Fuel Setting on the 3116 is checked by reading the maximum fuel rack travel.The Cat tool kit provides a long pin on a handle that inserts through the Governor link pin which has a drilled hole through the center.
Then a fork shaped tool is wedged between the head and the pin to eliminate any Governor movement.
The digital dial indicator arm is placed on the end of the injector rack pin on #1 injector.
The injector is manually put into no fuel position, the dial indicator is set to zero then rack is released. This measures the maximum fuel rack movement.
The Maximum fuel setting specification is on the top of the valve cover.
hi john,u seem to have been around the 3116 i have a problem its a 98 3116 in a gmc bluebird,wouldnt shut off with key,engine missing,tried looking for miss with temp gun, had 385 on second to last cyl,all others were around160, any ideas thanks,chris
ReplyDeletechris sounds like a stuck injector. pull the valve cover and see if that injectors rack is in a diffent position than all the rest when you move the rack linkage. first you need to remove the shut off solenoid so you can move the rack. all the injector racks that go through the injectors should move at the same time.. if one stays in the same place all the time it would be stuck. thats the quick check.
ReplyDeleteHi Chris,
ReplyDeletePull the valve cover and make sure each injector rack is moving freely. If one is stuck it will over-fuel causing a bad miss and cylinder temperature will rise. Without the engine running feel behind each injector for the rack pin. It should move freely, you can check out for a miss while the engine is running by doing this same procedure. Pushing each rack towards the governor side of the engine will put the injector into an over-fuelling condition.
The run-on condition you are experiencing could be caused by the stuck injector allowing fuel to enter the combustion chamber. Another option would be a faulty fuel shutdown solenoid. It should allow spring pressure to push shutdown rod out with no voltage to it.
Hope this helps,
John.
we got busy at the shop, sent it out to cat dealer,needs injectors,were realy not set up to do the job,we have 40 busses,all makes, with 2 mechanics you guys know how it is,thanks for the info,chris
ReplyDeleteI've gt a 92, Cat 3116 and went out the other morning to fire it up,,, It ran about 30 seconds and quit. I cannot get it restarted for the life of me. Filters were all changed about 2500 miles ago, and have had no issues,,, 2500 miles takes quite a while for me to put on about 2 mos). Anyhow, I suspect the fuel shut off solenoid. Don't laugh, I actually work on VERY small diesels, in the grey market tractors,,, they are extremely easy, very straight forward and a total no brainer. But this is my first on road diesel, so I'm not sure where to look for a solenoid bipass to see if this really is my issue or if I should be exploring other options. Does anyone have scematics of the bipass or of the shut off solenoid? Does anyone have any suggestions? Thanks a Million. Paula J
ReplyDeletegomulego@msn.com
Paula,
ReplyDeleteThe solenoid is an electro-magnet meaning when ignition power is fed to solenoid it pulls in a actuator rod allowing fuel to injectors.
When power is shut off spring pressure pushes rod inside solenoid and turns off fuel.
So if you suspect the solenoid,make sure there is power to it first from ignition circuit. If so unthread it from the governor housing and remove it completely.
If the engine runs then the solenoid is definitely the problem. The only other thing would be an open circuit to the solenoid.
Hi John,
ReplyDeleteI own a 1989 bluebird gmc. When I purchased it we checked all the turn signals, brake lights, etc.. They all worked. We converted the interior into a motor home. When we finished and got ready to travel, you guessedit, no turn signals, brake lights emergency flashers. Where do I start to find the problem? thanks Tom
Hi Tom,
ReplyDeleteIf there is absolutely no lights:
The place I would start is at the light assemblies, disassemble them and check for power and a good ground at each one. If there is nothing then trace the wiring back to the source.
I would also back-track to the beginning before you started the conversion and go through each step that might have effected the operation of the lights.
Hope this helps,
John
John is the fuel transfer pump on the 3116 cat timed to the cam? have a 3116 in a 98 c6500 that quit pickin up fuel, replaced filters would run for half hour then quit . now wont pull fuel from the primary , or from a jerrycan , secondary is right full of fuel. am thinkin its either the fuel solinoid(have yet to check) or the pump it self , any help would be appreciated ./ Dale
ReplyDeleteDale,
ReplyDeleteThere is no timing at all with the Governor which is driven off the Cam Gear and houses the transfer pump.
