TEMP warning while engine is cold, and/or while temp sensor taken out of circuit

[whoisthatguy]

This season, my TEMP sensor has been red for close to 55 miles. It remained on when I also plugged in an alternate TEMP sensor, and when I disconnected the sensor and connected the 2 wires at disconnected connector. All this time, I could not get over 6000 rpm, and the engine ran crappy at maybe 60% power. Then, out of nowhere, the TEMP sensor went out and suddenly I could get full RPM and 100% power. It looks like the CDI reset itself. Can anybody help shed some light on this issue.

 

[summ8rmk]

On the edge chassis, the temp light is also tied into detonation sensor.
If u det, ur power is cut off to save ur engine. Ur sled thought it was saving itself, maybe it was... bad fuel?

Sent it

 

[whoisthatguy]

The choke free play was too tight, for that time period. Then I readjusted it so that it was more than the 1/4" maximum recommended, only a few minutes before the CDI corrected itself. Too tight a choke cut off the air and ran the engine rich, for that time period that the TEMP sensor was stuck on.

 

[BeartoothBaron]

Hmmm, not sure how the choke could make it run hot... If something was shorting the temp sensor, that would indicate hot and most likely bring on the temp light and cause the CDI to go into limp mode. My sled has gotten hot enough a couple times to bring on the light, and it's a drastic change – it really pulls a lot of timing. Not sure what year we're talking about, but '02 and at least some '03s didn't have a Det sensor. I'd suspect shorting somewhere in the wiring, or CDI going bad. The temp sensor should read 2500ohm at room temperature, 190ohm at 212F (+/- 10%), just for one more thing to verify (this is per '02 service manual; not sure if it changed when they added the det sensor).

 

[whoisthatguy]

It is an 04 RMK 800. The choke was apparently kicking on a little bit, even with some freeplay, which was enough to change the gas to air mixture so that the det sensor was activating, and then the retard kicked in on top of that, to make sure the combustion was screwed up. It was also getting oily plugs at the time. The TEMP light came on immediately on cold startup. So the TEMP sensor coming on was not related to the engine temperature. Now that it is fixed, it has so much power that I can barely hold on.

 

[whoisthatguy]

It should be added that the coil turned out to be in some early stage of failure. I replaced it with a new after market coil for $31. TEMP light is still coming on but the engine appears to be developing full power. Will edit further when that is resolved.

 

[whoisthatguy]

Iksnay on the coil being defective. The CDI may have been partially defective but the real problem appears to be the stator. The TEMP light appears to be coming on due to a defective stator. I changed out both the coil and the CDI/ECU/ECM and it not only runs like crap but the headlight dims when I try to give it throttle, and the TEMP light is still on. The headlight should be getting brighter when I give it throttle. Iksnay on the stator causing the TEMP light to be coming on, but a new stator and another used CDI did make the engine start, idle smoothly and hit 6000 rpm in the shop (with belt removed).

 

[whoisthatguy]

After I installed a new stator and took it to the mountains, it still had crap for power and could not get much over 6000 RPM. That new stator did fix the dimming of the headlight when adding throttle. The TEMP light is still always on, even when cold. Multiple coil changes have no effect. Multiple CDI's have no effect. I am trying a couple more options and will get back.

 

[summ8rmk]

6k rpm issue makes me think exhaust valves.
Bellows are probably bad. They are cheap and easy to replace. Any oil leaks around the valves?

Have u tried using some octane booster?

Sent from my SM-G998U using Tapatalk

 

[retiredpop]

Temp sensor light comes on when a ground is applied on the B/W lead on Pin 8 of CDI connector. Check that lead with an ohmmeter to see if you have a ground on it. As noted above if you read the resistance of the sensor itself you should get 2500 ohms at room temp and 190 at 212F.
Does this sled have a TPS sensor on it?

 

[whoisthatguy]

TEMP light always on and motor runs like crap, mystery solved. Replacing Throttle Position Sensor had no effect. Replacing the Temperature sensor on top of the cylinder head had no effect. Replacing the regulator had no effect. Replacing the coil had no effect. Replacing the CDI had no effect. Burning incense and praying to the Snow Gods had no effect. Finally, I replaced the CDI wire harness with a used crappy one that I bought off of EBAY. Voila! TEMP light went out and the engine rapidly throttled up with the authority that it is supposed to.

 

[whoisthatguy]

Temp sensor light comes on when a ground is applied on the B/W lead on Pin 8 of CDI connector. Check that lead with an ohmmeter to see if you have a ground on it. As noted above if you read the resistance of the sensor itself you should get 2500 ohms at room temp and 190 at 212F.
Does this sled have a TPS sensor on it?

You were pretty close to precisely pin pointing the problem. The brown wire from the Water Temp Sensor goes to Pin 7 in the CDI coupling. In performing a resistance test, that brown wire from the water temp sensor plug failed, meaning that there was a break in the wire that probably occurred inside of the plug to the water temp sensor.