Fuel delivery problem?
01-30-2017, 02:15 PM
#1
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Fuel delivery problem?
Hi,
After sorting my bucking and 95% of my bad idle issues with a new upstream O2 sensor, I thought I'd be back running reliably.
However, after a couple of hundred miles I found that the Jeep was still having a 'stalling' issue.
When coasting to a stop, the revs can drop lower than they should do and then over the past couple of days I've had an issue with power loss and engine stalling (twice). these seems to happen when getting back on the gas after decelerating (at a junction or similar). Both times the engine cut out completely was when I was starting an incline.
HOWEVER, This only started happening when I was low on gas (i.e. the light was coming on on the gauge)
I filled up with fuel yesterday and the problem seemed to improve instantly, which makes me think this is a fuel delivery issue.
I'm thinking either blocked filter or fuel pump going bad, but wondered if the issue resolving with more gas in the tank eliminates either one of those.
One other thing I did consider was maybe the fuel vent/evap system. I'd read somewhere that blockages here can cause problems and that a sign of a blockage is difficulty filling up (i.e. the pump keeps clicking off). With the nozzle fully inserted, the pump would click off almost immediately after pulling the trigger.
Any ideas anyone?
Thanks
After sorting my bucking and 95% of my bad idle issues with a new upstream O2 sensor, I thought I'd be back running reliably.
However, after a couple of hundred miles I found that the Jeep was still having a 'stalling' issue.
When coasting to a stop, the revs can drop lower than they should do and then over the past couple of days I've had an issue with power loss and engine stalling (twice). these seems to happen when getting back on the gas after decelerating (at a junction or similar). Both times the engine cut out completely was when I was starting an incline.
HOWEVER, This only started happening when I was low on gas (i.e. the light was coming on on the gauge)
I filled up with fuel yesterday and the problem seemed to improve instantly, which makes me think this is a fuel delivery issue.
I'm thinking either blocked filter or fuel pump going bad, but wondered if the issue resolving with more gas in the tank eliminates either one of those.
One other thing I did consider was maybe the fuel vent/evap system. I'd read somewhere that blockages here can cause problems and that a sign of a blockage is difficulty filling up (i.e. the pump keeps clicking off). With the nozzle fully inserted, the pump would click off almost immediately after pulling the trigger.
Any ideas anyone?
Thanks
01-30-2017, 06:30 PM
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Year: 1999
Model: Cherokee
Engine: 4.0
1. Always post the year of your XJ when you start a thread. It's important in the advice you will receive.
2. Any check engine light? If so, post the EXACT code(s) here for comment.
3. A marginal battery is the #1 cause of stalling at idle. Have it load tested for free at any parts store. And yes, you can have a battery that is strong enough to start the engine, but marginal enough to give the engine management system fits. I have seen it more times than I can possibly remember.
4. Fuel pressure can be easily tested with a fuel pressure gauge, which can be rented inexpensively from parts stores. Call around for availability. Compare your readings to factory spec, which I can't tell you as I don't know the year of your XJ.
2. Any check engine light? If so, post the EXACT code(s) here for comment.
3. A marginal battery is the #1 cause of stalling at idle. Have it load tested for free at any parts store. And yes, you can have a battery that is strong enough to start the engine, but marginal enough to give the engine management system fits. I have seen it more times than I can possibly remember.
4. Fuel pressure can be easily tested with a fuel pressure gauge, which can be rented inexpensively from parts stores. Call around for availability. Compare your readings to factory spec, which I can't tell you as I don't know the year of your XJ.
01-31-2017, 03:22 AM
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Apologies,
'96 4.0 - I will add that to my signature or profile
No CEL/Code, yet!
I hadn't considered battery - that's the first time I've heard that. Just assumed it wouldn't make a difference when running off of the alternator, but will check it ASAP. However, engine isn't stalling at idle - it does idle slightly rough after 20-30 seconds of idling. The problem is more that the revs drop JUST AS you come to a stop and then pick up again quickly. Only recently have I experienced the engine cutting out completely under acceleration at low speeds and when fuel level is low.
I'm reluctant about testing fuel pressure as it will be an expensive option where I am, but it's probably going to need to be done so will ask around and see if I can find anybody who has one.
Thanks for the advice.
'96 4.0 - I will add that to my signature or profile
No CEL/Code, yet!
I hadn't considered battery - that's the first time I've heard that. Just assumed it wouldn't make a difference when running off of the alternator, but will check it ASAP. However, engine isn't stalling at idle - it does idle slightly rough after 20-30 seconds of idling. The problem is more that the revs drop JUST AS you come to a stop and then pick up again quickly. Only recently have I experienced the engine cutting out completely under acceleration at low speeds and when fuel level is low.
I'm reluctant about testing fuel pressure as it will be an expensive option where I am, but it's probably going to need to be done so will ask around and see if I can find anybody who has one.
Thanks for the advice.