UPDATE: won't start
Thread Starter
Junior Member
Joined: Feb 2011
Posts: 39
Likes: 0
From: Saginaw, MI
Year: 1991
Model: Cherokee
Engine: 4.0l
I have replaced the ignition coil, CPS, computer. tested power at the ignition coil and nothing. I am out of ideas anyone have some for me to try?
CF Veteran
Joined: May 2010
Posts: 1,680
Likes: 5
From: Western Michigan
Year: 1993
Model: Grand Cherokee
Engine: 4.0l inline 6
Does it crank and not start? CPS
Turn the key and nothing? NSS (try starting in "N", if it starts then it's the NSS.
Plus you need to give us more info on what "jeep" were trying to help you with.
Turn the key and nothing? NSS (try starting in "N", if it starts then it's the NSS.
Plus you need to give us more info on what "jeep" were trying to help you with.
Thread Starter
Junior Member
Joined: Feb 2011
Posts: 39
Likes: 0
From: Saginaw, MI
Year: 1991
Model: Cherokee
Engine: 4.0l
Sorry, It's a 91 sport 4.0l H.O Auto. Ya it cranks but won't start. I have replaced the CPS, ignition coil and computer. Switched all relays in the PDC. tested power going to the ignition coil with a light and nothing.
CF Veteran
Joined: May 2010
Posts: 1,680
Likes: 5
From: Western Michigan
Year: 1993
Model: Grand Cherokee
Engine: 4.0l inline 6
Might seem simple but did you get the battery load tested and check the charge. I'm going through the same thing and I have to get my battery checked.
Do you have and trouble codes?
Do you have and trouble codes?
CF Veteran
Joined: May 2010
Posts: 1,680
Likes: 5
From: Western Michigan
Year: 1993
Model: Grand Cherokee
Engine: 4.0l inline 6
also get a code scanner ( buy, borrow), or a fuel pressure gauge. You have to make sure its getting fuel. Most auto stores rent the gauges.
Thread Starter
Junior Member
Joined: Feb 2011
Posts: 39
Likes: 0
From: Saginaw, MI
Year: 1991
Model: Cherokee
Engine: 4.0l
Had the battery tested and they say it's bad. so got a different one now just have to switch up + end to post clamp. It's giving me no codes. I borrowed a fuel gage from my friend haven't had time to test it yet hopefully this weekend. Thank you guy's for the advice I will be posting back on this thread my results.
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Thread Starter
Junior Member
Joined: Feb 2011
Posts: 39
Likes: 0
From: Saginaw, MI
Year: 1991
Model: Cherokee
Engine: 4.0l
Replaced the battery, plugs and put the original computer back in. Now the fan comes on (didn't before). still wouldn't start. So I did another code scan on the dash and this time it's giving me a code #54 some sensor in the distributor so I was starting to take it out when a screw dropped down in it got it out and out came some metal magnitized box looking object. Anyone know what that is?
Senior Member
Joined: Apr 2010
Posts: 504
Likes: 1
From: Tucson, AZ
Year: 2002
Model: Grand Cherokee
Engine: 4.0 I6
Take a volt/ohm meter and check your coolant temperature sensor for 7,000 ohms or greater when the engine is cold. The sensor is on the thermostat housing, unplug the electrical connector from the sensor, take the leads of the volt meter and touch them to two of the prongs on the sensor itself, if it reads under 7,000 ohms than replace the sensor. The sensor is under 20$, use Teflon tape when you thread in the new one, make sure you have the volt meter set to the correct range when you take the reading.
Member
Joined: Feb 2010
Posts: 182
Likes: 0
From: Burtucky,Michigan
Year: 1999
Model: Cherokee
Engine: 4.0
Take a volt/ohm meter and check your coolant temperature sensor for 7,000 ohms or greater when the engine is cold. The sensor is on the thermostat housing, unplug the electrical connector from the sensor, take the leads of the volt meter and touch them to two of the prongs on the sensor itself, if it reads under 7,000 ohms than replace the sensor. The sensor is under 20$, use Teflon tape when you thread in the new one, make sure you have the volt meter set to the correct range when you take the reading.
Senior Member
Joined: Apr 2010
Posts: 504
Likes: 1
From: Tucson, AZ
Year: 2002
Model: Grand Cherokee
Engine: 4.0 I6
It tells the computer how to mix air and fuel based on the temperature of the coolant. You must be thinking of the coolant gauge sending unit. Other sensors related to the air fuel mixture are the MAT and MAP sensor, maybe some others I'm forgetting. One day my XJ would crank and crank but not start, the CPS was brand new, turned out to be the CTS. There's a lot of trouble shooting you can do with a Haynes/Chilton and a multi-meter.
Member
Joined: Feb 2010
Posts: 182
Likes: 0
From: Burtucky,Michigan
Year: 1999
Model: Cherokee
Engine: 4.0
Ive found that out in the last few days.I wasnt being sarcastic when I asked.....After posting and reading it,kinda read as if I was.
Last edited by AutomaticKrackr; Mar 15, 2011 at 08:52 PM.


