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2G Fuel Pump?

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eddyspaghetti

Proven Member
102
12
Mar 27, 2016
san francisco, California
Hello fellow DSM'ers, I'm currently looking to buy a new fuel pump but I'm not sure which one to go with. I have pretty much all bolt on's, full exhaust system, refurbished t25 and APR head studs.
EVENTUALLY, I'm going to start upgrading my car, bigger turbo, internals and all that good stuff. What I'm wondering is, should i go ahead and upgrade to a Walbro while I'm at it or would an upgraded fuel pump damage my car with what I have currently in it? Should i just buy another STOCK fuel pump? If so, can you guys point me in the right direction to which fuel pump to go with that would work best with my current set up?
Any help would be much appreciated, thank you
 
I'm gonna disagree here. A fuel pump upgrade does not change fueling. No need for a wideband at this point. Not a bad idea but there is no fuel altering.
you can disagree. I disagree with your assessment but only because I'd prefer to know a) if the new fuel pump was providing the necessary fuel in WOT and b) that the old stock regulator was capable of performing its job at idle and cruise
At the minimum for b) I'd look at fuel trims if that was a possibility but a) you're SOL with no feedback device.
The 190 might be the closest to stock but a lot of unmonitored assumptions are following its install
 
you can disagree. I disagree with your assessment but only because I'd prefer to know a) if the new fuel pump was providing the necessary fuel in WOT and b) that the old stock regulator was capable of performing its job at idle and cruise
At the minimum for b) I'd look at fuel trims if that was a possibility but a) you're SOL with no feedback device.
The 190 might be the closest to stock but a lot of unmonitored assumptions are following its install
I see your point. I am saying that without a direct way to control injectors its no different than stock. Once you start altering air or injectors all bets are off.
 
I did install a new Denso unit in my car. Everything else is stock. There is a rubber “foot” that goes between the metal hanger arm and the pump, and the Denso kit does not include a new one. Some brands appear to. I was not able to find that part alone anywhere. I reused my old one, and it seems secure, but would have liked to use a new one, after 30 years sitting in gas.
Cost was around $130 three years ago. You can get other brands for half that. Obviously you can get fancier, hi-po pumps for $$$. When the delivery volume goes past a certain point, the regulator and return line needs upsized too.
 
I see your point. I am saying that without a direct way to control injectors its no different than stock. Once you start altering air or injectors all bets are off.
I'm not 100% on board with it being no different (I'll leave it as "close enough") but, ok, I'll agree with it's not absolutely necessary. It's just a good idea due to so many variables on older parts and when things start getting changed around, even if it's close to original, it's at the very least a good idea as a useful feedback device to make sure the rest of the components are working. Hell, the intake may currently be spitting out bad Hz numbers too.
I'll back away from it being an imperative component here.
 
Marty mentioned the wally 450 a few posts back... i can verify there is an e8compatable 450lph... in fact ive been using it for going on 9 yrs.

As for fueling issues... if the regulator(stock) isnt over run(it will be at around 255lph) then pump size shouldnt make a difference.
 
this is all assuming that the stock fpr is operating exactly as it was designed to over 20 years ago, if it's still the original.
It has moving parts, it can wear out. Holes can develop in diaphragms. Things that can be determined with either logging or diagnostic tools, such as a gauge. Without either and you're throwing a more powerful pump at an unideal system.
Either or, there is a gauge. Assuming it's accurate and calibrated, this is all moot because the same discussion will arise with the next pump replacement question.
 
Be sure to keep the Spacer (see diagram below) from your original fuel pump. The Walbro install kits expect you to reuse that one part. It's the one part of the install that could make you wonder if it's really good enough. When I did this the first time, my spacer (1g) didn't sit straight on top of the Walbro pump. It was tilted. So that made the o-ring tilted too. So I ended up doing it different.
Since then, Walbro has been changing the plastic moldings that are on the top of the pump (outlet pipe and electrical block) and those are the things that the "Spacer" has to be compatible with, fit wise. I don't know what the latest is for the old OEM spacer from the 1990s (1990 - 1999) fitting on top of the latest Walbro 190 and 255 pumps, but it might be the thing that keeps it from being a pure plug-and-play. Other than that I really like the Walbro pumps.
This is a scan of the part of the install instructions that shows the spacer, o-ring, and cap. It's from an install kit I bought new in June of 2022. The "isolator" they mention is the molded rubber block (not shown in this diagram) that fits on the bottom end of the Walbro pump.

