Walbro wearing out after a year?

[SPD TRP]

Well I drove to Colorado from Houston and had no problems whatsoever on the trip up.

I have been there for about a month and the car is starting to have some issues.

I know the air there is very thin, and I am reminded of that every time I go up the stairs from the basement I rented.

I put the Walbro GSS341 in about a year ago, at which time I changed the filter and in tank sock.

The problem is that it starts to sputter with poor power delivery when asked to perform. The afr's on the wideband seem to be going lean when the power falls off.

Not trying to push this thing too much beacause I have to drive it back from Denver in a couple of weeks.

It seems to be a fuel delivery problem.
When I looked at my fuel pressure gauge on my aeromotive fpr it seemed to be fluttering a bit. So I checked the voltage at the pump---around 8.XX at idle. With someone watching the meter, I revved the engine, there was only a small increase in voltage, so I took the fuel pump resistor out of the loop so the pump will receive around 12 volts all the time.

The fuel pressure seemed to smoothen out on the gauge but the same problem persists.

I am wondering if Walbro's go out that fast or could it be the aeromotive fpr?

I don't think it is an ignition problem because it should go rich on the wideband if and when spark would fall off from the unburnt fuel.

I am going to order an in car electronic fuel pressure gauge so I can monitor it to see just whats going on while I am home for the weekend.

Well thanks in advance.

Wayne

 

[jetjock]

I don't think it is an ignition problem because it should go rich on the wideband if and when spark would fall off from the unburnt fuel.

I dunno what the problem is but in that case it would show lean.

 

[SPD TRP]

I dunno what the problem is but in that case it would show lean.

So jj, are you saying an ignition problem would show lean on the wideband?

 

[jetjock]

Sure. Ignition system problems typically result in high levels of HC. A WB can't measure HC. It only measures one thing: oxygen. A loss of spark would result in atmospheric O2 being left behind in the cylinder which would subsequently be seen by the sensor as lean. I'd suggest you pull off a plug wire and see for yourself but that's not a wise thing to do.

 

[ABQMK2]

A friend of mine (supraguy31) ran a walbro in his 7mgte powered MK2 and drove it to SILV and his walbro took a dump on him in a parking garage there and left him stranded. He is running a stock toyota fuel pump from a turbo MK4 now and has had no problems for quite some time now....(he also has 550's upgraded turbo ect ect)...HTH.

Jake

 

[SPD TRP]

A friend of mine (supraguy31) ran a walbro in his 7mgte powered MK2 and drove it to SILV and his walbro took a dump on him in a parking garage there and left him stranded. He is running a stock toyota fuel pump from a turbo MK4 now and has had no problems for quite some time now....(he also has 550's upgraded turbo ect ect)...HTH.

Jake

Thanks for the info Jake

 

[SPD TRP]

Sure. Ignition system problems typically result in high levels of HC. A WB can't measure HC. It only measures one thing: oxygen. A loss of spark would result in atmospheric O2 being left behind in the cylinder which would subsequently be seen by the sensor as lean. I'd suggest you pull off a plug wire and see for yourself but that's not a wise thing to do.

Ok, so my assumption of weak spark or dropping out ignition would show rich on the wideband is incorrect.

It seems that when the motor is cold, the problem isn't as bad, but when it warms up, it is alot more prevelant.

What direction would you point me in?
What ignition parts; in your opinion; are more apt to fail?

Under normal driving, the problem is pretty transparent; but once you put your foot in it the problem is very apparent.


Wayne

 

[jetjock]

It does look to be a fueling problem. Might be a restriction ie; bad filter, pump sock, crimped return line, ect. Either flow the line into a container for one minute or, much easier, do a snap throttle pressure drop test. With the car parked disconnect the vacuum line to the fuel regulator and quickly snap the throttle full open and release several times while watching fuel pressure. If it drops more than a couple of psi max you have a restriction/flow problem somewhere.

 

[kabanimk3supra]

did you ever drive the car on an empty tank? my brother has the same fuel pump. he ran it on an empty tank for a while and his fp went out as well.

 

[pimptrizkit]

yeah in tank pumps do not like being run dry,

i usualy fill up when i hit a half tank.

i thought i had an ebay walbro die on me , my gauge wouldn't show no more then 20psi when i was cranking up the fuel pressure, in tune it was a stuck gauge,


you say you have a frp, crank her up, if you shut off the return it should max pressure.

tho if your pump is on the verge this could make it go ...

what is your fuel pressure any ways?

ps, isn't the air thinner up there so you should natturaly be running richer?
or is that just my assumption?

 

[Matce]

yeah in tank pumps do not like being run dry,

i usualy fill up when i hit a half tank.

i thought i had an ebay walbro die on me , my gauge wouldn't show no more then 20psi when i was cranking up the fuel pressure, in tune it was a stuck gauge,


you say you have a frp, crank her up, if you shut off the return it should max pressure.

tho if your pump is on the verge this could make it go ...

what is your fuel pressure any ways?

ps, isn't the air thinner up there so you should natturaly be running richer?
or is that just my assumption?

the supra adjusts to thinner air AFAIK ... at least european supras do !

 

[Sawbladz]

It is my assumption that even though the air is thinner, it is still metered. Therefore the car knows how much air is coming in and gives the correct ammount of fuel to correspond to the metered air. Please correct if I am wrong in this assumption but that makes sense to me.

 

[pimptrizkit]

It is my assumption that even though the air is thinner, it is still metered. Therefore the car knows how much air is coming in and gives the correct ammount of fuel to correspond to the metered air. Please correct if I am wrong in this assumption but that makes sense to me.

no you guys are right,

i was just thinking about air density, and breathing oxygen and so so,

 

[figgie]

It is my assumption that even though the air is thinner, it is still metered. Therefore the car knows how much air is coming in and gives the correct ammount of fuel to correspond to the metered air. Please correct if I am wrong in this assumption but that makes sense to me.

actually no.

We have an Air Flow meter not a Mass Air Flow meter.

The system we use relies on air speed which is unaffected by air density. That why the 87-88 have a high altitude compensation sensor in the cabin while the 89-92 have it built into the ecu.

If the supra had a MAF instead of a AFM then you would be correct as mass IS affect by denisty.

 

[SPD TRP]

yeah in tank pumps do not like being run dry,

i usualy fill up when i hit a half tank.

i thought i had an ebay walbro die on me , my gauge wouldn't show no more then 20psi when i was cranking up the fuel pressure, in tune it was a stuck gauge,


you say you have a frp, crank her up, if you shut off the return it should max pressure.

tho if your pump is on the verge this could make it go ...

what is your fuel pressure any ways?

ps, isn't the air thinner up there so you should natturaly be running richer?
or is that just my assumption?

I usually fill it up frequently, as work pays for my gas.

I had also heard that the fuel in the tank assist to keep the pump cool.

I ordered one of those prosport electronic fuel pressure gauges so I can monitor it when it starts to act up.

Another thing about denver is the super unleaded is only 91 octane, not the usual 93 we have in houston.

My fuel pressure is about 32 with and 42 without the vacuum line.

 

[Matce]

The system we use relies on air speed which is unaffected by air density. That why the 87-88 have a high altitude compensation sensor in the cabin while the 89-92 have it built into the ecu.

thats what i meant. :naughty:

 

[jetjock]

Right. The IAT and barometric corrections are what allow the ECU to determine mass flow. The flow meter is only one part of that. For those really bored the guy who put the Karman in Karman Flow meter: http://tinyurl.com/24j4ol