Okay guys, for those of you who "have a miss", or "the truck runs on 4 cylinders" or need to fix burnt pins......or have fixed burnt pins and still runs like crap!!!

I've had all of the above happen to me, and 99% of the time it still ran like crap after every fix because there was still burnt wires further up the harness legs from the valve covers. This causes people AND SHOPS to incorrectly diagnose what is purely a burnt wire. I.E. Shop says you need a new IDM, or new harness, or PCM.....bla bla bla. If you want to save yourself alot of money, do this before you spend it to make sure.

This writeup is on how to remove the harness from the truck so you can take it to the bench in the shop and inspect it closely. Or in the living room....which ever you prefer.

Now, I can't remember exactly what each sensor is so my discriptions will weed out the people that shouldn't be doing this job if you know what I mean. Some will be correct, some won't. But if you can't figure out which ones are not correct, you should stop.

Okay, as always, this is described as if you are laying over the grill of the truck.

*******UNHOOK THE BATTERIES*******

1. Remove the intake tube from the air filter to the CCV housing. Or if you have a 6637/Tymar intake, remove it. Also remover the motor cover if you have one.


2. Loosen the 10mm bolt on the harness bulkhead, on the drivers side fenderwell just under the brake master cylinder. (Black square connector with about a million wires in it.) The 10mm bolt head is on the side closest to the firewall. This bolt will "lever" the bulkhead connector out. In other words, you DO NOT pry this connection appart.

3. Unplug both drivers side valve cover connectors

4. Unplug EBPV connector (should be right under the turbo compressor housing, 2 wire plug, black)

5. Unplug ICP sensor on drivers side head.

6. Unplug Thermo Nuclear reaction sensor on the back side of the HPOP reservoir.

7. You'll notice a wire running in between the HPOP rez and A/C compressor running down to the water pump and across the top of it. There are 3 sensors on it.
7a. Unplug the Water Temp sensor next to the thermostat neck.

7b. Unbend the bendy wire holder (metal wire holder...bend it back)

7c. Unplug the Warp Drive sensor to the left of the water pump.

7d. Unbend another bendy wire holder

7e. Unplug the Cam Position Sensor just below the left side of the water pump. This is the last plug on this leg.

8. Fish this leg of wiring back between the HPOP rez and A/C compressor. Sometimes you can just squeeze the wire beween them (up and over) other times I found you have to fish it below the compressor. Either way, bring it up to the top of the motor.

9. Remove the 13mm nuts on top of the HPOP rez that hold the motor cover holder, and the Large bendy wire holder.

******At this point you will notice another harness running across that holder. Leave it there, it's not part of the harness that we are removing, and will not hinder us from removing the engine harness. It is for the A/C and Alternator coming from another source.*******

10. Unplug the blinker fluid level sensor on top of the HPOP rez

11. Unplug the Exhaust Back Pressure sensor hanging just behind the HPOP rez.

12. Unbolt the Glow Plug Relay/ motor cover bracket. 2-8mm bolts
******DO NOT REMOVE ANY WIRES FROM THE GLOW PLUG RELAY*****
Just take the bolts out so it's loose.

13. Unplug the Fuel Bowl harness on the left side of the fuel bowl. Unplug the side closest to the HPOP rez.

14. Unplug both passenger side valve cover clips.

*****The bracket that the GP relay was mounted to is still there and over the front VC plug. You can fish the plug out from underneith it wiggling it twards the rear of the motor. It will be tight because the HPOP line is in the way. If you remove the bracket, the harness will go back in easier, but not needed.....unless you make a repair in the harness there and it's thicker when you are done.*******

15. Last piece. One wire runs from the GP relay area to the passenger side fender to the starter relay. On 95's it's routed above the coolant bottle and windshield washer box. 96 and 97 go underneith it. Now that being said, there are various "plastic ribbed wire holder thingys" pushed into various holes to hold them. (Like a door panel retainer clip that holds wire...you'll see)

16. Once that last wire is loose, you should be able to lift the entire harness off the motor

17. Now before you go tearing the harness apart, there's a few things to remember.

1. The harness will retain it's "shape" as long as you don't rip it all apart at once. This is VERY important. That way when you put it back in, it will litterally just "FALL" into place.

2. Only work on one leg at a time.

3. Take your time, if you "unwrap it". Wrap it back!!!

4. Save all your wire covering/ conveluted tubing/ foil/ and whatever else covers this harness. Put it back on, or use new stuff, your choice. And just FYI, the foil will be hard to not screw up. In some cases, I just used foil from the wife's kitchen to take it's place.

There ya go guys, this should take all of about 30 to 45 minutes.....even for someone who has never done this. And putting it back is about the same. And trust me, this is time well spent instead of trying to make repairs to it on the truck. Now, if you are just repinning a VC plug, don't do this. But if you do fix a plug, change a vc gasket, and or a UVC and your problem still exists.....this is the next step. Hope that helps guys.

 

No wonder Cody's trucks run like they do, with things like "Thermo Nuclear reaction sensors, bendy wire holders, Warp Drive Sensors, blinker fluid level sensors, wire covering/ conveluted tubing/ foil/ whatever else, and foil from the wife's kitchen. He's got way more stuff in his trucks than came with mine. lol. Good writeup Cody hopefully I dont ever need it. Reps sent.

 

Thank you sir, I try. LOL

 

Indeed that is a very indepth and well thought out description of the removal of the harness. It sounds like you have done this a few times. Reps sent.

 

How much it cost to convert to the fluid cooled/lubed blinkers? i need to do this. it is supposed to be worth at least 37.6hp and 69tq right??? LoL

 

if you add a racing stripe it helps your aerodynamics too, haha. excellent writeup

 

Great info cody.

You forgot to tell them about the wiggly pin though.

 

Good write up .. Tried to rep ya , (no joy)...

 

Good write up Cody! Reps sent!

 

Thanks guys. I'm more than certain I missed one connection or so in there somewhere. But at that point it should just fall right in line and not be a problem. But hopefully I got them all.

However, instead of repping me, tell me what those sensors are SUPPOSED to be. lol I can't remember for the life of me.

 

X2 (I also tried to rep you, but ............., no dice)

 

BTW what is this sensor?:
Thermo Nuclear reaction sensor

Any pic?

 

one on back of HPOP is IPR

 

Or is that not a sensor?
I don't remember seeing anything on the back of my HPOP.

 

Oh and cody, Why are we taking out the harness for the fuel bowl? That just disconnects and can stay in there. is there parts on there that would normally burn up? I removed just that section by itself when I had some issues.