R500 Air temp sensor, crimp or solder?

[Gridgway]

I have continued problems with the wires coming adrift from my air temp sensor. The unit itself has been moved to the collector on the air box to reduce vibration, but still the wires come off. previously they have broken, but this time they came out of the crimped connectors. I am tempted to solder them into some new connectors, but that will surely break again.

 

Any thoughts?

 

Graham

(it runs like a pig with the sensor disconnected!)

[Andrew Dent]

The cure here is to support your new joint and stop the vibration getting at the joint causing fatigue failure. Probably the best way is to support the wire with heat shrink along a length, then another piece over the top connecting the new covered piece to the sensor housing. Let me know if you want some heat shrink. Ive got several km s of the stuff at work of various diameters.

 

Slodering will create a joint with a defined edge and will break unless supported by HS.

 

Andrew

[Gridgway]

thanks Andrew, sounds a good idea. If you have some HS spare that would be brill. Shall we communicate off-line?

 

Graham

[Peter Carmichael]

There is heatshrink in your garage already

 

 

[Chelspeed]

It shouldn't run like a pig with it disconnected. When it comes disconnected the MBE will see a nonsense figure, zero volts. This will equate to either very high or very low degC. It sounds like your MBE is thinking that this is the real temperature and trying to mod the fuelling to this nonsense temp.

 

I assume you have access to the set-up and Caterham havn't password protected it or anything. In the MBE set up there are upper and lower limits and upper and lower default settings. Set the lower limit to the lowest temp you're likely to see, say 0 degC (I could set mine to 20 degC, lower than that and it stays in the garage....) and then set the default to the average or something safe, air temp defaul on mines at 25 degC. When the wires break the sensor says -30 degC, as this is lower than the lower limit it picks the lower default setting of 25 degC and assumes this is what the engine is seeing and adjusts the fuelling to suit.

 

Not setting this sounds like a lazy bit of set up work in whoever did the MBE.

 

 

[Richard Ince]

Running without this connected will make the engine run rich and wash the bores. The cars need a warning light to say this has failed.

[Gridgway]

Unfortunately I don't think we R500 owenrs have access to the MBE system. It is pw protected, although I haven't tried to access it, not having the software.

 

By running like a pig, I mean that tickover is very rough, there is quite a lot of 'puffing' from the TBs when the throttle is blipped and the enigine has noticable vibration mid-range. I understand they run rich in these circs. That would explain symptoms 1 and 2. It is perfectly poss that 3 is something different which caused the breakage in the wires.

 

Peter C, did you notice any of these when you drove?

 

We'll see tomorrow! I'll report back.

 

Graham

[Gridgway]

yep, as soon as I noticed I put it away until fixing it.

Graham