DF250 No Spark

[gc31553]

Hello all,
I have an ‘04 DF250 kicking my butt. The original power head dropped an intake valve at around 400 hours. I purchased a reman power head from an engine builder in south Florida. The first unit I received fired right up, ran for about 30 seconds, and locked up. The builder didn’t tighten a timing gear bolt which backed out and caused some damage. Fast forward a month I received a replacement unit. Now the engine will crank over but not start. Key on I get fuel pumps running. The fuel injectors are definitely firing. Just no spark. I do have a manual and I’ve tested the safety lanyard switch, verified the main relay is powering on, tested the safety neutral switches(in binnacle as well as the 2 located on engine)and that I do have 12v on the grey wire to the ignition coils. I’ve been over it many times to verify I havent left anything unplugged. I purchased an ebay ECM but it doesn’t even power on the fuel pumps(crap shoot I know). The manual I have gives good detail on how to test every component but no real trouble shooting guide on what conditions cause the ecm to not fire the coils. Could the engine locking up with the first reman have caused ecm damage? Is there a safety I’m missing? HELP before I go bald!!! Thanks in advance!!!!

[redlowrey]

All the coil grounds go to a connector on the harness, and one wire will go to the ground lug that bolts to the engine. have a look and see if you have not connected it.

[Plumber1969]

If this a fly by wire model? If so, check your start stop switch.

[gc31553]

Redlowrey,
sorry it has taken a few days to get back to you. I have ohmed all of the grounds to each coil to the block and all check good. I also have 13Vdc between said ground wire and the grey wire with the key on(per the manual) I’ve also purchased another ecm and still no fire. I just do not see anything in the manual that will keep the ecm from firing. It looks like most safety’s cut the injectors …..Still at a loss…..

[redlowrey]

Are you 100% sure that your injectors are working, because with your engine even though the neutral switch is telling the ecu it is in neutral, if the shift position switch is out of adjustment a small amount, it will still crank, but have no spark injectors or high or low fuel pumps, which you said did not work with the other ecu.

Just to see if your engines ecu is capable of doing a self test remove the connector from the crank sensor and and connect up a volt meter on AC and crank the engine note the voltage on the meter and within two revolutions the check engine light should come on with a crank sensor code.

Pull a connector off one of the coils and you will see a gray wire ignition supply, a black wire, ground and a different colored wire that will be the five volt turn on voltage the ecu uses to turn the coil on and off, connect an led test light to ground and probe that wire when some one is cranking the engine, if the ecu is in control it will blink when cranking.

[gc31553]

Red,
I haven’t actually tested the injector signal but plugs are soaked with fuel and if you crank the engine over with it out you get a mist of fuel/air.
I purchased a 3rd(used) ebay ECM but it behaves the same as my orginal(fuel pumps run, injectors fire, but no spark)
I would gladly purchase a new unit but I’m not convinced it is the issue so I hate to spend $1600 and that not be it.
Tested the shift position switch as per 3-61 of the service manual. I am getting 2vdc in neutral position.
Also tested the neutral safety on the engine as well as in the binnacle.
I have ohmed the lanyard switch.
Ive verified power on the dreaded “white wire” all the way to where it lands inside the electronics parts holder.
I have verified with key on I have 13Vdc on ignition coil connector (grey and black)and that I never get the 5vdc “fire” signal when cranking.
I ohmed the CKP per chart on page 3-53 (I get 215 ohm)

Will test it as you suggested this afternoon.

As far as ECM self test, Monday I tried cranking the engine with different combination of CMP and CKP unplugged thinking maybe there was conflicting signals and thought it might run with just one….I never got a buzzer or any check engine lamps….maybe you are on to something here?

[redlowrey]

Mate what book are you getting your info from, a df,150, 175, 2 volts in neutral, df.250, 2.5 neutral,1.3 reverse 3.7 forward. Did you have to fit all your old sensors to the motor or did it come with all the sensors installed.

[gc31553]

The manual I have says 2.3v. I hope the screen shot I attached shows what I am looking at. The meter I’m using rounds to the nearest volt…..

[gc31553]

The long block did not come with any sensors……installed originals

[redlowrey]

When you were cranking it with one sensor disconnected the check engine light should have come on, it might pay to pull the fuel pump fuse so you don't drown it with fuel while cranking over continually.
I would check the cam sensors for operation power signal and ground quick and easy just to make sure they are switching properly. Cam no 1 is the main input but ceck them both.

[gc31553]

Red,
I finally had a day off to check things out more and was able to find the issue. The reman power head they’ve sent me is so far out time it doesn’t even build any compression. I assume the ECM is seeing the conflicting timing signals from cam vs crank and not firing. This engine was supposedly “dyno” tested before it left the shop. This is the SECOND power head that this company has sent me. Now I can’t get any response from them.

I hope this post saves someone else

EVOLUTION MARINE
ANDY CAAMANO
Out of Homosassa Fl.

Stay clear!!!

-David