Won't start it's not the CPS
Thread Starter
Seasoned Member
Joined: Oct 2010
Posts: 259
Likes: 2
From: Eastern Oregon
Year: 2000 Sport
Model: Cherokee
Engine: 4.0
Ive searched and searched on here but running out of luck and need a guru at this point. She ran good 3 days ago driving to work, and there she still lies. I replaced the crankshaft position sensor and camshaft position sensor, to make things funner I can hear my fuel pump and when I turn the key and bleed the fuel rail it jets a stream of fuel and The fuses are all good under the hood. What am I missing? Any help would be awesome just don't tell me its the cps lol
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Ow..I'm not familiar with those, would need to see it. For lack of a better idea, a few squirts of starting fluid. If it did fire you could suspect something fuel. Easy enough to try.
Somebody should know a way to check spark. Guess we won't talk about an easy 3 minute cps test because bad new ones do show up.
The Key trick? Codes? No, maybe 92 on for that?
Well, just looked a bit, yea, Google Key trick. The code key is above in "info threads"
Somebody should know a way to check spark. Guess we won't talk about an easy 3 minute cps test because bad new ones do show up.
The Key trick? Codes? No, maybe 92 on for that?
Well, just looked a bit, yea, Google Key trick. The code key is above in "info threads"
Last edited by DFlintstone; Nov 5, 2011 at 01:33 AM.
You need FUEL, SPARK and AIR. If you don't have any of those, it won't start. Verify spark. No spark? Slap a new coil on there. Have spark after coil? Then verify fuel. You should hear your injectors 'clicking' or, you can pull out the fuel rail and see fuel spurting (or not) from the injectors. Or, check you fuel pressure at the rail.
After you verify FUEL, SPARK, and AIR, get back with us.
After you verify FUEL, SPARK, and AIR, get back with us.
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Thread Starter
Seasoned Member
Joined: Oct 2010
Posts: 259
Likes: 2
From: Eastern Oregon
Year: 2000 Sport
Model: Cherokee
Engine: 4.0
Thanks. Yea I'll give it a few tries today. Didnt think about testing the sensor but I'm sure it happens I've got pretty good luck for bad luck and it would be an easy fix
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
AC voltage CPS (KPS),test. Small clips on the meter leads really helps;
Unplug the connector at the back of the manifold with wires going down to the bell-housing/cps.
Probe the two wires to the cps with the meter set on AC volts. (a 200 scale on mine).
Crank the engine and note the voltage. (jump it if you battery is low)
Mine somehow works with only .3. My wiring/grounds must be pretty spiffy. .5 seems to be a good mark. One article talked of .5 to .8.
If it's low you can modify the mount. With the next largest bit that won't fit in the hole, enlarge the hole just a tad. Now when mounting it's crucial to maintain firm downward pressure on it while tightening the bolts. An assistant could help with that from above.
And, thank you Cruiser and TJ's link, think I got it right!
Unplug the connector at the back of the manifold with wires going down to the bell-housing/cps.
Probe the two wires to the cps with the meter set on AC volts. (a 200 scale on mine).
Crank the engine and note the voltage. (jump it if you battery is low)
Mine somehow works with only .3. My wiring/grounds must be pretty spiffy. .5 seems to be a good mark. One article talked of .5 to .8.
If it's low you can modify the mount. With the next largest bit that won't fit in the hole, enlarge the hole just a tad. Now when mounting it's crucial to maintain firm downward pressure on it while tightening the bolts. An assistant could help with that from above.
And, thank you Cruiser and TJ's link, think I got it right!
Thread Starter
Seasoned Member
Joined: Oct 2010
Posts: 259
Likes: 2
From: Eastern Oregon
Year: 2000 Sport
Model: Cherokee
Engine: 4.0
Got back to working on the jeep today. I pressure tested the rail and I have 45lbs so it not the pump and I tested my old sensors and they tested good. So I wasted money to fix what wasn't even the problem. I plugged into a diagnostics program and it's coming up with no problem
How do I check for spark with a coil pack. And what else could be causing no spark and no check engine light on
How do I check for spark with a coil pack. And what else could be causing no spark and no check engine light on
Thread Starter
Seasoned Member
Joined: Oct 2010
Posts: 259
Likes: 2
From: Eastern Oregon
Year: 2000 Sport
Model: Cherokee
Engine: 4.0
Alright played with the jeep a bit more today. I pulled the coil rail and tested it with a test light. It lit it up but was dim but I would think enough to give a plug spark. I also pulled the plugs and they are dry. Cranked it over for 30 seconds and couldnt get the cylinders filled with fuel. So from there I was sure it was a fuel problem so I opened up the intake poured some gas down and turned the key and still have nothing happening so now I'm under the assumption it's a fuel and weak spark problem. I put stethoscope to the injectors and I hear nothing. I have 45lbs at the rail so what's going on.
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