I would check the fuel shutdown solenoid first. It has total control over the fuel.
Check a previous comment I made on this post about checking the solenoid.
John , checked the solenoid as you intructed ,had powerat the solenoid , removed it an tryed to start engine . Still wouldnt lift any fuel , replaced pump had truck running , without shut off solenoid .Installed solinoid an engine ran for about 10min sarted to die , removed solenoid an now purrs like a kitten , have orderd new solenoid . Thanks for the assist , site has been very helpful , Dale
ReplyDeleteJust a tip on fuel delivery problems on cat 3116. We have a GMC top kick with a 3116 and out of the blue it started running very rough. With the fuel supply running through the center of the head if one of the injector seals goes bad it will allow cylinder compression into the fuel system. Easy way to figure this out is to pull return line off at tank to check for bubbles. To be positive you can connect a pressure gauge to return line and it should not be more than pressure before injectors. This site is very cool and it has helped me tremendously. Thank you all.
ReplyDeletehi john,i have a 3116 in a 97 GMC 8500.i rebuilt engine in frame less than 1000 miles ago. bored and sleeved # 1 cylinder, rings and rod bearings all 6 and ground the valves.motor had 90,000 on it when an unattended overheating problem scored # 1 cyl,i bought the truck that way.truck started and ran fine but seamed to lack power under load. i started out on a trip with it going up the entrance ramp it acted like it was running out of fuel.the rubber seal on the spin on filter blew out.i got the seal back in place got it started and made it a 100 miles down the road no problem, pulled in for fuel headed out same problem acted like it was running out of fuel and making an irratic knocking noice got back to truck stop fuel filter gasket blown out again. replace with new fuel filter headed out made it about a mile up the road same noice under load and started blowing white grey smoke heavily no power. restared truck next morning cold still grey white smoke irratic noice sometimes quiet doesnt seem to skip at idle but no power any ideas whats wrong? let me know thanks Rick
ReplyDeletecheck the return fuel, there may be a restriction. At the front of the head there is a 2 bolt manifold steel line which is the return[it has an orifice, remove the 2 bolts and check for blockage] the pressure fuel flows to the back of the head through a gallery to the front of the head to this return line. The only way I can see the gasket blowing out of the fuel filter is heavy back pressure on the return side.
ReplyDeletethanks for the reply john,i figurered it has to be some kind of back pressure problem. do you think that after i got the fuel filter seal tight it pop an o ring on one of the injectors to make it smoke? are the injectors working off of oil pressure? if so engine oil pressure or. a seperate pump? it was making a clicking tap noise on top of what i believe is the transfer or injection pump.it looks bell shaped with a bolt thru the center. is this some type of relief valve. i am back home now and 200 miles from the truck so i cant check any thing on it.just trying to figure out what might be wrong so i can take enough tools & parts to fix it or just haul it back home?thanks for any infor mation, rick. also i'm going to try and find a repair manual.
ReplyDeleteRick,
ReplyDeleteIf you can limp it home you'll have to check for air in the return side of the fuel system [run it with a clear tube hooked up or into a container].There may be compression leakage into the fuel system which is caused by the injectors not being seated properly into the head. Aother sign is a lot of pressure in the fuel tank after the engine has been run for awhile. Use the "search" box on my blog for "cat 3116" and all the related posts will show. There you'll find the "injector seating" procedure.
Rick,
ReplyDeleteI have a 1991 GMC topkick with a cat3116. I am having a problem getting fuel to the engine. The solenoid makes a clicking sound when I put the key in the ignition before I Start. So I assume the solenoid is ok? I have changed all my fuel lines on the engine and am about to change all my fuel hoses that go to the tank. I am going to replace my fuel filter and the tank pump. The engine previously had a stuck injector and I replaced that, but never got the engine running after. I can turn the engine and it turns when I try to start it, but can't get gas there. Any insight or recommendations.
Anthony
Your solenoid should retract when it gets power so the fuel rack can move and allow fuel to enter the gallery.
ReplyDeleteRemove the valve cover and look at the fuel rack and make sure it moves [slightly] when you turn the ignition on.
