Plastic Swiss Cheese and Limp Mode

[ProspectorJim]

So I became a member of the Limp Home Mode club the other day and have some questions. Do I have to take my ds450 back to the dealer, since it went into limp mode? My fan isn't kicking on, so what part would be causing this? Could it be the coolant Temperature sensor going bad?


I also want to cut some holes in the plastic to let the heat out. Post up some pics of your swiss cheese plastic!

[TNT]

Probably the fan relay went out; it’s up front high with the fuel pump and ECU relays, three in a row. The two outers swap or buy one it’s a good idea to carry an xtra if it won’t start(fuel) or fan won’t work first thing to check by replacing relays they are cheap! Next check the fan motor by continuity there. See if this fan does not solve your limp prob. Once you operate below the limp temp it should go off.

I took a ¾ wood drill bit and the area common to the tank cut horizontal rows of holes as many as possible.

[florentino]

Originally posted by ProspectorJim
So I became a member of the Limp Home Mode club the other day and have some questions. Do I have to take my ds450 back to the dealer, since it went into limp mode? My fan isn't kicking on, so what part would be causing this? Could it be the coolant Temperature sensor going bad?


I also want to cut some holes in the plastic to let the heat out. Post up some pics of your swiss cheese plastic!

i keep my fan always on .. and it worked for me i also put engine ice,

[ds450racer]

Check your fan relay as everyone else has said.
Ill post a pic of how i cut my plastics aswell.
Also the main way to stop limp mode is by making sure you get plenty of air to the rad while keeping it as clear as possible. Once you get mud in the radiator and the air stops flowing thats when the sensor will kick in. Try and get hold of a louver kit as this will cure the problem or if you cant get one ill post up another pic of what i did on my 08 bikes.

[ds450racer]

.

[ds450racer]

:D

[TNT]

Hows that working for ya the screen looks nice? Good job! I always said all ya need is a mesh screen like that. :D

How are you guy's wiring the fan always on?

[rooster300ex]

what is limp mode?????? Does the quad start limping lol:D j/k

[TNT]

Originally posted by rooster300ex
what is limp mode?????? Does the quad start limping lol:D j/k

Don’t know what they were thinking when they came up with the name but “limp home mode" is a protective circuit between the ECU and it’s sensor(s) that at specified overheat temp certain engine functions are limited resulting in a loss of power. Reason is to protect the engine in such a manner from blowing a head gasket, or ruining a head, or other expensive critical engine components that would prevent the quad from functioning at all. Limp mode gives the recreational rider the ability to return back to camp or their truck, but was never intended for extreme racing conditions. There are other protective features on the DS that protect over charging the battery and/or magneto.

It’s a nice feature on a quad but can be dangerous to extreme racers that run in high heat and humidity…… It can be removed most that run in these conditions remove it.

[ProspectorJim]

Could someone tell me what the part # for the fan relay is? When I called the dealer, they said there isn't one, which I know is wrong.

[ProspectorJim]

Originally posted by TNT
Probably the fan relay went out; it’s up front high with the fuel pump and ECU relays, three in a row. The two outers swap or buy one it’s a good idea to carry an xtra if it won’t start(fuel) or fan won’t work first thing to check by replacing relays they are cheap! Next check the fan motor by continuity there. See if this fan does not solve your limp prob. Once you operate below the limp temp it should go off.

I took a ¾ wood drill bit and the area common to the tank cut horizontal rows of holes as many as possible.

Found out today that it is definately not the Fan relay after I pressure washed my bike. It was starting hard and as soon as I got it started, the fan kicked on and it went into limp mode. My dad(car mechanic) told me that its probably the coolant Temperature sensor(The gray plug with two wires coming out of it, that plugs into the right side of the engine.). Does this sound right?

[TNT]

Originally posted by ProspectorJim
Found out today that it is definately not the Fan relay after I pressure washed my bike. It was starting hard and as soon as I got it started, the fan kicked on and it went into limp mode. My dad(car mechanic) told me that its probably the coolant Temperature sensor(The gray plug with two wires coming out of it, that plugs into the right side of the engine.). Does this sound right?

We finally got ours running(I'm not ready to put out dyno results yet till it's fullly tuned) but my boy said same thing it was starting hard to a point it drains the battery but we think it's the cam decompression he said but yours does sound like the CTS or an air temp sensor. If you had BUDDS you could be sure before you bought the part. Yeah it comes out of the case.

[TNT]

have your dad pull it and do a resistance check on it, one way to find out quick if that is it.