I've got an '84 6.9l and it didn't come w/ a tach as we all know.

I got the following from another member:

- tach sensor
- gauge cluster
- pump housing cover w/ sensor port

So I got the new cluster installed w/ out too much trouble. All the gauges work (except for the tachometer of course). I'm about to install the new pump housing cover since my original one doesn't have the port for the tach sensor on it. My question is... Once I screw the tach sensor into the port on the housing, what/ where do I wire it into to? The sensor ends in two wires: one is black and one is green. I'm not sure what to do with them? Is there a plug I need or is there wiring I need to splice them into?
Help?

 

I just looked at mine, the plug from the sensor plugs into two wires that are also black & green. These two wires are coming out of the same harness that feeds wires to the alternator. You have to see if your truck has these wires and plug (I don't know, but I kind of doubt it). If there is there should be wires under your dash for the gauge. If there isn't then you're going to have to find out how these are wired in.

 

Hopefully you have not pulled that all off yet you need to find a way to mark your timing before removing that housing otherwise you will be in a whole new mess of fun!

 

Aye, that's a good point too.

You know, my '84 didn't have a tach either, but the housing just had a plug where the sensor would go. Odd there would be a housing without even the hole, but I've heard they're out there.

 

Somebody did post how to remove the cover without completely screwing up the timing.
Basically you have to loosen (or remove?) the injection lines, remove the cover in front of the housing, remove the 3 IP pump bolts (and the 3 external nuts) then pull the IP straight back (it can be left sitting on the engine). Then remove the other gear cover bolts and carefully lift the cover straight up without disturbing the gear.
For precautionary measures, carefully clean where the two gears are touching and marking them somehow, but do NOT move the IP gear.
Carefully clean the mounting surfaces, and install the new cover dropping it carefully straight down.

If done correctly, this will not messing up the timing gears, just the IP timing itself. Since the pump has moved in relation to the housing, the timing will be off, but gears will all be in the right place, so no worse than a normal pump swap in terms of timing.

 

Sounds about right except there is only on position the pump can attach to the gear so as long as the gear is correct all you have to do is fine tune your timing

 

Yah thats kinda what I mean above, but not super clear... need a nap.
Thanks

 

No I haven't taken off the IP cover yet... been too scared to... I'll have to do some more reading till I know I'm not going to screw up the timing.

Chevy_eater: you have an '84 with a port on the IP cover? What gives? How'd I get so lucky? Also, I looked around and couldn't find the wires you are talking about which makes me sad. In a bit, I'm going to go check again, because I would really like it if they were there and I'm a little bit in denial I guess.

Starting to wonder if this project was a mistake... Got the cluster in so I might as well finish I guess...

Edit: Of course, I now realize I'm not sure HOW to finish this project. Anybody know any more about the wiring?

 

I can take and post pics of an 86 with the wiring for the tach but I won't be able to do that till after work tomorrow did you check the back of your plug harness? To make sure the wires were there?.... One of my parts trucks didn't have a tach but the wires for the tach were looked like factory zip ties holding them out of the way

 

I'm doing the same thing on my 86 right now. I have the cluster in and the tach sensor in the housing. My truck does NOT have the tach sensor wires in the alternator harness. I found a harness in the junkyard and bought it. My question is, if I replace my alternator harness with the one I bought that has the tach plug on it. Will it work? I'm worried the rest of my wiring harness that goes to the cluster won't have the needed wires for the tach to work even with the alternator harness plugged into the tach sensor

 

I have this same question. It appears that I don't have this alternator harness/ tach wiring either. I'm thinking about trying to get this wiring out of a parts truck like southtexasidi...

 

That would be extremely helpful. I'm not sure what the harness is supposed to look like. I don't *think* that the wiring is there, but I'm not sure what it looks like either. A picture would let me know what I'm even looking for.

 

Sorry if this is a stupid question but I thought you could do this without removing the injection lines? Is this step necessary or does it just make the job easier?

 

Ill try to get a pic if the alternator harness I bought the other day

 

here is the tachometer wiring schematic for a 1993 I don't know how much of it will apply to your truck



Mark