Help*Needed (from down under)

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Oct 3, 2012 | 07:48 PM

lou69

Thread Starter

Intermediate

Joined: May 2012

Posts: 46

Likes: 0

From: melbourne Victoria

Help*Needed (from down under)

HI there all
i own a 69 350/300 auto400, and recently replaced the engine harness prior to this the temp gauge used to go past 210 and then drop back down between 100 and 210 and stay there all day long.
after the loom change (and i know the temp sender is not in the loom) but now i start the car and the temp gauge just gets past 100.
i have taken 2 photos of the gauge reading and a temp gun (in Celsius)
i took the reading off the thermostat.
please take a look and pass any comments.
sorry about the links (photo bucket issues)
Regards
Lou

http://i963.photobucket.com/albums/a...ette/photo.jpg
http://i963.photobucket.com/albums/a...tte/photo1.jpg

Oct 3, 2012 | 10:37 PM

Aussie79

Racer

Joined: Mar 2002

Posts: 406

Likes: 1

From: Maroochydore QLD

I'll have a go at this seeing as no one "up over" wants to respond.

My guess is that the new loom has introduced less resistance or impedence in the circuit somewhere. The temp guage works by sending a 12V signal to the sensor and the sensor provides resistance based on temperature, you may need to add a resister in to the circuit to callibrate the guage, it will be hard to know what resistance would be required. My guess is that it is still working just not reading correctly, you could just live with it as long as the temperature rises so does the guage indicating an overheat problem. One simple test would be to pull the sensor and leave it connected, then submerge it is a pot of boiling water and see if the guage rises with the ignition on, if it does then its working fine but telling you porky's about the actual temp, this would also give you an indication of where 100c would be on the newly incorrectly callibrated guage.

Cheers, Dennis.

Oct 3, 2012 | 10:47 PM

lou69

Thread Starter

Intermediate

Joined: May 2012

Posts: 46

Likes: 0

From: melbourne Victoria

Thanks Aussie79
i was thinking that the new loom may have contributed to the lower reading.

do you think if i bought a new gauge it will give a better reading?
(i disconnected the green wire from the sender and grounded, and the gauge flicked from left to right)

cheers
Lou

Oct 4, 2012 | 07:15 AM

azza2u

Racer

Joined: Nov 2010

Posts: 310

Likes: 25

From: Brisbane Australia

Oddly my 68 with its original loom has the same issue with a new sender. I'm goung to be modifying the resistance at the sender to dial it in correctly.