narcosis

Read a lot of the threads on there about codes, specifically OBD1. I hooked up my Innova 3120b to my 95 GC and got six codes. When I tried to erase them, it would get stuck on a screen indicating it was retrieving the codes and would never finish. I tried all the tricks indicated on numerous forums by disconnecting the battery cables, holding the positive cable to ground for 30 seconds while sacrificing a kitten during a full moon. None of that **** worked.

I finally just used the dash and key method and miraculously it showed code 12 (battery recently disconnected) and 55 (end of codes). I'm not sure if it's a problem with the Innova or if there is some issue with the OBD or PCM in my ZJ. The point being, if you are using an Innova and can't clear the codes, go the quick and dirty route with the dash and key method.

The ASD relay can cause numerous issues if it starts going bad. I had rough idling, hard starting, skipping and significant spark knock that was so bad I thought it lifter tap. After I replaced the ASD relay all of it stopped.

dave1123

Funny you should say that! The other night when it was 12*F, my WJ started a slight stumble around 2000 rpm when under power, like at 55 mph on the highway. I have a CEL set for torque converter clutch that I don't pay attention to because it's the converter itself and I am NOT going to tear it apart just for that, but when I got where I was going, I checked the key codes and got a P1389, loss of ASD signal to PCM. It started normally and ran smooth except around the 2000 rpm range. Because of the 12* temp and 20 mph wind, I did nothing that night. The next day it was around 30*, so I pulled the ASD relay and cleaned the contact pins and sockets with electrical spray cleaner and reinstalled it. The problem hasn't reoccurred YET, but that relay has 206K miles on it so I'm going to replace it anyway. Mopar part, of course. The only other relay in the box that's the same is the fuel pump relay. Maybe I'll do both.

Thanks for the heads-up!

BTW, on advise from my mechanic, I've been running 89 octane fuel instead of the 87 I've always run and I seem to get smoother throttle response, smoother idle, an a little better fuel mileage. The weird part is I've tried the 93 non-ethanol fuel and not gotten any noticeable difference at all.

wingless

When I purchased an Innova 3120 for my '94 ZJ, my experience was that there were brief / infrequent / fleeting moments of functionality.

Most of the time was unable to obtain normal operation. This was duplicated with a second unit and cable / connector set.

The Innova units were returned. I purchased a Chrysler DRB II and have had flawless normal operation every time.

gertie240

Hey guys not tryng to thread jack but where is the plug for the OBD on a 94 GC

wingless

There are three diagnostic connectors on the '94 ZJ.

The OBD connector is dangling near the PCM.

The ABS connector is on the hump near the driver's feet.

The airbag connector is on the hump near the passenger's seat.