Make sure the rack moves freely. If you have a bad injector it will seize up the rack. Use your finger or a tool to move the rack, all you should feel is spring pressure.
When cranking, oil pressure moves the rack as well to supply fuel to allow engine to start.
Of course this is after you've confirmed the engine is gettting a good fuel supply.
John - My shop recently bought a 1990 GMC Topkick service truck with a 3116. Once the engine would start to warm up, it would develop a miss at idle. The slightest increase in throttle would make it even out. I found a great deal on the fuel tool kit, so I bought it and my diesel tech went through all the injectors. We found that most were a little out of adjustment. After running the adjustment we ran it and it sounds and feels smoother, but again, as it warms up it starts to develop a miss. The warmer it gets, the worse the miss gets. The engine has 300k on it and runs GREAT otherwise. It starts easy and doesn't produce any white smoke. Does it sound like an injector(s) to you?
ReplyDeletejohn,
ReplyDeletei have a 92 3116, i'm not getting throttle response...I have done a fuel rack adj, replaced the injectors, valve lash adj, replaced the injector pump, replaced the fuel regulating valve, solenoid, filters, primer pump...Any thoughts?
Does the governor operate properly? You should be able to view the fuel rack with engine running. There may be a possibility of internal linkage problems on the governor.
ReplyDeletei have 1996 3316 cat - well start to miss underload - not all the time - when it is missing it pumps blue smoke out exaust when climbing hill it well start to miss then clear up the miss agian and so on any sugguestion
ReplyDeleteIntermittent Miss could be caused by a bad injector. At the rear of each injector the rack pin can be moved by hand while the engine is running. This way you can determine a injector miss problem at idle.
ReplyDeleteThis is the first step I would take.
Thanks for the info John, I was told that there is a jam nut and a simple set screw adjustment that clockwise motion adds more fuel. Is this not the case?
ReplyDeleteI'm not sure on that but you'll feel the difference. This setting is usually locked out from the factory and the dial indicator setup determines if it needs adjustment. You don't want to over fuel your engine so take care with this adjustment.
ReplyDeleteon where about would the fuel setting would be?
ReplyDeleteThe fuel setting is right across from the governor linkage at the rack. You'll see the allen screw with a locknut. This adjustment comes locked up from the factory. For good reason, overfueling can be harmful to the engine.
ReplyDeleteValves vary from the extremely basic to the extraordinarily complex, and they are one of the oldest mechanical designs. Thanks for sharing great information, Hope to hear more updates from you ...
ReplyDeleteHi John, I've got a 96 GMC Topkick with 3116 that is having over heating problems. I've replaced T-stat, fan clutch & temp sender. The T-stat housing is around 216 but the hose just above there is only around 180ish. Any ideas where I should look next?
ReplyDeleteThanks, Jessie
i have a 1996 gmc topkick that is getting no fuel, the fuel shut off valve and fuel pump get no power. Any ideas where the fuse or possible relay is? I checked on top of the engine and under the dash and did not find a fuse for this circut. Thanks, Keith kkustomz1@aol.com
ReplyDeleteI have a 1991 GMC box truck with a Caterpillar 3116 engine. When the truck was new the national speed limit was 55 mph and the vehicle is goverened to 60. Is there any way to increase the top speed to 70 mph?
ReplyDeleteThanks,
Justin
hi i got a 1995 topkick with a cat 3116. we put on injectors and govener and it wont start but if you give it some starting fluid it will hit for just a few sec. please help me
ReplyDeletehi john i have a 94 3116 cat in a topkick i have rebuild the pump replaced injectors all fuel lines checked fuel shut off it is working properly but i can tack a srew driver push down on the rack and it starts right up with shut off on or not but when it starts it idlesup and down but driving it it up to speed its fine but let off of fuel pedal to stop at red light it shuts off and very hard to start
ReplyDeleteYou may have a governor problem. Oil pressure while cranking bumps up the rack slightly to start. Check the oil pressure line to the governor and the circuit itself.
