prov

Just got a sc300 soarer TT manual 1jzgte 1992

Im experiencing major fuel cuts at high revs, especially when the fuel tank is less than 10L.(faulty walbro??? )
Sometimes its really fuel cuts like if I was hitting a brick wall and other times its more like running out of fuel or a spark problem.
Stock Boost
FMIC
factory bov
New plugs
Walbro fuel pump + 12V mod

When it is raining or humid outside, the engine misfires a lot more, maybe a cracked coil or something.. since the plugs are new
I was hoping somebody could help me or had experienced a similar problem
Thanks

shonuff53

iTrader: (3)

before you get to crazy troubleshooting try and see if it is fuel cutting. these cars overboost with almost any modifications and especially in cool weather (rain,cold,moist).

prov

how can I see if it is really fuel cutting? It is really worse when the tank is low but still does it with 30-40l of gas.

shonuff53

iTrader: (3)

well, does it only do it under load? or does it also do it on a free rev in neutral without boost. hook up a boost gauge and check to see if it only is occuring when you pass around 11 lbs of boost. even if this isnt boost cutting if you dont plan on getting a standalone you might as well get a fuel cut defender or a boost cut controller which perform the same function just different brands, your going to need it if you do any mods such as air filter upgrades, exhaust upgrade, intercooler upgrade, all these mods can cause your car to overboost and fuel cut.

prov

I already have an HKS air filter, 3'' catback, big *** FMIC, greddy boost gauge (0.6bar). It wont cut in neutral, only when reving it over 5-6k with less than maybe 15L, less gas, harder fuel cut.Also, it seems to be running kind of rich but nothing too dramatic.

SCoupe

I'd take this car to a dyno facility for a tune, but before I'd go, I'd pull that pump for an oem TT replacement, cause imho....

BINGO ! Heavy odds on another failing Walbro. Supra Forums has numerous complaints on this very thing. Why the dual Walbro craze?The MKIV Supra TT fuel pump is incredibly reliable and flows the same or more than the Walbro.
http://www.supraforums.com/forum/sho...t=denso+walbro

"The Denso fuel pump 195130-1020 (the Supra Turbo MKIV pump) is one of the best in-tank upgrade choices if you are using injectors up to 550 cc/min and are providing at least 13 volts to the pump. When 18 volts are supplied, the Supra pump is good for injectors up to 880 cc/min. At 13.5 supplied volts no other in-tank pump, except for the R33 Skyline GT-R and A'PEXi BNR32 fuel pumps, flows significantly more fuel up to 70 psi line pressure or 27 psi boost. It is a direct drop-in replacement; all other non-Denso choices require some modification to the fuel pump assembly. It is as quiet as the stock pump. Best of all, it can cost only $180 at Conicelli Toyota. One disadvantage of the Supra pump is its relatively heavy current draw (at 13.5 V, 16A @ 43 psi, 19A @ 70 psi) and large decrease in flow as supplied voltage lowers. Good, heavy-gauge wiring (meaning re-wiring the fuel pump electrical circuit) is a requirement to get the most out of this pump.

Thats a good thing, because rich can help protect a boosted engine in a bad tune if that's whats happening.

prov

So I see a lot of bad comments about the walbro pump. Ill start by trying a TT supra fuel pump. Where can I find it ?

SCoupe

Well, new, the best sourse is CL Forum sponsor Carson Toyota, L-tunedparts.com . The tt pump lists for $348 and they sell it for $261. http://www.l-tunedparts.com

Used, they do show up on Supraforums "For Sale" threads every few weeks or so, like this one: http://www.supraforums.com/forum/sho...highlight=pump Just search pump in that section.

I'm not your mechanic so understand that there are certianly other possibilities in your system that could cause the trouble as well, but the Walbro is certianly a big suspect, cause as you read, there are clearly failure issues happening.

deathrow

Could also be a clogged fuel filter.

If you are really hitting boost cut you will see an error message on the dash. At around 13.5+ psi you will get the symptoms you are describing, but they will be unrelated to fuel level.