Hey yall,

Sorry if this has been asked before but I can’t get a clear answer and want to be 100% sure before I drop a few hundreds.

I need a new fuel pump for the Stillen supercharger FMU, the secondary one. I think it’s starting to fail + it’s super rusted and corroded on the outside, it just looks absolutely cooked.

From what I’ve researched, it was a Vortech Trex fuel pump… But the only ones with the Trex name on Vortech’s site are for 80s-90s Mustangs. I don’t think those are the right ones.

And then I found this one on Vortech’s site. It looks more accurate to the one on the kit currently. Just wanna double check though: https://vortechsuperchargers.com/products/155lph-inline-fuel-pump-w-ftg

Is this fine to use as a replacement? If not, are there any other options for the secondary fuel pump? I’m already aware I can use a Walbro 255lph in the tank, but I would prefer to have a complete kit so I would prefer to keep the secondary pump if possible. But I’m open to whatever options are available.

Thanks!

 

Ok quick update and one question

I was talked into just getting the Walbro 255lph. The acceleration surge issue is getting worse and more consistent. I think it’s time for a new pump asap

I did the reading about installing the Walbro 255lph for the Stillen S/C. Seems simple enough. My only question - did anyone require an adjustable FPR for this? I saw a forum post that said you have to get an AFPR and set it to 34psi for the stock idle. But it was literally just that one post, I haven’t seen anyone else mention this anywhere.

Thanks!

 

Sounds like you have the original setup with the Vortech FMU, pressure switch, relay and auxiliary fuel pump.

I'd give Vortech a call as their customer support is pretty good.

 

Also, have you read through the stickies in the Supercharger Forum? Lots of good info in there regarding fuel pumps/fuel management.

 

You have a wide band air fuel ratio gauge, right?. That will tell you if need an adjustable fuel pressure regulator.

 

Yessir I’ve got the AFR gauge on my dash. I did some more reading through the forums and I think I’ve got the info I need. I’m gonna install the walbro this weekend, reroute the fuel lines up front, and hopefully she’ll start driving smooth again

 

What kind of acceleration surge are you getting? Part throttle or full throttle? I ask because I had surging during partial throttle and it was due to my bypass valve.

 

It happens during partial and full throttle. I’ll also sometimes see the AFR gauge bounce around when the surging happens. This is good info to have though, if the pump doesn’t fix my issues I’ll consider the bypass valve

 

Hey yall, got an issue… so I replaced the fuel pump with the Walbro 255 LPH. It was driving absolutely perfectly fine and felt like a new car for 2 days. Then suddenly it started driving horribly. Rough idle, slow acceleration, took like 4 seconds just to get up to 20mph, it can get up to 80 at least but it takes some time. At the same exact time as these issues popped up, the AC suddenly wasnt blowing cold

then 2 days later, for no apparent reason, the AC was blowing cold again and a CEL appeared. I’ve got P0180 (fuel temp sensor A circuit) and P0304 (cyl4 misfire)

I’m a bit worried maybe I installed the fuel pump incorrectly? But it was driving perfect for a while, so I’m not sure what could have happened. Did anyone else deal with a P0180? The ECU is new btw, I doubt its an issue there.

The spark plugs and coils are practically brand new, replaced them last year. Fuel injectors should be fine. I’ll double check these things but this is just some context.

 

codes are unrelated but since you were in the tank i would look there first as the temp sensor is part of the sending unit.

misfire should be clear as day to notice with or without a code.

 

I don’t think there’s actually a misfire, I’m thinking there’s something weird going on with the fuel pump and sending unit.

I’ve got the Stillen supercharger kit on there and I got rid of the aux fuel pump that attaches to the FMU. I replaced the main fuel pump with a Walbro 255. According to the forum posts that I’ve seen, this setup should be perfectly fine. But for some reason idle is bad, acceleration is slow, and fuel economy is awful

My concern now is maybe I did it wrong, but there’s no writeup on how to do it right. Most posts just say “replace the fuel pump with a Walbro 255” and that’s about it. So I’m wondering if anyone ever experienced something weird after installing a Walbro 255, or if there’s anything special I need to do to the wiring or anything like that. It looked like it was a direct replacement, the harness connected perfectly fine, it fit just fine… And it even drove perfect for a few days.

I’m also wondering why on earth the AC would be affected by a fuel issue. I looked everywhere in the FSM and I can’t find a single thing that connects the AC to the fuel system. It can’t be a coincidence, this fuel issue had a direct effect on the AC temp.

Randomly one day when the AFR went high and the CEL appeared, the AC started blasting freezing cold air. Then when the AFR stabilized the AC stopped blowing cold again. And when it’s idling, the AC cools down, and when I accelerate it goes back to lukewarm air.

I’m still trying to troubleshoot but any clues or tips anyone can provide will be awesome