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  #1  
Old April 18th, 2005, 18:40
Kinamien Kinamien is offline
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Unhappy 1989 jeep cherokee Laredo need help plz

Well after being flamed off the full size jeep site I posted....
Ok well its a 1989 jeep cherokee laredo...4.0 6 cyl. The problem....The engine started one day then dead the next....I changed the plugs gap'd .035 changed the oil....replaced the muffler.now it turns over but doesnt fire? any suggestions for this poor first time Jeep wannabe mechanic...
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Old April 18th, 2005, 18:50
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Bryan C. Bryan C. is offline
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Re: 1989 jeep cherokee Laredo need help plz

Welcome to . Flameproof suits are needed at times, but we'll get you running again.

Cranks but won't start. OK. Do you have spark at the coil? Do you have fuel pressure? Did it die while driving?

Change any other parts or do any other repairs to it recently?

Need more info.

Might be a crank sensor if you have no spark.
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Old April 18th, 2005, 18:53
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jeepsrock jeepsrock is offline
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Re: 1989 jeep cherokee Laredo need help plz

A few things to check would be if there is spark and make sure the wires , cap, rotor , distributor are all in good shape.

Next would be the CPS or TPS...they both cause many issues...If they havnt been replaced b4 you should as it just might be good maintenence. I think the together they are under a 100$.

pete
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Old April 18th, 2005, 18:59
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Matthew Currie Matthew Currie is offline
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Re: 1989 jeep cherokee Laredo need help plz

Quote:
Originally Posted by Kinamien
Well after being flamed off the full size jeep site I posted....
Ok well its a 1989 jeep cherokee laredo...4.0 6 cyl. The problem....The engine started one day then dead the next....I changed the plugs gap'd .035 changed the oil....replaced the muffler.now it turns over but doesnt fire? any suggestions for this poor first time Jeep wannabe mechanic...
A good place to start is to determine whether or not you have any spark. One of the most common failures of the 4.0 you have is the crank position sensor, which the computer uses to set the timing. You'll get no spark without it. It's located on the bell housing, kind of tucked under the firewall, at about 1 o'clock as you stand at the front of the Jeep looking back. To begin with, you might try just unplugging its lead and replugging it. It isn't hard to figure out which plug it is if you have located the sensor itself. It leaves the wiring harness and kind of disappears down behind the engine on the driver's side. Sometimes just umplugging and replugging it will scare it temporarily back to life. If it does, you should still replace it as soon as you can. It's a bit hard to reach, and frustrating to do the replacement, but it's possible without exotic tools or skills. For further information, try searching this site using "CPS". It comes up often. Or report back to this thread, and I'm sure you'll get plenty of advice.

Of course it could be something else too, but this is a good thing to check first. If you have an ohmmeter, check the resistance between terminals A and B of the sensor (unplugged). It should read 125-275 ohms. If it reads shorted or open, it's toast.
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Old April 19th, 2005, 14:23
lumberxj89 lumberxj89 is offline
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Re: 1989 jeep cherokee Laredo need help plz

My 89 Laredo will do the same thing twice a year. I simply disconnect and connect a sensor and it fires right up. I believe the sensor connects to the MAP on the firewall. The sensor is screwed into the intake manifold next to the firewall, and has 2 wires coming off it. The wires are about 6" long and go into a disconnect harness. Unplug then connect the connector and see if the car will start. I usually have to do the unplug/connect procedure three times for it to work.
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Old April 21st, 2005, 08:11
Kinamien Kinamien is offline
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Talking Re: 1989 jeep cherokee Laredo need help plz

You betcha' that worked lumberxj89! and easy too...My next question is this just a quick fix to a upcomming bad problem? This site is the best! and stfu to the flamer site....This is my site for questions so be ready! thanks again!
Fred
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Old April 21st, 2005, 14:13
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Eagle Eagle is offline
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Re: 1989 jeep cherokee Laredo need help plz

It's probably a case of progressive corrosion on the contacts. Open it up and spary some electrical cleaner in there, then press it in and out several times to clean the contact surfaces back to bright metal.

Others may not agree with me on this, but I often use anti-sieze on electrical connectoins that are prone to corrosion. I've been using the nickel-based stuff because I have a huge can of it, but if I were buying it today I would pay a bit more and get the copper-based stuff. It resists higher temperatures, and several tech friends tell me it works better over long periods of time. In this situation, copper is more conductive than nickel.

The auto repair trade has progressed a long way from the days when I bought my first can of Never-Seez. Back then I would mention it to a mechanic and the usual response was "Huh? Whazzat?"
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