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Unread 09-21-2009, 05:36 PM   #1
Registered User
2007 JK Wrangler 
Join Date: May 2008
Location: Johnston, RI
Posts: 191
98 XJ 4.0 Starting Issue...

Ive got a 98 XJ 4.0 Auto. When I go to start it it cranks and cranks and cranks and will either stumble and not start or fire up. If it stumbles I can turn the key off and try again and she usually fires up. I just replaced the CPS and that did nothing for me. When I turn the ignition on I can hear a faint noise from the fuel pump. Other than this issue I have no other issues when its running.

The battery is good and the cps is brand new so Im eliminating those from the problem. I was either thinking a starter issue or fuel pump?

Also the cap rotor wires and plugs are probably about 4 months old now.

Thanks In Advance


2007 JKU- Pretty much stock
1998 XJ- Gone
1992 XJ- Sold
1990 YJ- Sold
rustedxj is offline   Reply With Quote Quick reply to this message
Unread 09-21-2009, 05:46 PM   #2
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2001 XJ Cherokee 
Join Date: Aug 2009
Location: Goldsboro, NC
Posts: 30
I came across a few threads on this. It's most likely a fuel delivery issue. Other members have said that it is either the check valve in the pump or the fuel pressure regulator. Either one will let the fuel drain back to the tank and not keep prime so cycling the key without trying to start it once or twice will usually get it to fire up quicker... I was going to replace my regulator but now the problem went away on it's own. It started to happen to me a day after wheelin' and getting stuck in water for a couple of hours but now it fires right up...
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Unread 09-21-2009, 06:44 PM   #3
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1995 YJ Wrangler 
Join Date: Jun 2006
Location: Maryland
Posts: 353
Happens to my 98XJ too, sometimes I will turn the key in the on position and let the fuel pump run for a few seconds and that works.

I too feel that it is easier to turn the key twice than it is to actually replace the issue.

I know this is not the best solution, but it works currently for me.
1995 YJ 2.5 RE SD, 2'BL 33x12.5 Dunlop Mud Rovers
1998 XJ Sport - RC 3" Full Pack, JKS Discos

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Unread 09-21-2009, 06:55 PM   #4
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1999 XJ Cherokee 
Join Date: Dec 2006
Location: Minneapolis
Posts: 1,353
Yeah, it's most likely a bad pressure regulator or leaky injectors. I'd bet it's the regulator. Time to drop the tank and install a new assembly. (It's not that hard.)

Don't waste your time on a check valve. That's what I did. I started with a bad regulator, installed a check valve, and ended up with bad injectors. Maybe they weren't related, but something tells me that doing it right the first time would have saved me a lot of time and money.
mortalenema is offline   Reply With Quote Quick reply to this message

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