Massimo msu 400efi intermittent problem

[Samuel Girten]

So I have a msu400 efi. Ran fine, pulled it into the shop to do my typical routine maintenance, cleaned air filter, change oil, etc. 

So now it won't run right. Starts and idles, stumbles on acceleration. If I baby it I can get it moving, but dies after a few hundred feet and then is hard to start. Will start back and idle just fine as long as you don't rev it up. 

So what I've done so far.

Verified fuel pressure at injector, never losing it. (54psi)

replaced fuel injector. Verified spark right after dying (sparking like hell)

checked valves. ( Proper clearance) replaced map sensor, idle control sensor, and tps. (No change)

disconnected negative battery cable for 20mins (no change)

checked exhaust, (free and clear) 

Checked air filter again and intake tube (all good)

After it dies or if I just let it sit before starting it, it throws code 113, which I've seen is IAT voltage too high or open circuit. I have a 4 wire sensor and am not sure the wiring back to the ecm nor can find a good diagram. Not even sure if this is a problem or just a code it would throw if it is just not running. 

Any help would be appreciated 

[Samuel Girten]

I've checked all connectors, can't find anything loose

[T-boss 410]

Any water get into any electrical or electronic components?

[Samuel Girten]

No, high and dry in the shop

[Samuel Girten]

I rechecked all of my connections again today, cant find anything suspect. 

 

[TapBoss]

Same oil filter used as replacement?  

[Samuel Girten]

Yep. 

[TapBoss]

What else was done besides air filter and oil change?

[Samuel Girten]

Nothing other than changed headlights that were out and changed winch controller. 

[TapBoss]

Still betting on a loose connection somewhere then, not much room to work on these things. 

[Samuel Girten]

Where would you think? I've checked all connections on motor sensors, fuel pump, coil, neutral switch, o2 sensor, ecm fuse box, and a couple on main harness going back to ecm and fuse box.

[TapBoss]

Ground wire? Not sure where it is on your model.

[ElbowRoom]

My bet is also on loose or corroded ground. Why did you change both headlights? Did both go out at the same time? That's unlikely. This again sounds like possible loose connection or ground.

[Samuel Girten]

No one went out last year, bought a set of 2 new LEDs and just changed both. 

[kenfain]

I'd take another look at the IAT sensor, for a bad connection. It really sounds like it was knocked loose or damaged somehow. 

[motojoe]

It sounds like your "Low Oil" switch is not working right and is sending a message to the ECU that it is low on oil.  Check all the connections especially the one that connects to the oil sending unit.