1994 4x4 XLT 4L intermittent starting problems
#1
08-30-2018
Join Date: Aug 2018
Location: Frederick
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
#2
08-30-2018
Welcome to the forum
I assume the dash lights come on like normal, and the CEL(check engine light) as well?
Get a can of Quick Start(ether in a spray can), and pliers to remove the clamp on Power Brake booster's Vacuum hose
When there is a No Start remove the hose and spray Ether into the hose, into the intake manifold, put hose back on
Now try to start the engine, this is the 50/50 Test
If it starts and dies then you have a Fuel problem
If it doesn't start then you have a Spark problem
50/50
Things to LISTEN for, when you turn on the key you should HEAR the fuel pump run for 2 seconds, it will only run for 2 seconds but it will do that EACH TIME you turn the key from off to on, so repeat as much as you need to confirm you HEAR IT, so you know what it sounds like.
It is not that quiet, you can hear the HUMMMMM from inside the cab, if you listen for it.
At the next No Start listen for the fuel pump.
The fuel system should hold pressure for a few MONTHS, not minutes hours or days, MONTHS, but older systems can loose pressure if they sit, so the 2 second run time for fuel pump doesn't get pressure up high enough, so cycling the key on and off 3 times can build pressure back up, try that before starting engine
Long shot is the Crank Sensor
Look on the front of the engine down by the main pulley, crank pulley, at about the 10:00 position is the Crank sensor
The crank sensor tells computer to start Spark and Fuel injectors when crank starts to turn, computer has no connection to Starter Motor, so it only knows when to start spark and fuel when crank sensor starts to pulse timing marks
These RARELY fail, and usually not intermittent, when they fail they fail, so long shot
I assume the dash lights come on like normal, and the CEL(check engine light) as well?
Get a can of Quick Start(ether in a spray can), and pliers to remove the clamp on Power Brake booster's Vacuum hose
When there is a No Start remove the hose and spray Ether into the hose, into the intake manifold, put hose back on
Now try to start the engine, this is the 50/50 Test
If it starts and dies then you have a Fuel problem
If it doesn't start then you have a Spark problem
50/50
Things to LISTEN for, when you turn on the key you should HEAR the fuel pump run for 2 seconds, it will only run for 2 seconds but it will do that EACH TIME you turn the key from off to on, so repeat as much as you need to confirm you HEAR IT, so you know what it sounds like.
It is not that quiet, you can hear the HUMMMMM from inside the cab, if you listen for it.
At the next No Start listen for the fuel pump.
The fuel system should hold pressure for a few MONTHS, not minutes hours or days, MONTHS, but older systems can loose pressure if they sit, so the 2 second run time for fuel pump doesn't get pressure up high enough, so cycling the key on and off 3 times can build pressure back up, try that before starting engine
Long shot is the Crank Sensor
Look on the front of the engine down by the main pulley, crank pulley, at about the 10:00 position is the Crank sensor
The crank sensor tells computer to start Spark and Fuel injectors when crank starts to turn, computer has no connection to Starter Motor, so it only knows when to start spark and fuel when crank sensor starts to pulse timing marks
These RARELY fail, and usually not intermittent, when they fail they fail, so long shot
Last edited by RonD; 08-30-2018 at 09:27 AM.
Thread
Thread Starter
Forum
Replies
Last Post
