Engine Mystery. Fuel Pump Maybe? - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 09-26-2013, 09:06 PM   #1
Newb
 
Join Date: Sep 2013
Posts: 7
Exclamation Engine Mystery. Fuel Pump Maybe?

I'm new to the Jeep world, I'm 19 so although I consider my self to be fairly familiar with cars, I'm well aware that I in fact have a long way to go. My Jeep "Sam" a 95 YJ 4cyl. cut out on me today which it has never done since I got him this May (except for some problems already taken care of.) Yesterday my Dad drove it till it was on the line and didn't put any gas, and since I have been without a job till yesterday I had to drive back home without putting any in (6-8 Miles). The next morning I drove to the nearest gas station (3 Miles) and filled it to the brim with money that I got from my cousin he owed me from contracting. I drove to the turnpike (25 minute drive) then drove on the turnpike (Highway speeds 20 minutes) and after I got off the exit and onto my college campus to park, my engine all of a sudden shut off. HOWEVER all electrical utilities were still on, I turned the key to the off position then tried to start it again and it ran. When I parked, the heater house was leaking some fluid so I went an hour later to "Autozone" and replaced it, thinking it might have over heated for a sec without me noticing thats why it was shutting off. After I left the store only a few blocks later it happened again; the engine rapidly drops from 1500 Rpm to 0 sounds like it might barely come back then quits, with all electrical utilities working. I checked the engine bay and there was no leak, I turned it on again revved the engine to 6000 for a moment, checked the engine bay and nothing changed. This occurrence happened one more time 20 minutes later on the highway but by that time I knew the drill and it kept on going. Currently "Sam" is in the upholstery shop getting his seats reupholstered and rubber liner installed so I have some time to research what the problem will be before i get him back.

To recap
Engine drops to 0 rpm smooth and quick within 2 seconds
No electrical utilities shut off during occurrence
Radiator, Spark plugs, spark plug wires, starter, heater hose, and oil have all been changed within the last 6 months.
Engine will only restart after turning the car completely off for a few seconds, trying to restart it without resetting all electrical utilities cranks it but thats all.
This Jeep is a 5 Spd. and has 183,000 Miles

My hunch tells me that the fuel pump is starting to go; I just want to confirm and be told if its possible that there are other (more financially reasonable) parts involved that could cause this problem and what brands would be the best. In the end I plan on giving this Jeep to my mom when I'm done getting it like new so I will pay what needs to be payed. There is still a lot I don't know about cars but I am an ok troubleshooter so please don't spare any details on what I should do to get to the bottom of this as well as: general information ,part names, and functions I should know to be able to call myself a decent DIY home mechanic. Thank you

Myfrstjeep is offline   Quote Quick Reply
Old 09-26-2013, 09:21 PM   #2
Jeeper
 
AllMudd's Avatar
 
Join Date: Apr 2013
Location: SoCal
Posts: 1,462
Check the relays by the battery. There is one that's the auto shutdown relay, and the ign relay. Take your horn and or A/C relay and swap them out. Sometimes with age these relays get old and weak and will not work when they get to hot. Thus turning the key off then back on it gives it a little time to cool and work for another 20 mins or so.

AllMudd is offline   Quote Quick Reply
Old 09-26-2013, 09:22 PM   #3
Jeeper
 
Join Date: May 2012
Posts: 57
Check my post here: http://www.wranglerforum.com/f8/87-4...ls-266721.html

Sounds like a problem I was having. Had to end up dropping the fuel tank and blowing the line out. Might want to check fuel filter and fuel pressure.
monkeybonezz is offline   Quote Quick Reply
Old 09-27-2013, 07:15 PM   #4
Newb
 
Join Date: Sep 2013
Posts: 7
Quote:
Originally Posted by AllMudd View Post
Check the relays by the battery. There is one that's the auto shutdown relay, and the ign relay. Take your horn and or A/C relay and swap them out. Sometimes with age these relays get old and weak and will not work when they get to hot. Thus turning the key off then back on it gives it a little time to cool and work for another 20 mins or so.
Ok, I'll definitely check that out when the Jeep gets back. Do you think you send me a diagram or some images of what exactly I'm looking for so I make sure I get it right the first time. Then I would assume to test if it was the relay I should drive the car for a while correct? I really appreciate the help I didn't even know there was a relay for that :s
Myfrstjeep is offline   Quote Quick Reply
Old 09-27-2013, 07:19 PM   #5
Newb
 
Join Date: Sep 2013
Posts: 7
Quote:
Originally Posted by monkeybonezz View Post
Check my post here: http://www.wranglerforum.com/f8/87-4...ls-266721.html

