dead tach and trans?
Thread Starter
|
New User
Joined: Jan 2011
Posts: 18
Likes: 0
dead tach and trans?
I changed my lift pump yesterday after noon took a look at it and thought 30 minutes or so and back in business. Well it was more like 2 hours 
ridgid line was rounded off and so on, anyway when I wraped it up it was just getting dark. She started up fine but now the tach moves a little when the engine is cranking but lays at 0 when running and when shifted into drive it doesnt engage right. Reverse is fine though, wtf did i unhook?
the truck is a 93 f250 2wd auto 7.3 idi na
Sonds like a bad joke my kids would play while i go in for a beer or something and disconect my trans and tach!
but i know i had to have hit something under. Any ideas?
ridgid line was rounded off and so on, anyway when I wraped it up it was just getting dark. She started up fine but now the tach moves a little when the engine is cranking but lays at 0 when running and when shifted into drive it doesnt engage right. Reverse is fine though, wtf did i unhook?the truck is a 93 f250 2wd auto 7.3 idi na
Sonds like a bad joke my kids would play while i go in for a beer or something and disconect my trans and tach!
but i know i had to have hit something under. Any ideas?
Posting Guru
Joined: Dec 2005
Posts: 1,528
Likes: 0
From: Peterborough, Ontario
Being a '93 it should have an E4OD in it, which relies on the tach sensor for inputs. Up top, to the driver's side of the oil filler, is the tach sensor. It's pretty common for the wires to get 'bare' where they enter the sensor, and the start causing issues. I suspect what has happened is at some point you must have disturbed a wire or something that leads to the sensor.
If you end up having to replace that sensor, it's a dealer only item.
It may also be in the wiring between the engine and passenger side fender, again, depending on how you accessed the lift pump to replace it. The tach sensor wires travel through there, IIRC, they are in the bundle along with the alternator wires.
If you end up having to replace that sensor, it's a dealer only item.
It may also be in the wiring between the engine and passenger side fender, again, depending on how you accessed the lift pump to replace it. The tach sensor wires travel through there, IIRC, they are in the bundle along with the alternator wires.
Thread Starter
|
New User
Joined: Jan 2011
Posts: 18
Likes: 0
thats right where i pulled the pump up through. i had to leave the ridgid line on the pump and disconect it from the filter houseing finessing at this point was thrown out the window. I will go out and trace those wires.
Thanks for the insite and fast reply
Thanks for the insite and fast reply
Postmaster
Joined: Apr 2008
Posts: 4,802
Likes: 1
I agree with greywynd, sounds like something got messed up with the harness for the tach sender. Or it's just a pure coincidence, and the sender decided to die on you at that exact moment - weirder things have happened, so it's not out of question. The important thing is to not drive the truck before you locate the problem and rectify it, because no tach means failure-management mode for the PCM, resulting in full line pressure which can do some internal damage (IIRC one of the clutch drums don't like it, or something like that).
Thread Starter
|
New User
Joined: Jan 2011
Posts: 18
Likes: 0
Greywydn when you say "Up top, to the driver's side of the oil filler, is the tach sensor." Do you mean oil fill? I see too wires and a sensor there that come from the same wire loom as the alt wires?
Thread Starter
|
New User
Joined: Jan 2011
Posts: 18
Likes: 0
those wires are fine and should have not ben disturbed but i guess the sensor could have just gone or something. I did disconect the starter solinoid wires and positive batery terminals to gain some room when working the pump out maby something shorted in the process?
Trending Topics
Thread Starter
|
New User
Joined: Jan 2011
Posts: 18
Likes: 0
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
Postmaster
Joined: Apr 2008
Posts: 4,802
Likes: 1
There is a test, you measure resistance between the two wires, first away from any metal and then right against a ferrous metal surface. Don't remember the numbers you're supposed to get, but I do remember that my tach sender passe said test and still didn't work like it should...
Posting Guru
Joined: Dec 2005
Posts: 1,528
Likes: 0
From: Peterborough, Ontario
I would double check the wires from the sensor to the inner fender, just too much coincidence that it happened at the same time. Maybe they got pulled a bit one way or another, disturbing a connection at some point. I know there's a connector at the sensor, can't recall if there's another one between there and the passenger fender or not.
Thread Starter
|
New User
Joined: Jan 2011
Posts: 18
Likes: 0
the od light is not on, pushing the od button does nothing eather.
I cleaned the plug conections and checked the fueses under hood and in cab.
a test with a multimeter set on ac voltage conected to the sensor showed an increase of voltage as i rev the engine. sensor should be fine? right?
has to be a bad conection some where else. any ideas of what or where to look next?
I cleaned the plug conections and checked the fueses under hood and in cab.
a test with a multimeter set on ac voltage conected to the sensor showed an increase of voltage as i rev the engine. sensor should be fine? right?
has to be a bad conection some where else. any ideas of what or where to look next?
Senior User
Joined: Feb 2010
Posts: 241
Likes: 0
have you checked plug in at transmission? if so check plug in at tcm that is at driverside firewall rectangle shape with 10mm bolt through the center of it looks like 50 wires coming out of it let me think about it a while went throuhg all of this awhile back but i had to replace the tcm.