93 YJ starting issues

[ANONYMUS]

Sup guys I am new to the forum and need some assistance.

First let me give you the specs on my Jeep -

1993
Jeep YJ
Inline 6
4.0
Automatic

Im having issues with intermittent starts on my Jeep. There will times that my Jeep has a hard time starting. I can go a few days with no problems then out of the blue it will not start. Engine will just crank over.

I just purchased the Jeep and according to previous owner he said that it was the ICM. Owner stated that Ignition Coil was replaced, Crank Sensor was replaced as well and pluggs. I have no issues with powerloss or idles.

Just need some advice on what it could be. Also would I be able to use a Cherokee CPU on my YJ?

Thanks in advance

[CJim7]

So...Have you replaced the ignition control module as that is what the previous owner said it was?

Cause that sounds like your problem..

[ANONYMUS]

Originally Posted by CJim7

So...Have you replaced the ignition control module as that is what the previous owner said it was?

Cause that sounds like your problem..

No I havent replaced that yet..I have been trying to find were its located.. I did do some searches and I know how it looks but I cant seem to find it on my Jeep.

Sorry this is my first Jeep so Im trying to learn the ins and outs of it.

[RLSumner]

I'm trying to remember where that damn module is. I think its either on the firewall, or on the inner fender. It should have a big plastic cover. Once you find it, heres a low tech trouble shooting method. With the engine running, give it a solid hit with the butt of your hand. If the engine stumbles, stalls, or shuts down, thats your problem. I know it sounds hillbilly as hell, but it works in a pinch.

[ANONYMUS]

Originally Posted by RLSumner

I'm trying to remember where that damn module is. I think its either on the firewall, or on the inner fender. It should have a big plastic cover. Once you find it, heres a low tech trouble shooting method. With the engine running, give it a solid hit with the butt of your hand. If the engine stumbles, stalls, or shuts down, thats your problem. I know it sounds hillbilly as hell, but it works in a pinch.

The only big plastic box I saw was directly under the brake booster. But I thought that was the CPU?

When I did my search about the ICM I was always seeing this Image :http://www.quadratec.com/Assets/Images/5545/5545-th.jpg

[ANONYMUS]

Anyone?

[Rollbar03]

check on the fuel rail and see if you have fuel pressure

[My1stNiceJeep]

You dont have the ICM Thats in the older carb'd Jeeps.Try the ECM with another.Ive used XJ ECMs with no problems

[ANONYMUS]

Originally Posted by My1stNiceJeep

You dont have the ICM Thats in the older carb'd Jeeps.Try the ECM with another.Ive used XJ ECMs with no problems

I went to my Jeep dealer and they gave me the ICM part number for my Jeep using my VIN.. According to their info I have a ICM somewhere. So idk.BTW would a standard trans 6 ECM work on my Auto Jeep?

Now Im running into some other issues. 2 days ago my Jeep conked out on me, I was using it all day and then just wouldnt start after I went to a tire shop. It wasnt getting any spark going to the pluggs.

First - I changed the crank sensor, still didnt do anything

Second - I changed the coil module, and that seemed to work Jeep started right up and let it run for a few minutes then tried to start it again, so far so good. But then when I was heading out to work I started the Jeep and its now misfiring.

Third - Changed the Plugg Wires cus they were arching, Jeep still misfiring.
Took out pluggs and looked fouled, cleaned them up and Jeep started right up with no issues. Took it for a 20min drive and even made a few stops, so far so good.

Now I just tried to start it and same thing again, its misfiring. Idk if pluggs are bad already, but cap and rotor are still ok.

[jpfrk2001]

Run a tank of 91 octane with injector cleaner through your system. Injectors could be clogged up.

Its a 93, Its almost 20 years old!

Things to do to these motors for maintence;
Cap
Rotor
Plugs
Plug Wires
Fuel Filter
Injector cleaner or flush fuel system
Check you FPR on the fuel rail
Check Fuel pressure In Accordance with Manuel(Go get a Chiltons manual NOW!)

After this much, then you start diving into sensors and Modules which means you start to spend $$$$$

And MY1stNicejeep is correct. I tend to find the People at the Stealership are FAWKING DUMB AS SH!T !!!

Get away from the dealer. They are there to rob all your money.

No ICM on a 1993 YJ. But you do have a PCM.

[jpfrk2001]

I just looked at my Schematics

Automatic
Idle
Speed
Motor

So its not a really referred to a ICM, but I think its the closest thing the dealer may be talking about
It is directly wired going to the PCM

[My1stNiceJeep]

If your spark is randomally quitting I would try the CPS sensor.Very simple to change.Manual and auto CPS are the same.Borrow one from a friend if you dont want to buy new.Takes less than 5 mins to swap.

EDIT:Just read you swapped it.Are you sure it was good?Sure sounds like the CPS

[jpfrk2001]

FAWK!!

Now my jeep just quit running on me!!

FAWK!!

[ANONYMUS]

Ok so I replaced the Cap and Rotor., but still having same issues.

Verified that its getting fuel. All wires have spark in them, pluggs are not fouling. Still sounds like its misfiring, even verified wires were in correct firing sequence. Im thinking that my PCM may be bad.

[jpfrk2001]

TPS now?

[ANONYMUS]

I found that the CPS I bought from my local parts dealer was defective. I put my old CPS in and is running with no issues. No more misfiring.