M7 2007 issues. Dealer can't figure it out.

[crackerjack]

For more than a year I have been having problems with a stock M7. It will run great and then Bog terribly at times. I do think deeper snow is almost always a part of the problem. It has also had some starting problems. Stop it and it has been running fine. Try to start it and nothing. Wait 5 hours while driving home and it starts when you get home. Looked for leaks in the intake. Switched cpu's with another M7 and still had the same problem. Runs great and then bogs to the point of dying. Have other M7's in the group and none of them have the issues with the same snow conditions. Dealer has went through the clutches and now says it must be water int he fuel. I always stabilize the fuel in the winter and have already had the fuel treatment for water in the tank because I thought that might be a problem also. Anyone have any idea's? Thanks for the help in advance.

 

[76FOMOCO]

http://www.snowest.com/forum/showthread.php?t=120066

BTW i don't think cat made an m7 in 2007, only 05.06

 

[rexbergstromconstruction@]

fuel pump or pick up tube in tank, just a thought

 

[crackerjack]

Mine is an 06' M7. sorry about the mistake. Dad and my BP tubes are routed the same, and we swapped brains... Mine was not at all frozen. So I doubt that is it but I can play around with it.
I drained the gas and put water remover in it again, it is in the garage this week where it is warm with the lid off so that should eliminate the water in fuel theory.

It will bog on the flats with a 3/4 full tank which I hope eliminates the fuel pickup issue. It could be a fuel pump but normally it would show wear and act up more and more eventually stopping completely? Don't you think....Keep the ideas coming. thanks

 

[smoothdawg]

Have your dealer do a fuel pressure test. That should eliminate that theory. Do you have spark when it won't start? Check it by pulling one of the plug wires off and plug a spare plug in with the end of the plug resting on the head somewhere and then pull the motor over.

 

[Elkhorn]

it could be electrical, a bad stator, acting up when it gets warm, I have heard of that happening on that motor.

 

[ARICH]

might be a far stretch, but unplug your tail light harness, right about your brake rotor and give it a try, its easy to do and its worth a shot

 

[Elkhorn]

might be a far stretch, but unplug your tail light harness, right about your brake rotor and give it a try, its easy to do and its worth a shot

i forgot about that tail light wire thing, that I know caused a friend of mines problem, check it in the back too, it can get pinched and short out

 

[m1000snowman]

not the stator

if its not the stator try the brake lights thing, how many miles on it,u need a good dealer, the dealer should be able to find it if its the stator hook it up to computer and see

 

[Luke The Drifter]

I remember reading a post on here about a guy who could not for the life of him get his M7's bogging issue figured out. He tried everything and nothing worked. That is until he rerouted the clear tube coming off his ECU to a spot where it wouldn't be in the hot air (I believe he had his routed down around the engine. Apparently it cured his bog and his sled rocked from then on. Something to think about I guess.

 

[crackerjack]

Thanks for the reply's. I will try the tail light and tube routing.

 

[Stanowski]

check the routing of your altitude censer tube, onmy m7 i have having similar problems and could not figure it out for the life of my, the tube comes out of your ecu box and most of the time you see them routed down below the motor, which is fine unitill snow gets in and melts under your motor, the tube then gets the moisture and messes with your ecu cause it to cut out in every which way possible, you want this tube routed up high, hope this helps.

 

[M7rocks]

A friend of mine has a brand new 07 M8 and the sled would just stop, then after a while, 15/20 min you could start it, sometimes it would go on with no other problems, sometimes we pulled it back to the trailer, dealer finally replace the whole wireing harness and PRESTO no more problems, I suppose that there was a break in one of the wires somewhere.

 

[JHG]

I say tail light harness or injector sticking open. My 07 used to have a sticky mag side injector.

 

[barbender]

mine did the same thing for the first year I owned it because of a crappy deals mistake they had pinched the wireing harnes between the balkhead and it would only short out once and a while and of course never in the shop. but had the exact same simptoms. good luck

 

[diggerdown]

Water temp or air temp sensors could be give problems too. They both affect the fuel flow,