Sender for AC temperature gauge
Discussion
I'm getting fed up with looking at a temp gauge reading about 120° when I know it's about 30° lower. I know the problem is that I have a Ford sender and an AC gauge. I've been told that I need a Vauxhall sended but can't remember which one.
It isn't an easy swap because the motor has been changed at some point so the sender hole on the manifold is sized for the Ford unit. This means that, potentially, to fix this problem I'll need to take the manifold off and have it machined to suit the correct sender.
Apart from putting a resistor in line to make it read corectly at/about the working temp does anyone have a clever fix?
It isn't an easy swap because the motor has been changed at some point so the sender hole on the manifold is sized for the Ford unit. This means that, potentially, to fix this problem I'll need to take the manifold off and have it machined to suit the correct sender.
Apart from putting a resistor in line to make it read corectly at/about the working temp does anyone have a clever fix?
Adrian@ said:
Thats the one. TVR were using it for several years before Vauxhall invented it.
Bought and installed sender... turn on ignition & gauge reads just below 40° (i.e. barely moves). Ran engine up to point where Kenlow cuts in..... temp gauge reads just over 40° .....
Putting a multimeter across the unit it has a resistance of about 70 ohms (cold), the one I took out (which over reads) is about 700 ohms cold. Nigel, any chance you could check your's? At least then I'd know if the unit is U/S or if it's the wrong one. I'm assuming TVR didn't put any clever resistance wire in the circuit, because I didn't when I re-wired it.
P.
Putting a multimeter across the unit it has a resistance of about 70 ohms (cold), the one I took out (which over reads) is about 700 ohms cold. Nigel, any chance you could check your's? At least then I'd know if the unit is U/S or if it's the wrong one. I'm assuming TVR didn't put any clever resistance wire in the circuit, because I didn't when I re-wired it.
P.
If anyone comes up with a part# or a specific year make and model of the car that uses an equivalent resistance range for its temp sender I would really like to know. I can't go pick up a used one; but, maybe I could find a way to order a new replacement. (My gauge is not accurate either because of the incorrect sender.)
Jim
'71 Vixen
Jim
'71 Vixen
All,
With a saucepan of hot water, a thermometer and a multimeter I calibrated the sender (giving a graph of Temp vs resistance) then with a potentiometer (variable resistor) I calibrated the gauge (again temp vs resistance). As I suspected the two are miles different but, but putting a 180 ohm resistor in parallel with the sender (using R=1/((1/R1)+(1/R2)) to calculate the value needed) I got a good match (on paper) of the two curves. Have wired this in at the gauge and it seems to be giving sensible readings now.
Incidentally, when I took the gauge out to do this I noticed that the gauge is marked as 24V and the power side is fed by a length of resistor wire, is this normal?
Phil
With a saucepan of hot water, a thermometer and a multimeter I calibrated the sender (giving a graph of Temp vs resistance) then with a potentiometer (variable resistor) I calibrated the gauge (again temp vs resistance). As I suspected the two are miles different but, but putting a 180 ohm resistor in parallel with the sender (using R=1/((1/R1)+(1/R2)) to calculate the value needed) I got a good match (on paper) of the two curves. Have wired this in at the gauge and it seems to be giving sensible readings now.
Incidentally, when I took the gauge out to do this I noticed that the gauge is marked as 24V and the power side is fed by a length of resistor wire, is this normal?
Phil
I have been recommended to resurrect this somewhat old topic in an attempt to obtain some guidance / information on the following:- I have been running a Vixen S2 for 15 yrs during which it has always had full AC instrumentation and an alternator. The AC temp gauge always soon gets to 200+ and stays there, without boiling so far. Its definitely got an AC sender. I have been advised that the gauge is probably reading high due to a combination of the alternator and AC instrumentation. Has anyone out there managed to overcome this problem and is successfully running AC gauge and sender on an alternator equipped 1600 crossflow?
Doug
Doug
dmilsted said:
I have been recommended to resurrect this somewhat old topic in an attempt to obtain some guidance / information on the following:- I have been running a Vixen S2 for 15 yrs during which it has always had full AC instrumentation and an alternator. The AC temp gauge always soon gets to 200+ and stays there, without boiling so far. Its definitely got an AC sender. I have been advised that the gauge is probably reading high due to a combination of the alternator and AC instrumentation. Has anyone out there managed to overcome this problem and is successfully running AC gauge and sender on an alternator equipped 1600 crossflow?
Doug
I cant help except to say WOW your 1st post in nearly 13 years as a pistonheads member !! Doug
Adrian@ said:
Andy are you still running the RB340 unit to allow you to do this? If so can I do a comparison to what I have to convert please.
before I send it on to Doug.
Adrian@
Doug, I have found my wiring diagram that shows the conversion with the alternator and RB340 unit in place since we spoke. I will forward it on to your aol.com address.
No, I ditched the regulator but I am using a little solid state voltage stabilizer to power up the AC guage. To be honest I don't know if it makes a difference or not because I've not tried running without it. It cost peanuts and I took the decision that when I had the dash off and was installing the new loom to wire it in to provide some steady volts. Looks like it might have been a good decision. before I send it on to Doug.
Adrian@
Doug, I have found my wiring diagram that shows the conversion with the alternator and RB340 unit in place since we spoke. I will forward it on to your aol.com address.
Edited by Adrian@ on Wednesday 18th February 22:07
Hello
I have a problem with my sender or temperature gauge in my TVR Vixen.
Searching on this forum did not help me (up to now).
I bought a sender from Burton so this item should be oke. It's the type with white collar.
http://www.burtonpower.com/temperature-sender-earl...
Checked the resistance (reading 440 ohms) that decreases when hot after some minutes running the engine.
But no reading on the gauge. The original AC type.
Checked the power to the gauge and earthing directly to the block shows max reading.
I ditched the regulator and there is (as original) no stabilizer.
Whatever is wrong?
Hans
I have a problem with my sender or temperature gauge in my TVR Vixen.
Searching on this forum did not help me (up to now).
I bought a sender from Burton so this item should be oke. It's the type with white collar.
http://www.burtonpower.com/temperature-sender-earl...
Checked the resistance (reading 440 ohms) that decreases when hot after some minutes running the engine.
But no reading on the gauge. The original AC type.
Checked the power to the gauge and earthing directly to the block shows max reading.
I ditched the regulator and there is (as original) no stabilizer.
Whatever is wrong?
Hans
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