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TOP SWAP Fuel Pump Questions

dbextreme

dbextreme

New member
Today I was driving and my car just hiccupped then died.. No start at all afterwards. I opened the hood, hit the Schrader valve and just a little drizzle came out. I know not a good way to check fuel pressure, but I was in the middle of the road.. Towed the car home, turn key I can't hear the pump kick on like I usually can. First thought is pump is fried... concerns:

  • GT car originally with L36
  • 1999 model year
  • I assume the GT has the low flow LPH pump originally compared to a stock GTP
  • I have XP cam with 42.5# injectors so I assume my stock high mileage pump couldn't keep up?
  • I only have ONE relay, not two. I assume GTP's come with two, GT's come with one. Will this hinder me?

I have researched and come to this conclusion. I will be getting the 255LPH pump and install it in my car. I am still researching the venturi situation, but any of you that have insight on that would be appreciated. Since I only have one relay I assume I have to get the hot wire upgrade to bypass it all together, or will this still cause me issues??? Also pricing pumps, I see the W Body store has the 255LPH pump with the wiring harness for $129.. Is this price to good to be true? Anyone have experience with the W Body store pumps, I've heard mixed reviews? I've contacted MOAR and hopefully will hear back from him.. Racetronix is up on my list.

Regarding Venturi setups, I assume my car does NOT have a venturi pump. Is it ok to go back to non venturi is my car does not have it now, or should I upgrade? How do I upgrade my canister or can I?

I will get outside tomorrow and test some stuff to make sure it is a faulty pump, but I'm already 99% sure this is my problem..
 


Ok I tested for voltage at the pump, I have it with key on. I turn have the key turned on with my ear to the top of the sending unit and it sounds like a sick hissing... I prime and prime and prime with just a little poof of fuel to the rail and nothing so I'm assuming I burnt my pump up. Even if not, I'm still replacing it with a better unit AND the hotwire harness. Question is now,

1) I assume I have a non venturi setup based on no bronze nipple?
2) Will a non venturi 255lph be just as good as the venturi setup? I have heard venturi is better since it's submerged in fuel constantly, but I don't want to switch out canisters and am wondering if anyone is running a non venturi setup with upgraded pump?
3) What brand of pump? I have heard walbro pumps can't go below 1/4 tank. I see the Racetronix pump claims to be a walbro so that's out I assume?
4) Anyone use the Intense, WBody store, or ZZP pumps?

Any help would be appreciated.







 
I know my buddy frosty on here was sure he didn't have a venturi setup, then ordered an AEM 300 LPH E85 pump I believe that was non venturi, and when he went to install it, SUPRISE! he has a venturi canister. He was able to modify it to make it work, and he goes to almost empty... like 1/8 tank or so often and doesn't have too many issues. I thought he made a post about it somewhere....
 
Oh and his stock pump held up to about 170k, he is also a topswapped GT, and he put down just shy of 300 WHP on E85 with 60LB injectors and that was the limit of his stocker, with a good rewire.
 
I believe I've seen his post, but with his pictures I could not tell what modifications he did to the canister. I mean pushing it all the way to the bottom to seat in the hole that sucks from the factory sock is the way I want to set it up, but all the aftermarket pumps are 1" or more shorter then the stockers. I assume shims or something to fill the gap will work... Also my stock pump has two holes in the bottom with a sock attached to one inside the canister and the other is attached to the hole that sucks from the sock outside the canister. I dunno..

Yeah, I'm pushing 176K on my car now and I've owned it since 2005 and it had 68K on the clock when I purchased it so I assume the pump is OEM.

I saw the AEM pump, but it's "E85". I'm not running E85 in my car, no stations near by. I might as well flip a coin. LOL
 
well it being E85 pump is just saying its compatible, works great on gas too from a few people that I know that have it. I'll show frosty this thread so you can have his input too.
 


I messaged him and he got back with me. confirmed my thinking and still talking to me about it. I appreciate it. Just a bit confusing on the my car being a GT with the dual sock setup... just no venturi "setup" on the pump... I am wondering if all the canisters are the same, just different pump configurations?
 
can you look at my canister and tell I can provide more pics if needed??? If so, why does the nonventuri "setup" have dual socks.. once to suck from outside the canister and one to suck inside?? Don't mean to ask stupid questions, but I can't find real clear answers...
 
Yes I believe that is the reason. Also I believe the pump sits lower in the cannister on venturi cannisters. My car came with a venturi pump/cannister and I switched to the AEM pump which is non-venturi. I asked ZZP if it would be better to switch to a non-venturi cannister and they said its better to run the venturi cannister and drill the hole because the pump sits lower on the venturi cannisters, which is slightly better.

I'd give you more from my car as an example but you wouldn't want me to do that.
 
Makes sense.

How did your stock fuel pressure regulator and tune work together with the AEM pump? I was talking to Frosty about it also, he mentioned his tune and FPR needing tweeking as well.

I'm looking at the AEM-50-1000 pump instead of the 50-1200 (no E85 near me so I don't need the pump for it) The 50-1000 seems to have the same stats, just not E85 specific.
 


Another question.

The small hole on the top of the pump itself between the electrical plug and fuel outlet, did you leave it open or did you block it? I have heard two different way to install the pump, one person even used it as a venturi barb hole (needless to say he burned the pump up in a couple hours.. LOL) but I was wondering if this was a vent or if it's for another feature that needs to be left alone (left open) or blocked off when installed in our cars? My old pump is solid on top with no hole other then electrical plug and fuel outlet.
 
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