mcx 240 troubleshooting help.. too much fuel

[djones000buck]

Hey guys.. getting fault code 84 for the TORS.. So I bypassed the switch and cleared the code. Not getting the code anymore so it's bypassed properly, I also double checked the TPS, which checks out through diag..

However, sled is still running stupid rich.. 8 gallons in 30 miles coming back to truck, no boost leaks or vacuum leaks, gauge holds pressure at even throttle pressure, is there anyway to verify whether the mcx injectors are overfuelling?

Sled runs ****ty at idle/low speeds, runs good at midrange (with the exception of still getting too much fuel) and cant run WOT either, sort of stumped and got 3 more days of riding planned..

Any help appreciated

 

[Zipperno]

Try to unhook the mcx injectors and see if the stock fuel system works. If that clears the ****ty idle/low speeds you know its the mcx stuff thats the problem...

 

[Thistledoo]

crimp the fuel line going to the secondary inj will rule out a dribbler

 

[djones000buck]

thanks for the response, would i just unhook the wires at the mcx control box, or where is best to unhook the mcx injectors, didn't bring my install book

 

[djones000buck]

ok thanks I will go give'r a try

 

[Zipperno]

thanks for the response, would i just unhook the wires at the mcx control box, or where is best to unhook the mcx injectors, didn't bring my install book

Thistledoos suggestions is probably the beste way. Just crimp fuel to the mcx injectors.

There has been some issues withc mcx injectors.

 

[ROBERTSONYAMAHA]

It is most likely bad injectors. What Brendon said will work or just pull the injector rail out of the plenum and turn the key on and get ready to start cleaning up fuel. We used to get bad injectors every now and then, been a bit more frequent lately, hopefully it was just a fluke or bad batch. How new is your sled? - Cody

 

[djones000buck]

update:

got the fuel line unhooked from the mcx injector rail, but due to the massive amounts of fuel this thing was getting, it's loaded up, she fires once, stalls, fires again, stalls, so i'm going to run to the station quick and let it set for a half our, grab some ether to try to help dry it out...

thanks for all the help, I'll update here in a little bit

 

[djones000buck]

quick one before I take off for a bit, if I pull out the injector rail with the via the two hex screws, and crank it over with the injectors out and they are spraying, that tells us the injectors are bad? My thinking was the kit wouldn't compensate additional fuel until say over 9 pounds of boost..?

As a sidenote I ran diagnostics on the TPS also, which had a high range value of 90 and low range value of 16, which appeared correct, just wondering if it could still be an issue

talk to yas in a bit...

 

[Thistledoo]

do you have the electric pump that turns on with the key? Or using stock pump in tank?

Usually the injector sticks shut or wide open from what I have seen. If its wide open then it will flood the engine fast and youll never get it started. If you flooded it u may have to pull plugs and clean it out. Once you get it running try and let it warm up good so its not in warm up rich mode.

 

[julio]

bad injectors

if you lost an injector check the oil for fuel. they will put so much into the cylinder that it contaminates the oil.

 

[djones000buck]

Got the mcx injectors out with the fuel rail, cycle the key on and off and don't have any fuel squirting out. I am assuming the injectors would be ok then? Pulled all the plugs and as suspected they are black as can be. Compression tests good.. any next thoughts?

 

[julio]

too much fuel

check the stock injectors, but I think those should spray a little when you turn the key on then stop. I have heard of the stock ones getting messed up as well..
another thought, did you check the mcx injectors with all the electrical hooked up? just to make sure the box is not malfunctioning.. julio

 

[djones000buck]

Well guys, finally tracked it down last night.. Ground from the MCX computer broke (chaffed against the aluminum subframe...) We are back in action...

Can anybody explain what happens with the MCX computer electrically such that when the ground wire is disconnected or broke, the stock fuel system overfuels? Is that a safety mechanism to keep the sled from leaning out under boost?

thanks again for all the input...