wil440

I haven't got the stock filter, plugs are tied up and causes no bother at all, I use a Cat filter head and Cat filters How I see it Dodge made such a pissant job on the fuel side I'll do it all myself, mechanical lift pump, Cat filters..... soon to be bigger Cat fuel/water separator and Cat fuel filter side by side Also am I missing something I thought 3um was a finer filter medium than 7um...... if so how does a 7um filter catch what a 3um filter misses or did I get it the wrong way round ??

I got a PS pump seal kit and a vac pump seal kit sent to me from Rockauto, removed both and separated them, the PS pump drive was badly worn on the drive segments and the seal path was grooved so I had to then order a complete pump which took another 7 days to get here, no big problem for you guys as you can just go to the parts store, no so here in the UK. Also the new vac pump seal was that poorly made I reused the old one, it was a Dorman 904335 seal kit

I'd be checking there is actually oil in there and then add friction modifier, like you say sounds like non went back in

I'd also be doing a oil change first, with friction modifier. Cat do one which I use. Stopped all the scrubbing and clunking on my truck. Also when draining the old oil if chunks or metallic paint drop out you know you need to investigate further. I'm happy my truck has LSD

The above wasn't directed at you or your truck, apologies if thats how it seemed more to people that get low pressure alongside next to no flow through the return and think their vp will be ok

Thanks for posting this Tractorman... gives me some idea of whats going on, I'm still not sure if I have a problem or not, I have low fp at idle coming up damn fast with rpm, to the point of my fp regulator cannot get it back to tank fast enough, only thing I can see that would cause excess return flow is a broken spring just to the right of centre on this picture.... OR as you say in your next post that it is flow not psi that matters Now that is one interesting read, my low pressure fuel system is really bucking the "required".... I think I need a flow gauge as well as a fuel pressure gauge, I could blow the face off of my fuel pressure gauge by clamping off the return from the T at idle easily, now I would then be in the "ok" fuel pressure club..... would there be any cooling flow back to tank... no One thing I will again say I have tested MY return flow and checked my fuel temps and my lift pump is mechanical and my basket and draw straw is clean and not blocked so please don't compare your carter in tank sucking through the bottom of a pond and think it will be ok cos it won't

Always best to follow the diagnostics. Way cheaper in the long run

150f fuel temps would be more of a concern to me, mines 110f to max 120f, and we just had 6 days of temps coming up from africa

No. There is a short steel tube 1 1/2" I think with a small tube welded into at an angle, this goes into the filler hose with the angled small tube pointing to the inside of the tank. On fuel Boss website I think I saw it. I'd take the quick disconnect off of the tee at the cylinder head, 3/8th fuel line will push over the ridge and use a jubilee clip, take the other end to the filler neck and see what flow you have at idle, with a passenger and a bucket you could check at wot also..... do the same at the basket and you now have the tee return in 3/8th rubber, easy enough to then make or buy the fuel boss filler hose return

Surely if the internal vane pump is regulated at 100 psi but the 14psi overflow valve is in the vane pump discharge the vane pump pressure will be 14 psi ? More likely the overflow valve is in the vane pump inlet and the 100psi regulated pressure is in the vane pump outlet or high pressure inlet section. ? My fuel temps don't got over 120f so while I haven't measured return flow It is full 3/8th rubber line wide when put into the tank neck, I fitted a Fleetguard FF5319 last night, at least 25% longer than the cat 1R0750 I took off. No change. I checked the overflow and it looked ok but as they are cheap here I changed it anyway. Yes I have mechanical LP. I can use the higher gearing and idle pressure is 10 to 12 ish but I'm curious as to why I have to use high gearing, I feel something is or might not be right. My next step is to test with another gauge then I'm going to strip the pump and check it as it has been on high gearing since new.

I'm getting good flow at 5 psi at idle with a brand new cummins overflow valve... same flow and psi as the old one I just removed. I need to check further me thinks..

The pages in the link are Cat media Page 1 says high efficiency filters removes 98% of particles down to 2 micron https://dieselfuelfilterkits.com/docs/cat_filters.pdf To be fair the cat media article is 2001

Interesting... my Cat SIS web Lists it as a high efficiency 2 micron filter 1R-0750 i'll check it when I get to work as sis is on my work laptop, easy to test as I can put pressure gauge into filter inlet and measure the difference FF 5320 is what's coming

I've done a lot of checking and testing on this on my truck last week and my truck has a bleed orifice in the overflow valve at the vp and it flows a huge amount of fuel back to tank at 5 psi at idle, I have an assassin mechanical pump and use cat 2 micron filters, I've been running my assassin on high gearing to get higher idle pressures through the 2 micron filters but last week I changed the gearing back to low to test and have 5 psi at idle and 25 psi at 2k ish. I have tested the return from the Tee by replacing the steel line with 3/8th rubber and having the tank end in the filler neck to check return and it's a lot I have a 5 micron fleetguard filter on it's way to see if that gets me higher than 5 psi on the low gearing... more to test than anything else. I replaced the overflow valve with the correct part number from Cummins 467-445-003, same as the old one and the same 5psi at idle, I will add my pressure increases really fast straight off of idle So on my truck at least FP doesn't need to be 15 to get return flow, this 5psi I'm seeing must be attributed to my 2 micron fuel filters but I will keep testing until I'm sure, I don't know why because my fuel temps are 110f to 120f and it takes ages to get to 120f and never on a full tank and I can just use the higher gearing pulleys and be fine.... lets just say i'm curious

