M5OD SWAP issue

unoleisu · Oct 24, 2010

Got a problem.... I have a 87 BII, 2.9, A4LD, bw1350. I'm nearly done swapping in a M5OD from a 92 Explorer 4x4 2door. I am unshure if the M5OD is original to this exporer vehicle.
I'm working on wiring from the 5 pin "cannon" connector from the BII harness. The backup lights are wired in. ( Black w/ pink stripe, and Purple w/ orange stripe connected to a switch on the upper driver side.)

The Red w/ blue stripe and red w/ yellow stripe are supposed to twist together (one is for 4x4 Low, and the other is start safety?) and then connect to the Blue wire going to the switch on the M5OD, and then the White w/ pink stripe wire is supposed to connect to the other blue wire going to the M5OD. These blue wires go to a switch on the passenger side of the M5OD, up near the Shifter.
On my M5OD, this blue wired switch is baddly dammaged and needs replaced. I thought it was the neutral safety switch. I need to know exactly what it is called, and does, because NAPA, Autozone, and O'reily's can't Identify it, so they can't get me a replacement.
HELP!!!!!

Also can someone verify that I have these wires going correctly? I'm using the info on the Tech Library

Earl43P · Oct 24, 2010

You shouldn't need it (NSS).

Read some discussion about that in this thread: http://www.therangerstation.com/forums/showthread.php?t=92596

unoleisu · Oct 24, 2010

I understand that (I) shouldn't need tthe switch. My concern is that, in theory this switch is to help "idiot proof" the system. If the starter or the 4X4 low can be "accidentally" ingaged at the wrong time.....it probably will be at some time or other. The switch, as I understand it is to only let these conditions happen when the tranny is safe in neutral. At some point in time, I'm sure my wife or daughter, (or God forbid, one of my sons) will drive this truck.

No-one ever seems to recall the VERY SPECIFIC instructions for these type of things, and I really don't care to fix a mistake later if I can avoid it now.
I don't want to come across as any kind of jerk. I just want to rig this truck the best way I can.
So....rather than ignoring the NSS... can anyone give me good technical knowledge on this subject?

adsm08 · Oct 26, 2010

The sensor on the passenger side is the Neutral Safety Switch. It's most important function is idle strategy.

If left unplugged it will prevent the starter from engaging, but if plugged in the starter will work if the clutch is in. Doesn't matter what position that switch is in.

Looking over the wiring diagrams, if you do this right, I don't believe that not having that sensor wired up will allow your wife or daughter to shift the transfer case into Low while in gear, because the clutch switch figures into the circuit for the shift motor as well. Basically, it looks like it wants to see the clutch in, with the trans in neutral for a low range shift. If the clutch is in, (and it should be since you basically have to be stopped) then you shouldn't have an issue.

unoleisu · Oct 27, 2010

Thanks Jim! good helpful info.
Ok, I went ahead and rewired the NSS, and basicly have completed the swap. The truck starts and runs fine, but idle seems to get weeker over time until it starts dieing if I don't give it a little gas. I read that I need to retime the engine, but my book doesn't tell me how a manual vs. Auto should be timed. It just gives instructions for one way to time it. (87 2.9L) Is this my issue?
Also, the switch that connects to the clutch petal doesn't have anything to connect to. Where is the wireing supposed to go?

I test drove the truck and it is MUCH better than the A4LD, (at least running up my driveway and down to the corner, and back) except my clutch petal dosen't seem right. I don't get full ingagement of the clutch until just before the petal hits the firewall. I have a new clutch kit (10"), new slave cylinder, new Clutch master cylinder (for a BII, since the Explorer CMC didn't bolt up right and sit at the correct angle for petal pushrod travel.) I compared the new pushrod length with that of the explorer, and one from the other (85)BII. The new one is about a half inch shorter than the 85 BII, and maybe an inch shorter than the Explorer one.
I tried the 85 BII pushrod, better, but not good enough. I am thinking about modifying the length of the Exp pushrod until it "seems" about right. Anyone know what length it should be?
Oh, yes, I re-bled the system, twice.
Any advice here? Am I totally missing something?

adsm08 · Oct 27, 2010

Which switch did you use for the clutch pedal? The 4.0 switch will not find anything to plug in to. The 2.9 clutch switch will have a plug on that harness. It will be filled by a little jumper. It's just a 2 pin plug with a piece of wire that runs from one cavity to the other. I'll try to get a pic of mine tomorrow. My clutch switch is broken and I have it bypassed with the jumper from an auto.

As for your clutch pedal travel... did you bench bleed the master? If not, do it. If you did, that may just be normal. The 10" clutch does have some unique grabbing qualities when placed behind a 2.9L.

unoleisu · Oct 28, 2010

hmm... The clutch petal came out of my 85 BII with a 2.8L / fm145. The switch attached to it had two plain black wires. I'll look and see if I can find the jumpered plug you spoke of, on my 87 BII 2.9 harness.

The new clutch master cylinder was bench bled before installation. I had to re-use the quick connect hose to the slave cylinder. It was in pretty good condition. And, as I said, I Bled the whole system twice.

When I tried the Exp pushrod, the clutch system felt great, and seemed to dis-ingage the clutch fine, but the petal at rest was way to high up. (about 3 inches or more above the level of the brake petal.)
I appreciate the help, Thanks!

unoleisu · Oct 28, 2010

Ok, Surprise! Upon investigating closer, I found I actually have 2 switches on the clutch petal. I did find the jumpered plug you spoke of. It has two red wires with light blue stripes. after pulling the jumper, it plugged into the first switch (no wires) which has a long traveling white rod that connects to a secondary lever that is at the high end of the petal. This switch ingages when the petal is fully depressed. I assume it is the ignition safety switch.
The second switch is a black one with the black wire I mentioned before. It is mounted right next to the first switch (why I thought there was only one). It ingages when the petal is at rest (all the way out). I looked at the 85 BII 2.8L and found where I had disconnected it. It plugged into a connector on the passenger side of the steering coloumn, that had two green wires. I found the same connector on the 87 BII 2.9L , with a jumper. I couldn't find in my wireing diagrams what this was for, so I plugged it together anyway. Now I will go see what happens!!!!

gribly · Oct 28, 2010

Sounds like the second switch is for the cruise control to disable it?

unoleisu · Oct 28, 2010

gribly said:
Sounds like the second switch is for the cruise control to disable it?

Hmmm... The 85 BII 2.8L that the switch came off of, didn't have cruise....I believe... I'll take a look.

I took the rig out for some test driving and am very happy with the improvement. Deffinately better than the original A4LD!! It was well worth the effort IMO.

Now I need to start preping for the next phase, BW 1354 Manual (have an electric, but want manual instead) 8.8 rear (have a 99 8.8 with disk brakes, but gear ratio is wrong for me), and dana 35 ( I believe I have on old Exp, but tag is missing)

M5OD SWAP issue

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