Yesterday just west of Jackson, TN on I-40 rest stop closed, pulled into the worst Pilot station ever just to take a break. Sign said cars and RV's. After break could not turn around without unhooking toad. Never shut off the engine. Leaving station engine would only accelerate to 1500 RPM in 1st gear. Fortunately Adult Video place had parking I could pull into. 1800 max rpm in neutral. Checked all I could think of: fuel kill solenoid, fuel filter bowl (filters replaced a week ago), 400 miles since last fuel fill, no abnormal indications. King throttle control tested by the guy in MN in DEC and nothing found, good condition. Returned to truck side of Pilot as maybe they had a mechanic. Even difficult making the turn there, but found another place to stop out of the way. Did some more checks and head scratching. Decided to shut off engine and see if it would start, it did. Started Gen and turned on boost, no different. Noticed throw rug jammed under seat side of brake and throttle pedal, pulled it out and could get more than 1800 rpm in neutral. Decided to pull onto the road again and see if I had some power. Everything had returned to normal and we continued on our way at up to 70 mph to Tom Sawyer CG in West Memphis. I'm not sure the rug had anything to do with the problem, since the electric stuff is mounted in the middle of the pedal. The brake pedal may have not been releasing fully,but doubt that was the case. Searched the forum and found at least one similar incident. Was it just coincidence that it returned to normal when I removed the rug? Maybe restarting the engine solved the problem. Any good guesses? C8.3 300 Cummins mechanical diesel engine.
My issue could have been a stuck turbo waste gate valve. At least that's what Cummins could diagnose. Cumminbs worked on the turbo (6 or m0re years ago) and it's been fine ever since. BTW, Steve at King Controls also refurbished the Throttle control free of charge.
That was nice, I paid $75 plus shipping. Leaving the CG now may not have wifi until we get back to Austin.
A couple years ago I was at FT complaining about lack of low speed braking. Almost rear-ended cars a couple times. the tech pulled out the floor mat from behind the brake pedal. All was fine. Duh! Watch rugs and rugs around the pedals.
My problem was a broken spring inside the cutoff solenoid. It started and ran fine at first, then when I stopped and started out again, no power. To test, if you lose power let it idle and push up on the rod at the bottom and if it moves farther up, replace the solenoid. Simple to do.
Seems like Jerry's low RPM could only be fuel solenoid or King Cruise Control (if not using air throttle), or pedal movement obstructions. King Control is supposed to have some low RPM limitations if it does not see an electrical ground on the brake light circuit. I have heard that some have added an old-fashioned incandescent brake light bulb in a new socket after changing brake bulbs to LED, but I am not sure it is necessary. New socket could be located anywhere, even near King Control box.
Cummins has a redesigned larger fuel shutoff solenoid that uses a new mounting bracket. It has been out for several years and may do a better job than the original solenoid. We also have had the dreaded only drive at low RPM problem from a fuel shut off not fully retracting. After we found the problem, we drove for weeks holding solenoid up with cable ties and shutting down engine by cutting off cable ties, until we could get the new solenoid, which is electrical plug compatible to original.
The fuel shutoff solenoid is only used on mechanical C8.3 engines. I guess the ISC & other engines use the computer to control fuel flow..
The fuel shutoff solenoid is only used on mechanical C8.3 engines. I guess the ISC & other engines use the computer to control fuel flow..
More.. Quote from Barry & Cindy
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Boy do I know now about this system!!!! :'( :'(
JohnH
Well, I am back home in Austin and had no more loss of power problems. Thanks for the suggestions. I plan to replace the fuel cutoff solenoid although it seemed to be fully open. I could not pull it up anymore than where it was. If I had manually opened the throttle when this occured maybe I would have been able to determine if it was the King Control or the engine. I'm thinking it is the King Control as I still have intermittent cruise.
Intermittent brake light issues will cause intermittent King cruise actions. And maybe King throttle actions? King has one if its wires connected to brake light.
