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Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbro 25
So, we've been kicking around some discussions lately and wanted to try and keep my discussions organized and seperated a bit from my main build thread.
Quick summary: Meanmini has a replacement fuel tank that apparently has no sump baffles. She has a Walbro 255 lph HP and has no fuel issues normally. However...
At Cecil running just under 1/4 tank and launching harder than she ever has (due to slowly stepping things up) she found her limiting factor - fuel slosh and pump starvation.
Randy (GLHS60) has suggested running the newer style pump housing or the newer jet pump technology. I just scored this 1994 pump module from ebay: http://pages.ebay.com/link/?nav=item...192801&alt=web
I really just need the reservoir and hanger as i'll have to try to fit my walbro inside.
These newer modules have the sender built in, but in 89 they used a seperate sender. It appears the resistances are the same. I could use everything on the new module and use the wiring harness to make the conversion.
The 1994 fuel tank has one opening, but has no baffles either. If i used it to get rid of the seperate sender hole, then i would end up again with no sump baffles.
My thought was to also change fuel tanks to the Dorman 576013 which has a baffled sump.
I want to fix this once, since i have to go back into this unexpectedly. If with this newer style pump hanger with a built in reservoir there is no further benefit to be had by having a baffled sump, then i might be better to either simply install the new retrofit into my existing tank, or get the 94 tank and eliminate the seperate sender. No really sure which to do.
shackwrrr or Vigo had mentioned about using the newer reservoir style hanger and fitting the older pump to it. If you have some further tips or suggestions i would appreciate any input, or from others who may have done similar.
If i had more time and money when Brian had Mini for all his other great work, it would have been nice to have the tank sumped and an external pump. But one can only do so much and i already had this walbro 255 in tank pump ready for the buildup.
I did watch a cool Airtex fuel pump installation video, which said the vans had a fuel tank drain line. I had noticed a stub fuel line with a cap but never knew what it was for. I figured it was some emission stuff that was plugged.
https://youtu.be/t5JX_AATbtM
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
The capped fuel line is indeed a drain line. You can start a siphon from it. If you have shop air, an easy way to start that flow is to wrap a rag around the tip of a blow gun and slowly force some air into the filler neck. Obviously you can blow things up if you put 90+psi in the filler neck but if you just apply a little pressure and the drain hose is attached to that plugged line, it should start a siphon flow.
You can also disconnect the fuel hose between the fuel rail and strut tower and put a piece of hose into your gas can or whatever and used the fuel pump to pump the fuel out by jumping power to the coil positive terminal which will run the fuel pump through the ASD circuit.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I thought it was neat. I didn't know it was a drain, and i had planned on using my return line to pump my fuel into a container with the engine running.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Both the Cargo van and several other turbo vans that I have raced did the exact same thing. I get being as light as possible when trying to get a new PB, but just race it with a half of tank of fuel and forget it...
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I was good at over 1/2 tank, and i've been good at a bit under 1/2 tank. At Cecil i was right around or just above 1/4 tank and i was ok the first pass but after not so.
Looking back, i might have had a couple times close to 1/4 tank where i could have had this happen and think it was something else.
I can race with 1/2 or a full tank just fine, but i might need every little bit of weight savings to break your van's record and try to break Joe's record! ;)
What i don't want is to have things just right at the track and then have to add more fuel, if that will throw my pump gas to race gas ratio. When things are going good, i don't want to make that kind of change.
But i get what you are saying. I want a simple and cost effective solution.
Having to race with 1/2 tank means i'm rolling with about 70 pounds of fuel weight.
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5 Attachment(s)
Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
So my ebay spectra premium SP117 pump module came in today. This was the pump for a 1994 caravan. Attachment 59866
So firstly, what is the line that is just hanging there, the black tubing? It is actually the biggest diameter tube. The small one is the return, and the other large one is the pump discharge. Is this black tube something for emissions/purge can?
Looking it over and seperated the housing. Wow, its got some guts.
Tried to remove the pump, but it would not just pull out, so rather than break something, figured to ask.
Attachment 59867
The other thing i'm thinking with this style pump, with the amount of bypass flow for this jet arrangement, do i need more than a 255lph in this housing to make this work and supply my fuel needs?
