won't start - was getting crankier each time

druidwood · 09-20-2018, 02:39 PM

Hi. My engine (1991 bluebird, cummins 5.9) will not start. It cranks strong, but no smoke from exhaust. All safety locks were removed long ago, brand new and charged batteries, 1/2 tank of fuel, no obvious kinks or leaks, pre-filter looks good when drained some, fuel filter put in maybe 200 miles ago and it is full and looks clean. Pumped manual lift pump with a stick from above and I can clearly hear a sound which sounds like fuel, not air. Does this mean the lift pump is not the culprit?

There is a giant spring under fuel lifter with completely rotten rubber boot - think this is just the governor, so shouldn't have anything to do with starting? Other ideas? Bus has only been driven once in 2 years, but started regularly. However it has been getting harder and harder to start each time. Once started it runs just fine, but due to having it not road ready haven't been able to test under load.

Would gladly hire a mobile diesel mechanic, but they won't bother unless you have a fleet and my build is not in a good place for getting it towed so trying to figure this out myself. Appreciate any info.

BlackJohn · 09-20-2018, 07:17 PM

Quite a few things come to mind re your no start.
So, no smoke is no fuel right, if it is cranking fine?

Why would that be....stale fuel from sitting, algae growth, the pump, etc?
New filter 200 miles ago, might be plugged depending on the length of sit time.

Do you have a grid heater or glow plugs?
Clean and tighten all connections and bring those batteries up to full charge again while you check out things.

John

Marceps · 09-20-2018, 09:22 PM

Do not rule out the battery.

druidwood · 09-20-2018, 09:23 PM

No sign of algae or debris in pre-filter, looked clean. Opened top of fuel filter and was full and looked clean. Priming fuel lift makes nice "pshhh" noise of gas being expelled. Bus has grid heater. Batteries get a charge after each attempt at starting, crank is good and strong, but no exhaust, so gas not getting through or possible solenoid or such is not working. Think gas is getting through low pressure system, so sort of wondering about solenoid at this point (that might be wrong but it is listed near the top on Cummins check list). Connections on it looked clean, honestly couldn't see anything obviously wrong anywhere from looking above and below.

MIGHT have found a mobile mechanic, but last one cancelled after boss heard it was a bus, guess it is a pain to access, but then they are getting $110 an hour.

On the positive side after studying so many schematics I now have a much better idea how diesels work. I think if mechanic doesn't come through I will try testing the solenoid - out of my depth but would be worth a shot. I assume if priming lift pump emits gas, that it works? Engine really shakes on cranking so think it is ready to go if it just got gas, or properly pressurized gas. Once I get it started it runs great, just taking more cranks each time to get it to start.

druidwood · 09-20-2018, 09:28 PM

Heh Marceps. I do have new batteries, added them one at a time so I wouldn't mix leads. I also tried starting with AC charger on 50 amps and no go. Crank is strong but no smoke and no smell of diesel. I was pumping the gas pedal like crazy until I read that is bad for diesels as you need to let the oil circulate before raising the rpms.

Of course anything is possible.

cycle61 · 09-20-2018, 10:43 PM

It sounds like a fuel issue for sure, is there an electric solenoid valve after the lift pump that could be sticking or burned up?

Edit: Just saw you're in Gold Bar. I've got a coworker up there, and I pass through frequently. Small world.

BlackJohn · 09-21-2018, 05:51 AM

Ok, on diesels there is no gas so fuel is the terminology to get used to using.

Solenoid it could be, an easy test. Usually you can hear it energize too as they are loud like a bang or knock.

Grid heater ..does it get hot? You should be able to hardly hold your hand on the steel in the area of it. Do not use ether with a grid heater.
Can you check the power on the grid relay? One side of the larger cables is always hot to ground, 12v. The smaller wires on the coil should come alive with the key on in the heating mode before startup. If not then time to trace them back and see why no power. 12v directly to that relay will prove the relay and the grid heater.

Time to bleed some air from the lines. Crack open the fuel line fittings that are in the system and work towards the engine block from the earliest filter, pump, etc.

You can do this and save your money, patience is key.
A great lesson for you here. Likely not the last time bus will not start so def a learning experience. Enjoy!

New batteries do not necessarily mean fully charged. Get a hydrometer and check the specific gravity of the cells.

John

druidwood · 09-21-2018, 11:31 AM

So my knowledge (what little there is) comes from the Cummins quickserve site diagrams.
There is a clicking in the control panel when I turn the key (assume box type solenoid working?). So is it the electric fuel shut off solenoid you are referring to? I will have to look harder as I can't see it where shown in this picture.

