M1000 mag side quits pumping fuel

[Reaper]

08 M1000, ported, piped, RKtech head, boondocker box. The sled runs great for a few miles then the mag side cylinder quits fueling and the egt goes cold. As long as I back it down to about 4500 rpm then it will start fueling again but you cant tach it past about 4500 or it quits fueling again.

Out of all the testing I have done this is what I have, I can get the problem to follow the mag side injector lead. If I switch the injector leads then the problem goes to the pto side hole. It does this with or without the boondocker box hooked up. I have ohmed the injector wires to the ecu plug and everything ohms out fine.

Im leaning towards a bad ECU but would like some feedback.

 

[Sledbrain2]

I had a 02 800 with a bad tps that gave a lot of fits until I found the out that was the problem. Mine would run well then hesitate like you hit the kill switch. Dealer can do an easy check on the tps to tell you if its bad.

 

[diggerdown]

Those little wires can break right at the plug, you may need to re-wire the plug or put a different plug on it. Some shops will have the pins and connectors, others want to sell a whole new harness.

 

[Reaper]

If it didn't come and go and if it didn't happen at the same rpm everytime I would think the wires also. Pretty strange deal for sure.

 

[SLEDIOT]

The stock programmer is reading to much outside of the stock parameters for heat, water temp, o2 sensor and exhaust temps. So it cuts the fueling out on magside to protect your motor. My 09 did this when I piped it and put a timbersled intake on. You need to install a fuel pressure regulator on and dial it down to 36-38 psi and your setup will work. I have this same setup on an 09 with the D& pipe system. When I installed the RKT head I just upped my Octane a wee bit with Av gas to compensate. Cheers and good luck

 

[Reaper]

Thats pretty interesting, never heard of that. Would it throw a code? I am running 1 gallon of 110 octane to 4 gallons of premium. Ran this identical setup all last season without any issues. Only thing that was changed is the pistons and rings. EGT's never show a hot condition.

 

[m8magicandmystery]

just because it is reading outside the parimeters does not mean that they are outside the parimeters...its just a brain fart...

 

[Reaper]

Update: The problem now seems to switched to the pto side from the mag side, just tonight I changed out the ECU with no change and I also put in a new exhaust temp sensor with no change at all.

It did let me tach it up one time then it went back to its problem.

I dont have a fuel pressure gauge so I cant check the pressure but it looks like I might have to locate one.

Still open to any suggestions.

 

[SLEDIOT]

What air intake are you running? Is it possible that you have a worn out exhaust donut and you're breathing exhaust into your motor? Cracked pipe?

 

[Reaper]

BDX intake with the shelf, pulls all air from the nose cone. New speedwerx single last season, donuts are as new.

 

[Reaper]

Solved:

Problem ended up being excess fuel/oil in the bottom of the crankcase. I have been over fueling it seems with the boondocker box and the excess would start getting sucked up into the cylinders when I started revving past 4500+.

The temps around here have been in the negatives so I dont know if that had any bearing on it, more than likely was just me running the motor extra rich. So I dropped my numbers by about half and adjusting slowly watching temps.