Here are some other pics:
Attachment 59868
Attachment 59869Attachment 59870
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
The black hose is the siphon tube for draining the fuel manually if necessary.
Not sure I understand your jet question ?
Thanks
Randy
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Well for one, i can't get the actual pump out. That plastic tube on the pump discharge that goes down for the jet looks like the same oring slip on like whats in the other hanger section, but it doesn't slide apart.
I'm wondering if it is fused together and cant be seperated?
The jet question is, with this setup it uses alot of flow in a recirc for the jet action, correct? Will i need a larger pump than my 255lph in order to still supply enough fuel for 500hp at the rail?
This stock replacement is rated for 50 gph, (~190 lph).
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I feel for where your at with the Van right now you need to either run more fuel at the track,
get another tank and have a sump welded to it,or run a fuel cell.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Hi Wayne:
I don't have any experience with the unit pictured, it may be "fused" together.
The two I worked on were an approx. 1994 Dodge Spirit and a 1997 Caravan, both factory assemblies.
They weren't fused together but were tough to take apart as they are sold as assemblies.
I think Vigo mentioned he took a 1994 unit apart?? I'm guessing it was a factory assembly??
I believe he installed another pump, as I did.
The purpose of the canister, or housing, or bucket, in this instance, is so you don't need baffles in the tank.
Even under hard acceleration the pump is in its own little "surge tank".
Fuel pums push better than they suck and sloshing uncovers the pickup.
The jet sucks like a vacuum cleaner, using the venturi effect, to keep the canister full.
The jet doesn't reduce the pumps ability, it enhances it.
Vigo is a shop teacher, hopefully he sees this and explains it better!!!
Thanks
Randy
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I follow you Randy and i appreciate the explanations. They are easier to understand with the part right in front of me so i can see how it works.
What i mean is there is always some flow returning around through the tubing within the module for the jet. If the pump flows 50lph recircing around for the jet, that means that flow doesn't get to the fuel rail to return from the FPR. Which means i have reduced some of my available flow at the rail because it is recircing around withing the pump module, does it not? My pump only flows 255lph, and some of that then would just stay flowing around within the tank for the jet effect.
Now if i simply sumped the tank, and used my existing pump and hanger without the jet type pump module, all 255lph is flowing to my rail.
I hope Vigo does see this, so he can respond to how to remove the pump from the can. Maybe Spectra Premium fuses the plastic, and maybe another brand does not.
I have the stock type baffled sump tank on the way, so when it gets here, I'll see how the baffle is shaped. Worst case i just make that work, or add to the baffles.
I wonder if i'm better off to just sump my tank and do an external pump? If i wasn't concerned about the cost right now that's probably what I'd do.
-Tank welding
-External pump
-Pump Suction filter
-Tank Isolation valve
-Fittings
It would all add up to a bit.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Where does the return dump to? Maybe do some mods to use the return flow to run the jet pump instead of the fuel pressure feed.
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1 Attachment(s)
Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Quote:
Originally Posted by
shackwrrr
Where does the return dump to? Maybe do some mods to use the return flow to run the jet pump instead of the fuel pressure feed.
Before it arrived, i thought this was how it may be set up.
The return just dumps back into the canister/reservoir. It is the little stub piece in the top part of the canister, and it looks like there may be a check valve in that plastic stub.
Attachment 59875
The return line doesn't have the same pressure as the pump discharge, so i wonder if the jet would still operate properly?
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
The jet pump is based on flow not pressure so it would work just fine.
Here is an aftermarket one
http://www.radiumauto.com/Venturi-Je...-Kit-P760.aspx
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Good point!!
But I was just reading a fuel pump jet patent and it said not to use the return as the jet looses effectiveness under high demand this way.
""As to using the returning fuel to power a jet pump, this approach has been found to be unsuccessful under conditions of high fuel consumption by the engine. Specifically, when the engine is using more fuel, less fuel is returned to the jet pump and thus less fuel is pulled into the reservoir by the jet pump.""
Fuel diverted was mentioned:
The jet pump assembly diverts a small portion of the fuel exiting the electric pump and aspirates a larger quantity of fuel from a fuel chamber defined by the fuel tank and into the reservoir.
Interesting conversation!!
