no fuel, tank full - 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 03-11-2012, 09:54 PM   #1
hgh
Newb
 
Join Date: Mar 2012
Posts: 11
Cool no fuel, tank full

Greetings all from western Canada. My son has a 93 Wrangler which I'm led to believe is a YJ. It has a 4.0L in line 6 with MPI. No engine mods. The fuel pump died and we changed the pump. We installed a new pump and everything was ok after some cussing and kicking of the tires and swapping a good fuse with a new one. I say that I swapped a good fuse with a new one as I checked the fuse with a multimeter and it tested ok, but it works and it's outta my shop. A few months later it acts up again, and again since the fuel pump isn't working we change it. The new pump doesn't work. At this point I check the original pump and its NFG. I check the second pump and it will work when power is applied to it. We returned the 3rd pump and now we are trying to get the second pump to pump.

I've checked for power at the pump connector and I get 12.? volts for just long enough to be able to read that it has 12.something but not long enough to read what the something is. I've checked for power at the fuse, and checked the fuse and replaced the fuse but no luck. I've checked that there is power to the relay and have swapped the relay with the horn relay and after the swap the horn works, but the pump still doesn't pump and after switching back, the horn still works. The fuel rail has no pressure in it. I understand that there is a roll over switch but I have no idea whether this vehicle has it or where it might be. The vehicle hasn't been rolled.

What determines how long power is on to the pump? If it's the ECM, can I test it? There's a half tank of gas.

hgh is offline   Quote Quick Reply
Old 03-11-2012, 10:48 PM   #2
Jeeper
 
Jeep716's Avatar
 
Join Date: Aug 2010
Posts: 397
Mine did this. There is a sticky on replacing three capacitors in the ECU. Did the trick for me.

Jeep716 is offline   Quote Quick Reply
Old 03-12-2012, 07:47 PM   #3
hgh
Newb
 
Join Date: Mar 2012
Posts: 11
stickies

I looked at the stickies in this forum and I didn't find the one you referred to. Would you please direct me?
hgh is offline   Quote Quick Reply
Old 03-12-2012, 09:45 PM   #4
Newb
 
Join Date: Feb 2012
Posts: 11
Had Same Issue

hgh,

I'm fairly new to the site, but I am currently working on my son's 95 YJ Wrangler. I had no fuel at the injector rail to start with and went thru all the steps to make sure I had spark, etc.

I dropped the fuel tank, and installed a new fuel pump and did the same test as you did with a voltmeter at the connection location below the plate which would be in the tank and got the 12.5 volt reading for roughly 3 seconds and back to zero as the fuel pump primes the system when the key is moved to the ON position.

I thought I had it, but to no avail. The engine would crank, but no fuel. Now this is on me, I didn't change the wiring and plastic snap clip that was on the old pump. The new fuel pump came with a new plastic snap on connector, I reused the old one. I was in a rush to get it running.

I found out that the old plastic connector looked good until I dug deeper and the wire was broke inside the plastic at the metal piece that connects to the motor. Long story made short. After I changed the plastic connecter that snaps in the top of the pump all was good with pressure at the rail. Unfortunately, the injectors were dirty and I had to take the rail off and have them cleaned out by a friend. It started after we installed the rail again. I hope this is some help.

Good Luck, Fuseman
Fuseman is offline   Quote Quick Reply
Old 03-14-2012, 01:37 AM   #5
hgh
Newb
 
Join Date: Mar 2012
Posts: 11
Quote:
Originally Posted by Fuseman View Post
hgh,

I'm fairly new to the site, but I am currently working on my son's 95 YJ Wrangler. I had no fuel at the injector rail to start with and went thru all the steps to make sure I had spark, etc.

I dropped the fuel tank, and installed a new fuel pump and did the same test as you did with a voltmeter at the connection location below the plate which would be in the tank and got the 12.5 volt reading for roughly 3 seconds and back to zero as the fuel pump primes the system when the key is moved to the ON position.

I thought I had it, but to no avail. The engine would crank, but no fuel. Now this is on me, I didn't change the wiring and plastic snap clip that was on the old pump. The new fuel pump came with a new plastic snap on connector, I reused the old one. I was in a rush to get it running.

I found out that the old plastic connector looked good until I dug deeper and the wire was broke inside the plastic at the metal piece that connects to the motor. Long story made short. After I changed the plastic connecter that snaps in the top of the pump all was good with pressure at the rail. Unfortunately, the injectors were dirty and I had to take the rail off and have them cleaned out by a friend. It started after we installed the rail again. I hope this is some help.

Good Luck, Fuseman
The pump came pre assembled and wired to a new plastic connector. I have power for less time at the vehicle side of the connector than it took to read this reply.