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One of my first "bolt ons" was an AFPR. It has a gauge :thumb: When I was fighting fueling issues, that was a very helpful tool/mod but that has nothing to do with the OPs question.
Now I log it and monitor it in cabin.
Nice diagram.
 
Be sure to keep the Spacer (see diagram below) from your original fuel pump. The Walbro install kits expect you to reuse that one part. It's the one part of the install that could make you wonder if it's really good enough. When I did this the first time, my spacer (1g) didn't sit straight on top of the Walbro pump. It was tilted. So that made the o-ring tilted too. So I ended up doing it different.
Since then, Walbro has been changing the plastic moldings that are on the top of the pump (outlet pipe and electrical block) and those are the things that the "Spacer" has to be compatible with, fit wise. I don't know what the latest is for the old OEM spacer from the 1990's fitting on top of the latest Walbro 190 and 255 pumps, but it might be the thing that keeps it from being a pure plug-and-play. Other than that I really like the Walbro pumps.
This is a scan of the part of the install instructions that shows the spacer, o-ring, and cap. It's from an install kit I bought new in June of 2022:

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I dont believe I ever had a spacer.. just fuel line from pump to hanger.

Or is this 1990 specific?
 
I dont believe I ever had a spacer.. just fuel line from pump to hanger.

Or is this 1990 specific?

Well, I don't know what years and models used a spacer. My stuff is all 1990, yes.
If you had just fuel line from pump to hanger, that sounds like you didn't have a female receiver tube for the pump outlet pipe to fit inside of. But any of the models that were made with the female receiver tube, I would think would have had the spacer, o-ring, and cap arrangement, and the spacer would be to hold the o-ring in correct position. Without the spacer, the o-ring just gets blown out of the receiver.
 
Well, I don't know what years and models used a spacer. My stuff is all 1990, yes.
If you had just fuel line from pump to hanger, that sounds like you didn't have a female receiver tube for the pump outlet pipe to fit inside of. But any of the models that were made with the female receiver tube, I would think would have had the spacer, o-ring, and cap arrangement, and the spacer would be to hold the o-ring in correct position.
Makes sense... ive not got the opportunity to play with a 90... its possible I modified it too... 9 years is a long time to remember
 
It is this tube I believe. I saved 2 as originals and re-modded the already modded hanger that just uses a hose between the pump and the delivery line.
Here, circled in my picture, I think. You can even see the "spacer" on the pump just above the one circled.
Sean, isn't your hanger like the one I show here?

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It is this tube I believe. I saved 2 as originals and re-modded the already modded hanger that just uses a hose between the pump and the delivery line.
Here, circled in my picture, I think.
Sean, isn't your hanger like the one I show here?

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Honestly i believe mine does not have that bottom flare to the pump... maybe ill pull it
. Good reason to throw in a 525
 
If the wife will "buy that story", go with it......ROFL
One of my hangers came out of my 92 and it had the bell on it also. The rest of mine are all 1990's also, to be clear for the post.
 
If you ever need an adapter nipple for the shitty fittings that makes you slip the pump into the hanger,

The nissan xterra 1999 v6 denso fuel pump comes with the hanger slip bushing. I believe subaru also uses a similar slip pump design in a 2002 wrx. Edit, this pump is the same denso part number for a 2004 wrx

Anyways heres the denso part number if youre desperate like I was. My local autozone had one and I needed it so yeah if youre desperate and feeling spendy

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Edit again
Map performance sells then for $3? If youre not in a dire rush


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If you ever need an adapter nipple for the shitty fittings that makes you slip the pump into the hanger,

The nissan xterra 1999 v6 denso fuel pump comes with the hanger slip bushing. I believe subaru also uses a similar slip pump design in a 2002 wrx. Edit, this pump is the same denso part number for a 2004 wrx

Anyways heres the denso part number if youre desperate like I was. My local autozone had one and I needed it so yeah if youre desperate and feeling spendy

Hey thanks for posting that!
With this Evo rubber grommet, is it still supposed to have a spacer underneath it?
I noticed a while back that the Evos were using a grommet like this, and it looked good to me.
I'm going to buy a couple of those Evo grommets to try out for fit and so-forth.

To do my own Walbro 255 the first time (in 2009) I was able to buy 1 foot (!) of Viton soft rubber (60A durometer) from Small Parts. Which you can't do anymore. So I have about 8 inches of that stuff left LOL and that's probably all I'll ever have. It is 1/4" ID by 9/16" OD.

