Hi Jonce,

The 85 tach won't work at all with the Zetec ECU signal.  I tried it on mine
while I was at Bostig a few months ago.  It won't destroy the ECU or
anything like that (as long as you don't ground the green wire to the
chassis), it just won't do anything at all.  I don't have the definitive
answer as to why it won't work, just the "been there, done that" to know
that it won't work for you (assuming the tach in your van is the factory
original).

I was planning to just forgo the tachometer altogether, since the Zetec can
safely rev past 6,500RPM (way higher than I would probably ever let it), but
I found that I couldn't hear or feel the engine at stoplights or when
stopped in traffic and I kept thinking that maybe it had stalled.  It was
always running fine and ready to go when I let out the clutch, but just the
sickening thought of being stalled in traffic was enough to get me to swap
in the later tach.

Jay Brown

Date: Sat, 15 Mar 2008 00:52:01 -0400

From: Jonce Fancher <streetbugs@WHISPLLC.COM>

Subject: Re: Tach year breaks/ part numbers

Great Info Jim!! Thanks a Bunch.

But Now I can ask the REAL Question. Since Now I know the Tach part numbers
did change. At Bostig I am told I must change the Tach on my 85 to a 86-91
for reasons of being more sensitive for the to pick up the tach signal. The
85 is

suppose to be LESS sensitive in sensing the signal. But IF the only diff is
the Buzzer then I should be good to go with the 85.

I guess my questions are:

1) Will I harm the brain of the bostig using the 85 tach but if it is the
same as the up to 91 just no oil buzzer then I should be Fine

2) If it is different (being not sensitive to pick up the signal) would it
damage the bostig brain. My theory is it just wouldnt work or pick up the
signal.

3) I did have a late model cluster once and when I put it in it would buzz
so I just sold it. The tach worked in the 85 but the tach was from a 86-91
vanagon. would a 85 tach work in a stock 86-91 vanagon?

4) Are there any resistance checks I can make to my tach to see if it would
be the same internally as the 86-91?

5) Anyone got a 86-91 they would like to let me borrow to check out? or
anyone got one to sell or trade for something? I think Ive got a new 2.1L
water pump as well as other items for trade if needed.

Just trying to figure out if I need to swap out the whole mess or just play
with the thing and see what happens. I asked Bostig and they said I need to
swap it but couldnt give me more info on why it wouldnt work. I certainly
dont want to fry

my brain and Im not afraid to swap my cluster. I just want to figure out
what the actual specs that make it work and or not work.

Thanks again.

Jonce