We have a rare issue with our Mule 4010 (Year 2010). While running the starter engine we get sparks on both cylinders and the engine starts without any problems. After turning off the starter engine the rear cylinder stops working. With the spark plug outside of the cylinder we can clearly see, there are sparks while the starter engin is running. But directly after turning off the key, the spark of the rear cylinder is missing. We changed the Computer which generates the sparks but it did not help. The picture is still the same.

Any ideas what could cause this problem? How does the computer decides to generate sparks or in which cases he stops generating sparks?
Thank you very much in advance for any suggestions.

Michael

PS: Has posted the same in the Mule-Forum without any reply, trying here.

 

Welcome to KF
Let me make sure that I am understanding correctly.
The key is on, the starter button has been pushed to start, both cylinders spark. But when you release the starter button, you lose the spark from the rear cylinder. You have replaced the ECU and the same issue occurs.
Not knowing the mule sequence of operation or have an electrical schematic, I would look for a grounding issue first. Worn or burnt threw wires kind of thing.
Not much help, but good luck

 

Thank you Dragone#19 for your reply!

You understood me correctly. The problem is exactly as described.
We checked the cables and optically was anything fine. We also checked that there are no short circuits in the spark giving cables. They are working fine, because we have the sparks.
Sorry that I have to ask again.Grounding problem means there is a grounding where it shouldn't be or do you think about a missing grounding, of an ECU input for example. Where should we look for grounding problems. Any suggestions.
What is fascinating that the problem only exists on one of the cylinders and all cylinder specific cables are well.

Thank you again
Michael

 

ok, check the molex connection for I think White for #2 ignition coil. (The online electrical diagram photo is horrible.) Check for a loose pin in the connector that the ignition coil wires plug into. blk/y from ign coil 1, white for ign coil 2 look like grounds for the coils. If you have a bad connection on white at the molex connector or on the ign coil, then the coil is unable to function to make a complete circuit. Hopefully you get the gist of my thinking so far. (This was my grounding question in my last post and what I think may be happening)

Do you have voltage going to the ignition coil after the starter button has been released? Yellow/white looks like power in for both ignition coils from the molex connector and look spliced together downstream of the molex connector. Unless it is loose on ign 2, I am not suspecting power in issues.

Check for loose connections, ie loose molex pins and adding electrical grease in the molex connectors help out.

Again, good luck

 

add on for clarification:

Molex connector = the plastic quick connect harness tabs.

 

If the connections are good and with proper voltage, then I would suspect a bad ign coil.

 

Thank you again Dragone#19 for your reply!

I will try to check it until Friday. While further searching in Internet yesterday I found and bought the maintenance manual, May be it helps. I has not read anything yet.

Saludos
Michael