Sounds like a problem I was having. Had to end up dropping the fuel tank and blowing the line out. Might want to check fuel filter and fuel pressure.
It looks like Ill have to syphon the gas out since the tank is full. From a scale from 1-10 how difficult would dropping the tank be and are there any special tools I need? How would I check the fuel pressure as well? I'm sorry for asking so many questions, Ive just never a touched a fuel system except when i took out the fuel injectors from my old 93 Lexus SC400.
Myfrstjeep is offline   Quote Quick Reply
Old 09-28-2013, 06:00 AM   #6
Jeeper
 
Join Date: Jan 2013
Location: Houston,TX
Posts: 125
Dropped mine tonight took me twenty minutes to get it off, thirty to get it back on. The tools needed were:
1/2" socket with extension
1/2"wrench
5/16" &1/4" nut driver
Mr.Mud is offline   Quote Quick Reply
Old 09-28-2013, 07:58 AM   #7
Jeeper
 
Join Date: Jan 2013
Posts: 212
I am leaning toward a fuel issue. You can check fuel pressure at the fuel rail. Should be a shrader valve on there. Next time it dies take the cap off the valve and depress it and see if there is fuel pressure. If there isn't, there are several possibilities, first and cheapest would be fuel filter. If you ran it to where the gas tank was almost empty, some trash could have gotten in the filter and is clogging it up. But, more likely it is your fuel pump. The fuel pump uses the gas in the tank as a lubricant and when you ran it almost dry it could have damaged it causing it to periodically shut off. I recently replaced mine. Got it from partsgeek.com for about $125. This was the complete sending unit with a new pump.

A couple of hints. Get a manuel or check forum for write ups on changing the fuel pump. If you want to increase the capacity of the tank remove or shorten the vent tube while you have the tank out, much easier, and all you need is a pair of needle nose pliers. Check all fuel lines, if they have never been changed you will probably find some dry rot and they should be replaced. Go ahead and change the fuel filter while you are under the Jeep. While you have the tank out it is a good time to clean the inside of the tank. The plastic baffle in the bottom of the tank that the sending unit sits in, on mine had deteriorated and broken loose, leaving plastic pieces in the tank. I just removed what was left and used paper towels and WD40 to wipe the inside of the tank to clean it out.

This is not difficult to do. All you need is a floor jack and about a 2' piece of wood, common hand tools, and it never hurts to have an extra set of hands. If the tank is full it will be much easier if you siphon out most of the gas.

If you do not already have one, get a Haynes manuel or something similar. Check this forum and youtube on how to do everything. Plan out your work and good luck. Keep us posted on what you end up finding.
__________________
1991 YJ 4.0L, K&N air filter, SS headers, 31X10.5, Congo Cage, etc...
CMike357 is offline   Quote Quick Reply
Old 09-28-2013, 09:47 PM   #8
Newb
 
Join Date: Sep 2013
Posts: 7
thank you.
Myfrstjeep is offline   Quote Quick Reply
Old 09-28-2013, 09:53 PM   #9
Newb
 
Join Date: Sep 2013
Posts: 7
Quote:
Originally Posted by CMike357 View Post
I am leaning toward a fuel issue. You can check fuel pressure at the fuel rail. Should be a shrader valve on there. Next time it dies take the cap off the valve and depress it and see if there is fuel pressure. If there isn't, there are several possibilities, first and cheapest would be fuel filter. If you ran it to where the gas tank was almost empty, some trash could have gotten in the filter and is clogging it up. But, more likely it is your fuel pump. The fuel pump uses the gas in the tank as a lubricant and when you ran it almost dry it could have damaged it causing it to periodically shut off. I recently replaced mine. Got it from partsgeek.com for about $125. This was the complete sending unit with a new pump.

A couple of hints. Get a manuel or check forum for write ups on changing the fuel pump. If you want to increase the capacity of the tank remove or shorten the vent tube while you have the tank out, much easier, and all you need is a pair of needle nose pliers. Check all fuel lines, if they have never been changed you will probably find some dry rot and they should be replaced. Go ahead and change the fuel filter while you are under the Jeep. While you have the tank out it is a good time to clean the inside of the tank. The plastic baffle in the bottom of the tank that the sending unit sits in, on mine had deteriorated and broken loose, leaving plastic pieces in the tank. I just removed what was left and used paper towels and WD40 to wipe the inside of the tank to clean it out.

This is not difficult to do. All you need is a floor jack and about a 2' piece of wood, common hand tools, and it never hurts to have an extra set of hands. If the tank is full it will be much easier if you siphon out most of the gas.