The way I use the Viton tubing, it replaces the spacer, o-ring, and cap. All 3 parts, replaced. Grease it up with a thin smear of Molykote 111 Compound because it fits tight into the receiver tube. And it does work really well. It can't move in either direction when it's put together, so it's very secure.
In this pic I took last year you can also see how the new Walbro 255 pumps have different plastic parts on the top than they used to. The spacing between the outlet pipe and the gray part of the electrical block is very close at the bottom now. That's where I'm not so sure that our old OEM spacers will fit right down to the deck of the pump. You can see I had to bevel the lower end of my Viton a little bit to fit in there. I don't know if these gray plastic parts are the same on the latest 190 LPH Walbro.

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Hey thanks for posting that!
With this Evo rubber grommet, is it still supposed to have a spacer underneath it?
I noticed a while back that the Evos were using a grommet like this, and it looked good to me.
I'm going to buy a couple of those Evo grommets to try out for fit and so-forth.

To do my own Walbro 255 the first time (in 2009) I was able to buy 1 foot (!) of Viton soft rubber (60A durometer) from Small Parts. Which you can't do anymore. So I have about 8 inches of that stuff left LOL and that's probably all I'll ever have. It is 1/4" ID by 9/16" OD.

The way I use the Viton tubing, it replaces the spacer, o-ring, and cap. All 3 parts, replaced. Grease it up with a thin smear of Molykote 111 Compound because it fits tight into the receiver tube. And it does work really well. It can't move in either direction when it's put together, so it's very secure.
In this pic I took last year you can also see how the new Walbro 255 pumps have different plastic parts on the top than they used to. The spacing between the outlet pipe and the gray part of the electrical block is very close at the bottom now. That's where I'm not so sure that our old OEM spacers will fit right down to the deck of the pump. You can see I had to bevel the lower end of my Viton a little bit to fit in there. I don't know if these gray plastic parts are the same on the latest 190 LPH Walbro.

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Yes that is exactly what I used that rubber piece to do. It slipped over the end of the pump, and fit extremely tightly into the fuel pump socket in the hanger. My car was missing the adapter and had a walboro pump from a mustang installed in the hanger, I replaced the pump with a denso rated at around 190lph and it looked identical to a factory pump. I used the evo/wrx grommet on the end of the pump with no other fittings except the grommet

People said to use O-rings and inbetween them use rubber tubing, but I was never able to get a strong seal, after a day or two the pump would always blow the orings out. The car would still run and drive but had severe issues in boots

I believe I used wd40 to lube the rubber piece to slide in. I wanted something that would pretty much evaporate so the rubber wouldnt stay lubricated after installation

I used this on a 2g, never gave me any problems
 
Here's an assembly drawing that STM shows on their page for this fuel pump grommet MR431121. MAP shows the same diagram on their page.
It shows the grommet as 05288 highlighted in yellow.
There is no spacer shown under it. So that's good. That's the design intent, apparently.

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Here's STM's page for the grommet:
 
My fuel pump comes in Tuesday; i ended up going with the Walbro 190 from STM

Good!
When you open up your tank, you'll see a fuel pump hanger that is much shorter than the 1G hanger Marty showed in post #37.
It's not a problem for the Walbro 190/255/350. Any of those pumps will fit in there real nice.
But for future upgrades, keep in mind that the Walbro 400 and up are bigger and longer physically. Making them work with the 2G AWD pump hanger is a bunch of stuff. Not too hard to do with the 1G hanger, but gets a little ugly IMO with the 2G hanger.
Good luck with it!
 
No i wasn't second guessing STM, i was second guessing JDT racing
Hi guys, I know this might be a little late but when I see my company name, I need to step in and introduce myself to those that do not know of JDT Racing in the DSM community. My name is Josh and I am the owner of JDT Racing. I know my company has not been around for as long as STM but you will not find a company more dedicated to making sure the customer gets what they ordered. For that reason, we only sell in stock parts and all orders placed before 2pm EST ship same day. We have a 5 Star Rating on Google and a 100% Positive Feedback rating on eBay with over 46,000+ orders sold. As for Walbro/TI Automotive parts, we stock the full line and we also supply some of the supporting vendors on here with fuel pumps wholesale.. We put up $500 towards the prize pool for the Shootout in 2023 and if all goes as planned with our 1G DSM Race car we will be at the DSM Shootout in 2024.

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