Fuel shutoff Solenoid C8.3 Cummins

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Fuel shutoff Solenoid C8.3 Cummins

August 31, 2017, 11:33:15 am

Last trip, had some trouble to get the engine to start because the solenoid was not pulling up and opening the fuel shutoff valve. Sometimes it worked okay and sometimes it did not. When it did not, I would leave the ignition key on, walk back, raise the bed, pull up the rod and it would lock in place and then go back and start the engine. It would fire right away and continue running until turned off. Can't believe how much Cummins and others want for that solenoid. Peterbuilt seems to be the lowest at about $375. Larry B has a China knockoff for about $90. Has anyone tried one and if so how long has it lasted? First opportunity, I am taking the old one off and checking if it can be salvaged. I know the boot is torn.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #1 – August 31, 2017, 12:11:10 pm

Quote from: Jerry Whiteaker – August 31, 2017, 11:33:15 am

Last trip, had some trouble to get the engine to start because the solenoid was not pulling up and opening the fuel shutoff valve. Sometimes it worked okay and sometimes it did not. When it did not, I would leave the ignition key on, walk back, raise the bed, pull up the rod and it would lock in place and then go back and start the engine. It would fire right away and continue running until turned off. Can't believe how much Cummins and others want for that solenoid. Peterbuilt seems to be the lowest at about $375. Larry B has a China knockoff for about $90. Has anyone tried one and if so how long has it lasted? First opportunity, I am taking the old one off and checking if it can be salvaged. I know the boot is torn.

Before you replace the fuel solenoid, check to see if you have a 3 or 4 pole constant duty solenoid that feeds to the fuel solenoid. That is at least 50% of the possibility of low voltage to the fuel solenoid.

My previous coach had a 8.3 Cummins, and there was a solenoid mounted on the side wall of the engine compartment that fed to the fuel solenoid. Replacing that constant duty solenoid solved the fuel solenoid issue on my coach.

If you do have a solenoid near the fuel shutoff, some part numbers and sources are here: Zero battery in AM followed by engine quit!! (Defective Solenoid) - Page 4 -...

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #2 – August 31, 2017, 12:23:45 pm

The boot on mine was shot - removed solenoid, cleaned and made new boot from rubber glove finger. Good finger was too small so had to use thumb. More than a year ago and still functioning

Jim

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #3 – August 31, 2017, 12:32:17 pm

Jerry,

I replaced our OEM fuel shutoff solenoid 3 years ago with a "Genuine Cummins Part" that was stamped "Made In China". It has worked perfectly since I installed it. I don't know if you can buy one from any source that is not made in China. Here are links to my threads on the install:

Good Price for Fuel Shutoff Solenoid?

Fuel System Science Project (See reply #16 through Reply #20)

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #4 – August 31, 2017, 01:08:29 pm

I just went through this drill. I cleaned and replaced the boot first with one from Genos garage. It soon failed and I ordered a LarryB but received the flat connector rather than the round connector required. After that I decided to order a cummins part. I had both parts side by side. Yes they are both made in China. But that's where the similarities end in my opinion.

The replacement Cummins part required the installation of a new bracket. It appears to be more substantial and better made than the original it replaced. (See Beamalarm) The low-cost piece, the metal bracket, was definitely better metal quality and machined in a superior manner compared to aftermarket. It is quite pricey. Mine with shipping came to 400 as opposed to 165 for the LarryB super solenoid. But when I had them side by side it was the right choice for me.

I did the entire system as Chuck outlined.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #5 – August 31, 2017, 02:27:31 pm

We did the George & Steph new coil route several years ago and it continues to work great. Larger coil, probably better operation.

The solenoid has two coils, one weak one powered by ignition, and one strong coil powered by aux start solenoid that is only 'on' during engine crank. Strong coil pulls up and weak coil keeps it pulled up.

When our original solenoid failed, we found the coil would open just a little, enough to start & drive about 10 mph. It acted like we had clogged fuel or air filters, so we changed filters, but that did not remedy our problem.

For a temporary fix, from the rear engine door, we manually pushed up solenoid, held it up with cable tie, started & drove. When arrived at destination, cut cable tie to shut off engine. Repeated this for several weeks until the new Cummings solenoid and bracket was installed by us.

The ONLY thing that stops our engine is turning off fuel flow by closing the solenoid by removing ignition power.

