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Power shift that bitch!
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Discussion Starter #1 (Edited)
need some input....

I did my pump gas tune today was prepared to do pump and race but had a dilemma.

Here is my set up:

Greddy T-78 kit,
upgraded fuel system (850cc injectors, -6 fuel lines, a walbro 255 pump and a stock fuel pump...etc),
Stock cams,
Tuning with Apex Power-FC

i did 566rwhp and 511.5 rwtq at 19psi on pump gas. Did some runs at 16-18psi and everything was running smooth a/f was 11.0 across the rpm range, we left the fuel and timing alone and increased the boost to 19psi. With nothing changed it lost fuel pressure at the top end and went lean. The fuel pressure was near 40psi at idle and increased to 60 psi when the boost kicked in and the waste gate started to open, then the fuel pressure began to drop around 6000 rpms and was going way lean and we got out of the throttle once that happened. So we added more fuel in the top end and took out timing and still no change. Thinking it could be a faulty pump not sure.

Thanks,
Michelle
 

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SupraWoman98T said:
need some input....

I did my pump gas tune today was prepared to do pump and race but had a dilemma.

Here is my set up:

Greddy T-78 kit,
upgraded fuel system (850cc injectors, -6 fuel lines, walbro 255 and stock fuel pump...etc),
Stock cams,
Tuning with Apex Power-FC

i did 566rwhp and 511.5 rwtq at 19psi on pump gas. Did some runs at 16-18psi and everything was running smooth a/f was 11.0 across the rpm range, we left the fuel and timing alone and increased the boost to 19psi. With nothing changed it lost fuel pressure at the top end and went lean. The fuel pressure was near 40psi at idle and increased to 60 psi when the boost kicked in and the waste gate started to open, then the fuel pressure began to drop around 6000 rpms and was going way lean and we got out of the throttle once that happened. So we added more fuel in the top end and took out timing and still no change. Thinking it could be a faulty pump not sure.

Thanks,
Michelle

I'd say you're probably on the right track...also check to see if one of the lines came off of a pump in the tank too. Or possibly no power to one of the pumps.
Its certainly a fuel delivery problem.

Tim
 

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Michelle,

Those are terrific "pump gas/low boost" numbers for a T78. Way to go!

However, you said "pump" in your first post, which seemed to mean singular pump. Do you have 2 fuel pumps? I assume you must or else your car wouldn't run at all, but just wanted to clarify that.
 

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Steve Theodore said:
Michelle,

Those are terrific "pump gas/low boost" numbers for a T78. Way to go!

However, you said "pump" in your first post, which seemed to mean singular pump. Do you have 2 fuel pumps? I assume you must or else your car wouldn't run at all, but just wanted to clarify that.
Steve,

a walbro 255 pump and a stock fuel pump...etc),


I had to read it twice to catch that part too ;)


Tim
 

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Supra Owner Since 1996
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2,723 Posts
Congrates! Definetly good numbers on pump for the 78. I guess I better get some fuel.
 

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Power shift that bitch!
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1,518 Posts
Discussion Starter #7 (Edited)
sorry for my poor wording it was late when i got home stayed at the shop till after 10pm...lol

I did some daily driving and it ran pretty smooth, but when i boosted at lower boost started to lose some pressure, so now i am definately thinking the fuel pump is the issue or a fuel filter could be clogged.
 

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1994 Toyota Supra Turbo 6spd
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1,513 Posts
wow great #'s for p ump gas.. is that 91 octane with 19psi?

11 deg of timing at peak torque at 19psi?

when i had my 19psi run with 100 octane (to be safe) my peak torque at 19psi was like 16 or 17..
stock motor 264 cams with the 76gts turbo it made 650whp so that's pretty compareable?
 

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Power shift that bitch!
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1,518 Posts
Discussion Starter #10 (Edited)
So, i replaced the stock fuel pump with another walbro 255 pump and the fuel pressure held at WOT. So last night we fine tuned. We left it at 550/501 18.5psi and 10.2 a/f

Oh and all the pulls were done in 3rd gear. Anyways, I will try to get back in there next week to race tune.
 

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2jz powered
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Michelle,

Do you know what was involved in getting the power fc to work on usdm supras? Are there any extras sensors that needs to be wired in? Thanks in advance.

~Kevin
 

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Power shift that bitch!
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1,518 Posts
Discussion Starter #13 (Edited)
SoarerTT said:
Michelle,

Do you know what was involved in getting the power fc to work on usdm supras? Are there any extras sensors that needs to be wired in? Thanks in advance.

~Kevin
i got a jdm harness and Apex sent me conversion sensors and took out one. I had to find the USDM pinout config and a JDM pinout config. When looking at the JDM config you can see which sensors were needed and which ones were replaced. That was it, then it started right up.

I can get you the exact details on the sensors tonight or tomorrow.
 

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SupraWoman98T said:


here is a pic i just took....

I noticed in your dyno graph that your fuel cut is set for the jdm 2jz. When I installed my Power FC, I noticed mine was also so I adjusted mine to 7,500rpms using the commander.

I think you should raise your fuel cut and tune it again, I believe there is more peak power to make! Especially on your setup!

I am not a tuner, so I maybe be wrong, just an idea.
 

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Power shift that bitch!
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Discussion Starter #15
it definately seemed like i ran out of rpms....
but its also still pretty rich. I figured i should keep it that just incase (fuel pressure pretending to be fixed...lol).
 

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SupraWoman98T said:
it definately seemed like i ran out of rpms....
but its also still pretty rich. I figured i should keep it that just incase (fuel pressure pretending to be fixed...lol).
Awesome! Will at least you know that you can give it some more rpms and make even more power gains! Congrats on the numbers! It feels good complementing a fellow Power FC user lol :)
 

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Power shift that bitch!
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Discussion Starter #19
tunign wasnt that bad...actually i find it easier than other ems. I am still leaning but i got most of it down. The tricky part of the whole thing was the timing. Thats what seemed to be time consuming. Other than that, its a pretty user friendly system...oh and the commander is great too it also can display a map graph :)
 

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Power shift that bitch!
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Discussion Starter #20
SoarerTT said:
Michelle,

Do you know what was involved in getting the power fc to work on usdm supras? Are there any extras sensors that needs to be wired in? Thanks in advance.

~Kevin

jdm harness with adapter
map sensor
intake air temp sensor

removal of maf sensor.

and the pinouts, a few were moved according to the configs.
 
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