Thanks
Randy
Quote:
Originally Posted by
shackwrrr
Where does the return dump to? Maybe do some mods to use the return flow to run the jet pump instead of the fuel pressure feed.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Sorry for the late response. The one i took apart was a factory unit for a 1994 3.8 T&C and i don't remember the guts looking exactly like that, although from the outside it looked the same. I can't tell from the pics posted what the best approach would be to getting that pump out. Sorry. :(
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Well, i've tried a few times to seperate this fuel pump, but i can't break it down any further than the pics earlier.
I'm thinking of just breaking this apart and using the reservoir around the pump and the baffled sump fuel tank to see if that works.
Or i just will change tanks and hope that works.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Too bad you couldn't find a used OEM takeapertable unit and return the Spectra.
Sorry if I led you on a tough road.
More G.M. guys seem to like the jet than others.
Best of 2017 Wayne!!
Thanks
Randy
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Quote:
Originally Posted by
GLHS60
Too bad you couldn't find a used OEM takeapertable unit and return the Spectra.
Sorry if I led you on a tough road.
More G.M. guys seem to like the jet than others.
Best of 2017 Wayne!!
Thanks
Randy
I'm considering ordering this one, to see if the pump can be removed and replaced with my walbro. But wish i knew it would work, so i don't end up with another paperweight!
http://pages.ebay.com/link/?nav=item...539907&alt=web
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Wayne, have you considered running the Spectra TBI pump in tank and the 255 external??
I believe Vigo runs an intank TBI without the jet and 255 external, but he would have to verify.
If so, you would get the benefit of the Spectra jet action in the tank to leisurely feed the external high pressure 255.
Its late, what am I missing??
Thanks
Randy
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I guess that is possible. Slug still uses two fuel pumps, but the seconday only comes on with higher boost, to ensure enough fuel volume under the demands of higher boost pressure.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
The question is, will the TBI pump supply the volume.
Not sure if Vigo uses a TBI pump to supply his external 255 or not.
For some reason I thought this had been done, hopefully someone knows for sure.
Sure is a great day for the USA!!!
Thanks
Randy
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I haven't run a tbi pump in line with a better pump, but i do believe it would work just fine. However, i would be surprised if there were actually a tbi-specific pump module by that time, and if it's the same as the v6 pump it's pretty well established that the v6 pumps in all of these cars are equivalent to what came with the turbo engines. So theres a possibility that any 'pump module' you could get for a later van would be equivalent to a stock turbo pump anyway.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Right, I was thinking of 1989 TBI pumps, Wayne's 1994 replacement pump should work for a normal Turbo Mini.
As fine as a Spectra pump might be reliability wise?? Should be fine supply wise to an external 255.
It would be cool to verify the jet cures the low fuel launch issue !!
What was it Clint Eastwood that said, "do you feel lucky today Wayne"??
You have the parts on hand right??
Thanks
Randy
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I never really feel very lucky Randy! That's why now in my mid 40's i would rather only have to do things once. I already kick myself for not realizing about the no tank baffle and having to address this.
My walbro 255 is an in-tank unit, so i don't know what's needed to try and use it external, or if i would need a new pump.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Im a little late to this discussion, but have you considered this instead of getting a sump built into the tank: http://www.jegs.com/p/Holley/Holley-...95943/10002/-1 Just pipe this to the Walbro or run an external pump.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Quote:
Originally Posted by
83rampage
That product looks like another good solution. It is pricey, but it may be worth it for simplicity.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Yeah I hear you on the price.
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1 Attachment(s)
Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Here is the baffle in the Dorman replacement tank.
Attachment 60038
Its basically a bowl with a hole in the bottom welded to the bottom of the tank (and raised up just slightly from the bottom of the tank).
I'm considering the Hydramat mounted inside this. Or, trying to use that reservoir plastic pump housing to try and keep enough fuel to prevent air from entering pump.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I feel like between that pump and baffle (assuming theyre physically compatible) you should have no fuel problems anymore. In fact, given that you have a secondary fuel pump already, i would just install the pump module you have as-is and run it.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Quote:
Originally Posted by
Vigo
I feel like between that pump and baffle (assuming theyre physically compatible) you should have no fuel problems anymore. In fact, given that you have a secondary fuel pump already, i would just install the pump module you have as-is and run it.
I think there may have been some confusing statements.