I don't want to seem ungrateful for your reply as at this point I'm wondering wtf? What controls the length of time that the pump is on?
hgh is offline   Quote Quick Reply
Old 03-14-2012, 09:34 AM   #6
Jeeper
 
Join Date: Mar 2012
Location: San Antonio
Posts: 124
Quote:
Originally Posted by hgh View Post
The pump came pre assembled and wired to a new plastic connector. I have power for less time at the vehicle side of the connector than it took to read this reply.

I don't want to seem ungrateful for your reply as at this point I'm wondering wtf? What controls the length of time that the pump is on?
What he's referring to is that the broken wire ends (probably) shifted away from each other due to the pump vibrations, and that would account for the loss of power to the pump.

Basically, check your wiring and connectors.
Dassquatch is offline   Quote Quick Reply
Old 03-14-2012, 11:03 PM   #7
hgh
Newb
 
Join Date: Mar 2012
Posts: 11
Quote:
Originally Posted by Dassquatch View Post
What he's referring to is that the broken wire ends (probably) shifted away from each other due to the pump vibrations, and that would account for the loss of power to the pump.

Basically, check your wiring and connectors.
My problem is that the power doesn't stay on long enough. I'm guessing that the power comes on for 3-5 seconds under normal circumstances. It should stay on longer to fill the line and the rail and continue to stay on for a max of 5 seconds after the power draw from the pump increases from trying to pressurize the gasoline in the line that is not being used because the motor is not running. Btw, I'm checking for power at the vehicle end of the pump connection without the pump being connected. I have checked connections at the fuse box and the relay box. I've checked the fuse. I get 12.?V but it lasts about 1 second.

I'm going to cut a hole in the floor so that I can get the pump out without having to take the tank out...again, and check all the connections. At the very least it will be one more thing that I can say I checked and if it's the problem, I'll be a happy camper.
hgh is offline   Quote Quick Reply
Old 03-15-2012, 12:03 AM   #8
Supporting Member

WF Supporting Member
 
Frenz's Avatar
 
Join Date: Jan 2012
Location: Pittsburgh
Posts: 527
Send a message via Yahoo to Frenz
look at the computer ECU.. located driver front fender. is it an 828? replace that for about $100. 2 symptoms of the dreaded 828 are fuel and spark.
__________________
Join the NRA ..
EXCITEMENT is BUILDING
Frenz is offline   Quote Quick Reply
Old 03-16-2012, 08:49 AM   #9
Newb
 
Join Date: Feb 2012
Posts: 11
Pump time

hgh wrote----The pump came pre assembled and wired to a new plastic connector. I have power for less time at the vehicle side of the connector than it took to read this reply.

I don't want to seem ungrateful for your reply as at this point I'm wondering wtf? What controls the length of time that the pump is on?


hgh, no I don't think you are ungrateful, I just went thru the same problem about a week ago. I learned that the pump primes for a very short time when the key is moved from the OFF position to the ON position, to pressurize the system again. I spoke with my mechanic and asked the same question as you mentioned, that the pump should run longer. He said as we try to start the vehicle by moving the key from ON to RUN, is when the pump continues to have power and pressurizes it more, but that the fuel pressure regulator makes sure it doesn't over pressurize.

When I was doing my test with the voltage meter, I too was getting a voltage for a very short time at the connections just under the cover for the fuel tank. Making me think I was good to go and reinstalled the tank to later drop it again because I had no fuel pressure at the injector rail.

Once I removed the pump and wiring again, I re-examined the connector on top of the pump to find that the wire had broken off of the little female connector on the inside of the plastic, so I replaced the connector and all was good.I then had pressure at the injector rail.

I hope you find the problem soon, I know how it can get, my mind was wondering all over the place as to what to do next. You'll get it eventually. Good Luck to You

Another quick test is to remove the gas cap and as you move the key from OFF to ON position, not CRANK/RUN. Have someone put their ear to the hole for the gas cap and they should hear the pump prime if it is working properly. You may have to do this a few times to make sure that they hear it, but they should be able to hear it. Please let me know how it all works out for you, I am curious as to what the solution to this problem will finally be .

Fuseman
Fuseman is offline   Quote Quick Reply
Old 03-16-2012, 07:56 PM   #10
hgh
Newb
 
Join Date: Mar 2012
Posts: 11
Quote:
Originally Posted by Fuseman View Post
hgh wrote----The pump came pre assembled and wired to a new plastic connector. I have power for less time at the vehicle side of the connector than it took to read this reply.

