Engine/Transmission (1998.5 - 2002) is 23-24 psi fuel pressure to much?

[DMcPherson]

I just installed my olley black fuel pump with the original pump in place. I now have 23-24 psi at idle. i think this may be a little higher because the WVO mix, maybe has trouble going through the bypass in the pump. not sure though. theres not much room for a regulator and I am thinking of removing the stock pump.

let me know what you think. Thanks. Dan

 

[Gary - K7GLD]

In a word, no.



I ran about 26 PSI at idle for quite a while with no issues - down the road PSI, especially towing kept PSI just under 20 or so. Then I added a Frantz sub-micron fuel filter, and now idle PSI is about 22, and down the road about 16 or so - right where I'd like it to be. Getting up closer to 30 PSI or more, and keeping it there for extended periods might make me a bit uncomfortable - and Bosch really pushes for down around 15 - but you should be OK.

 

[RCenters]

I run just a holley volumax @ 22psi and so far its been great i trashed the factory lift and filter and went aftermarket,, lines also

 

[DMcPherson]

I think I will remove the stock fuel pump. the holley is regulated to 14 so it should be ok, Ithink between the two it adds up. right now with both I cant pull down past 16psi WOT. stock I could pull to about 4-5.

Thanks, good to know I will be safe untill I remove the stock pump. I am kind of lazy and dont really want to do it this weekend :{

 

[EricBu12]

FYI,



Bosch recomends no more than 16 psi for any of the injector pumps...



I have 2 pumps but have a mechanical regulator after the stock pump set at 15 idle... . To put a regulator here, use tubing and a "T" ... one of the legs go to the regulator, then run a line back to your inlet for the holley...



Since the 2 pumps do well on flow, I get no less than 13 WOT... . Been like this for 4 years.

 

[tking]

I've read on the forum that some guys have hard start issues when pressures get too high.

 

[PRout]

Some more reading material. .

http://turbodieselregister.com/forums/showthread.php?p=1419379#post1419379

 

[Fishin Guide]

FYI,



Bosch recomends no more than 16 psi for any of the injector pumps...



I have 2 pumps but have a mechanical regulator after the stock pump set at 15 idle... . To put a regulator here, use tubing and a "T" ... one of the legs go to the regulator, then run a line back to your inlet for the holley...



Since the 2 pumps do well on flow, I get no less than 13 WOT... . Been like this for 4 years.

I constantly hear people repeat this. And other pressures that Bosch specifies.



has anyone actually spoken to Bosch? Or, do we have an engineer that designed the thing to chime in on pressures?



I think because we have an overflow valve, everyone assumes that it controls overall fuel system pressure. I can tell you that I can take out the overflow and still maintain more pressure than is "recommended". But, we all know the overflow valve is to keep a small amount of fuel in the VP while it's running...





BTW, mine has been running trouble free for well over 40K at 40+ at idle and cruise and no less than 25psi ever.



Dave

 

[DMcPherson]

Some more reading material. .



http://turbodieselregister.com/forums/showthread.php?p=1419379#post1419379

that is some good info. thanks

 

[Steve St.Laurent]

I constantly hear people repeat this. And other pressures that Bosch specifies.



has anyone actually spoken to Bosch? Or, do we have an engineer that designed the thing to chime in on pressures?

Actually, yes. There was a Bosch engineer at the TDR nationals back in '03 doing a tech talk and was asked that question. He stated that they wanted to see no more than 11 psi for the VP44 (he quoted it in a different system but it worked out to 11 psi). When asked why the stock system was 15 psi he had no answer. When I first went to a pusher pump system (June 2001) running at 20 psi I talked with Dodge engineers and they said at that time the more pressure the better up to a point and that 20 psi would be no problem. I've been running at 20 psi continuous since 2001 (had 60,000 miles on the truck at that time) and now have 195,000 miles on my original June build 98 VP44 (which was when the "problem" VP44's were built).

 

[Tractorat]

Well, Im really glad to see this discussion. I just had a warranty replacement LP in the tank on my 02. Then, because my low pressure LED kept lighting, my mechanic said I should add a secondary LP. This gave me 25 and idle and 15 at WOT. After I had the 2nd LP install is when I noticed a lot of discussion sayng that this was way too much pressure. And that the vp would suffer. When I asked my mechanic about this, (he specializes in diesel, and works on a lot of Dodge trucks), he was very adament about that being hogwash. And that the high pressure that I now have wont hurt anything, and is actually good for the engine.



