 years for about 190k miles with a total of 220k on the VP I have now.

Quote

I also ordered a viton ball and spring from Vulcan

Did Eric at Vulcan recommend which particular spring for a Fass since he only sells airdog supply parts ??

 

 

I also remember reading, for what ever its worth, That too much fuel  pressure to a VP44 is not good for it . For what ever reason...??

 

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Edited March 21, 20187 yr by GSP7

No I just ordered it from they're website. I got the 17lb spring so when I do the spring mod I dont lose any psi. Bc I noticed my spring got a little shorter after the mod and I had to stretch it a little. 

1 hour ago, GSP7 said:

 

What is different about the "new" ball and spring that Fass sent you and what came in the pump ?

 

 

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It wears a nice groove in a ball from sitting and works it's way in to spring, and for whatever reason doesn't work right after. You can probably get away using same spring if you coil the end of it so ball won't get stuck but it's not easy to put ball back in on the opposite side of where the groove is, I've done it to my old air dog but took few tries. They are cheap and they know it causes this problem, they should send you new one.

31 minutes ago, 01dodge24v5.9 said:

No I just ordered it from they're website. I got the 17lb spring so when I do the spring mod I dont lose any psi. Bc I noticed my spring got a little shorter after the mod and I had to stretch it a little. 

I stretched mine out a bit after mod but do you have to be careful not to do it too much, initially I was close to 20 psi but with time it settled to about 17 cruising

3 hours ago, GSP7 said:

I also remember reading, for what ever its worth, That too much fuel  pressure to a VP44 is not good for it . For what ever reason...??

The VP does not like high pressure when starting. The ECM regulates the starting pressure by turning the lift pump on and off rapidly. Pressures north of 20 psi while running are not recommended as that is hard on the VP. Fuel temp does play into this since the fuel is cooling the computer on the VP. 

Take the risk of blowing the front seal out of the VP44. Excessive pressure above 12 PSI during starting could create hard starting. 

No. The front seal will not fail from perceived "high" inlet pressure. Stop pushing that internet myth. 

7 minutes ago, jlbayes said:

No. The front seal will not fail from perceived "high" inlet pressure. Stop pushing that internet myth. 

 

Ok. Then please explain how the front seal pops out of a VP44?  I've seen 3 reported after having high fuel pressure. 

Please explain how those of us running 30psi have not pushed a seal out? How stock trucks with under 10psi push the seal out? It is NOT a pressure problem.

34 minutes ago, jlbayes said:

Please explain how those of us running 30psi have not pushed a seal out? How stock trucks with under 10psi push the seal out? It is NOT a pressure problem.

Wow !,,,, 30 psi to a vp44,,, You da man !

 

 

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