If you do not already have one, get a Haynes manuel or something similar. Check this forum and youtube on how to do everything. Plan out your work and good luck. Keep us posted on what you end up finding.
Ill definitely keep Everyone posted. I would really hope its just the filter but if not and it is the fuel pump and etc. My biggest question is I'm waiting on my paycheck so till then should I just drive and pray or put some "sea foam" in the gas tank and the crankcase? The engine is due for an oil change anyway and i was wonder if it would be better to add the additive with this old hardware.Rather than expose the new pump and all to it
Myfrstjeep is offline   Quote Quick Reply
Old 09-29-2013, 08:29 AM   #10
Jeeper
 
Join Date: Jan 2013
Posts: 212
Seafoam the crankcase before you change the oil. Differing opinions on gas tank. I personally don't think it matters that much, especially if you clean the tank as discribed above, while you have it out. There may be some gunk in the fuel lines that will end up in the new filter but this should be minimal and that is what the filter is for. When I use fuel additives it is more for keeping the top end of the engine and injectors clean than it is for fuel lines and such.
__________________
1991 YJ 4.0L, K&N air filter, SS headers, 31X10.5, Congo Cage, etc...
CMike357 is offline   Quote Quick Reply
Old 10-03-2013, 09:54 AM   #11
Newb
 
Join Date: Sep 2013
Posts: 7
Quote:
Originally Posted by CMike357 View Post
I am leaning toward a fuel issue. You can check fuel pressure at the fuel rail. Should be a shrader valve on there. Next time it dies take the cap off the valve and depress it and see if there is fuel pressure. If there isn't, there are several possibilities, first and cheapest would be fuel filter. If you ran it to where the gas tank was almost empty, some trash could have gotten in the filter and is clogging it up. But, more likely it is your fuel pump. The fuel pump uses the gas in the tank as a lubricant and when you ran it almost dry it could have damaged it causing it to periodically shut off. I recently replaced mine. Got it from partsgeek.com for about $125. This was the complete sending unit with a new pump.

A couple of hints. Get a manuel or check forum for write ups on changing the fuel pump. If you want to increase the capacity of the tank remove or shorten the vent tube while you have the tank out, much easier, and all you need is a pair of needle nose pliers. Check all fuel lines, if they have never been changed you will probably find some dry rot and they should be replaced. Go ahead and change the fuel filter while you are under the Jeep. While you have the tank out it is a good time to clean the inside of the tank. The plastic baffle in the bottom of the tank that the sending unit sits in, on mine had deteriorated and broken loose, leaving plastic pieces in the tank. I just removed what was left and used paper towels and WD40 to wipe the inside of the tank to clean it out.

This is not difficult to do. All you need is a floor jack and about a 2' piece of wood, common hand tools, and it never hurts to have an extra set of hands. If the tank is full it will be much easier if you siphon out most of the gas.

If you do not already have one, get a Haynes manuel or something similar. Check this forum and youtube on how to do everything. Plan out your work and good luck. Keep us posted on what you end up finding.
Alright so, I got my Jeep back today and it drove fine. Until I had gotten off the turnpike and drove into my school (20min Highway 10 minutes city) But I was driving in the city earlier for 20 minutes and it was fine. After the first shut off I restarted it and proceeded to reach a parking space so as to not obstruct traffic; the car then shut off 2 more times in the process, Each within 5 minutes. After I had parked I proceeded to leave the car on; the car ran for 10 minutes uninterrupted on idle and after revving it for a minute it seemed the car wasn't gonna die out. I turned it off depressed the shrader valve and there was pressure; next I switched out the Auto shut down relay for the fog light relay, although the idle was a little rocky when I first turned it on it evened out and was fine the next 3 times I turned it on. My conclusion is: it is the Auto shutdown relay and that it only fails after reaching a temperature from an extended period of running at mid to high RPM's, this would explain why I after I stopped driving it and left it on idle it did not shut down. As well as why it had shut down each time the car was in motion, leaving me to believe that the reason why I would be able to restart the car after a minute or so was because thats how long it takes for the relay to cool down the minimum amount of degrees to function. Although swapping out one old relay for another isn't exactly the best troubleshooting; if indeed the engine doesn't cut out within the first 30 minutes on my way to get my brother from school (double the turnpike time in total than the time to get to my school) I can invest in buying the new relay with confidence. However I have decided to still drop the fuel tank and check the lines, pump, and filter for maintenance reasons once i get to a quarter tank and syphoning the gas wont be such a mission. Please let me know your thoughts and opinions as to whether I'm on the right track or not, as well as what you think it could be.

Myfrstjeep is offline   Quote Quick Reply
Reply

Tags
2.5 engine , fuel pump , jeep yj , problem

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




» Featured Product

All times are GMT -5. The time now is 04:49 PM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC