Fuel Pump questions (1 Viewer)

[COS80]

My 97 has the TRD supercharger. From the day I bought it, the fuel tank pressurizes and the pump gets whiny as the tank empties and/or as temps climb. I assumed the noise and the pressure were related, but someone on here suggested they weren't. I'm replacing my charcoal canister tonight.

I asked the previous owner about the whine, and he said it's an aftermarket high-flow pump. I'm skeptical, because it doesn't do it all the time, plus I can't find upgraded pumps, except for one on RA that's only $19. Can I pull the pump to inspect it without replacing a bunch of gaskets and such?

The truck stinks to high heaven, especially when cold. This is either a hollowed-out cat or high-flow injectors (or both). The cat doesn't ring like it's empty. Can anyone tell by looking if these are upgraded injectors?

Finally, I haven't seen anything on this, but is an upgraded fuel pump necessary to feed the supercharger and/or my injectors properly? The pump noise makes me uneasy when I'm miles from a paved road, and I want to replace it, but I don't want to ruin my performance, either.

 

[BTLSHP]

Is the fuel tank getting positive pressure or vacuum? Mine was developing a vacuum as the fuel levels went down and it would take many seconds to equalize before filling with gas at a station.

Anyway, that root cause was the EVAP system canister ball valve had varnish itself in place.

 

[COS80]

Positive. It will actually spittle when I remove the gas cap.

 

[BTLSHP]

Positive. It will actually spittle when I remove the gas cap.

I would still start with EVAP system. Run it a bit with the line from the tank disconnected and then try gas cap, or pull the line before opening the gas cap once. My instincts tell me that with a properly functioning EVAP system there should be no pressure differential tank vs. ambient pressure.

 

[COS80]

I am replacing the canister tonight.

 

[COS80]

Canister is replaced, but I'm going to need some miles and some warmer weather to confirm the improvement. Meanwhile, I'm still wondering if anyone knows the answers to these questions (I'm hunting but not finding - not unlike an elk hunt):

1. I see mentions of using Denso 950-0226 for the V8 4runner, but nobody says why... is it just cheaper, or does it flow more?
2. Do I need a higher flow pump for the S/C or injectors?
3. Can anyone tell me how to determine whether I have factory-spec 1FZ injectors?

 

[COS80]

Confirmed my injectors are p/n 23250-74080, which appears to be a stock 1FZ injector, but the p/n on Amayama is 23209-74080. Are they the same injector, but what I have are aftermarket Densos?

I also found a lot of discussion about Supra fuel pumps, along with a lot of debate about its necessity, even for a supercharger. Something tells me this is what I'll find in my tank, because I saw several people talking about it being noisy.

 

[CharlieS]

I am running the denso pump for a v8 4runner in my 80, mostly because the denso one made for the 80 was hard to find.

You need to swap over the wire connector and use the ribber bits for the 80, but otherwise it is an easy change over.

I haven't had any issues, and don't know what other benefit it might have. Higher GPM flow? No idea.

On the stock engine the fuel pressure regulator manages fuel pressure to the injectors. Excess fuel is returned to the tank. Seems like an increase (if any) in GPM is of little value. Unless I'm thinking about this wrong and higher volume and pressure aren't related the way I'm imagining. Wouldn't you need a FPR that allows for higher pressures to get any benefit at the injectors?

 

[COS80]

I am running the denso pump for a v8 4runner in my 80, mostly because the denso one made for the 80 was hard to find.

You need to swap over the wire connector and use the ribber bits for the 80, but otherwise it is an easy change over.

I haven't had any issues, and don't know what other benefit it might have. Higher GPM flow? No idea.

On the stock engine the fuel pressure regulator manages fuel pressure to the injectors. Excess fuel is returned to the tank. Seems like an increase (if any) in GPM is of little value. Unless I'm thinking about this wrong and higher volume and pressure aren't related the way I'm imagining. Wouldn't you need a FPR that allows for higher pressures to get any benefit at the injectors?

I believe it's more about volume than pressure. Unused fuel is returned to the tank unless increased horsepower allows the engine to consume more than the pump can provide. It does seem doubtful that this engine with a supercharger could outpace the stock pump, though some say the higher volume is to prevent lean conditions at WOT. Others say, "baloney".

I just don't want to make a $300+ mistake.

 

[baldilocks]

Super chargers were not installed at the factory as far as I know, which would mean that all 80’s got the same pump. Toyota had no way of knowing which vehicles would get a super charger.

 

[voorland80]

Confirmed my injectors are p/n 23250-74080, which appears to be a stock 1FZ injector, but the p/n on Amayama is 23209-74080. Are they the same injector, but what I have are aftermarket Densos?

I also found a lot of discussion about Supra fuel pumps, along with a lot of debate about its necessity, even for a supercharger. Something tells me this is what I'll find in my tank, because I saw several people talking about it being noisy.

it's interesting lexuspartsnow shows 23250 prefix for the '94 1uz but actual part number is 23209-50020
but 23209-74080 is what i see for the 1fz ('97 lx450)
have removed supercharger but don't recall noticing any loud noise from fuel pump - most likely have stock
fun fact: both '94 sc400 and '97 lx450/fzj80 use same fuel pump, just the fuel sock is different. also, all the rubber bits & bobs for the fuel injectors (minus 1uz cold start) are the exact same.

 

[COS80]

it's interesting lexuspartsnow shows 23250 prefix for the '94 1uz but actual part number is 23209-50020
but 23209-74080 is what i see for the 1fz ('97 lx450)
have removed supercharger but don't recall noticing any loud noise from fuel pump - most likely have stock

Clear as mud....

 

[voorland80]

Clear as mud....

yea need to work on that - but I know what i mean

 

[COS80]

No, not you, the situation. I'd know what you meant, too, if this wasn't so weird.

 

[landtank]

I’ve had pressure for years with my TRD SC. When I’d get out of the truck in the summer you could smell something like kerosene from under the hood. Stumbled onto the problem a year or so ago and haven’t smelled it since.

There’s a vacuum hose that connects to the EVAP system that runs from the front of the engine to the back along the fuel rail. Just before the intake opening there is a small T hose that plugs into an orange plastic valve and then there is a second small T after the intake opening and it plugs into the intake.

Both small T hoses looked to be a formed elbow and when checked the elbows had kinked and collapsed. This basically disables the EVAP system.

Once I replaced the hose thins have been fine.

This is likely the issue with all the charcoal canister problems as well. Not just SC trucks.

 

[COS80]

I think I found those hoses, but they all appear to have been replaced already.

 

[COS80]

The previous owner just informed me that the pump is a Walbro GSS342.

I am finding some evidence that these are known to be noisy.

 

[Batameez]

Noisy, and I would call it a reliability downgrade from a Denso pump.

 

[ajax1]

My buddy went through two walbero pumps, finally convinced him to run the supra pump, he is turbo.
You should be good on the stock pump if you are just running the super charger how Toyota intended,
I had the orange and black valve mentioned up in the other post damaged replaced it and tank pressure went away.

 

[baldilocks]

I’m having trouble finding the Denso application for the FZJ80: 950-0100???

Oem is spendy but last long time. Original equipment was Aisin. Search “Aisin 23221-66040”