ReplyDeletehi there , i was asked to look at this gmc topkick that won't shut down . i have worked on trucks for 25 yrs and never worked on one of these 3116 cat 1992 . well i checked the fuel sol. for power on & off . the electric is working with the key . the fuel sol. is attached with what looks like a adjusting nut , that you would use a small spanner wrench on . this is on the fuel pump . is that the shutdown and how would i take that off ? or do i look somewhere else for the problem not shutting off ? thank you andy
ReplyDeleteThe solenoid is spring released with no power and it lengthens to move the fuel rack for shutdown. It is threaded into the Governor housing clockwise. There is a special tool that hooks into the row of holes around the solenoid but you can use a tool to grip onto the body and remove it, use care.
ReplyDeleteI have 1994 topkick with the 3116 cat, the truck was running great and out of nowhere it started spitting and sputtering like it was running out of fuel and started puffing white and black smoke, I checked the turbo outlet for oil, the lines for cracks or pinholes, pressurized cooling system and also did the cat bottle test for headgasket. I live in a small town and every truck mechanic is very unfamiliar with these engines, Ive been going through your posts and have checked what im familiar with any suggestions? Ill check back on your post or you can reach me at (928)855-9600 thanks
ReplyDeleteKramer,
ReplyDeleteYou might have air in the fuel system. Check the steel lines running along the block (common problem rubbing through) and back to the fuel tank. Run a hose before the secondary fuel filter into clean diesel and see how it goes. This bypasses the lines and fuel tank.
A 91 GMC TOPKICK WITH A CAT 3116. UNIT WILL NOT SHUT DOWN WITH KEY. FOUND FUEL SHUTOFF SOLINOIND GETTING POWER AT ALL TIMES. TRACED WIRES BUT COULD NOT FIND RELAYS. IS THERE AND WHERE IS THE RELAYS FOR THE SOLINOID. MY GUESS IS IT IS STUCK.
ReplyDeletei have a 90 gmc topkick with a cat 3116 motor and it runs for about a minute and then starts to run rough and blow lots of black smoke and stalls and wont start back up. i changed the fuel filters and air and still does it
ReplyDeletejohn...i have a 91 gmc top kick with a cat 3116..it is a toterhome..it runs great and does fine on level ground but has no power going up hills under a load..it just puffs a little blue smoke..it has a turbo but you never hear it..any suggestions?..thx Justin
ReplyDeleteI have a 96 topkick. today it was harder to start than usual. but it started. then, it started sputtering and missing, more and more until it died. now, it will crank and start for about a half second and then die. where should I start?
ReplyDeleteFuel filters is the first step then check all the fuel lines. Make sure the fuel shutdown solenoid working as well. It clicks on with ignition and should stay on while cranking.
ReplyDeletethe adjusting pin is smaller than the pin holes in the governor and rack linkage. My question is which way do you throw the slack, so the pin holes line up or push the rack linkage deeper into the gov housing. Also instead of using the dial indicator I bent a piece of square key stock so it looks like a allen wrench and milled the one end down to the fuel setting demension and used it like a feeler gauge between the injector stops.
ReplyDeletethe insertion tool is smaller than the dia. of the holes in the rack linkage and governor. My question is which way do you throw the slack? so the holes line up or do you rotate the rack linkage into the governor housing
ReplyDeleteCapt ziptie
ReplyDeleteDon't worry about the slack just set the rack as per normal and you will be alright. The specs allow for this with plus or minus numbers.
Hello, I have a 93 Chevy Kodiak with a cat 3116. The problem I am having is that the truck is stuck at full throttle. I was told that a stuck injector could cause this. I pulled the valve cover and checked the rack and injectors. everything is moving smoothly. all injectors look to be moving the same. Could this be a problem with the governor? Most of my experience is with newer electronic engines. Any help or guidance would be greatly appreciated. Thanks Richey
ReplyDeleteThis comment has been removed by a blog administrator.
ReplyDeleteRegnad
ReplyDeleteA stuck injector will cause the entire rack to seize up and the engine won't run. I would disconnect the governor linkage and see if the rack goes back to idle. There is a tube between the governor hsg and head that has a clip on it that you need to remove. slide the tube towards the head it's got orings on both ends. there is a circlip on the linkage connecting the rack and governor arm. Disconnect that and see what happens when you crank it up. It may be the governor if the full throttle problem goes away.