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Your Old Cummins Won't Stop Running?

81K views 36 replies 25 participants last post by  Starchief_59 
#1 · (Edited)
If you recently turned up the fuel on your 89-93 Cummins and still have the stock injectors and now your engine won’t stop running when you turn off the key, this is write up will hopefully solve your problem.
The first part of this write up is the same as another write up I did, but I figured I could kill two birds with one stone and do a write up on the Fuel Shutoff Solenoid (FSS). It’s just removing the injection pump top. Maybe I’ll do a 3200RPM spring install write up as well…

First, if you own a 91.5-93 with an automatic transmission with overdrive, you’ll need to remove the three bolts holding on the throttle position sensor and move it out of the way. Then remove the throttle rod by simply popping it off. Also remove the two banjo bolts making sure to not lose the washers behind them.


Next, loosen this bolt thing and remove this plate thing. :D


STOP!! TAKE A MINUTE TO MARK, TAKE A PICTURE, OR JUST NOTE WHERE YOUR THROTTLE INDEXING IS. IT WILL SAVE YOU FIFTEEN MINUTES OF FIDDLING WITH IT LATER WHEN YOU TRY TO START YOUR TRUCK.
Lift out the plate, the plastic pieces and spring noting how it all goes together.


With a ball end allen wrench (if you don’t have one, get one. It makes life so much easier. That being said, it is possible, harder though, with a regular allen wrench.), loosen the four bolts that hold on the pump top. The fourth bolt can be a pain and is where the ball end allen comes in handy. You may have to remove the idle screw. I don’t but it’s not the stock piece anyway…


Lift the pump top off and push the throttle rod through partway. Pull it the rest of the way from the bottom so you don’t lose parts.


Now you can get to the FSS. I’m guessing there’s a special tool to remove it but I use a good ole crescent wrench at an angle. Unplug the wires and unscrew the solenoid.


Now I removed the spring and plunger quite awhile ago so I don’t really remember what it looked like before but this is what it needs to look like after. Now I’ve heard of guys sanding down the plunger or removing the rubber from the plunger all together and the FSS working again but I’ve never done it so I can’t say. I just wish I’d have heard of that before I tossed it… You can find out more information on it or replace the solenoid all together (although until you get bigger injectors to relieve the pressure in the injection pump or turn down the fuel, the solenoid will probably fail again.)


Screw the FSS back in. Tighten it as well as you can and you’ll know it’s pretty good when the spades are back in the original position.
If you don’t go the replacement FSS route, you can always install a pull cable on the manual fuel shutoff lever. I have heard of people cutting of the top of this bracket in order to get to the FSS easier but as you can tell, it’s not necessary.


Now back out the fuel screw while counting the turns so you can put it back where it was and reassemble the pump.
If I missed anything I’m sure someone will chime right in! I hope this helped someone like I’ve been helped so many times on CF! Stay Classy.

EDIT: READ THIS ENTIRE THREAD AS THERE ARE OTHER WAYS TO GO ABOUT DOING THIS. THEY ARE DESCRIBED IN OTHER POSTS THROUGHOUT THE THREAD AND THEY MAY BE HELPFUL. THERE'S MORE THAN ONE WAY TO SKIN A CAT!! :D
 
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#5 ·
Nice write up:thumbsup:
 
#8 ·
How did you get your governor spring in? And it's really not that bad. I just broke it down quite a bit so someone like myself could understand it. :hehe:
 
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#7 ·
good to help people. I agree sticky !! :thumbsup: :thumbsup:
 
#9 ·
Thanks for the write up but I will say that I would NEVER remove the pump top just to get the solenoid off. Too damned hard to get the throttle setup back where it belongs.

I made a special wrench that I carry with me plus I cut off that part of the plate that sticks up in the one picture. The wrench is an Combination wrench that fits to solenoid and I bent it 90 degrees just past the open end section. Then I can put it on the solenoid and turn it using a large screwdriver or another wrench in the boxed end section. I have changed about 6 of the plungers and needed an easy way to get to the solenoid.
 
#11 ·
I made a special wrench that I carry with me plus I cut off that part of the plate that sticks up in the one picture. The wrench is an Combination wrench that fits to solenoid and I bent it 90 degrees just past the open end section. Then I can put it on the solenoid and turn it using a large screwdriver or another wrench in the boxed end section. I have changed about 6 of the plungers and needed an easy way to get to the solenoid.
Yeah that does make sense. If you do it more than once or twice, this would be the way to go.
 
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#10 ·
I just took the top half of the pump off, never touched the throttle lever. Also, I cut the bracket on the back of the injection pump off flush so I can get to the solenoid. Makes life real easy.
 
