Having that experiment go on... and still not knowing what to do, i decided to do something else. I opened and cleaned the ECU, yes i know... that is probably not my problem but check what i found....

 

Yuck! Well if you get to a point you find the ECU is not grounding the relay when it should you have something to suspect. I suppose a guy could attach the meter on ohms and see if socket 85 is grounding for 2 seconds after ign is turned on.

I did see a post once referring to the renix ECU as "aircraft grade". They don't fail often. Transistors for the injectors are known to fail (rarely I suppose).

Easy test, see if that fuse blows with the pump unplugged. If it didn't blow until you repaired the ground, that points to a problem with the unit, not the wire going back there.

 

That's ugly. That white trash (no, not you, DF! ) looks like an electrolytic capacitor puked all over your ECU. That ain't good. And three of the chips on the right are... wrinkled. Likely due to heat from excessive current. Again, not good. I tried looking up the chip numbers and came up blank, which is unusual.... The long one is probably a microprocessor. The other two may be, as well. OR EEPROMs. No matter, it's not a good picture.




In any case, I think you need a new ECU.

 

Note from DJ to Batmam
Both of your tests with the Test Light had procedure errors.

Test #1 QUOTE: I put the test light wire to the positive instead of the negative and touched the relay; more preciously the orange with black strip (85). And nothing lighted up, so somewhere in that line there is power going to it instead of ground.

The orange with black strip (85) wire is just a wire between the ECU and the Fuel Pump relay it will only test as be a ground connection after the ECU has determined that the engine is running and the key has been returned from the start mode to the run mode. At that time ECU closes an electronic switch which turns the orange with black strip wire (85) into a ground wire which will energize the Fuel Pump Relay.

So all of those conditions will haft to be met before your test would have proven a ground connection and if that were true your Jeep would be running and there would be no reason for the test so quite trying to prove you have ground at the orange with black strip wire.

Test#2 QUOTE: Having the test light in the positive terminal again I touched the orange wire (87) and guess what happened, there was light. So it means there is a ground where it should be power.

That is exactly the results I would have expected if you had the Fuel Pump Harness plugged into the Jeeps Fuel Pump Harness back there by the Fuel Tank. The Fuel Pumps Motor windings were completing the path to ground. Repeat that test with the Connectors unplugged. And report back your findings.

Regarding the ECU I would hold off on the problems with it until we have the Fuel Pump pumping fuel.

 

I'm not so sure there Mark. I can be a little trashy, whoops I mean, looks to me more like it somehow got water in there. A cap big enough to do that should be easy to see, plus there is no "shrapnel", bits of anything it blew out. Batman, those cylinders with the X scratched on the end are capacitors. They blow up sometimes, the X scratched is to lessen how hard they blow, relieves pressure before it goes nutty high.

X2, (+ you). I'd fix what's broke first.

 

Thanks, I always thought the X was there so you can tell when the cap is domed up.

 

Guess if it's just domed it stopped short of blowing. I'm no electronics tek, but I've fixed a couple TV's a battery charger, a car stereo, I forget what all. Flintstone here can see a blown cap and change it, and that is about the full extent of my knowledge!

BATMAN, Sometimes people with an 87-88 ECU switch to the superior ECU from 89 or 90. No phit, ask Cruiser. If you have the bank, pick up one with a number ending in 428 or 429.

See here>

 

They can leak without blowing up.

But water? Okay, maybe. It's still history either way.

 

Wow BlueRidgeMark i didnt even notice those being wrinkled. I actually just cleaned the white and cleaned it to the best of my knowledge, put it back together, and you guys guessed right... nothing new happened.

So maybe a new ECU is in order.... gotta save some money and wait for one to pop up

 

As for djgrayxj. I tested all those conditions with the key on and off... both gave me the same results....

 

Ok... so here are my findings....

Using the DC to find the voltage.... at the starter motor relay

i have with the key off/on: battery terminal= 12/12, ballast resistor (orange)= 0/0, EGR (green)=0/0 but the minus sign would come up at times but still 0, ign (green)=0/11.23

Fuel Pump Relay....

Key off/on: 30 (red)= 11.92/11.75 , 86 (yellow)= 0/11.22 , 87 (orange)= 0/0 , and 85 (orange/with black strip)= 0/11.24 This shows my ground is getting power... but no power on fuel pump side (87)

Fuel Pump Ballast Resistor....

key off/on: both are at 0/0

As for the test light experiment:

with the key off touching 30 (red)=test light off, 86 (yellow)=test light on but very weak, 87 (orange)= very bright, 85 (orange w/ black strip)= test light on but very weak again.

with the key on: 30 (red)=test light off, 86 (yellow)=test light off, 87 (orange)= very bright, 85 (orange w/ black strip)=test light off

 

here is my multimeter... hopefully i have it set to the right setting

 

ok, DF if i understood correct... i used the black lead of the multi meter to a ground on the chassis and used the red lead of the multi meter into the connector... so at the current setting i went to the fuel pump connector towards the fuel pump side...

Black lead to chassis as a ground and red lead into the connector; gray wire= 2.2-2.3, purple (center wire)= 31.8-31.9, black wire=.7-.5 ohms

I decided to test the connector side towards the inside of the vehicle, same settings black lead to the chassis and red lead into the connector; black wire=0, center (not sure if its white or tan) =102.9-102.8, pink/purple w/black strip=0

hope i did this right... dont know what all this means though...

 

Yea! See, meters don't bite! Firstly, your readings on the pump side don't really mean much, (to me anyway). Not sure what I'd check there other that does it run with power and ground. The power is the one that's not black, (ground), or pink, purple or violet, (the fuel sender).

After seeing your ECU, 85 is what has my attention. For now never-mind it shows power, doesn't hurt anything. (wouldn't expect that though, maybe I'll check mine later)

Please do this to check one function of your ECU. On ohms, (it doesn't know or care, which lead is where) On ohms (200 scale), secure one lead to a known good ground, and the other in socket 85. Watch the meter as you turn on the ignition. This should ground 85 for just two seconds, maybe not enough time to get an actual reading. The numbers should change, and maybe settle on low ohms, 1,2,3,4...?

That terminal on the starter relay should show power only while the starter is cranking.

Now back to your original, now two problems. The power wire to your pump, (terminating at 87) shorted and likely blew a fused link. That's why you have no power at 30. 30 should always be hot. Somewhere back there I posted the color of the link. (I think it said orange or blue). See if the fuse blows, or if your meter shows continuity to ground from socket 87 with the pump un-plugged. The meter should continue just showing a "1". If the meter shows any connection, or if the fuse continues to blow, BINGO, your original problem was the wire back to the pump grounding. (hence burning up a fused link)(use the meter, the fuse might not always blow)

 

DF i have power at 30 for the fuel pump relay