sped64

my friend has a 1992 f-350 7.3 litre,the tach jumps around at idle,where do they get the tach signal from.could not find part listing for tach sensor at part store web site.thanks for any input.

chipset

It's in the manual for that vehical. Buy one.

sped64

hey chipset,why respond to a question if you have no useful info it is obvious that it would be in a manual.just thought I might get the answer without spending money.It is not my truck and was trying to help out a friend.I am not a ford guy and if I was I would avoid this forum.I am a tried and true MOPAR man,when I ask questions on my mopar site I get actual information from the members.so take tour rusty blue ovals and..........nuf said

chipset

That is very usefull information. You wanted to get the information without spending his
money ? Your friend, as you say, will have to get the manual for the truck sooner or later. Your not going to be around forever giving him or her free info. Are you being payed for all your time and research ? I get payed when i answer the phone. Thing is almost all info that is needed is in the manual for that perticular vehical. Almost. They can pay me anytime the phone rings or save one phone call and buy the manual. You wanted an answer to your post, i gave you one. What can i say. Some tach feeds use
the alternator. Some use the pump. Some use the crank sensor. some use the cam sensor. You don't even tell us what engine. I assume the 7.3 is a diesle. Is it a turbo or non turbo ? Most of them used to use the alternator at one time. How do you know the tach is good ? Maybe the printed circuit board is bad in the cluster. Have a pro shop that knows what they are doing look at your friends truck. It could be as simple as a bad wire connection. 3 minuet fix. It's good that your trying to help. Make sure you get
payed. I'm sure your time is worth something. If it's not money make them buy the beer.
Good luck.