Several years ago I had this intermittent mid or low power situation also. All intermittent conditions are so baffling with the variables involved that could--or could not--be affecting what is happening. (Really pissed off a few Texans on the single lane aerial ramps in Dallas as I chugged along at 23 mph for a time....) Best logical clue I came up with back then was the effect of shutting down and restarting, as this would sometimes make the trouble go away.... After chasing several of the suggestions your have been offered already, I took a close look at the fuel shut off controller on a work bench. A "keeper" ring on the moving rod was jammed inside and would only allow partial opening at times. I fiddled with this, re-seated the ring, cleaned all the parts of rust and corruption, and put it back on. It has worked correctly ever since. I have a new spare I carry with me. Good luck. andy1
I am reviving this topic. Since the first time I had the loss of power it has happened again a couple of times in about 4000 miles of driving. The last 2 times were different in that it occurred while driving. Both times I was able to get it back to normal by pulling off the road, let the engine cool (although it wasn't hot), shut it off and restart. Before shutting it off I did check the fuel solenoid and it was always fully open and I could not push it up or pull it down. The last 2 times were on rolling interstate. I'm thinking that maybe the turbo waste gate may be sticking open after a max power pull up a hill, power reduced on downhill, turbine slows and then on the next hill the turbine cannot provide the boost needed to develop full power. I took off the waste gate actuator and the waste gate lever moves freely. The actuator is made and operates like a miniature air brake can. There is a spring in the can to retract the rod and it is hard to pull out. The actuator is connected to the manifold via a tube and 2 short pieces of rubber hose. I plan to replace the hose just in case it could be collapsing internally trapping pressure in the actuator. Does this sound plausible? I wasn't thinking about the waste gate when I was having the problem, but if it happens again I will check that too. I don't plan on going anywhere until Oct.
Today I thought that I would call the local Cummins dealer here and get a replacement fuel shutoff solenoid just in case that is the problem. I know the replacement is different from the original. I was quoted a price of $377 for that part. Does that sound reasonable? I'm not buying some made in China part off Ebay. Anyone know of a source for genuine Cummins parts at a reasonable price?
Jerry when the Cummins dealer hands you the box it will probably say made in China. Its an unfortunate problem.
Over the years I have had the problem happen to me once or twice. I stop, shut engine off, restart and all is well.
I felt something was in the fuel tank that floated over the pickup and restricted fuel flow. Once you stop and shut engine off what is blocking the pickup drops and lets fuel flow again. I have looked in tank as best as I can but have found nothing in it that I feel could be blocking flow.
Here is a link to a thread from last year when I replaced my solenoid. It has some good photos of the "correct" replacement part. This is exactly the same part that was sold (at that time) by the local Cummins dealer. The prices have probably gone up since then...what hasn't? Do a Google search - you may luck out like I (and several other members) did. Good Luck!
Good Price for Fuel Shutoff Solenoid? (http://www.foreforums.com/index.php?topic=21607.msg161357#msg161357)
When you do get around to replacing the solenoid, you may find there is a slight problem with the throttle cable bracket. Here is a link to a post showing the modification required (at least on my engine) to make it work (scroll down the page to photo of solenoids, and bracket mod):
Fuel System Science Project (http://www.foreforums.com/index.php?topic=21795.msg163522#msg163522)
When it happen to me it turned out to be lift pump. But based on the fuel lines Bern'd replaced I also had serious cracks that were probably sucking air. So I believe it was a combination of fuel line failure and lift pump.
That is a possibility that I have not thought of. Since the tank has baffles it would be impossible see past the nearest baffle.
I will watch for a better price since I am not going anywhere for awhile. It doesn't happen very often, so whatever I do, it may take a long time to know if that fixed it.
Thanks for all the replies.
What condition is the fuel feed line physically in?
If the line has been in place long enough to have been stressed due to a blockage (debris in the tank) for some reason, any place along the entire line, a portion of that line could be collapsing.
Do you have pressure gauges in front and behind the fuel filter manifold assembly??
I've found (you name it) floating in the bottom of fuel cells, including the debris from plastic fuel tanks breaking down.
Shop towels, windshield wipes, plastic wrappers, bugs, bottle caps, etc., etc.. pc
Jerry, check out this amazon listing. Need to know the spacing on your unit but the price is great and I've been using it for over two years with no problems. Also check out Larry's site for a stronger solenoid.
Amazon.com: LarryB's FS20 Dodge Cummins Fuel Shutdown Solenoid with 2-1/2"... (http://www.amazon.com/LarryBs-Cummins-Shutdown-Solenoid-spacing/dp/B00D2C21IW/ref=pd_sim_sbs_263_3?ie=UTF8&refRID=107SKNM6X1GF3D5B4KW1)