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cummins 3.9 engine problem

Started by mark_h, December 25, 2017, 02:29:04 PM

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mark_h

Hi guys- Merry Christmas!
I've enjoyed reading your stuff for awhile and have learned a lot from it.
I have a 2010 puma 409 forwarder(I know, I know) with a cummins 3.9 in it. recently the engine has been dying for no apparent reason. I thought it was contamination in the fuel, or clogged filters, but changed them, went over all that, and the problem has just gotten worse, with the engine not starting now.
on the computer, it reads a fault code of spn# 53, fmi#9, which the folks at cummins say is not a valid error code for a cummins motor.
anyone have any suggestions on what could be wrong, or have any idea what those codes mean? oh, and I also replaced the fuel lift pump. diaphragm pump, no pump in the tank on this.

Skeans1

Are you getting fuel up to the injectors? Or to the injection pump? This is a QSX 3.9 correct? After those are answered I'd look at possibly a crank sensor if it has one then also the cam sensor if it has both it needs them to fire.

mark_h

yeah, fuel is definitely primed to the pump, and also to the injectors. qsx? yeah, I think so, but would honestly need to double check that. thanks for tip on the sensors, I've come to the conclusion it must be something electronic.

starmac

Make sure the fuel solenoid is opening all the way. I have seen on two different cummins where the injectors were getting fuel, but not enough to fire. On both instances the y would produce smoke out of the exhaust pipe leading us to believe something else was the problem.
Old LT40HD, old log truck, old MM forklift, and several huskies.

mark_h

thanks. how do I get to the fuel shutoff solenoid? everything seems so contained in this injector pump, with just a wire harness, and the fuel lines coming to it. where is the crank sensor? would it be on the side of the engine by the flywheel?

mark_h

and it has been smoking out the stack while cranking. however the last time I tried to start it it didn't.

Skeans1

Normally they'll be on the front cover of the engine either side or front
These are 5.9 pictures but should help you out.
https://www.sbmar.com/articles/cummins-marine-engine-position-sensor-locations-qsb-qsc-qsl-qsm/

starmac

Mark, the wires or at least a wire will be going to the fuel solenoid some are just an electric plunger screwed in to the pump, some are a solenoid hooked to a mechanical arm on the fuel shutoff. On the two that I have had the pleasure of dealing with, the one with the arm can be manually held while someone cranks the engine. The electric one that was screwed in had to be pulled out for the engine to crank, then you can just stick your finger in the hole to kill it.
Older bigger cummins had a thumbscrew to turn the solenoid to manual, None of the newer ones has anything like that that I know of.
Old LT40HD, old log truck, old MM forklift, and several huskies.

bushmechanic

I assume that this is a pump/line/nozzle engine and not a common rail. There is a screen on the inlet line supplying the lift pump did you check that? The SPN 53 is a code usually used in Cat for something in the transmission, can't remember now but something about a clutch comes to mind. Can you erase the DTC's and check them again, current codes affecting the engine will chime in immediately. 

mike_belben

If there are any vacuum formed S bend fuel lines, take them off and look inside.  Ive had several cummins oem formed hoses delaminate and jam shut on the suction side.  Altho any hose could do this ive only seen it in cummins 90 elbows.

If it has a mechanical lift pump pull it apart and look for a broken spring.

If there is a fuel heater with a screen inside look for a gelled screen or a burned heater connector thru the plastic thats letting air suck into it.

On dodge trucks ive seen the in-tank fuel strainer bowl screen gel up with algae. 

Pull off all your grounds and file them up.  ECM grounding is critical. Make sure you have a zero volt reading at all grounds and that the resistance from any metal component to ground is single digits.
Praise The Lord

kiko

Yes. Spn 53 fmi 9 is not an engine code.   Double check that code.  From your description you have a tier 2 engine with the vp30 electronic injection pump.  The engines with these pumps can be difficult to start when fuel prime has been lost.  They will make a lot of fuel smoke when cranking but will not start.  A bump of starting fluid will often get it through this "flood".  However you will need to disconnect the two power wires to the grid heater before using the starting fluid to eliminate the risk of an explosion in the intake. use the starting fluid sparingly.   Your problem could have been the supply issue that you have been working on or there could be more issue .  The main engine position sensor is made inside the injection pump itself.  The other is located right below, under the injection pump.  Since the engine is smoking the fuel system, electric system is at least attempting to work. These pumps are notorious for failure.  There are very sensitive to contamination.  I no longer fill the fuel filter before installing , because half of that fuel is unfiltered.  Install the filter dry and crack the supply line to the injection pump and pump fuel until fuel with no air is at the pump. Doing it this way is s pain, but it seems to have greatly extended the life of these pumps on my customers machines.  The most common fuel related code on this engine is spn 1078 fmi 8 fuel pump cannot reach timing demanded by the ECM.

kiko

I just reread your post.  If it is not smoking don't spray it.

mark_h

Bushmechanic, that is correct it is not common rail. I looked for a screen when replacing the lift pump, did not see one, there is an inline fuel filter before it however, and even the old one looked clean. I can't seem to erase those codes, they show whenever the engine is not running, go away if it does start.
Kiko, it is tier 2, yes. I thought someone had called it a vp 44 or something pump? Don't remember for sure. I should mention that whole injection pump was replaced for the previous owner, I'm talking a few hundred hours ago.
We did try some starting fluid, yes. Honestly it did not seem to help at all.

kiko

Diagnosis is difficult from a distance.  Do just going to throw some things out there.   The shaft on the pump are prone prone to break.  Removing the screw cap on the front cover of the engine will give access to to where the pump shaft goes through the timing gear.  Remove that cap and see if you can wiggle the gear around if do the shaft is broken.  Also you can make sure the ecm is powering up by unplugging say the temp sending unit with the key on engine off and see if it generates a new code.  There is a relay for the fuel on off located in the engine harness.  In most cases it is on the right side of the engine toward the flywheel, usually cummins provided excess wire for remote location, some manufacturers just wadded this wire up.  It is just a shielded bosch relay.  Again koeo plug and unplug the relay and see if it clicks.  Vp44 and vp30 are similar, and have the same wiring config.  I have the wiring schematic for this engine but want be near it tomorrow.

kiko

Here is a partial picture or the wiring diagram I had sent one my guys on a road call.  Again never mind it says vp44, all wiring is the same.

 
Maybe hard to see

mark_h

Thanks Kiko. If the pump shaft is broken, could the engine run fine at all rpm for a while than just die, run again, than not start? even an injection pump known to fail lasting only 3-400 hours seems terrible. I will check that gear the next time I go by the machine. it was so cold here today I did not go to work on it today. I will try to check that relay as well. by temp sending unit you mean the coolant temperature sensor for the engine?

kiko

Mark, as I stated earlier it is hard to get the full picture without being at the engine.  So my understanding was that at this point it would no longer start or smoke when cranking.  But if it smokes when cranking and sometimes fires off then the shaft is not broken.   Any sensor will work for the test as all the sensors "report " to the ecm , you could use the boost pressure sensor( MAP. Manifold air pressure) , intake temp, or coolant temp. This test just let's you know that the ecm is powering up.  As soon as you plug chosen sensor back in the code will clear off.   If you get it to run and then it dies out or stalls out immediately remove the fuel filter, if it is not full all the way to the top you have a fuel supply issue.  You have a suction leak or clogged fuel line. Refer to the earlier replies from bushmechanic and Mike_belton as they are spot on as to places you may find your issue. Also I have learned over the years not to assume that a part is good only because it is new.

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