Screaming park and low brake pressure alarms makes listening very hard.

UPDATE: OK, I believe this is what you are both referring to (see new picture). I found a video which shows spring as part of solenoid so think replacing this would be a good start.

druidwood · 09-21-2018, 01:47 PM

So did not have the right tools to get into the bolts holding the fuel shutoff solenoid, so tried pushing the piston in and out and it moved freely, then pushed it all the way in. Just on the off chance that it did something I started her. Started right away and died 3 times, then rough and now fine. I could have introduced air when I opened the fuel filter.

Guess without the boot that gunk has gotten into the little piston so will endeavor to borrow tools to get it out and replace it, or perhaps just a cleaning and new boot. Thank you for help. Youtube videos also helped me see how to remove this, once I knew what "this" was.

druidwood · 09-21-2018, 03:53 PM

Spoke too soon. Won't start again and this time plunger valve doesn't want to stay compressed but pops back out.

BlackJohn · 09-21-2018, 04:12 PM

If you are going to own a bus you need tools, not borrowed tools.
So things work manually kind of but issue still exists.

Others with that setup can take you through it. Take the solenoid off, clean and check it if you happen to know how. I am not certain of its operation and design, so...
Run it and warm it up good and burn off some of the sitting fuel. That's why these love to run steadily so they don't gum up and strand you without warning. Could happen anywhere with no warning so you have to know what to do.

Get to know where things are on that engine. Each engine is a different beast and without knowing engine compartment layout, you can't troubleshoot. They don't work cheap and many are on here so hope you hear from some.

John

druidwood · 09-21-2018, 05:38 PM

Yup, ordered some 3/8 drive sockets (metric) and some elbow joints and extensions to get into these tight spots. Got engine to start again - I did several things but I think unplugging fuel solenoid reset it or something. Ran smooth this time and I took it for a spin down the driveway and back. Anyway happy to have bus moved so I can work on getting stove pipe and vents in. Will get part off and hope replacing it does the trick. Certainly seems to be the culprit.

Thanks again John for your help.

BlackJohn · 09-21-2018, 07:23 PM

This I think, is how the fuel solenoid works on your bus and other Cummins engines.
Glad you are winning, learning and knowing your bus.

John

Mekanic · 09-21-2018, 08:33 PM

You could Totally replace that shutoff solenoid with a pull cable and fix it for good. Put the cable handle in a somewhat hidden place and it can even be a anti theft device.

You would have a diesel that requires NO electric to run at all.

Elliot Naess · 09-26-2018, 03:38 PM

What Mekanic said.

I tossed Millicent's solenoid and its "timing relay" (or whatever it is called) and installed a simple push-pull cable.

For one thing, the solenoid often fails.

Also, the solenoid is controlled by a small relay hidden somewhere and it also commonly fails.
(That relay has a timer in it, so the solenoid receives full voltage to kick in, and then lower voltage to keep it engaged the rest of the time. Full voltage all the time would burn out the solenoid.)

You simply install an old-fashioned manual choke type push-pull cable to the lever that the solenoid operates (on the injection pump), and sneak that cable out to a spot you can reach from the driver seat.

Mekanic · 09-26-2018, 05:20 PM

I should also have mentioned this:
Going the pull cable route does bypass one thing. On anything with a Cummins i have seen They always have a oil pressure, coolant overheat temp, and coolant level sensors that will shut down the engine If you ignore the red light and chime for 30 seconds.

I think the red light and chime will still work if you go the cable route.

Shawna · 09-26-2018, 10:48 PM

Seems theres a safety switch that prevents the bus from starting no matter if the alarm or something to do w the door possibly being open.wish I knew how to tell you but that was a problem for me when I first got mine w a new battery and all!

druidwood · 09-26-2018, 10:56 PM

Think this is the problem. New part from Hong Kong for tractor which hopefully will do the trick as part # matches

Tango · 09-28-2018, 10:41 AM

Tossed my solenoid and replaced with a push/pull rod thru the dash. They are among the most common issues on Cummins. Lose it.

And don'r forget to address the KDP (Killer Dowel Pin) issue.

druidwood · 10-04-2018, 01:52 PM

So what a relief, the bus now starts. Linkage on tractor fuel shutoff solenoid (exact model that was in bus) was different as was thread size but got it to go together. Didn't work. Gave it a day and thought perhaps spring isn't depressing enough as old linkage is too long with new part, tested that and it was the issue. So one more time reaching my arms into the tiny, dirty, dark and tight spot to remove/replace part again. I am NO mechanic so glad the fix was something I could figure out. The mechanic bypass solution which others have mentioned is good to know and glad I understand what all that linkage is about.

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