Has anyone here replaced their fuel shutoff solenoid? My 1990 is intermittently not shutting off with the key. Sometimes it works correctly for days, sometimes it will shut off if I repeatedly cycle the key and lately I have had to kill it with the shutoff lever on the injector pump. Its in a tight spot but it looks but it doesnt look impossible. If anyone's done it please let me know how it worked out...dont want to go to a cable just yet especially cause I have the part. Is this a job I should pay someone to do that knows what they are doing? Truck and pump are stock.

 

Use a hammer and chisel to turn it. If the FSS is bad it should not run though. You are still getting power to it, could be a short, or the ignition switch is bad. Try pulling the wire off the FSS next time, it should die.

 

Im no expert but I thought from reading some of these posts that this solenoid could become inoperative in either position...stuck in no start position or stuck in no shutoff position. Some posts even refer to the FSS actually shutting the truck off while driving down the road. I have owned 8 of these trucks and have never had this problem but it looks like its not that uncommon.

 

It's possible the plunger could get stuck in the "open" position. Hence the reason for the manual shut off on the side of the pump.

 

You can also lose a chunk of rubber out of the plunger, letting fuel past and causing the motor to keep running.

 

I have a backup FSS as a spare just in case for situations like this. Found it on Ebay for under $20.

Brand new, in the box.

Not ever looking forwards to changing it, but at least I have one.

 

I cant seem to keep one going in my truck to save my life.

 

Turning in the fuel screw on stock injector has long been the demise of FSS plungers. But also consider their age. The fuel will take their toll on the tip sooner or later. I took a deep offset 15/16 wrench and cut it and ground on it until it fit nicely.

 

This may sound like a dumb question: when I change the FSS will it leak fuel out or is there a chance of it losing its fuel prime?

 

It will leak a little fuel but not too much. Mine never lost its prime.

 

Hammer and punch/chisel have worked best for me, never lost prime either and very little fuel comes out.

not sure if you know but the old VW diesel pumps use the same FSS and they can be found very cheap(under$20) while the dealer can get over $100, I've had a few of the cheap VW ones now and havent had a problem.

If its the original FSS then its best to replace it but if it happens again then there is a fix in the sticky for a torn shutoff plunger. This is very common with a turned up pump, my old truck wouldn't last one full throttle run without tearing.
https://www.dieseltruckresource.com/...d.php?t=117593

 

I ordered and received one off Ebay. It was about $10.00 .Its almost against my better judgement because its too cheap. But I haven't seen any posts that would indicate that a $100.00 one is ten times better. Time will tell. I think this truck is all stock as far as the fuel system goes...its a 1990 Getrag with 4.10s ...but it is notably quicker, louder and seems to rev higher than my identical non i/c 1991 (same drivetrain)and it has a much more audible turbo whistle. but it looks stock. Not sure of its entire history as the last owner passed away.Thanks for the help.

 

Some people were very good at hiding adjustments from the nosy police. But I really don't know anything about that.

 

Replaced FSS on my '95 W-2500 because of occasional no start. Now starts more often, but still not consistent, particularly when cold. Electrical connector looks clean, have 12 volts at the red wire, black is neutral. Is there a relay or fuse upstream of the connector that could be giving me a problem?

 

This would better be answered in the 2nd gen forum, but may just be a problem with the adjustment of said solenoid.