greatwhite

Well, I just burnt up my 3rd ECU in my manual 86 2.5L. I need some help and hope i can find it here. Well here is a pic of my second burn up, I didnt get pictures of the first on:

After replacing the second one i traced the burnt capacitor/resistor to pin 8. So i believe cause im not sure if the ECU had some hidden layers on the board which could be changing the power. The chilton says its the WOT sensor. I disconnected that sensor but no good. Burnt up the third one.

Anyone have some suggestions or what I would like to know. Is there a way to by-pass the ECU and "hot wire" the system. I found out that when that part of the ECU goes i dont get spark and the fuel pump does not work. I can run power to the fuel pump and put it on a switch but is there a way to run power to the starting system and get the jeep to run? Heres whats in the engine compartment.

BlueXJ

The only one I know of that has torn into the ECUs of XJs of the Renix era is a guy names Jon Kelley he has a website and he is in the business of selling battery cables and other wiring upgrades.
http://www.geocities.com/JeepI6Power/index.html
There is a e-mail addy in there somewhere you can e-mail your pics to him and he might just know what to tell you. I have no idea. I have never seen a ECU mess up. That is always the stealerships fix for everything on older Jeeps that they can't just plug into their computer to diagnose the problem.

whowey

Jon's handle on NAXJA is 5-90...

XJ Stryker

Wow i was thinking this is a question for 5-90 myself. We all think alike don't we. He is the electrical Renix subject matter expert over in Naxja if he can't fix ya. You might as well sell the heep lol.

BlueXJ

Didn't know if greatwhite was a NAXJA user or not so I thought that Jon's business was the quickest route to contact him.

XJ Stryker

He may not be but we won't hate on em for becoming a forum user over there also. heck Blue Whowey and I are paid members over there.

whowey

Ahem........

XJ Stryker

Sorry fixed... what is your handle over there I am still XJ Stryker

EDIT: OH

W_howey whats up

5-90

Hm - looks like I'm going to have to figure out what the WOT sensor is for - I've worked more on 4.0L than I have 2.46L. Gotta correct that oversight...

A stupid question - have you checked the wiring for the WOT sensor? There could be a wiring defect causing all your trouble...

Meanwhile, I'll have to start pillaging around to see what I can sort out. Working from a 1990FSM, but it should be close enough for what we need to do.

greatwhite

well, i rechecked all three boards and i came up with something. I dont know how i ever came up with pin 8 but i was way off. Its pin 3, the ignition switch. What would cause that? I did put a new (well gently used) column in it. Where do i start with that? Sounds like the WOT sensor is not the problem.

XJ Stryker

I just replace an Ignition Switch on my Jeep. It is under the dash on top of the steering column. It might be burnt out as mine was. Really easy to get too. Pull the lower dash off like 6 cross tip screws a couple of light bulbs and what not. Then there are two 15 mm bolts that hold the steering column up... you are probably familiar with those if you replace the steering column. Once it drops down the ignition switch is right on top. I have seen them at advance auto parts for 17 bucks. So it is a inexpensive swap. Mine had burnt the wiring harness too so i had to go to the junk yard and cut the connector out of one to replace mine. But took me about 30 minutes to swap it out. Lil bit of an uncomfortable position to work in though.

greatwhite

I will have to give it a try. Cant say that the one on the column was good when i got it so that could be the issue.

greatwhite

Well here it is, it doesnt look bad. Is there a way to put the power for spark on a switch so i dont have to rely on the ECU? or does the ECU do more then that and its not doable. I tried looking in my Haynes and Chilton but it does not say, does anyone know which prong operaters what?

5-90

Hm - even my FSM (1990 - should match up to your 1989) doesn't give a pinout diagram of the ignition switch - irritating.

So, let's see what we can do with wiring colours. I do have earlier FSMs, but they're (still!) crated up and I haven't had a chance to get to them yet. This should work for 1989 and 1990, and might even work for 1987-1988 as well (ChryCo changed the colouring of some of the wiring, but that's about it. May parts themselves to interchange.)

Oh - and if you've still got the old ECUs, I'd like to talk to you about adding them to my own collection for analysis. I'm trying to reverse engineer the RENIX system, since the last known patent holder (Actia Corp.) hasn't even returned any of my letters yet... All I have are I6 ECUs.

Callout will be wire gage : colour/tracer (if any) : circuit serviced.

12AWG : RED : COM Power Feed to Ignition Switch (common)
14AWG : DKG : START circuit feed to Starter Motor Relay
12AWG : ORG : RUN feed to various fuses (Note 1)
12AWG : BRN : RUN feed to various fuses (Note 2)
12AWG : YEL : START/RUN feed to various fuses (Note 3)
20AWG : VIO : Feed from COMMON to engine coolant temperature sensor (for gage/IP lamp)
The 20AWG VIO wire is also shared with a feed to the park brake switch/brake lamp switch setup, and comes off of the same terminal.

NOTE 1 - This lead runs to a splice that feeds the ABS IGN fuse (if you have ABS,) the common bar for the Power Window circuit breaker (#6, 30A) and the clock fuse (#3, 10A - feeds to the digital clock and emissions maintenance timer.)

NOTE 2 - This lead feeds the Gages fuse (#17, 7.5A; feeds chime module/IP/speed control system) and TCU fuse (Automatic Transmission only, #13, 7.5A; feeds NSS and TCU.) This wire is also tapped for the "F" lead on the alternator's regulator connector.

NOTE 3 - Please refer to NOTE 2.

If you do post to this thread, please bear in mind that I've got to get used to checking this board - you can leave me a message at 5-90 AT naxja DOT org or dragonland2001 AT yahoo DOT com to let me know that I should check. I'll keep this kicking around in the back of my mind while I'm working on other things...

From the look of things, you can group the 12AWG ORG and 12AWG BRN wires to a toggle switch, but you will lose the various ACC functions (the 12AWG BRN is tied inside the ignition switch to the RUN and ACC terminals.) I'd probably run them through a small toggle and use that signal to actuate a relay, if it were me. A similar mod can be done with the 14AWG DKG wire to the starter motor relay, but no inline relay should be needed for that one (that wire passes about 1/4A.)

greatwhite

thanx for the info and sure i think i can part with the old ECU's, do you want all 3? By the way the issue was on my 86 2.5L pioneer. Would the wires still be the same? Also, does it matter on switching from tilt to no-tile? Thats what i did. PM about the ECU's