Baaad Noise 93 Jgc

[BUGDUST]

Recently Started Having Problems With 4.0 93' Jgc. Fuel Pump Is Most Likely In Need Of Replacing. Pressure Is Right Around 20-25 Throughout Acceleration. Will Hesitate Badly And Stall At Times. More Concerning Is Very Loud Rumble/rattling Noise At Bottom Of Engine While Running And Hesitating, Until Engine Catches Up And Runs Smooth

[dksob81]

I think the hesitation/stalling problem, could possibly be a bad Throttle Position Sensor.

[BUGDUST]

Originally Posted by dksob81

I think the hesitation/stalling problem, could possibly be a bad Throttle Position Sensor.

THANKS FOR THE SUGGESTION. I HAVENT CHECKED THE TPS YET, BUT SUSPECTED THE FUEL PUMP AND PUT A GUAGE ON IT. IT READ AROUND 20-24 MAX, UNDER ACCELERATION THE READING USUALLY DROPPED. SRTRTING SEARCH FOR FUEL PUMP, 1993 JGC 4.0 CANADIAN. CALLED LOCALLY AND WAS TOLD THAT CANADIAN VERSION WAS DIFFERENT THAN AMERICAN. ANY IDEAS? THE LOUD NOISE TURNED OUT TO BE THE BOLTS HOLDING THE CONVERTER TO THE FLYWHEEL WERE LOOSE. I WILL ALSO CHECK THE TPS, JUST TO BE SAFE.

[dksob81]

the low fuel pressure, could be contributed by a bad TPS as well, or clogged Fuel Filter. may want to replace (if not done so recently) the Fuel Filter. Cheap easy and should boost your mileage a lil.

[Cam7]

Fuel presure is 20 lbs to low. Most probally bad pump. Never heard of Canadian being Different. Probally have to remove the pump and match it to a new one if the Canadian version is really different. My 93 XJ 4.0 has a Bosh as orignial part. Not sure about ZJ of that year.

[BUGDUST]

Originally Posted by dksob81

the low fuel pressure, could be contributed by a bad TPS as well, or clogged Fuel Filter. may want to replace (if not done so recently) the Fuel Filter. Cheap easy and should boost your mileage a lil.

with the exception of checking pressure at the fuel rail is there another way of checking fuel pump? is there a certain volume the pump should put out per min. ? if i were to wire the pump direct just to check volume without involving the tps or any other part of the system, just pump output

[dksob81]

I dunno, I am not sure what the GPH (gallons per hour) is on the OEM fuel pump.