hey yall,
I've got an '83 turbo. i'm looking at the walbro pumps to keep the IP strong, I know it needs to be low pressure but how low? Would 6-8 psi be too high?
Thanks
hey yall,
I've got an '83 turbo. i'm looking at the walbro pumps to keep the IP strong, I know it needs to be low pressure but how low? Would 6-8 psi be too high?
Thanks
I've been running my pump at around 8-10 psi into the injection pump for a while now. In my experience that much pressure won't be a problem
"8-10 psi into the injection pump for a while now" That is too high a supply pressure/fuel rate. You will affect the pressure regulation within the pump body. That said it could have some positive effects. You want to have the lowest supply pressure 3-5 max and 1-3 ideally . The vane assembly in the VE is a robust supply/transfer pump.Originally Posted by dancinggecko
Normally there is no need for the lift pump, however I have seen OEM in the ford ranger a e-lift pump in association with the 4d55 but it may relate to the twin fuel tank setup. I don't know if in that application there is any different sort of IP calibration. Would be interested to learn.
Great to hear, thanks
Sure there's technically no need for one, but it definitely improved pump life and performance, and I do not envy the person who has to bleed one of these pumps with out a lift pump helping you along. Believe me, it is a whole lot easier.
I had some concerns about the internal pressure of the pump, but then I spent some more time looking at the design of the pump and other applications of Bosch VE pumps. That extra few PSI is fairly negligible in relation to the internal pressure of the pump. The flow rate of the pump is restricted by the head/plunger size and the injector orifice size, so it won't be forcing more fuel through it that the engine can handle. The injection pressure is regulated by the cam plate and the injectors, so it won't cause problems there. At worst it might cause a seal to blow out prematurely, which would certainly make a mess, but would certainly not damage the pump.
Then you look at other applications that use these style pumps and they almost always have some sort of either mechanical or electric lift pump, and fuel starvation is the biggest reason these pumps die. I'd much rather worry about a slightly higher than necessary supply pressure. The vanes in a VE aren't bad if that's all you've got, but they don't give you much of a safety margin.
I wrote a considerably long message and I got a message waiting for moderator to approve. That's the second time it's happened and the message doesn't show up. hmmm
It's not the max fuel volume of the plunger at all. It's the effect of the fuel volume transfered at a given meetering sleeve position. And the amplification of those psi.
I agree it's nice to pump fuel to the IP quick. doing it myself by times. Can prevent a lot of wear due to cranking dry. and restore supply pressure when getting creative with switching fuels.
Using them to satisfy a thirst for fuel volumes sort of defeats the advantage of the diesel imo. lol
It's about a pump's calibration specs. I can't tell you why a specific pump application is set up on the test bench to achieve it's fuel volumes and efficiency based on the application's supply pressure. How far away are the tanks? Are there pre and post filtration? Is there a lot of elevation to gain? Did it intend to get run with a supply pump, because it needed it?
Presumably the ranger with the e-lift pump is calibrated differently then the pump in the L200/mighty max and my delica - all kinds of the ve style pumps were fitted OEM without lift pumps.. The high price of that ford lift pump must reflect it's internal regulation - a key consideration. they want like $500 for that ford pump (which cross applies with all kinds of gas engines oddly enough), compared to the relatively cheap in line pumps. Mechanical lift pumps on a cummins with a ve are internally regulated. The stanadyne db2 which has a relatively weak in comparison vane pump assembly, is calibrated at a 5psi supply pressure on the 7.3
Calibration wise, the transfer pressures are at the root of it. but I appreciate at a certain point in it's life cycle, calibration gets tossed out the window for one reason or another.
While it could prolong vane pump life, and mask other supply problems like sending unit and fuel line issues, etc, and improve performance on a worn pump, it also affects the injection timing. I think it could have a negative effect on efficiency, for one, because transfer pressures rely on venting to the housing, which may be be troubled. It may cause or exacerbate leaks at the shaft seal and elsewhere. increased cycling causes fuel washing at the same time as it cools the pump. 200k mile pumps can have noticeable drive shaft bushing wear from constant leaking past the seal. The things are so dynamic it's hard to say where the +/- balance is. Cost of repair being part.