Current install has just one in-tank walbro 225lph (HP) installed in the unbaffled tank.
The 94 van pump module i pictured i could never remove the actual pump to see if it could accomodate the walbro 255.
You think i should install the stock type 94 pump module, then use a secondary external pump?
I wanted to try to stay with just a single pump setup.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
You could verify the jet theory by just trying the new Spectra assembly as is.
That is what I would do, then if the launch issue is acceptable run the 255 external like I believe Vigo does.
At this point very cost effective!!
Thanks
Randy
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I really can't even try a test like that. That Spectra module is only like 175 lph.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I would just swap it in, leave the secondary pump working as it already does, and see if there are any issues with fuel flow. I highly doubt there will be. The second pump in series takes almost all the load of making pressure off the first pump, which means it can push a larger volume of fuel against that lower resistance.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Quote:
Originally Posted by
Vigo
I would just swap it in, leave the secondary pump working as it already does, and see if there are any issues with fuel flow. I highly doubt there will be. The second pump in series takes almost all the load of making pressure off the first pump, which means it can push a larger volume of fuel against that lower resistance.
I think the confusion is i only have one pump installed.
Mini does not have a secondary pump.
So, if having a two pump setup is the recommedation, my walbro 255 is an in-tank pump, i probably need to get an in-line 255lph pump instead? Or, try to cobble conversion fittings together?
Also i'll have to figure a mount and location, as well as how to wire.
Using the existing fuel pump wiring to drive two pumps might not be the best idea, but i could power a primary side of a relay with the same intank + wire. Then i need the relay secondary wires to the second (in-line) pump.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
Oh, I dont know where i got that, then. Sorry!
I've done what you mentioned on my Spirit. I used the stock pump power wire to trigger a relay that took the actual pump power from my amp power wire which was right inside the spare tire well anyway. So i didn't have to run a larger power feed specifically for that purpose. On my Lancer i did run a new power wire for both the intank and external pumps. I triggered its relay off the coil positive terminal (which is the same ASD circuit that powers the fuel pump anyway).
If you are doing ok with one pump, i don't necessarily think adding another is the go-to solution. I guess i sort of brought it up by accident since i didn't understand the setup.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
I'm afraid I'll be running into the same issue. I am running a 340lph in tank pump using a SPI tank and hanger. I was able to get the SPI pump out of the hanger and side the Aeromotive pump in. So far its working on, but I am afraid what might happen on a hard launch with 1/4 tank of fuel.
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
So if I understand this correctly:
1. you have an unbaffled tank
2. you have a walbro pump you have used and want to continue to use
3. a 94 style pump assembly which you cannot change the pump and appears to need a baffled tank as well
Seems to me no matter what you need some way of trapping some fuel by the pump pickup in low tank situations.
I would just go simple and do 1 of 2 things:
1.Buy a baffled tank (Dorman 576013) for $117 from Rockauto (or whoever) and use the walbro as set up so it works with the baffle. The factory baffles seem kind of cheesy but they clearly work. I think using hydramat in a baffled tank is going to cause its own problems.
2. Use the hydra mat in your current unbaffled tank. Looks like there is a mat that may connect directly to your Walbro for $160 or adapt another hydramat if it doesnt for about the same money. Holley is a company with a good name and I'm sure hydramat works as advertised. This would be my choice
Use the 94 pump/sending unit as a paperweight (or sell it in the classifieds) since it appears to need a baffled tank anyway and cant be adapted to fit your Walbro.
I don't mean to spend your money but I've been down roads like this and trying to save a dollar usually costs more in the end (including frustration).:thumb:
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Re: Minivan fuel issues (tank baffles/ jet pump/reservoir /94 style pump hanger walbr
The module style pump assembly has many benefits, that's the heart of the discussion.
Pump modules are used instead of baffles, but how much better are they under hard launch conditions.
Thanks
Randy
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Is this on your L body Mike??
I don't think there is a module style for them although I would like to try one.
Thanks
Randy
Quote:
Originally Posted by
contraption22
I'm afraid I'll be running into the same issue. I am running a 340lph in tank pump using a SPI tank and hanger. I was able to get the SPI pump out of the hanger and side the Aeromotive pump in. So far its working on, but I am afraid what might happen on a hard launch with 1/4 tank of fuel.