cranks but won't start - INTERMITTENT
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Year: 1999
Model: Cherokee
Engine: 4.0
cranks but won't start - INTERMITTENT
3 times over the past 3 weeks ( about once every 10 starts ) my stock '96 4.0 cherokee cranks but won't start until I depress the accelerator pedal about 1/2 way. All the other times it starts right up. Runs fantastic once started. I've owned it for 5 years and had no problems. No recent changes or work. No key codes and no codes or pending codes via Actron scanner. Any ideas?
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Year: 1990XJ/1989MJ
Model: Comanche
Engine: 4.0L Renix
Evaluate the CPS connection. Do you notice any other similar circumstances when it won't start? Things like very humid or when warm or cold or maybe first start after sitting for two days?
Read this>>>>https://www.cherokeeforum.com/showth...ed=1#post73869
Read this>>>>https://www.cherokeeforum.com/showth...ed=1#post73869
Last edited by BlueXJ; 11-14-2008 at 06:30 PM.
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Year: 1999
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Engine: 4.0
Evaluate the CPS connection. Do you notice any other similar circumstances when it won't start? Things like very humid or when warm or cold or maybe first start after sitting for two days?
Read this>>>>https://www.cherokeeforum.com/showth...ed=1#post73869
Read this>>>>https://www.cherokeeforum.com/showth...ed=1#post73869
Distributor cap and rotor have been on for about 40,000 miles, so I'll be buying an Accel set tomorrow.
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Year: 1990XJ/1989MJ
Model: Comanche
Engine: 4.0L Renix
If you will take a few minutes to check that CPS connection it will probably cure your problem. I sent you the write-up and a description ofwhere it is located is there too. Might take 5 minutes to locate clean and replug it. Humidity may be your connection problem.
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Year: 1988
Model: Cherokee
Engine: 4.0
Blue is 100% right, if your Cps "crank positions sensor" is not working then your engine will just crank and crank and crank, it wont allow the spark plugs to fire, cause your computer doesnt know what stroke, what cylinder is on, hense for if your cps doesnt work neither will any of your ingnition circut until you fix it. so dont waste money being a parts changer, fix it right the first time!
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I did unplug and replug the CPS. It wasn't wet or dirty. I didn't do any tests on it however. I will do so later this week. Wouldn't a bad CPS trigger a code, though?
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Year: 1999
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Blue is 100% right, if your Cps "crank positions sensor" is not working then your engine will just crank and crank and crank, it wont allow the spark plugs to fire, cause your computer doesnt know what stroke, what cylinder is on, hense for if your cps doesnt work neither will any of your ingnition circut until you fix it. so dont waste money being a parts changer, fix it right the first time!
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Year: 1988
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Engine: 4.0
Then you got a fuel issue, to double check, this is what i do, i spray a little starting fluid in the intake and if it starts up everytime that i do that, then it's lean, so first thing you would need to do after you do that is clean the intake, fuel rails, injectors, or if its a carb, the carberator. If it isnt your dd, when was the last time you were at the pump? Gas has a 28 day shelf life, doesnt matter how often you start it up, if the gas has been in their too long. just some suggestions.
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Year: 1990XJ/1989MJ
Model: Comanche
Engine: 4.0L Renix
The CPS is getting and receiving a +/- 5v signal so anything that moves the connection in the slightest can effect the signal. Gas pedel can be one of them.
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Year: 1999
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Then you got a fuel issue, to double check, this is what i do, i spray a little starting fluid in the intake and if it starts up everytime that i do that, then it's lean, so first thing you would need to do after you do that is clean the intake, fuel rails, injectors, or if its a carb, the carberator. If it isnt your dd, when was the last time you were at the pump? Gas has a 28 day shelf life, doesnt matter how often you start it up, if the gas has been in their too long. just some suggestions.
I use fuel system cleaners about every 3,000 miles. Last fill-up was 10 days ago with 87 octane.
I will check fuel pressure and check the CPS later this week. I'm also putting on a new distributor cap and rotor because the old ones have 40,000 miles on them.
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Year: 1990XJ/1989MJ
Model: Comanche
Engine: 4.0L Renix
If you do that and it cures the problem post that, so that everyone knows you have cured the problem. If you find another culprit post that as well so that we can all broaden our knowledge base.
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Will do, but it'll be a while before I know if the problem's gone, since it is very intermittent.