Without a complete reseal or even troubleshooting the IP an epump can make a big difference in driveability with a worn IP because it will advance injection timing, either by boosting the transfer pressure and or acting on the timer. It can mask a bad supply pressure regulator. A better approach is to advance the pump's timing manually. And inspect the IP regulator for bad orings and loss of function, perhaps even setting it higher. it's today's fuels and the fact many of us have less then ideal pumps and fuel supply. Does your truck run better when you've a jug of ATF in the tank? It's both the viscosity and the sealing aspect of it. Does it start and run better with a e-pump? it's likely because it overcomes the supply/transfer struggles.
The internal pressure of the pump (transfer) is going to exceed the supply considerably of course, but that doesn't have anything to do with the spill of transfer pressures back to housing and fuel metering.
I've been told the very best piece of equipment for priming and sluething supply system is the mighty vac a hand held vacuum pump which not only gets the fuel there but tells you if it will hold there (esp. if it has a gauge).
I'll try again as the message hasn't shown up
Re: pump life. It can keep vane pump wear down when there are problems. These pumps can be good for 300k+ miles if not abused. During priming it certainly cuts down on dry pump wear. But so can a vacuum pump, which, has the added benefit during priming of showing if the supply system has air leaks in need of repair. The mighty vac is your best friend when it comes to priming and sleuthing.
Re:performance. It can mask a worn pump's issues and prolong drive-ability. So if you're pressure regulator valve is faulty or there are leaky seals it can help with that.
On a good pump, it can amplify the transfer pressures. It will affect fuel volumes as a result. and at low speeds overwhelm the supply pressure regulator and affect the timing advance mechanism. That is why applications designed for supply pumps have internal regulation of pressure in the supply pump. cheap carter/purolator does not. That's the reason the supply pump on the Ford ranger 4d55 is so damn expensive (like $500!), as are other regulated e-pumps. Mechanical lift pumps on the cummins and international 7.3 have internal pressure regulation, and the IPs are calibrated based on the designed supply pressure. in the case of the Stanadyne which has a weaker vane in the pump then the ve style, it's calibrated at 5 psi.
The call for supply pumps comes from the applications of those engines. What is the tank elevation and distance relative to IP. and is it going to vary based on the variety of configurations like long cab and chassis or extended wheelbase. Is there switching that might introduce air.
There will also be more fuel circulation which can help cool a pump, however the drive shaft seal is at risk as is the shaft and bushing, which on these are an expensive repair. I've seen the washing damage to bushing and shaft. The whole supply and return system sees more use and wear.
In an application like these where the pump is calibrated at no supply pressure, of which there are all kinds i.e. all those VW's up to 2003, the addition of the supply pump should not have a lot of flow. But it should also not restrict the flow when the pump in the IP is really sucking.
It's a really good idea to have a pressure/vacuum gauge on the fuel supply between the IP and filter so that the supply situation can be monitored. It can tell you a lot about what's going on including condition of filters. Hope this helps someone.
...diesel guys are a totally different beast when it comes to engines - I feel like a noob
I agree with everything you said about too much pressure and the damage it can cause. There is a risk of pressure blowing out seals or wearing out components faster than they otherwise would.
I disagree about what constitutes too much pressure, particularly on the version of the VE pump that came standard on the 4D55/4D56. Some obscene supply pressure like 50-60 PSI, sure, that's putting a ton of force on these cast aluminum housings and the components therein. I won't argue against that. I will argue that 10-15 PSI is not going to hurt these pumps, particularly if it is regulated to avoid any pressure spikes. I don't see how a stronger lift pump can cause these problems you discuss so long as they are supplying reasonable pressure. An unregulated pump supplying high pressure, maybe, but we're talking maybe low teens tops. Even unregulated pressure in the neighborhood of 8 PSI, like that OP was experiencing would not be a problem, and my current lift pump is a regulated pump we have set to right around 12 PSI (can confirm, they are not cheap units).
