1st Gen Dash with 4.0?

[DisturbedMXer8]

I've been doing a bunch of research lately out of curiosity, and from what I've seen it looks like the first gen dash is not compatible with the 4.0. I know it has been done before (4.0B2), so what I'm curious about is what exactly isn't compatible? The Tach, fuel, temp, battery, oil gauges and warning light assembly I'm assuming. What about the dash lights? Speedo? I know the speedo runs off the cable from the trans in my 2.9, so it's the same for the 4.0, right? I'm not very concerned about all of the engine wiring, but I am concerned about a possible future 4.0 swap working with my 88 dash. Cuz if it doesn't, it's kind of a deal breaker for me. I've come to love my 2.9 over the years, and seriously consider just rebuilding it when it needs it and running it for 10 more years. Can anyone shed any light on this for me? I've spent a lot of time scouring the site and can't find much info on this particular subject...

 

[holyford86]

everything is compatible, you just have to wire it, the only one that actually would receive a signal from the EEC is the tach, you need good wiring diagrams for your donor and recipient and you can make the swap a relatively easy chore

 

[4.0B2]

EVERYTHING in my dash works fine. you just gotta wire it in... each little unit in the first gen dash has to be matched to the wiring harness for the 4.0

remember, good wiring diagrams for BOTH... and trace out which wire goes where on each harness.


edit: oh wow. i missed holyford86's comment... yeah, what he said! lol

 

[Hahnsb2]

FWIW my 94 4.0 does not work properly with the 1st gen tach, it reads very high. It sounds like the older ones work fine though.

 

[DisturbedMXer8]

So it's all of the gauges and warning lights, then (i.e. CEL, oil pressure light, etc...)? Also, does the 2.9 use the EEC for the tachometer? I wasn't sure if it was just hooked up to the coil or not (because I know that would no longer work with the 4.0 coil packs). Sorry for all of the questions, I just want to make sure I'm looking into the correct things, haha.

 

[4.0B2]

I do know I had to splice a wire for the tach. I don't remember old it was to the EEC or motor.

 

[AllanD]

everything is compatible, you just have to wire it, the only one that actually would receive a signal from the EEC is the tach, you need good wiring diagrams for your donor and recipient and you can make the swap a relatively easy chore

The Tach is actually not connected to the EEC on either a Gen1 or a 4.0 Gen2.

While the PCM gets a tach signal from the ignition module so does the tach,

Yes, a 4.0 has EDIS6 ignition, but EDIS6 isn't actually that different from the earlier ignition systems.

If you really study both ignition systems in the EVTM manuals you
will come to the realization that all ford really did besides adding more coils is shuffle the componen ts around the engine compartment.

My 1987 Tach is connected to the Tach lead on the EDIS6 module for my
1994 4.0 engine and it works fine.

You should be aware that the sender for the phony guage typically installed in most Gen2's when connected to a Gen1 dash will make the oil light glow dim when there is pressure. and it will be OFF when there is no pressure at all...

The temp guage sensor works fine.

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[DisturbedMXer8]

Interesting. So basically it's just a matter of finding out where everything is supposed to go and splice it in correctly? I just want everything in my dash to work just like it does with my 2.9. If the oil light is weird, is there a fix for that? Or would it just be best to get some aftermarket gauges to go with?

 

[holyford86]

Interesting. So basically it's just a matter of finding out where everything is supposed to go and splice it in correctly? I just want everything in my dash to work just like it does with my 2.9. If the oil light is weird, is there a fix for that? Or would it just be best to get some aftermarket gauges to go with?

swap the guage senders for the coolant and oil pressure from the 2.9 onto the 4.0, they'll fit right on

 

[AllanD]

swap the guage senders for the coolant and oil pressure from the 2.9 onto the 4.0, they'll fit right on

Exactly.

 

[Dugan]

FWIW my 94 4.0 does not work properly with the 1st gen tach, it reads very high. It sounds like the older ones work fine though.

my 89 ranger with a 2.9 reads wacky also