Million mile motor in a 3 block pickup truck.... Nah I'm joking, I'm in the UK, parts are hard to get not like you guys and mine touch wood is as reliable as it can be at 22 years old, my truck was not maintained here in the uk properly, it is now and yes I've done the required fuel mods, I haven't and won't go down the road of big power as long as it pulls my 5th I'm happy, 1000 mile trip 2 weeks ago with only a fractured fuel return line, easily bodged with silicon sealer (now fixed) I would advise to drop the most expensive scanner on it you can borrow beg or steal for a few minutes and see what if any codes are present/logged, newer Snap On comes to mind, if any are present thats a good tool to either get the cost down or walk away, check back here to id any codes in the article section

To be honest I think a vp needs flow not pressure, problem is flow needs to be the same at idle and wot

Yes thats correct Jag my truck has a small bleed..... don't know about other years. a fuel boss uses the return in the filler neck I'm looking at fitting that very same thing

The vp is constantly supplying fuel to the injectors.. lets say it needs 1 gallon per hour at a given rpm, if your lift pump is capable of 1 gallon per hour nothing will be returned from the vp, this is what keeps it cool and ok. in this scenario you have zero over capacity, and to check how much fuel is going back disconnect the push on fitting at the tee at the left rear cylinder head and a 3/8th rubber hose pushes over the steel stub just nice. Put it into the filler neck and start the truck. Works better with a mechanical pump as idle is the lowest flow

to get huge flow you need over capacity not pressure, and for the technical writers that was direct from Cummins not Dodge or Chrysler but Cummins but hey what do they know The only return that is anything is the vp, the return from the back of the cylinder head really isn't much compared to the vp this is from a Bosch certified fuel shop who see vp's every single day here in the UK spoken to on thursday, bearing in mind Dodge was a tad late to the vp party compared to Europe. The overflow has a bleed orifice which is open all the time and is nothing to do with the relief valve My fuel temps are max 120f at 1/2 tank or thereabouts, 110f max full tank with a mechanical pump not electric so i'm not worried at all

Jag If you take a look at the overflow valve there is a drilling in it that is always open, certainly on a 98.5, this with a mechanical pump at least sends a lot of fuel back to tank all the time, I'm pretty sure most of my excess fuel is returning to tank from the VP overflow whether it's through the small drilling at idle or close to idle or the actual 15psi relief, my pressure regulator is in a separate return line and that's what stops psi going above 25. I was thinking depending on what the 5 micron filter does I may use the higher gearing for the pump which gets me around 12 to 15 psi at idle and drill the pilot relief in the overflow a tiny bit bigger doing this will mean nearly all excess fuel will be returned from the vp. Just to recap IF the overflow is a genuine Bosch 467 445 003 it has a bleed orifice and does not need to see 14/15psi to flow fuel back to tank, if the lift pump is man enough there is plenty of flow BUT while looking for a overflow valve all in the USA I found some pictures show NO second small drilling, I just picked up a genuine Bosch valve 8 miles from home here in the UK I will add DO NOT take this as true on another truck, I have spent time checking my truck and I am happy I'm getting good flow back

Well I sortoff are as right now I'm at 5psi at idle on the low gearing for the assassin, 2 micron Cat filter with my gauge on the VP side, correct me if I'm wrong but isn't the stock filter 10 micron ?? I'm seeing a huge amount of volume going back to tank but only 5psi at idle, now if I clamp off the TEE return I get some serious psi at idle, open return line the volume back is considerable, I've changed the overflow which has a bypass anyway before the 15psi regulation thats built in, if I gear the pump up I'm all good but I'm thinking too much psi is just increasing the fuel temps for no reason, I do have a 5 micron Fleetguard filter on it's way to test. I'm happier with huge flow rather than huge psi and my fuel temps are very low, we'll see when the 5 micron filter is fitted and to clarify 5psi at idle and 25psi at 2k and I have checked for flow with the return placed in the filler neck to see whats happening

I have an Assassin mechanical pump with a drawsraw in the fuel basket for supply, easy to do with the tank dropped

70% of the fuel should go back to tank at all times and WOT is where max heat is generated, I read the service manual yesterday on this very subject. I had the return line off recently to replace it and put the tank end into the filler neck and ran the truck to see whats returning, I have a really good flow back to tank and this is with a new overflow valve and the assassin geared low

On the assassin you fit a drawstraw to the fuel basket, this is the "new" supply, the tee at the rear of the head goes to the smaller connection on the fuel basket and the fuel pressure regulator which is in the kit goes to what was the old fuel supply, most of what is in the fuel basket is chopped out, looks to me like the Fuel Boss uses a 1 1/2" steel tube in the filler hose with a 1/2" stub welded into it for the returns Mechanical pumps don't need an electrical pump to prime the system, if the system is bone dry then you drop the pump down and prime with a drill, takes about 5 minutes, if there is fuel to start the truck it bleeds itself, I've had most of my lines off today fixing the steel return from the Tee which had cracked, didn't bleed it once