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Discussion Starter · #2 ·
which one are u thinking of going with jon? i heard some pretty decent stuff from the 255 and the 340....im not an expert at it but i think the 255 is an inline and the 340 is an intank. maybe someone can offer better help than me..i just wanted to give u some advice
 
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Discussion Starter · #3 ·
I installed new injectors Friday night and it didnt help lower my EGt nor A/F. I noticed a fuel drop after 4th gear pull or higher so I think its either my stock pum pis maxed out for some odd reason or my FP is leaking.
I did leakdown test on the whole system and made sure everything is leak-free.
I think I'm just gonna spend that $130 and get a Walbro 341 pump and see if ithelps out at all.
 

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Zerosoul said:
I installed new injectors Friday night and it didnt help lower my EGt nor A/F. I noticed a fuel drop after 4th gear pull or higher so I think its either my stock pum pis maxed out for some odd reason or my FP is leaking.
I did leakdown test on the whole system and made sure everything is leak-free.
I think I'm just gonna spend that $130 and get a Walbro 341 pump and see if ithelps out at all.
man, you are having the worst luck with the egt's. im geting ready to put in dual 340's(come with the sp fuel kit). good luck getting your problems sorted out
 
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Discussion Starter · #6 ·
you tell me!
thanx for the encouragement.

BTW, does Walbro pumps fit stock bracket perfectly or do I need to perform any modification?
 
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Discussion Starter · #7 ·
check out http://www.autoperformanceengineering.com/

they sell walbro pumps dirt cheap! ($109 for the 255lph supra one) I got my pump from there. If you email the guy he's real helpful and will tell you whether or not he keeps it in stock. He has a lot of popular pumps in stock usually but I don't know about a supra pump.

-Xerxes
 

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2,215 Posts
Zerosoul,

This is a long shot but I recently had this problem. There is a factory electrical connector that plugs into the top of the fuel tank. The half on the tank side has male terminals and the other part has female terminals. When mine was plugged together the female terminals weren't fitting tightly on the male terminals. Voltage drop was enough to actually cause my pumps to stop working one day. I popped the female pins out of the connector and squeezed them a little with needle nose pliers so there was some resistance when they slid over the male terminals, ensuring good contact. You could also hook up a volt meter across the power and ground wires going into the tank and check the voltage the pumps are getting.
 
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Discussion Starter · #9 ·
I hooked a voltmeter to the 12V powersource to the fuel pump ECU and with car idleing, the meter reads about 13-13.1 V. (I'm in 12V mode). I'm gonna try to mearusre it during acceleration....I was told it should go above 13.5-14V?
 
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Discussion Starter · #11 ·
Zerosoul said:
thinking of getting one, has anyone ever had problem with Walbro fuel pumps?
Nope, never heard of anyone having problems with them. They are quite popular.

Just curious, how do you plan to measure the voltage under acceleration? Are you going to leave a voltmeter under your car?
 
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Discussion Starter · #12 ·
not under the car, in the car in the back. the fuelpump powercable runs from the fuelpumpecu (driverside in the back)direct to the fuelpump. you see the line below the reserve tire.
 
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Discussion Starter · #13 ·
Jonas,

Why dont you just go with the Bosch pump? It is an OEM pump (911 TT), flows a lot of fuel, and doesn't draw a lot of amperage.

It is pretty simple to install as well. I can help you with that if you like.

According to Dimitri, it is the same as that upgraded HKS pump ($800) and flows enough for 650 rwhp.

You can get the pump from Dimitri at Directed-engineering (www.directedengineering.com).

That's what I've gone with and I am real happy.
 

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The Bosch pump doesn't appear to flow enough for a big single car. It might flow 650 rwhp at some low fuel pressure, but not for a single running 25 + 43 (base) psi = 68 psi. It is capable of flowing at very high fuel pressures though.

I've seen 2 tests of this pump on the internet and they both looked like this: http://member.newsguy.com/~gtfour/fuelpump.html
 

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A walbro kit for a 1st gen Eclipse is the best one to get for the Supra. It comes with a foam sleeve that helps to quiet the pump a bit. Its a direct replacement, other than splicing wires.

Some walbro's are a bit noisier than stock, but I believe they are a better pump due to cost and much lower operating current.

Check your fuel pressure first.... The stock regulator tends to loose pressure over time(thats what Mohd from MKIV found to be the problem on his car, constanly high EGTs).
 
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Discussion Starter · #16 ·
did some research, even the 341/342 high pressure Walbro pumps are rated 255LPH whereas a stock supra OEM pump flows 260LPH. so the only advantage on going to Walbro is doing the twin Walbro setup.

which HKS pump are you taljking about? HKS intank "large" pump is the same as Mazda Cosmo pump, which has same flow rate and part # as supra pump, so HKS pump=supra Denso pump.

maybe there is another HKs pump that uses Bosch pump?

I emailed Dimitri already, waiting for his reply, but I wwant to make sure there is enough voltage going into my pump before I buy a new pump...this stock pump I'm using is off of my friends 98 supra with only 40,000miles.
 
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Discussion Starter · #17 ·
another thing I learned, no matter what pressure the fuel pump is under, as long as it flows enough to feed the size of your injectors, (10-15% additional for safety), than your pump is fine.

here are some good articles of supra pump VS other pumps...seems like everyone loves supra Denso pump:

http://www.geocities.com/lutransys/jlucius2/j2-2-fuelpumpguide.htm
http://www.roadraceengineering.com/fuelpumpflowrates.htm
http://www.roadraceengineering.com/fuelpumptechtip.htm
here is a clear description of Walbro pump which basically flows less than a stock healthy supra pump:
http://www.vfaq.com/pump-Walbros.html



by looking at Grant's link on Bosch pump, at 70PSI the pump is not flowing enough for 6 550cc/min injectors. so I would guess the Bosch pump Jonathan got has more flow?
 
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Discussion Starter · #18 ·
cr133r said:


Check your fuel pressure first.... The stock regulator tends to loose pressure over time(thats what Mohd from MKIV found to be the problem on his car, constanly high EGTs).
I have HKS adjustable FPR in place after stock FPR so it regulates my fuel systems FP. right now its set at stock spec....
 
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Discussion Starter · #20 ·
Grant said:
If your fuel pressure is rising 1:1 with boost you don't need a new fuel pump.
it raises 1:1 untill top of 4th gear 5800rpm when it start to drop about 5psi till redline. I leak checked the whole system and doesnt seem its leaking from FPR. might be the pump is maxed out since FP drop is a symptom of pump maxing out.
another thing is Chris from HPF kept telling all the BPU surpa runs 780EGT with probe at top of DP. he says all the car he dynoes or tune runs that EGt.
 
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