Start then dies

Performance mods and Advanced Stroker discussion.
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MilehighGS
Posts: 4
Joined: November 11th, 2019, 3:33 am
Stroker Displacement: 4.6
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Xj

Start then dies

Post by MilehighGS »

Hi all! Just installed my first 4.6 build and ready to fire it up. It's a 2000 xj and fires right up..........but then it dies.......I've replaced fuel pump, checked wiring........looked for the fuel pump ballast.........nothing. Hope anyone can help me.
TJBUD
Where's the "any" key?
Where's the "any" key?
Posts: 27
Joined: April 20th, 2022, 9:32 am
Stroker Displacement: 4.7
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: TJ

Re: Start then dies

Post by TJBUD »

Milehigh,
Not any takers on this thread-is it diagnosed yet? Since it starts then dies I’d go back to basics (fuel, spark, sensor codes):
1) with the key turned to the run position (not start) does the fuel pump run about 3 seconds? It’s normal for it to time out if you don’t start it. But the question we’re trying to answer is does the PCM send power to the fuel pump relay when the ignition is in run.
2) what is the fuel pressure? On my 98 the spec is 49psi-I think 2000 is the same.
3) after 1) does the fuel system hold pressure? Shouldn’t lose more than about 10psi in 20 mins. So, is there a fuel escape path that’s bleeding down fuel pressure (stuck open injector)? Ideally have a helper watch a fuel pressure test gauge at the rail as you start, run, die to see if the pressure drops.
4) on a 2000, is it one ignition coil or 6 coils (coil in spark)? If 1 coil it’s easy to check if there is voltage to the coil with the key on run? If 6 coils can you check this on one or more?
5) Is the PCM storing codes? Even if the check engine light is off, the PCM may have “pending codes”. If you have a bad sensor (crank position, throttle position, cam position, etc) there may be pending codes that aren’t stored codes yet.

I hope this helps or you’ve solved it already,
TJBUD
MilehighGS
Posts: 4
Joined: November 11th, 2019, 3:33 am
Stroker Displacement: 4.6
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Xj

Re: Start then dies

Post by MilehighGS »

Thanks TJ!
The pump does prime with key on, for a few seconds. There is steady pressure at the rails with no drop. I have plugged a scanner on it for ant codes and nothing.
Do all 2000's have a chip key? I'm questioning the key I am using to start it up with. It is a newer cut key my son had.
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amcinstaller
I love JeepStrokers.com!!
I love JeepStrokers.com!!
Posts: 611
Joined: May 22nd, 2008, 11:57 pm
Stroker Displacement: 4.6L
Vehicle Year: 1980
Vehicle Make: AMC
Vehicle Model: Spirit
Location: Red Deer, AB, Can

Re: Start then dies

Post by amcinstaller »

I forget exactly which light it is in that year but chrysler had a few different security lights in that Era,
- small round inscription red light
- red light up high by the windshield
- yellow picture of a key with a circle and crossing it out in the cluster

Generally if the key is the issue, the light will be flashing
1980 AMC Spirit Restomod in Progress
SilverXJ wrote:Roller rockers won't help that mess you have created. Nor will God for that matter.
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Cheromaniac
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Re: Start then dies

Post by Cheromaniac »

If it had been an anti-theft system security key issue, the engine wouldn't even crank.
Have you checked the crank and cam position sensors?
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
MilehighGS
Posts: 4
Joined: November 11th, 2019, 3:33 am
Stroker Displacement: 4.6
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Xj

Re: Start then dies

Post by MilehighGS »

Cheromaniac wrote: May 31st, 2023, 11:34 pm If it had been an anti-theft system security key issue, the engine wouldn't even crank.
Have you checked the crank and cam position sensors?
Has new crank sensor, installing cam sensor tonight.........fingers crossed!
MilehighGS
Posts: 4
Joined: November 11th, 2019, 3:33 am
Stroker Displacement: 4.6
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Xj

Re: Start then dies

Post by MilehighGS »

New cam sensor did nothing.........
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Cheromaniac
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Posts: 3199
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Vehicle Year: 1992
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Re: Start then dies

Post by Cheromaniac »

This might help you troubleshoot the issue:

https://mechanicbase.com/driving/car-st ... uel%20pump.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
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