cranks but doesn't start
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Junior User
Joined: Aug 2017
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cranks but doesn't start
So I got this '96 Jeep Cherokee XJ that cranks but doesn't start. It's got around 180k on her but I keep everything in good shape. Batt seemed strong.
I used to drive it everyday but this past year I've driven it only about twice a week. It's been just slightly slower to start in the last couple of months, but just barely slower. Was guessing it had something to do with aging plugs or something.
Drove it yesterday and everything was normal like always, sat overnight and today it cranked but didn't catch.
Any ideas on where to start?
I used to drive it everyday but this past year I've driven it only about twice a week. It's been just slightly slower to start in the last couple of months, but just barely slower. Was guessing it had something to do with aging plugs or something.
Drove it yesterday and everything was normal like always, sat overnight and today it cranked but didn't catch.
Any ideas on where to start?
Scope Wizard
Joined: May 2019
Posts: 6,530
Likes: 25
Well, without some Basic trouble shooting.... ie do you have fuel and spark, it's a Crapshoot...the Crank sensor is a common failure item I've probably replaced more of these than anything else on those old jeeps.
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Junior User
Joined: Aug 2017
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So far I've been able to run a couple tests..
Hooked up a fuel pressure gauge and first key turn got it up to only 20psi. Second turn got it up to 45. And third and subsequent turns got it up to 48. It only fell to 43 after 2 minutes so I think that means the fuel pressure is good.
Hooked up a spark tester between a plug and wire and it didn't light at all when cranked so I'm guessing I've got a spark problem. I'll start by doing a tune up with new rotor, cap, wires and plugs then see what happens. After that it I'll go after the crank position sensor and spark sensor.
Hooked up a fuel pressure gauge and first key turn got it up to only 20psi. Second turn got it up to 45. And third and subsequent turns got it up to 48. It only fell to 43 after 2 minutes so I think that means the fuel pressure is good.
Hooked up a spark tester between a plug and wire and it didn't light at all when cranked so I'm guessing I've got a spark problem. I'll start by doing a tune up with new rotor, cap, wires and plugs then see what happens. After that it I'll go after the crank position sensor and spark sensor.
Scope Wizard
Joined: May 2019
Posts: 6,530
Likes: 25
the crank sensor is the Spark Trigger if you will 
when it fails you get no spark.
EDIT: I don't know if this is any help to you ..... https://troubleshootmyvehicle.com/je...crank-sensor-1
when it fails you get no spark.
EDIT: I don't know if this is any help to you ..... https://troubleshootmyvehicle.com/je...crank-sensor-1