My 2cents worth.



TRat

 

[Fishin Guide]

Actually, yes. There was a Bosch engineer at the TDR nationals back in '03 doing a tech talk and was asked that question. He stated that they wanted to see no more than 11 psi for the VP44 (he quoted it in a different system but it worked out to 11 psi). When asked why the stock system was 15 psi he had no answer. When I first went to a pusher pump system (June 2001) running at 20 psi I talked with Dodge engineers and they said at that time the more pressure the better up to a point and that 20 psi would be no problem. I've been running at 20 psi continuous since 2001 (had 60,000 miles on the truck at that time) and now have 195,000 miles on my original June build 98 VP44 (which was when the "problem" VP44's were built).

It's good to hear some first hand info.



I am working on a bypass sytem that will end up regulating me to about 25 psi. With my new Vulcan fuel system, I cannot pull it down below 38 PSi. That's up from 22 PSI with the stock module and plumbing.



Dave

 

[Gary - K7GLD]

I constantly hear people repeat this. And other pressures that Bosch specifies.



has anyone actually spoken to Bosch? Or, do we have an engineer that designed the thing to chime in on pressures?

Actually, yes. There was a Bosch engineer at the TDR nationals back in '03 doing a tech talk and was asked that question. He stated that they wanted to see no more than 11 psi for the VP44 (he quoted it in a different system but it worked out to 11 psi). When asked why the stock system was 15 psi he had no answer.

(SIGH!)



Actually, Bosch engineers are really not much different than a lot of us in THIS forum - each seems to have his own personal view as to the "ideal", or "recommended" PSI for the VP-44.



Over the last several years, I have heard - and read - at least *4* different "official" recommendations from various Bosch "experts" - and the recommendations have run all the way from as low as ZERO PSI, clear up to 16 PSI.



The Bosch guys on the LOW end of that scale emphasize that ANY operating POSITIVE PSI is all the VP-44 actually needs - anything above that up to 16 PSI or so is over and above actual "need", but still acceptable.



SO, the REAL question is, which of the Bosch "experts" do YOU choose to believe? :-laf

 

[mhenon]

I've been living with the in-tank pump and 5 psi for a year now. I don't care what the "experts" say... staring at low fuel pressure (0 psi @ WOT) all day makes a guy nervous.

Finally broke down and got the Vulcan pusher kit. Now the in-tank pump is keeping a head of pressure to the carter (which is mounted down by the tank) and I've got 26 psi at idle, 24 down the road and 22 at WOT. Haven't put a load on it yet but I don't think it's going to budge.

I'll take this any day over constant low pressure and wondering when the VP's going to puke.

Mike

 

[GiesJ]

This is from a thread over on the DTR, the quote is by Don M (Nov of 05). I can't say I'm smart enough to understand the VP-44 and all of its intricacies, but I respect what Don says. Maybe this will help? He is talking specifically about his Helix cam and a mechanical fuel pump:

The 30 PSI system is the best route, IMO. Back when the 12 V mechanical pump started being installed in the 24 V with the VP-44 pumps, people were seeing around 55 PSI on average. Even at idle it could be as high as 50. That was years ago and no reports of failures were reported from this pressure. Remember the internal feed/suction vane pump inside the VP44 is raising the pressure over this value to the plungers. Anything you can do to increase pressure to vane pump is a good thing. To a point of course.



Back when things were getting going hard we tested, on the dyno, many pressures that made the best HP for the 24 VP44 engines. 22 PSI and up was the best, with no more or less power made at 50 up to 72 PSI. At 72 and up we lost a few. Probably from cavitational losses.

 

[NoSeeUm]

FYI,



Bosch recomends no more than 16 psi for any of the injector pumps...



I have 2 pumps but have a mechanical regulator after the stock pump set at 15 idle... . To put a regulator here, use tubing and a "T" ... one of the legs go to the regulator, then run a line back to your inlet for the holley...



Since the 2 pumps do well on flow, I get no less than 13 WOT... . Been like this for 4 years.

What type of regulators are you using?



Jim