#12 ·
hey there. I have done my shutoff solinoid 3 times now and all you have to do is remove that bracket off the back of the pump. There is no need to cut it (the bracket) or to remove the top of the pump. Its just four bolts that hold it on. a few are kinda hard to see but its the easiest way to do it i think. I think 3 are allen bolts and 1 torques head. Also the third time i did mine i just sanded the rubber off the end of the plunger that goes inside the FSS and it works great and has been for about 6 months now. But i have heard that some plungers wont work because when you sand the rubber off, some of them have a small hole though the side of the end that seals off the hole. But mine didnt and it worked great.
 
#13 ·
What is that Large (looks like 1/2" steel line) Going into the front of your pump?
 
#14 ·
It's just my fuel line from the lift pump. I might have :D twisted the factory line in two when I first got the truck so I had to use a union...
 
#15 ·
I havent looked at many of these pumps but mine doesn't have a fuel line in the front.. Only the Banjo in the back??? Maybe im wrong.. Ill have to pop the hood tonight.
 
#16 ·
maybe not the FSS?

all,
I was told the no-shutdown scenario is probably not related to the FSS plunger/seal going bad because of increased fuel pressure relating to turning our VEs up. The most likely cause of fuel leakage past the FSS plunger is metal particles from worn/broken springs in the high-pressure distribution block area just below the FSS location working their way back through to the plunger seat. Bad ju ju here. Pump rebuilds in order. Easiest way to determine this: Remove FSS via methods described above, and examine plunger seat area (use a magnet maybe?) for metal shavings or pieces. If present, no amount of FSS replacement will cure the problem. YIKES!

Good luck...mine won't shut down occassionally.

Kodthree
 
#17 ·
All of the 6 plunger failures I have had had large chunks of missing rubber from the plungers. Never did find evidence of where the chunks went a couple of the times. I turned the pump back down and so far it has not given any more problems.
 
#18 ·
I used a heavy choke cable for fuel shutoff, both on my 93 Cummins and on my Kubota mower. Solved both problems. My Yanmar tractor already had manual shutoff from the factory. When my TDI gets to that point, I won't be able to go that route because it's CR and all electronic.
 
#19 ·
ok now can someone post a picture of the wires running into the sollenoid? i have no clue where it is or what wire needs hot
 
#20 ·


As far as what wire is what... I guess I never looked into that!
 
#21 ·
hey guys
i struggle to get my VE to turn off... do the high HP 12/14mm pump guys just run pull to stop? also any pics of a plunger with the rubber shaved?

any thoughts on getting plungers made to solve this non stop issue?
 
#22 ·
Is there any problems with leaving the shutoff pulled back as a lockout for the fuel? I heard the pump will leak, anyone know if thats true?
 
#25 ·
To answer your question:

I put engine-kill-cables on all of my trucks and "gut" the solenoids, thus eliminating the very real possibility of the solenoid failing without warning in some busy multi-lane highway or intersection with no warning at all (I have known of this happening many times).

ALWAYS use a LOCKING engine-kill cable and ALWAYS leave the lever in KILL position with the cable locked anytime the engine is not running.

Saturn Surplus has some ideal genuine military locking engine-kill cables and that is what I use.

No harm will come from leaving the lever in KILL position; it cannot leak unless the O-ring on it's shaft dies from old age and modern fuel.


The reason that it is imperative to always leave the cable/lever in KILL position is to prevent the engine from starting should the truck be sitting parked and some other vehicle {or cow (don't laugh, it has happened) --- or elephant or dinosaur} should bump the truck; were this to happen and the cable/lever in RUN position, the engine would start and who knows where the truck would end up or what disastrous things will occur before it stops. :shock:


As for solenoid removal, it is a simple matter to walk it out and then back in using a slim cold-chisel or punch; I have done this many times with nary a negative issue.
 
#23 ·
I've never heard of such a thing. Doesn't mean it's not true I guess. What do you mean a lockout though?
 
#24 ·
I want to be able to leave the fuel shut off in case someone hops in intending to steal it only to find it wont start. Hopefully they are stupid enough not to know how it works. Then I will also have a master switch on my electrical as well.
 
#26 ·
Being as my cummins is wrapped in chevy there was no room for the intercooler and the factory hood latch to get along. So when my fss quit I had a handy factory installed kill cable to use. But mine returns to run after shutdown. I've often wondered about it starting and have tried letting her roll out of the driveway and dropping the clutch. Only got some ugly marks on the sidewalk and an ear full from the wife.
 
#29 ·
Kill cable

I have heard there is a cleaner looking way to connect the cable to the fuel shut off lever? What would that part be called with a set screw to hold cable into lever for a cosmetic look?
 
#32 ·
Negative. I can say that with confidence because I've experienced it. It may slow it down but it won't kill it completely.

If I scraped the plunger off and then installed it with the oring and left out the spring. Will this work to bypass the FSS?
Not sure... why not remove the plunger all together?
 
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