Having a problem with fuel. MCI102A3 with Series 50 DD.
Bus died on the way home from the garage after the oil cooler repair. Restarted with difficulty. Finally run well. Got another mile or so and died again. Wouldn't start. Bypassed fuel filter, DD 382 (plastic bowl on topside). Started and ran fine. Good power. So back to garage, heated (local temps in the teens), to figure out the problem. Several calls to knowledgeable people for confirmation of trouble shooting method. Confirmed that line from tank to filter inlet was clear. Pressurised tank and fuel sprayed into can. Not the first time the filter unit has caused trouble. So found a bracket for a Cummins dual spin on filter. Plumbed in place. Filled filters with diesel. Started engine. Ran for a bit then appeared to pickup fuel from the tank. Then the engine quit. Wouldn't restart.
Pulled filter inlet line from tank connection and placed into a bucket of fuel. That would prove or eliminate the fuel tank and line. No start after four 30 second cranks
Pulled fuel return line to check for fuel when cranking engine. No fuel return.
Plumbed fuel pump suction to fuel bucket at or above fuel pump. Many cranking sessions and no fuel from return line and no engine start.
I say bad fuel pump.
Your thoughts would be appreciated.
I can say I am somewhat frustrated as the weather here is snow,lots of snow, and cold for the next few days. >:(
Happy New Year ;D
How about plumbing an electric fuel pump to bypass the OE pump. That would tell you your OE pump is bad if it runs that way.
JC
I'm assuming that your fuel system is set up the same as a two stroke. If it isn't then ignore the following.
Don't assume right away that the mechanical engine pump is bad, these things last forever.
Since these engines use suction pumps an air leak in the tank to primary filter line will result in no or poor fuel delivery. This won't show as a fuel leak because the line is sucking in air.
As lost says, use an electric pump at the tank or from a small can of fuel. If there is a leak in the tank to primary filter fuel will spray or leak out and the problem is solved. This saves a lot of engine cranking and expensive starters. This should fill the fuel filters also.
It doesn't take much of a leak to fill the line with air. These leaks are also easy to plug because they are sucking in air and the mechanical fuel pump is pretty low pressure. The only high pressure is at the injectors.
There is also a check valve at the primary inlet. If this leaks the fuel will drain back into the tank via the supply line and will give the same symptoms as a supply line air leak.
These are two of the most common causes of your type problem.
If this doesn't work we can go from there.
it is also possible that there was some air in the system and if it got to the pump it could cavitate the pump. if that happens it will never pickup fuel. I put an electric pump with a shut off valve in mine to prime the entire system. after replacing all the hoses and filters I flipped on the pump, primed it, shut off the pump and valve and the engine fired up and never missed a beat.
just my .02
Not being a smarty pants, but confirm you are getting it primed before worrying about anything else.
An electric rig for future install would be nice, a garden sprayer will work right now, if you have one. Make up some fittings ate get the fuel to come through with that and then do your trouble shooting to find the air leak
happy coaching!
buswarrior
Removed
Update:
Broke everything down into sections and confirmed that suction line was clear and not leaking.
Used a bucket of fuel and got engine to fire, But it took a while to fill the engine and get return flow.
Replaced DD 382 filter unit with a Cummins dual spin on filter bracket.
Filled cartridges and started engine. And then it died, no fuel. And very little return flow. Cranked maybe 6 times at about 30 seconds per crank to get engine running again. Shouldn't have been that long because I had pushed fuel through the suction line with air from the tank. Suspected pump.
Installed new pump. Filled first spin on with fuel. Proved suction line clear again. Both into tank and to bulkhead fitting in the engine room.
Started engine. Started quickly. Finally sputtered and died with no fuel. Cranked starter and engine started to sputter at about 10 secs and running before 20 secs. Much different than the previous dry line start.
Final resolution: 1)apparently an air leak or internal check valve problem in the DD 382 filter. According to local DD shop supervisor not an uncommon problem. 2) Pump wasn't broke just worn out. And the fiber joining piece, pump drive to engine drive adapter, came out in three pieces. So changing out the pump was a good decision. However, I didn't confirm with pressure testing the worn out pump so there is no empirical evidence. The quicker than previous start with a dry line is fairly convincing of a worn pump.
Engine was built in 1994 and had the original pump.
Thanks guys for your ideas.
Bill