yellowstang84

first off hello every one i am new to this forum and new to jeeps

i have a 98 cherokee limited 4.0L and it cranks and will not start. i will start out by sayin g whati don't have, i have no power to coil, injectors and everything else powered by the asd relay. the relay has 12 volt power full time and when the key is in run from the ignition. also the wiring to althe components is good. i don't have a ground control from the computer. all the grounds are good at the computer. i thought it was the computer so i replaced it and still same thing.

any help is greatly appreciated, thanks

sgtskid

Did you check the crank position sensor?

yellowstang84

would that cause the asd relay to not be controled from the computer

sgtskid

not sure exactly but I do know it would cause you to not have spark.

yellowstang84

agreed there.. its just i don't have 12v at the coil or the injetors. the crank sensor would provide the signal for the computer to pulse the injectors. i think my issue is more before i even crank the motor over since the computer isn't turning the asd relay on

yellowstang84

i guess i need to know what tells the computer to turn the relay on, or what input is missing that the computer isn't grounding the relay

yellowstang84

after further investigation i thought it needed a computer so i bought a used one after instal still no start. scaned codes and i have p1600 no description and p0700 trans module problem. does anyone have any suggestions.
thanks in advanced

96Cherokee113

Go for the CPS(Crankshaft Position Sensor), a common problem with Jeeps and causes a no-spark condition. Happened to me, but in my case when it went, it blew out the ignition coil and the pick-up coil too. Here is where it is located.



Now that you know where it is, unplug the connector and measure the resistance with a multimeter set at 10k. You measure it between points B and C. It should show no resistance whatsoever, if it does, it's toasted and needs to be replaced. Sometimes it's just a bad electrical connections and you can clean the connector, plug it in, and it'll work fine.

Here is a pic of the connector http://fototime.com/78EA763821BA137/standard.jpg .

If that's not it, it could be the Camshaft Position Sensor (aka pick-up coil or stator) which is located under the distributor cap.

Hope this info helps you out.

yellowstang84

well i finally got it running.after many days of checking everything i talked to another mechenic and he told me the computer has to see the cranking before it will ground the asd relay. so after replacing the cps it fired right up. wishing i understood the system a little sooner... thanks for the help everyone