I don't want to seem ungrateful for your reply as at this point I'm wondering wtf? What controls the length of time that the pump is on?


hgh, no I don't think you are ungrateful, I just went thru the same problem about a week ago. I learned that the pump primes for a very short time when the key is moved from the OFF position to the ON position, to pressurize the system again. I spoke with my mechanic and asked the same question as you mentioned, that the pump should run longer. He said as we try to start the vehicle by moving the key from ON to RUN, is when the pump continues to have power and pressurizes it more, but that the fuel pressure regulator makes sure it doesn't over pressurize.

When I was doing my test with the voltage meter, I too was getting a voltage for a very short time at the connections just under the cover for the fuel tank. Making me think I was good to go and reinstalled the tank to later drop it again because I had no fuel pressure at the injector rail.

Once I removed the pump and wiring again, I re-examined the connector on top of the pump to find that the wire had broken off of the little female connector on the inside of the plastic, so I replaced the connector and all was good.I then had pressure at the injector rail.

I hope you find the problem soon, I know how it can get, my mind was wondering all over the place as to what to do next. You'll get it eventually. Good Luck to You

Another quick test is to remove the gas cap and as you move the key from OFF to ON position, not CRANK/RUN. Have someone put their ear to the hole for the gas cap and they should hear the pump prime if it is working properly. You may have to do this a few times to make sure that they hear it, but they should be able to hear it. Please let me know how it all works out for you, I am curious as to what the solution to this problem will finally be .

Fuseman
We tested the pump today while it was in the tank. We just put 12V to the connector and the pump worked. When I tested the connection from the vehicle it had 12v but for a very short a time and with the line empty.

The pump doesn't run long enough to fill the line. We used an external power supply and filled the rail and it ran and then we disconnected the external power and used the vehicle power and it stopped running after the fuel in the rail was used up. There is some thing in, I believe the computer, that controls how long the power is available and there has to be something, I'm guessing an increase in power consumption from the pump, that says the line is full and gasoline isn't needed.

How do I test the computer without purchasing another? If I get one from a wreck there is no guarantee that it will work, If I replace the computer with a different one and the problem is solved then we're laughing. On the other hand it doesn't work, is that computer not working or is the problem somewhere else?
hgh is offline   Quote Quick Reply
Old 03-18-2012, 10:30 PM   #11
Jeeper
 
Jeep716's Avatar
 
Join Date: Aug 2010
Posts: 397
Here is the repair I did and cured my blues.

http://www.jeepforum.com/forum/f12/h...ur-ecu-591031/
Jeep716 is offline   Quote Quick Reply
Old 03-20-2012, 09:23 AM   #12
hgh
Newb
 
Join Date: Mar 2012
Posts: 11
no fuel tank full

I found the problem. A previous owner had scraped a little of the insulation off the blue wire located just behind a connector located on the pass side. I physically traced the wires from the tank and found this connector and twisted it to look at its condition and spotted the bare spot on the wire. It is just bared as if someone took a knife and scraped away enough to put the end of a test probe in there. I twisted the connection and i guess that twisted the little strands of wire together and that gave the wire enough capacity to care the power to the pump. We'll be leaving that for now as it is just behind the connector about 1/2 inch and its almost impossible to splice in another section of wire.
hgh is offline   Quote Quick Reply
Old 03-26-2012, 09:19 AM   #13
hgh
Newb
 
Join Date: Mar 2012
Posts: 11
Thumbs down no fuel tank full

I posted in haste. The problem has re-occured. As I said previously this wire was stripped enough for a meter probe. No matter how much I twist and squeeze this wire there is not enough power going through it to start the pump. There is 7.65V going through there. I'm still looking for information on what turns on/off the power to the pump.


There is a wrinkle to add. We were using the jeep to pull another vehicle in the yard just like last time. We were trying to finish putting my 66 Chev panel truck in a shed while I work on other projects which are side lined because of this effing jeep.

hgh is offline   Quote Quick Reply
Reply

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
2" spring spacers w/no bump stop extention brendend TJ General Discussion Forum 18 10-12-2012 07:20 AM
VA: FS: Mopar Fuel Filler Door (82210285AB) - $80. Shipped adg44 Classifieds Archive 30 04-27-2012 07:22 PM
95 YJ no spark please see picture !! Z131 YJ Tech Forum 36 03-17-2012 09:20 PM
Fuel pump replacement questions jstone326 TJ General Discussion Forum 16 03-12-2012 07:50 AM
Stupid factory fuel hose.... Dassquatch YJ Tech Forum 3 03-11-2012 04:03 AM


logo carid shop wrangler parts carid fender flares custom wheels store avs deflectors at carid

» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 02:25 AM.



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