Fuel Line Pressure Questions (1 Viewer)

[csd1982]

I have been having issue with my 75 Fj40. It sputters at low RPM and eventually it would not turn on. It seemed to be starved of gas.

I replaced the original fuel filter and not it will start. However the sputtering is still there just not as bad and if I dont keep pressure on the gas peddle it will die in ideal.

I think maybe the fuel pump is going. I want to check the fuel line pressure however I don't see a valve. Do I have to install one to check the pressure and what should the pressure be?

I did replace the spark plugs and wire's already but I really think its a fuel delivery problem.

 

[Josie'sLandCruiser]

Hi all,

I'd check out the fuel pump, and the idle solenoid.

The carburetor does not need much fuel pressure, I think the range is like 5 - 8 PSI? Yes, you would need to plumb-in a spot in the fuel line to attached a fuel pressure gauge.

The idle solenoid is mounted in the base of the stock Aisin carburetor, and is crucial to proper engine idle. Sometimes the connection to this solenoid is bad, leading to malfunction.

Good luck,

Alan

 

[DSRTRDR]

in the base

 

[DougAustinTx]

I have one 2F that has 2 pounds of fuel pressure and one that has about 4 lbs of pressure. I would imagine the 4 lbs is more likely to be correct. but both engines run fine.

 

[fieldsken1]

No 1 just take the fuel line off and crank it over and see if the fuel is comming out fairly good. It does not take much. no guage needed. No 2 reconnect fuel line and Take air cleaner off and look down the carb and give it gas and see if you have a constant flow into the intake if not the carb is no good. acc pump maybe no good

 

[sadam_husain]

if the problem is fuel supply it would be starving at open throttle where fuel consumption is higher rather than at idle where fuel demand is low

could be fuel solenoid, blocked idle jets or the engine may need a bit of a tune up

 

[zags]

The first thing I would check for is a vacuum leak. loosely cover the top of the carb with your hand or close the choke while it is idling. If the rpms increase, it is running lean and may have a vacuum leak.

 

[csd1982]

if the problem is fuel supply it would be starving at open throttle where fuel consumption is higher rather than at idle where fuel demand is low

could be fuel solenoid, blocked idle jets or the engine may need a bit of a tune up

Where is the fuel solenoid located?

 

[csd1982]

The first thing I would check for is a vacuum leak. loosely cover the top of the carb with your hand close the choke while it is idling. If the rpms increase, it is running lean and may have a vacuum leak.

I have the stock FJ40 gauges so I cannot see the RPM's then. Anyway else to do this check?

 

[sadam_husain]

Where is the fuel solenoid located?

Its on the carb, theres a wire coming off it that livens up when the ign is turned on and it opens the valve on the solenoid, if theres no power to it or the solenoid isn't working the engine wont idle, all my 2F engines have had one so I assume your 1975 F or 2F has one

 

[zags]

I have the stock FJ40 gauges so I cannot see the RPM's then. Anyway else to do this check?

Just listen. You will notice it smooth out and increase speed. Also, I meant to say cover with your hand or close the choke.

 

[Pin_Head]

I think maybe the fuel pump is going.

I did replace the spark plugs and wire's already but I really think its a fuel delivery problem.

Your reasoning is flawed. Fuel delivery problems show up at high speed, high load situations and not at idle when the engine only needs a tiny amount of fuel. It is more likely a vacuum leak or an idle fuel cut off solenoid problem.

 

[csd1982]

Just listen. You will notice it smooth out and increase speed. Also, I meant to say cover with your hand or close the choke.

So I'm back home and did your test.

When I start up the rig I have to keep slight pressure on the pedal so it won't die in ideal. When I close the choke the car revs up for like 2 seconds and than just dies. Does this sound like a good indicator that I have a vacuum leak somewhere?

Also when I look down the carb after it stalls and open the choke there is a ton of vapor almost like smoke it's so thick in the carb on the side that has the choke valve cover. Is that normal as well?

 

[SouthMS40]

Have you pulled any of the spark plugs to verify whether or not your too rich instead of too lean? Black soot on the head of the plug means it's too rich.

 

[DougAustinTx]

Sounds to me like you need to have someone who understands carburetors take a look at yours. Your test with the choke butterfly shows that the carb isn't flowing fuel very well at idle and then you choked it out with too much gas at the end of the test. That's all the vapor you're seeing.

 

[sggoat]

Agree with Pin_Head--vacuum leak(or solenoid)