Fuel system diagnostics
#1
Fuel system diagnostics
A little background first. '93 Super w/ 2.3 L 5 speed manual tranny. This truck has always been very reliable starting. Starts first time every time. Recently, I've had to bump the key 3 or 4 times to get it to run. It will start every time but will die immediately. 3rd of 4th attempt it will finally idle properly and run perfectly. Idle will be within spec, power will be normal, will easily rev to 5k when entering the freeway, etc. Turn it off and it will fail to start properly again. Changed fuel filter, no change. Have not checked fuel pressure at the rail as I don't have a fuel pressure gauge, but the fact that I don't have any issues while on the road doesn't seem like it would be a fuel pressure problem. Pulled the pump and did note a small separation in the filter bag at he fuel pump inlet. When the key is turned I can hear the pump run for 2-3 seconds. No CEL showing. Any and all suggestions are welcome. Is the in-tank mesh bag replaceable separately?
#2
MY BAD
To make a long story short, problem was not fuel related. I had replaced the ignition lock cylinder and ignition switch a while back. Either I did not adjust the ignition switch properly or there was a manufacturing tolerance issue with the new unit. Today I noticed that when the truck was running, just a minor movement of the key towards the off position would turn the ignition off. I figure the return spring in the new lock cylinder was moving the ignition switch beyond the run position when the key was released. Installed the original unit and carefully adjusted per the manual. Back to "first time, every time" starting. Starting issue did not show up 'til about a week after the ignition work. Must have taken some time for the new switch to loosen up.
#3
Sweet, glad you found/fixed the problem and most "importantly", posted your finds.
*was it hard/expensive replacing all that? I don't even need a key to start mine anymore, lol. You know one day the whole thing is going to lock up.
*was it hard/expensive replacing all that? I don't even need a key to start mine anymore, lol. You know one day the whole thing is going to lock up.
Last edited by Inspector; 03-01-2010 at 12:24 PM. Reason: clarification
#4
Replacing the lock cylinder is really a no-brainer. Disconnect battery, remove the steering column shroud (2 screws), turn the key to the run position, depress the lock cylinder locking pin with a small punch and withdraw the cylinder assembly from the steering column.The replacement lock cylinder was $14 at Autozone. If you're having trouble locating the lock pin access hole, just look at the replacement cylinder. Hold it up to your existing cylinder and the hole position should be very evident. Total time should be around 15 min +/-. If the only issue you have is not needing a key to start your truck the new cylinder should do the trick.
If your having trouble with things not turning on/off in the proper key position you may need to replace the ignition switch. Replacement swith is $10 at Autozone. You'll have to remove the facia below the steering column. There is also a metal shroud under that. Remove that also and remove the 2 bolts securing the steering column to the dash. The ignition switch is located on the steering column secured by 2 nuts about a foot back of the steering wheel. When installing make sure the key is in the lock position. The switch comes with a wire bail inserted into the side of the housing. This locates the switch in the locked position. Place the new switch over the studs and make sure the actuating rod from the lock cylinder engages the slide on the new switch. Secure the switch to the steering column with the the 2 nuts. Remove the wire bail from the switch and connect the wiring harness. Bolt up the column and replace the various covers. Reconnect battery and check ignition for proper operation in all positions.
This outlines it pretty well on my '93. There may have been some changes from your '90 to my '93 so I suggest you get a repair manual and double check before proceeding.
Good luck
If your having trouble with things not turning on/off in the proper key position you may need to replace the ignition switch. Replacement swith is $10 at Autozone. You'll have to remove the facia below the steering column. There is also a metal shroud under that. Remove that also and remove the 2 bolts securing the steering column to the dash. The ignition switch is located on the steering column secured by 2 nuts about a foot back of the steering wheel. When installing make sure the key is in the lock position. The switch comes with a wire bail inserted into the side of the housing. This locates the switch in the locked position. Place the new switch over the studs and make sure the actuating rod from the lock cylinder engages the slide on the new switch. Secure the switch to the steering column with the the 2 nuts. Remove the wire bail from the switch and connect the wiring harness. Bolt up the column and replace the various covers. Reconnect battery and check ignition for proper operation in all positions.
This outlines it pretty well on my '93. There may have been some changes from your '90 to my '93 so I suggest you get a repair manual and double check before proceeding.
Good luck
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