We have made a mod to crank engine to build a little oil pressure before starting by delaying the starter from powering the strong coil. We use the mod with every start.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #6 – August 31, 2017, 04:27:29 pm

Barry did you replace the relay at the same time? The relay is part of the kit for the 5.9 and 8.3 in some aftermarket pieces and the diesel boards indicate you should do both. I wasn't sure on this so I haven't done so.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #7 – August 31, 2017, 11:31:04 pm

Not aware of any relay in our fuel shutoff solenoid circuit. As far as I know the electrical circuit is quite simple with ignition power and a wire connection on the Aux Start solenoid post that is connected to starter solenoid.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #8 – September 01, 2017, 06:22:13 am

I had the same problem with my fuel solenoid, the pull in winding would not work and then it would work fine for awhile and then not work. It quit last winter and I got a new one through Amazon and it works great and I think I paid less than $50

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #9 – September 01, 2017, 08:35:47 am

That intermittent problem was ours as well. As I went through the fuel system things would be great with a noticeable improvement and then I would be creeping along at 10 mph until we built up speed and then things would be fine up to 60 or so and then flat line. Since I am a neophyte with these things, I attribute intermittent speed to higher current flow to the coil opening the fuel but still not opening fully.

As I did research on this, I found the primary cause of fuel solonoid failure is a starter that hangs up and damages the coil. This is what apparently happened with mine. My starter hung and I kept the ignition on to long. After I got the starter engaged again the fuel solonoid problem began.

Glad your happy with your part. Long ties have gone into my spare kit along with the rope line for the King.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #10 – September 01, 2017, 12:37:30 pm

I installed a Larry B solenoid on October 31, 2013 and am just now having trouble. actually it could be a wiring problem and will check that out this week. Great price and the folks at Larry B are easy to work with.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #11 – September 05, 2017, 12:25:24 am

I removed the fuel shutoff solenoid today and did some tests with an ohm meter. Appears that the pull up coil has a break in the connection at the solenoid, sometimes makes contact, sometimes not. Also tested it a few times connected to a 12v battery. Found that the armature ( round metal rod ) has very little pull on it from the hold coil, that is until it contacts the top of the solenoid and is held there electromagnetically with enough force to overpower the spring. No way to repair the connection, and due to deteriorated rubber boot, rusty, needs replacing. The rubber boot holds it all together when it is not mounted in place on the engine. Lasted 22 yrs and 104k miles though. Working on getting a replacement. Not a critical item as the shutoff valve can be opened manually, and held open with a wire tie if the hold function is inop, as many members have said. Coach in storage, no rush to fix. Old solenoid was stamped Synchro Start 3919422 with 2.5" spacing for the mounting bolts, and square head valve connection for anyone contemplating replacement using something other than the Cummins Kit with a new mounting bracket and larger solenoid. There is really nothing wrong with the old mounting bracket, it just won't accept the larger solenoid that Cummins has decided to switch too. The connection at the valve arm could have used a bit of lube in the past.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #12 – September 05, 2017, 12:46:26 am

Jerry, does this one look like what you need?
Amazon.com: USAutoElectric SOL22035 Solenoid, Replaces, Yanmar, Cummins,...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #13 – September 05, 2017, 08:38:44 am

Quote from: craneman – September 05, 2017, 12:46:26 am

Jerry, does this one look like what you need?

Don't think that one would work. Photo below shows the original solenoid off our coach, and the genuine Cummins replacement. There are some critical specs that must be met by any replacement solenoid:
1. Wiring connector shape, pin orientation, and number of wires.
2. Mounting bolt spacing.
3. Length of "pull stroke" on the rod.
4. Connecting device on end of rod.

Instead of trying to come up with "something that might work" off eBay or Amazon, I suggest buying the correct part, either from Cummins or a trusted aftermarket supplier. Saving a few dollars on a "bargain" part may later bite one in the posterior.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #14 – September 05, 2017, 10:19:08 am

Re: post 10: it seems that our starting problem has to do with the fuel pump leaking so I'm thinking that the solenoid from Larry B is working fine after four years. It was an easy install...I told my ten-year-old grandson what needed to be done and let him hang over under the bed and do the work. That's what grand kids are for!

