Fuse block & wiring

[ParadiseMJ]

What is involved with removing the fuse block and wiring from a junkyard donor. My fuse block is saturated and corroded. If I have to replace and re-wire the block, that sounds like a nightmare of wires.

 

...and if I do get it all off and out is it just plug n' play.

 

The donor is an 89 automatic with a column shift. The patient is a 5 speed BA-10.

 

The 5 speed also looks like it has 2 plugs for the TPS. I assume it's meant for 1.) a 5 speed and 2.) an automatic. One is just hanging out off the harness.

 

Also, would the ECU from the 89 donor plug right in to the 88.

[cracker]

(subscribing)

 

I pulled a JY fuse block out and holy crap was there MANY wires.

 

I gave up and started moving items over to a new fuseblock as they failed.

 

(I think someone asked me for a pic of that last time I posted this :doh: )

[Eagle]

Unplug the main harness on the engine compartment side of the firewall wiring block. You'll see a single bolt in the center. That holds the engine compartment side to the passenger compartment side. Remove that bolt and the connector will pull apart.

[Wildman]

As Eagle stated, there is a bolt from the engine bay, it takes a 1/4" socket and a universal to remove........you should remove your old one first to see if the engine bay side is also shot.

 

On the inside, there are 2 sheet metal screws holding the fuse block to the fire wall.

 

An easy way to replace the fuse block is to replace the entire wire harness, it's all plug and play, ever single connector is different enough that you can't make a mistake by connecting the wrong connector.

 

The best way to replace the interior harness is to remove the dash, as the harness is clipped to the back side of the dash.

 

See this for dash removal.......viewtopic.php?f=2&t=14170

 

If the donor is a auto, you will not need the transmission harness, or the tranny computer.

 

There is a difference in the ECU's.........

 

4.0 - '87-88 = Manual #5409 - Auto #5406

4.0 - '89-90 = Manual #5429 - Auto #5428

 

That's the last 4 numbers on the label (IE: 5400-5428)

 

An auto will switch with a manual........but......I wouldn't do it. There also a difference in the idle RPM's between the auto and the manual, and this reads back to the ECU.

 

There is no difference with the column shift vs. the manual/floor shift, the steering column is difference, but not the connectors at the base.

 

The other difference you'll find, if you need to do the engine bay harness, is the '88 will have the C101 connector, and the '89 will not, no big difference there.

 

Your correct on the TPS, the manual only uses one of the connectors, the other connector is for the auto TPS, which in turns.......reads at the auto ECU *see above*

 

So, it all sounds like alot of work, but, it's really not, once you get the dash out, your half way there, getting it back in.........well, your almost done :D

 

But, before you even start this........Replace the Clutch Master Cyl.

 

So.......considering all this info, and with your rust free CA MJ's......is it worth it :dunno:

[ParadiseMJ]

That's everything I needed to know, thanks guys. I messed with the engine side of the connector but did not see the bolt. I have this donor half way pulled apart and the patient dash is already taken apart, but not completely removed. All the wiring in the donor looks great. All wrapped and not krinkly.

 

The engine side of the patyient harness all looks good and I don't really want to futz with that, it all works.

 

As far as the clutch MC, the PO saw the leaking, replaced the MC and seals but I'm thinking I want to lay in and "additional seal" or at least some sort of spacing to keep hydraulic fliud from seeping down the inside if it's a chronic problem waiting to happen again.

 

Thanks again, I'll keep you posted.

 

Note: I've found this CFC MJ and I'm busy stripping everything I can use for my build. So far no one else has touched it, but it's supposed to storm out here next week, so I think I'm safe leaving what's left til better weather.

[Wildman]

That bolt your looking for is not seen, it's tucked into the engine side of the block........You'll see a "recess" on the center of the block, and that's it........it's kind of a feely type thing :roll:

[Akula69]

I have never seen such a concise post about the harness swap and differences - cudos to Wildman for that

 

I have done it several times, as wellas renewing the old harnesses. I can't add a single thing.

[87mjdriver]

not trying to hijack,

 

I just need some clarification.

 

I have a 87 5 spd, could I swap in a 89 auto engine side harness?

in other words can the 2 halfs mix between auto and 5 spd, and (c101) connector and non connector

 

allen

[Akula69]

The main problems with the 89 to 87 swap is the C101 connector (up on the firewall near the connection for the windshield wiper motor) and the transmission sub harness. You can work around both.

 

The C101 on the 87 harness joins the top engine harness (injectors and sensors) to the main bay harness, and the ECM harness. On the 89 harness, the top and main harness join with built-in plugs, and the top harness has the ECM connection built in, so the firewall connection is just not used.

 

The 89 harness has seperate plugs for both the auto and manual transmission sub-harnesses, so you'll end up with several unused plugs on the bay harness after you plug in your manual trans.

[Wildman]

 

:yes:

 

In most cases........the manual and the auto engine bay harness are the same. You'll find several connectors that are not used on either one, IE: the TPS, 2 connectors for an auto, and one connector for the manual tranny (with the 2nd one just laying there dormant)

 

Eliminating the C101 connector should have no effect on the connection to the ECU, providing the proper ECU is used (See above)