12 Valve Engine and Drivetrain Talk about the 12V engine and drivetrain here. This is for 1994-1998.5 engine and drivetrain discussion only.

Voltage required to trigger Fuel Shutoff Relay?

Thread Tools
 
Search this Thread
 
Old Jul 5, 2010 | 09:36 PM
  #1  
lessnessmen's Avatar
Thread Starter
Registered User
 
Joined: Oct 2003
Posts: 4
Likes: 0
From: hollywood
Voltage required to trigger Fuel Shutoff Relay?

1995 ClubCab, Auto, 160k miles, stock.

Fighting fuel shutoff solenoid troubles. Can lift up on arm and get engine to run. Everything I have read points to the relay if you can lift the arm and it will stay up. Took relay apart and cleaned the contacts inside. Still couldn't get the solenoid to function properly. Broke out the digital volt meter and started checking things. I am getting only about 9 volts out of the brown trigger wire at the relay. Checked it all the way back to the power distribution/fuse/relay box by the battery. Same voltage all the way throughout. I cut the brown wire by the relay and used a jumper wire straight from the battery and the relay closed and the solenoid pulled up.

Are 12 volts required to make the relay function?
Reply
Old Jul 6, 2010 | 04:16 PM
  #2  
gorms's Avatar
Registered User
 
Joined: Jul 2006
Posts: 1,497
Likes: 23
From: SE Mass
I don't remember if those used dual voltage or dual windings in the solenoid (leaning towards the latter) but there are two stages, one for pull (on start) and one for hold (on run). Once my engine bay cools off a little I'll pull the meter out and check. I don't ever remember hearing of anything on the truck being 9 volts, maybe 5 through the PCM. Corrosion problems anywhere?
Reply
Old Jul 6, 2010 | 04:41 PM
  #3  
patdaly's Avatar
Administrator
 
Joined: Jan 2007
Posts: 8,372
Likes: 172
From: Streator Illinois
Definitely 2 circuits, this is from Infidel:

https://www.dieseltruckresource.com/...0&ppuser=25501
Reply
Old Jul 6, 2010 | 06:30 PM
  #4  
infidel's Avatar
Registered User
 
Joined: Dec 2003
Posts: 14,672
Likes: 9
From: Montana
Brown wire voltage that triggers the relay is the same small brown wire on the starter.
It could be loose or corroded under the insulation where you can't see it not allowing enough juice though to trigger the relay.

Name:  starter_curcuit_diagram.jpg
Views: 3947
Size:  36.0 KB
Reply
Old Jul 8, 2010 | 09:28 PM
  #5  
lessnessmen's Avatar
Thread Starter
Registered User
 
Joined: Oct 2003
Posts: 4
Likes: 0
From: hollywood
Updated for future searches...

Start with the easy stuff. The boot on my solenoid was trashed. The outside looked fine from what I could see, but the engine side was all gummy and falling apart. I finally had some help and was able to check the voltage better while someone cranked the engine over. The whole starting system is pulled way down during cranking. I my case it was pulled down from 12.5 to around 9.8 (condition of batteries would play a big part on how far your voltage is pulled down). When I found the voltage at the brown wire to only be around 9 I was sure I had problems elsewhere and stopped looking at the simple stuff.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ChrisPickup
12 Valve Engine and Drivetrain
6
May 7, 2006 09:49 AM
winkle
12 Valve Engine and Drivetrain
2
Oct 3, 2005 10:37 AM
JARHEAD
12 Valve Engine and Drivetrain
4
Jul 31, 2004 07:03 AM
nevrenufhp
12 Valve Engine and Drivetrain
3
Dec 18, 2003 07:38 PM
Palmetto_kid
12 Valve Engine and Drivetrain
15
Nov 17, 2003 02:47 PM




All times are GMT -5. The time now is 11:43 PM.