5.9 cummings 12v question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**richard2717** · 09-04-2023, 02:29 PM

guys
I have a 96 5.9 12 valve in a ferd work truck. Truck has sat since beginning of 2020 but ran and drove great when I set it up. It had been started and drove around the yard at least once a month since. I needed it the other day on a job a couple miles from the shop so I fired it up and away we went. Engine idles fine and revs up fine with no load but going thru the gears seems to lose all power and the most I could get out of it was about 25 mph which was still a struggle. Never once tried to shut off just has no power. Drove it back to the shop with same conditions happening. Any ideas what I should be looking for? would the fuel be going bad? Going over it smoked black smoke like crazy coming back was not as bad but you could definitely smell the raw fuel.

Thanks
Richard

truckster · 09-04-2023, 03:13 PM

How are the fuel filters? That would be the first place I would look. Also the water separator if it has one.

**richard2717** · 09-05-2023, 02:41 PM

I just got a new fuel filter for it today and am going to try to get that changed out this week.

bnorth · 09-05-2023, 06:01 PM

Check the air filter sounds like it is choking the engine. Fuel filter is probably fine if it was smoking hard and down on power it has fuel but not air.

**richard2717** · 09-07-2023, 12:48 PM

Quote:

Originally Posted by bnorth

Check the air filter sounds like it is choking the engine. Fuel filter is probably fine if it was smoking hard and down on power it has fuel but not air.

Air filter was the 1st thing I checked because that was the 1st thing that came to mind with the smoke. Even took it for a drive without it and it does the same thing. No load everything is fine. 1st & 2nd gear is fine and will rev till the gov kicks in. Go to 3rd and it will not rev higher than 15-1800 rpms. Still have to change the fuel filter but been too damn hot to worry with it.

**Dieselwrencher** · 11-02-2023, 06:14 AM

Did the fuel filter fix your problem? If not verify your fuel shut off solenoid is pulling the lever all the way up. If not you may not be getting full fueling.

**richard2717** · 11-02-2023, 08:03 AM

Quote:

Originally Posted by Dieselwrencher

Did the fuel filter fix your problem? If not verify your fuel shut off solenoid is pulling the lever all the way up. If not you may not be getting full fueling.

Forgot to post back here. I did change the fuel filter. It had been on there since 2019 (truck has not had 20 miles put on it since I brought it home from buying it) I have not driven it back on the road yet but I have a long driveway of about 2000 ft and it seems to be a lot better now.

One thing that I am not sure if related, but the pedal will no longer return to idle on its own and I had to use my foot under the pedal to lift it back up. I put an external set of springs on the engine side to help bring it back to idle for now. It is just a yard truck so to speak at this point. Since I am not very familiar with the diesels I will grab a picture of what I did to see if you think that might have been my issue as well

09-04-2023, 02:29 PM	#1
richard2717 Equal opportunity joke ofender Join Date: Oct 2011 Location: Eastern Shore of MD Posts: 10,135	5.9 cummings 12v question guys I have a 96 5.9 12 valve in a ferd work truck. Truck has sat since beginning of 2020 but ran and drove great when I set it up. It had been started and drove around the yard at least once a month since. I needed it the other day on a job a couple miles from the shop so I fired it up and away we went. Engine idles fine and revs up fine with no load but going thru the gears seems to lose all power and the most I could get out of it was about 25 mph which was still a struggle. Never once tried to shut off just has no power. Drove it back to the shop with same conditions happening. Any ideas what I should be looking for? would the fuel be going bad? Going over it smoked black smoke like crazy coming back was not as bad but you could definitely smell the raw fuel. Thanks Richard __________________ Members I have met. Dually Jams, OlBlue60, ScottH, Tommyboy24, Dujobo, Warbucket, 2003 Silverado, Notsolo, my90k5, 6t727t2, Special-K ,Jack_71C10, tabarcus,72blazer_mud_bogger,pwdcougar,RSavage,EricSean,1Rippen6,invicta455,tennaragtop71,arks, Kendal,Bennett68C10, Perpendicular, Chainsawman, McGeesCustomMinis,ShortbedClayton,longblue72,6768chevylover,Tim71,Travisarmenta,Ol' Drippy,fleetmitch,georgieb51,Dave,bcnya2,Dadsburb https://paypal.me/6772GMtruckparts Most women like the strong, silent type… Fortunately for me, my wife prefers the out-of-shape, mouthy type.

09-04-2023, 03:13 PM	#2
truckster Registered User Join Date: Jan 2001 Location: Orem, Utah Posts: 7,978	Re: 5.9 cummings 12v question How are the fuel filters? That would be the first place I would look. Also the water separator if it has one. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

09-05-2023, 02:41 PM	#3
richard2717 Equal opportunity joke ofender Join Date: Oct 2011 Location: Eastern Shore of MD Posts: 10,135	Re: 5.9 cummings 12v question I just got a new fuel filter for it today and am going to try to get that changed out this week. __________________ Members I have met. Dually Jams, OlBlue60, ScottH, Tommyboy24, Dujobo, Warbucket, 2003 Silverado, Notsolo, my90k5, 6t727t2, Special-K ,Jack_71C10, tabarcus,72blazer_mud_bogger,pwdcougar,RSavage,EricSean,1Rippen6,invicta455,tennaragtop71,arks, Kendal,Bennett68C10, Perpendicular, Chainsawman, McGeesCustomMinis,ShortbedClayton,longblue72,6768chevylover,Tim71,Travisarmenta,Ol' Drippy,fleetmitch,georgieb51,Dave,bcnya2,Dadsburb https://paypal.me/6772GMtruckparts Most women like the strong, silent type… Fortunately for me, my wife prefers the out-of-shape, mouthy type.

09-05-2023, 06:01 PM	#4
bnorth Registered User Join Date: Aug 2020 Location: Salmon Arm BC Posts: 201	Re: 5.9 cummings 12v question Check the air filter sounds like it is choking the engine. Fuel filter is probably fine if it was smoking hard and down on power it has fuel but not air. __________________ 1970 C10 l/b 292/4spd Build: http://67-72chevytrucks.com/vboard/s...d.php?t=811062

11-02-2023, 06:14 AM	#6
Dieselwrencher 6>8 Plugless........ Join Date: Sep 2007 Location: Prairie City, Ia Posts: 17,142	Re: 5.9 cummings 12v question Did the fuel filter fix your problem? If not verify your fuel shut off solenoid is pulling the lever all the way up. If not you may not be getting full fueling. __________________ Ryan 1972 Chevy Longhorn K30 Cheyenne Super, 359 Inline 6 cylinder, Auto Trans, Tilt, Diesel Tach/Vach, Buckets, Rare Rear 4-link and air ride option Build Thread 1972 GMC Sierra Grande Longhorn 4x4 1972 Chevy Cheyenne Super K20 Long Step side tilt, tach, tow hooks, AC, 350 4 speed 1972 C10 Suburban Custom Deluxe 1969 Chevy milk truck 1971 Camaro RS 5.3 BTR STG3 Cam Super T10 1940 Ford 354 Hemi 46RH Ford 9" on air ride huge project *Tired of spark plugs? Check this out.*

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