Crank no start.
Alright, I have a 98 classic with a 96 H.O. In it. Yesterday I started it up perfectly fine, came back home and parked it in the driveway. Came out to it this morning and tried to start it and it just cranks and sometimes it sounds like it’s right about to start but then nothing. It has spark, has about 44 lbs of pressure at the fuel rail. Just changed the CPS, all fuses are ok and still won’t start.
so it has fuel, air, and spark, but won’t start. Running out of ideas, please help.
so it has fuel, air, and spark, but won’t start. Running out of ideas, please help.
CF Veteran




Joined: Nov 2010
Posts: 5,841
Likes: 117
From: In the middle of Minnesota!
Year: 1999
Model: Cherokee
Engine: 4.0
Three things come to mind.
First not all spark is created equal. What color is the spark? You need a strong, snapping BLUE spark to fire the engine. Yellow/orange spark indicates a weak spark which could be related to a failing ignition coil. The coil on your vintage can easily be tested for both primary and secondary resistances with a meter and a manual.
Second thing is that you are on the low end of the fuel pressure spec. If memory serves me, the spec is 49 plus or minus a couple psi. Now fuel pressure gauges can be inaccurate so if the problem persists, getting a different fuel pressure gauge and getting another reading would be a good idea.
Third is that you should verify that you are getting a pulse TO the fuel injectors from the computer. A "noid light" can tell you that quickly.
Good luck and keep us updated!
First not all spark is created equal. What color is the spark? You need a strong, snapping BLUE spark to fire the engine. Yellow/orange spark indicates a weak spark which could be related to a failing ignition coil. The coil on your vintage can easily be tested for both primary and secondary resistances with a meter and a manual.
Second thing is that you are on the low end of the fuel pressure spec. If memory serves me, the spec is 49 plus or minus a couple psi. Now fuel pressure gauges can be inaccurate so if the problem persists, getting a different fuel pressure gauge and getting another reading would be a good idea.
Third is that you should verify that you are getting a pulse TO the fuel injectors from the computer. A "noid light" can tell you that quickly.
Good luck and keep us updated!
Last edited by tjwalker; Mar 6, 2022 at 05:46 PM.
Junior Member
Joined: Nov 2011
Posts: 35
Likes: 2
From: Nova Scotia
Year: 1995 for parts, a 1998 for parts, 2000 just ok patched, 1999 a good one!!
Model: Cherokee
Engine: 4 litre
I would check the crank sensor, I also have a 99 that died on me recently, I tested the crank sensor following a YouTube video i found with my muiltimeter, mine was the crank sensor, i replaced mine with a Mopar one that are supped to be much better.
Junior Member
Joined: Nov 2011
Posts: 35
Likes: 2
From: Nova Scotia
Year: 1995 for parts, a 1998 for parts, 2000 just ok patched, 1999 a good one!!
Model: Cherokee
Engine: 4 litre
Hey, Sorry just read your post again and this time noticed that it has spark,
So, this time i would check the timing as the chain may of jumped, or there could be a distributor problem. To do this I would make sure you turn the engine over by hand to get # 1 at TDC on the pulley timing mark, check the dist with the cap off to make sure rotor button is pointing to #1 and with the valve cover off #6 rockers should be rocking (one closing and one opening) Hope this Helps!
So, this time i would check the timing as the chain may of jumped, or there could be a distributor problem. To do this I would make sure you turn the engine over by hand to get # 1 at TDC on the pulley timing mark, check the dist with the cap off to make sure rotor button is pointing to #1 and with the valve cover off #6 rockers should be rocking (one closing and one opening) Hope this Helps!
Junior Member
Joined: Sep 2021
Posts: 41
Likes: 0
From: NORTH CAROLINA
Year: 1990
Model: Cherokee (XJ)
Engine: RENIX 4.0
Alright, I have a 98 classic with a 96 H.O. In it. Yesterday I started it up perfectly fine, came back home and parked it in the driveway. Came out to it this morning and tried to start it and it just cranks and sometimes it sounds like it’s right about to start but then nothing. It has spark, has about 44 lbs of pressure at the fuel rail. Just changed the CPS, all fuses are ok and still won’t start.
so it has fuel, air, and spark, but won’t start. Running out of ideas, please help.
so it has fuel, air, and spark, but won’t start. Running out of ideas, please help.
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