Hi, I am Ray from Canada,

I just acquired a nice red jeep cherokee 1998, with a 4L, with almost 180 000 miles on it. No rust and beautifull red.

It works fine, lots of torq, runs fast, and good milage.

However, to start in needs a long crank, and can take a long 3 seconds to get to run.

The details:

1. I just changed the gas pump, new from amazon and I have gazoline pressure.
2. Long start when hot, like if I put gas and restart, it needs 3 seconds. The coolant temperature is at normal 212 deg f.
3. Less long start in the morning if cool outside.
4. If I stop and immediatly start, it takes only ,5 seconds, almost as if it is ok,
5. New crank shaft position sensor.
6. New wires on the spark plugs.
7. Good spark plugs.
8. Almost new distributor cap, it is clean.
9. Seams good rotor position sensor.
10. Good coolant temperature sensor.
11, and no check engine except for the dam oxygen sensors..

What a challenge, can it be someting between the crank shaft position sensor and the cam shaft position sensor ? could it be that the motor is cranking untill the computer finds the timing ?or could i be the MAP or could i simply be the o2 sensors ??

thanks for the help, I am sure there are experts on this forum.

ray

 

Was the CPS Mopar?

I'd pull the starter and have it bench tested at my local auto parts store - however being you're in Canada I don't know if such services are as widely available.

Also replace the O2 sensors with NTK if you've got codes. It's hard to diagnose effectively if you've got codes. Your computer could be having a problem getting a reading from the sensor. I'd do the codes and then the starter test if new O2's doesn't fix it.

 

Thanks pat,

The two codes are P0138 and P0137, high voltage,

I will replace O2 sensors and see if it cures

Question, would a ECU reste be usefull ?

ray

 

I don't think you need to, but if you do, here's a good thread with info:

https://www.cherokeeforum.com/f2/jee...-46047/index2/

I replaced the O2 sensor on my 95 and did NOT need to reset the ECU. (It got reset anyway when I had the cable off for nearly 2 weeks while replacing my clutch).

 

Double post.. derp

 

Before you replace them, check the O2 heater fuse. It's in the PCD (Power Distribution Center), in the engine bay.

If that's okay, you only need to replace the upstream sensor, ahead of the catalytic converter. The one at the back of the cat does not affect how the engine runs. It's only there to tell the computer when the cat needs to be replaced.


With many of the sensors for these vehicles, aftermarket sensors don't work very well, or only work for a short time. It is strongly recommended to purchase only NGK or Mopar branded parts. Yes, they are more expensive. This is true for the CPS and the O2 sensors, especially.


Also, please test your fuel pressure. Don't assume a new fuel pump has cured a fuel problem.

 

Did you check the starter? If its covered in enough oil and dirt, it will have trouble starting, and can eventually kill it. Mine was filthy. After a good cleaning it did start a little faster.