In regards to the difference between pumps were "calibrated" for a supply pump and those that were not, you reference the Ford ranger pumps as being one such pump. (Unless I misunderstand what you are saying in which case I apologize, and you may disregard what follows) I have disassembled pumps from 4D55s from both Ford and Mitsubishi applications. They are identical. In my experience I simply have not seen any major internal differences between these pumps that were equipped on vehicles with a supply pump and those without.
I feel like we are basically on the same page as far as too much pressure is not a good thing, but we seem to be in disagreement as to how much pressure is too much on these pumps. With the pressures I have run I have experienced no problem, except for possibly a seal failure, some of which can also be attributed to a 40 year old injection pump that had probably never gotten new seals since it left the factory. Not a serious risk of damaging the pump in my opinion, but rather obnoxious when you leave a puddle of diesel whenever you idle somewhere for too long.
I also agree with the need for a pressure gauge. In my opinion that goes without saying as it can tell you a lot about what's going on at any given time with your engine.
For what it's worth the lift pump I'm using is an Airdog Raptor that was intended for an 1989-1993 Dodge with the 12 valve Cummins. Has done great for me on the interstate, as I frequently take 4+ hour long trips. That motor is surprisingly happy to sit at 3000RPM for the whole time, and that big lift pump keeps the fuel flowing nicely.
For what it's worth the lift pump I'm using is an Airdog Raptor that was intended for an 1989-1993 Dodge with the 12 valve Cummins. Has done great for me on the interstate, as I frequently take 4+ hour long trips. That motor is surprisingly happy to sit at 3000RPM for the whole time, and that big lift pump keeps the fuel flowing nicely.
I think we're on the same page, and we differ in opinion on where the line is. I wouldn't recommend any more then 5psi. I'm saying it has an effect on the pump's operation. First gen Dodge cummins was 3psi min 5psi max to IP, right? Guys are ramming fuel in them ve's to try to get more fuel to burn or smoke.
You wouldn't see the differences IN the pump unless a guy could crawl in there and count fuel units into the plunger (this '83 pump is supposed to have a bigger head/plunger so that hi-po folks can get more fuel volumes). You'd see them in the metering of the fuel on the test bench. the IPs proper operation depends on the relationship of transfer and case pressures as I understand it. May be that explains why performance will improve when you put a lift pump on a truck with a leaky IP. It helps the pump achieve injection pressure.
A supply fuel pressure gauge alone mightn't tell you your fuel is gelled or your sending unit is plugged.
It happened in my mazda ranger one time I left the coast at 10 degrees celcius and hit 20 C below freezing inland, felt some stuttering and looked down at my pressure/vacuum gauge to see it bottomed. Thankfully had a second tank on a switch I could put some fresh diesel in. I had used an inline e-pump with the veg oil tank to allow for an earlier switch to the oil in cold temps and shut it off when everything warmed up as indicated by the supply gauge. I didn't want to put pressure on it. 150k miles I put on running veg oil.
the rear end in my 5sp delica is like 5:1 and any highway driving had that 4d56 at 3000 rpm doing only 55, which it didn't seem to mind at all. I had completely resealed the pump and the thing ran tops, climbing mountains like a champ.
We didn't grab ahold of the diesel here in the North Americas quite as much, so the capacities we have for passenger diesel aren't as spread around. Not that it's of huge consequence as we'll be fueled by electrons soon if they have their way....diesel guys are a totally different beast when it comes to engines - I feel like a noob
Still, fuel supply on gas engines has similar considerations.
I'm interested to know what it's done to improve the highway driving. Did you struggle with getting fuel to the pump in the past?
