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98 12v tach

12K views 12 replies 5 participants last post by  Deputydog 
#1 ·
hi all I am new here

99 f 350 w 98 12v

98 12v the tach sensor on the front by crankshaft can this be used or do you have to use the cam sensor off a ford

I have not tried mine yet have it temp wired

blk grnd
red 12v switched hot
yellow tach input

this is how I have it wired do you think it will work
 
#2 ·
I beleive Destroked has everything you need to make the tach work.
 
#3 ·
I am sure they do and ford cummins does also but then that would take all the challenge out finding out if I can use the original dodge/cummins tach sensor

if that doesn't work I can I know I can use the cam sensor off the ford

thanks for the reply
 
#4 ·
I think it has to do with the number of pulses. I think my 6.0l is looking for 60 or 60-1 or something like that, so I got the tach ring to match from GOS. Your 99 was that gas or a 7.3l? I think the Cummins is only a single pulse. or single gap, IIRC, it has been a few months since I messed with my tach.
 
#5 ·
trying to get my tach working

I am not going to go to destroke or ford cummins half the fun of doing a conversion is figuring it out

I tied the dodge setup didn't work

so I did the ford setup with the cam sensor take #85 the cam sensor wire and the #48 wire the tach wire and wire them together before pcm

wondering it I might have the sensor to close to the harmonic about .030

I ground in the 2 extra notches so I have 4

I tested wire from sensor to the pcm block I haven't tested the other to the tach yet
 
#6 ·
You have to keep the cam sensor and the crank sensor wires seperated until you get to the sensor then wire them together if you run them together they will pick up signals from each other and cause problems, the shielding on the wires is crap, I think you can wrap one in aluminum foil but that is a pain and doesn't look very good.
 
#8 ·
I think if you have a common rail you can just use the crankshaft sensor for tach but I think there is still a cam sensor signal from somewhere. I never tried it with just the crank sensor, but mine seems to be working very well with both. How do you know your computer is looking for 4 pulses? the V-10 looks for 40-1 and the 6.0 is looking for 60-2 yours could be looking for 12 pulses it depends on what motor you had to start with.
 
#11 ·
I think you will have to bypass the ford PCM for the tach to work. 02-up have to run through the pcm so the air con will work.
 
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