91 YJ Fuel Problem... any thoughts? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > 91 YJ Fuel Problem... any thoughts?

Year End Clearance Sale! Save 20%NEW!! HMF 50"-52" light bar mounting brackets!! Introducing MONSTALINER™ UV Permanent DIY Roll On Bed Line

Reply
Unread 04-11-2005, 11:05 AM   #1
BRad704
Nothing to see here...
 
BRad704's Avatar
 
Join Date: Apr 2005
Location: Memphis, Tennessee
Posts: 1,619
91 YJ Fuel Problem... any thoughts?

My 91 4.0L just quit going down the interstate one day. I've tried an new pump, filter, strainer, relay and it keeps blowing the fuel system ecu fuse. the only other thing I can think of is a bad ground or shorted out power lead.

Does anyone know a way to find/isolate these elec problems?

I've been on ramps in teh driveway for 3 weeks and cant take it any more!!!!

BRad704 is offline   Reply With Quote Quick reply to this message
Unread 04-11-2005, 11:27 AM   #2
jdjonesdr
Registered User
 
Join Date: Aug 2004
Location: Dominican Republic
Posts: 103
You need to do a search...

This has been covered many times on the jeepforum.
Your problem is probably electrical, and very possibly the ignition module under the wiper water bottle on the left front fender.
Look at your tachometer when your turning the engine over. Does the tach needle bounce up and down a little? If it doesn't, the module is giving you headaches. You may want to try to find one in a junkyard somewhere that you can plug in and try.
Also, if it's the module, you can sometimes push the vacumn advance lever back and forth a few times, and if you hear a faint clicking noise, you may be able to get the module to fire again.
Hope that helps. This advice comes from personal experience. Same thing happened to me
__________________
DOMINICAN STORM RIDERS JEEP CLUB, SD,RD, Member #1, 1990 Cherokee, 4.2, Autmatic, A/C, Stock.
It's my seventh jeep, had em' all my life, did all my 4 wheelin' on sand dunes.
My jeep loves me.. right?
jdjonesdr is offline   Reply With Quote Quick reply to this message
Unread 04-11-2005, 04:40 PM   #3
wasaw
Registered User
2005 TJ Wrangler 
 
Join Date: Nov 2003
Location: Hermitage, Tennessee
Posts: 29
Racefan318, we had the same problem when we first purchased our '91 YJ. We checked all the wiring in the fuel electrical system, per the schematic. Ending up finding that the wires coming up from the O2 sensor, from the downtube on the exhaust pipe were shorting out aginst the block. Simple fix: replaced and shielded the four wires. Good luck !!!
wasaw is offline   Reply With Quote Quick reply to this message
Unread 04-12-2005, 08:07 AM   #4
BRad704
Nothing to see here...
 
BRad704's Avatar
 
Join Date: Apr 2005
Location: Memphis, Tennessee
Posts: 1,619
Quote:
Originally Posted by jdjonesdr
This has been covered many times on the jeepforum.
Your problem is probably electrical, and very possibly the ignition module under the wiper water bottle on the left front fender.

So the ignition module will cause the fuel system to cut out? I am not getting presssure to the fuel rail.


Wassaw, were did you find the schematic for the wiring?
BRad704 is offline   Reply With Quote Quick reply to this message
Unread 04-12-2005, 09:58 AM   #5
wasaw
Registered User
2005 TJ Wrangler 
 
Join Date: Nov 2003
Location: Hermitage, Tennessee
Posts: 29
I used the Chilton Jeep Wrangler/YJ 1987-94 Repair Manuel, Chilton #8535. I had to take the schematic to work and blow it up on the copier so thjat I could read it (getting older). The Haynes Repair Manual 1987-2000, # 50030, also has decent schematics. When blown up, I like the Chilton better. BTW racefan, I found my short purely by luck. .
wasaw is offline   Reply With Quote Quick reply to this message
Unread 04-12-2005, 10:20 AM   #6
BRad704
Nothing to see here...
 
BRad704's Avatar
 
Join Date: Apr 2005
Location: Memphis, Tennessee
Posts: 1,619
I guess its time to buy a book.

Luck doesnt usually run on my side lately.
BRad704 is offline   Reply With Quote Quick reply to this message
Unread 04-25-2005, 03:57 PM   #7
BRad704
Nothing to see here...
 
BRad704's Avatar
 
Join Date: Apr 2005
Location: Memphis, Tennessee
Posts: 1,619
turns out that wasaw was completely right, down to which wire was burnt up.

for what ever reason the four wires from the O2 sensor ran up beside the exhaust manifold and block without any cover onthem. So now that wire has been replaced and run out of the way of the exhaust.

4 weeks, a fuel filter, fuel pump, fuel strainer, fuel relay, 2 maxi fuses and 12 hours of labor later... the problem was resolved with a piece of wire I already had in my garage.

oh yeah... Haynes wiring diagrams suck. I'm an engineer and they still suck.
BRad704 is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
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


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.