Yeah, that's part of why we went with as big of a pump as we did. I had tried just using those little Carter fuel pumps for a while, but they couldn't keep up, even on a stock pump with rebuilt injectors. I also plan to go to a 12mm pump head instead of the current 10mm head at some point, so it was also a bit of future proofing to make sure I wouldn't have delivery problems when we did that.
I actually had an issue several years ago where the pump lost prime. At the time we were just relying on the internal vanes to supply the injection pump, after that we put on one of those little Carter pumps. When I started making those long interstate trips the truck would act like it was starving for fuel around 3-3.5 hours in. We eventually put in a fuel pressure gauge and confirmed that was the issue. Once we put the Airdog in I have been able to maintain constant fuel pressure all the way. Still on a stock pump with stock injectors. Only thing we've done there is advance the pump timing a few degrees
There would need to be a reason the pump couldn't keep up. Something was obviously wrong. IN the photo are two supply regulator valves. The bottom is from a vp37 VW and is exploded just the way it came out of the faulty pump, after fishing out with a magnet. The tamper seal paint was in place on the regulator. The piston retainer had fallen out allowing it to fall from the cylinder so that what Stanadyne folks call transger pressures wouldn't be achieved. The upper valve in the photo is from a diesel kiki NA. Its bottom oring was hardened and flat, which might have allowed leakage between the supply and case, but surprisingly it didn't break apart when I took it off.
The supply/transfer pump vanes or journals could have scored very badly from dry running. And it could relate to air leaks and supply restrictions.
BTW I was using the Mitsubishi diesel ranger OEM lift pump to fill my f250 transmission with new fluid yesterday, and it fed approximately 10 GPH.
https://youtu.be/SqBlqdeP3uE?t=72
Automatic or manual? Surprised the little pump could handle that high of a viscosity if it was for a manual. We haven't been inside that pump for a while. We actually took it off to get resealed and to put it aside as a candidate for the 12mm plunger. We put on a newer 4D56 pump in its place. Haven't tried running it without a lift pump, but then I also don't really I intend to take that lift pump back off
That was mercon v atf in a ZF 5spd. What it calls for.
How's the newer pump working for you? Do you watch egts? I intend to do the same on my 4d55 Ranger build with a 1990 4d56 pump, only without lift pump. I had inspected and re-sealed it, punched in the pressure regulator a hair, and tweaked for a slightly higher then original boost. When I did that work I was also resealing a 4d55t pump for a guy in exchange for a parts truck - where the lift pump came from - along with spare injection pump. Fair deal we agreed. That IP I resealed is the one I mentioned had had damage to the drive shaft bushing. It had been run on the parts truck I inherited with the lift pump that, when I tried pumping atf, it took a long while before it spit out a big, diesel-pickled bug and began flowing.
Newer pump runs fine. Performs the same as the older one. We tweaked the AFC on it to match what we had done to the 83 pump and advanced the timing to match. I do watch EGTs, I have my thermocouple placed immediately upstream of the exhaust manifold outlet flange so I am measuring right before where it goes into the turbo. Running down the highway I usually see EGTs in the 600*F-700*F range. On flat ground on the interstate it tends to sit around 900*F. Hottest I have seen it get is about 1250*F, and that is when trying to pass someone going up some of those long grades you'll get. Cools off nice and quick when I get off the throttle though.
The timing would move ahead some when the epump is running. you would know if timing was too far advanced by the bad noise and when you put the pedal down and it slows down. The 4d56 exhuast manifold has a convenient egr port on the number four outlet to block off and insert temp gauge I use. Trying to decide if there's advantage in running the egr-less 4d55 intake on the current build. On the 56t delica I never saw above 1100F steady mountain climbing but I hadn't turned up fuel very much.
Is there somewhere on here you've shared the rest of your set up? What are you running for injector nozzles?
Just running stock nozzles. Planning on getting a set honed out for more flow at some point, but that will happen after I get a larger head for the injection pump.
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