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #15 – September 05, 2017, 11:09:38 am

Thanks to everyone who replied. I did some more testing this morning with a 12v battery, and the pull coil worked every time and never let go even with me moving the wires at the solenoid. So maybe the problem is elsewhere as suggested by Dan AC7880. It is an intermittent problem though which makes it hard to tell where the problem is and if you have really fixed it. LarryB does sell new boots and even just the coil. If I can't find a Cummins kit at a decent price I think I will get a complete LarryB solenoid as he seems to be slightly better quality than the real cheap stuff. Can't see paying big bucks for a part that is not going to strand me somewhere if it fails.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #16 – September 05, 2017, 11:17:59 am

Jerry scroll down on Craneman's Amazon site and you will find one with 3919422 part # for $37.28and I'm fairly sure that's
what I used and it worked perfectly. As far as buying OEM I bought thermostats from Cummins and they have only lasted just over 2 years and I'm in ST John's Newfoundland and it doesn't look like I will get new ones until I get to Halifax. The engine is running
cold and the fuel mileage sucks. I would buy them on line but know where to ship them

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #17 – September 10, 2017, 06:08:39 pm

I bought the Larry B's replacement a year ago. Got it because I was upgrading components and the boot on the original was a shambles. When the solenoid came in, it had the incorrect connector. Simply spliced the old connector on and it worked great....till:

On my way to John Day Oregon down the 395 to see the eclipse, my U280 acted like I had a clogged fuel filter. It kept shutting off. So First thing I replaced the filters (it was time anyway). After priming the system, it kept shutting off. Asked the girlfriend to crank while I looked from the back. Saw the solenoid would engage up at start then drop back down. Ok, I know it's the solenoid. Used the zip tie to keep it open until destination. It was a madhouse weekend where nothing could get done, and a very small town, so decided to use the same method to get it back to my Daughters in Longview, WA. I checked the relays and they are all good. Wiring is all good. Will swap the boost solenoid and the Aux start solenoid next just to be sure (they're the same part, right next to each other). If it's the solenoid, I'll contact Larry B's for a warranty replacement (with the right connector).

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #18 – September 10, 2017, 10:13:22 pm

Inside the solenoid is a spring. This spring will break. Sometimes it will work and sometimes it will hang up. When you need it most.......well you know the story. I replaced mine 8 years ago with probly some chinese knockoff but it is still working. If I have problems, no hesitation.....hello China.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #19 – September 10, 2017, 10:47:54 pm

Looks like you diagnosed the fuel shutoff problem. Pulling up with start, indicates the aux start solenoid connection is working ok, and the shutoff pull-up coil is working. Since it falls down after start, it indicates that the shutoff is not getting ignition voltage that is needed to 'keep' it up. Check for voltage at solenoid, maybe using a straight pin thorough the wire insulation for a meter connection. If voltage is present, the shutoff hold up coil may have failed. If no voltage, shutoff is probably ok.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #20 – September 21, 2017, 06:01:17 pm

I have installed a new LarryB solenoid, that I bought from another forum member. It did not have the correct connector as it was for a Dodge truck with a Cummins engine. I spliced my old connector on the new one after verifying that it worked properly. Staggered the splices so that they are not at the same place in case the heat shrink tubing wears through. Not sure that my problem is solved as it was intermittent, but it worked perfectly after the install. The hole spacing 2 1/2 inches is the same as the old one although it is larger (see pictures). I also had to run a 1/4" drill through the square rod end in order to get it on the shut off valve arm even though the hole measured 1/4". In addition I ground off some of the flange on the original mounting bolt heads, for more clearance with the solenoid body. Although it is larger than the original, I have no idea if the pull is greater. If it fails, I will let you know. Could not justify big bucks for an item that would not strand me somewhere if it did fail.

One other thing that I discovered by accident is that the engine will start and run without the solenoid installed. The shut off valve seems to have a spring inside that moves it away from the closed position a little bit. Doubt if it would allow enough fuel through to generate much power in that position.

Re: Fuel shutoff Solenoid C8.3 Cummins

Reply #21 – September 23, 2017, 06:39:21 pm

Update on my fuel solenoid: contacted Larry B's website and let them know mine went awry. Larry called me a day later and asked me questions about all the troubleshooting steps (connectors, ignition solenoid, power at the plug, etc). after confirming I did my homework, he sent a replacement to my daughters, came 2 days later. Installed and no more issues! I have to give Larry B credit, the solenoid was a year old, and warranty is only 3 months, but he corrected the issue immediately. He even sent the one with the correct connector! Great service!

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