Lotus Elan

Zetec temp sender woes

PostPost by: TAS » Sat May 05, 2018 10:11 am

Following on from my intro post I?m trying to solve my erratic temp gauge. I?m pretty sure it?s not running hot but the gauge runs between 120-140. It took me a while to fine where the sender was, it?s on the right side of the block below the throttle bodies, not on the water rail. When I put a meter on the sender it reads 0 or 12volts alternatively which I guess means I have no voltage stabilizer. The sender also looks nothing like a smiths one, it has a round terminal and is 22mm, I think it may be a ford one.

I?m going to change the sensor first for a smiths one once I can get a deep enough socket to get a purchase on it, I?m not planning on taking the throttle bodies off!

Should I see 10 volts on a meter?
TAS
First Gear
First Gear
 
Posts: 22
Joined: 09 Apr 2018
Location: Sussex

PostPost by: Chancer » Sat May 05, 2018 11:35 am

No.

Swinging between zero volts and battery voltage is how the voltage stabiliser works.

Zetec water rails might look nice but completely cock up what was a very well considered cooling system, at the very least you need to drill a 3/16" circulation hole in the thermostat which should have remained at the back of the engine where it belongs.
Chancer
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1391
Joined: 20 Mar 2012
Location: Northern France/ Sussex UK

PostPost by: TAS » Sat May 05, 2018 11:43 am

Chancer wrote:No.

Swinging between zero volts and battery voltage is how the voltage stabiliser works.

Zetec water rails might look nice but completely cock up what was a very well considered cooling system, at the very least you need to drill a 3/16" circulation hole in the thermostat which should have remained at the back of the engine where it belongs.


Great, the new sender might be enough. Already got the hole in my thermostat :D
TAS
First Gear
First Gear
 
Posts: 22
Joined: 09 Apr 2018
Location: Sussex

PostPost by: pauljones » Mon May 07, 2018 8:35 am

Tas.

Can you post some pics of where your at?

I ask because i have my zetec out, i can have a look at mine for you. I have omex temp sender which i believe is different to my emerald one. And i also have the standard one on twincam too. So 3 possible different ones.

My silvertop zetec has a water rail and the sender was fitted to it and not under the bodies on rhs. Are you sure thats not oil?

My temp gauge reads high (as does fuel) because it was rewired 12v with no voltage stabiliser. I can live with it for now. Was thinking of using 12v gauges if and when i re do the dash.
Kick the tyres and light them fires...!!!!!!!
pauljones
Fourth Gear
Fourth Gear
 
Posts: 968
Joined: 09 Feb 2008
Location: Gosport sur la mer,South hants

PostPost by: Bud English » Mon May 07, 2018 2:26 pm

Taz- I'm not sure the ford sensor is compatible with the smiths gauge. I also don't think you'll find a smiths sensor that will work in the CHT location.

Some of the zetec motors, like yours, have a cylinder head temp sensor and no coolant temp sensor. It's located on the intake side of the head. It actually measures the temp of the head and doesn't even contact coolant. When you remove it you don't even have to plug the hole. My crate motor came that way. I put two coolant sensors in my water rail, a smiths sender for the gauge and a GM sensor for the ECU. Over kill, maybe??

http://www.webcon.co.uk/Downloads/K4001 ... lack%20Top)%20Eng%20Temp%20Sensor.pdf
Bud
1970 +2S Fed
"Every Lotus that an owner modifies makes yours worth that much more." - You're welcome!
User avatar
Bud English
Fourth Gear
Fourth Gear
 
Posts: 933
Joined: 05 Nov 2011
Location: Winnemucca, NV, USA

PostPost by: TAS » Mon May 07, 2018 3:11 pm

I?ll take some pics when I get home. I guess ideally I could put a sender in the top hose, the joiner has a boss in it.
TAS
First Gear
First Gear
 
Posts: 22
Joined: 09 Apr 2018
Location: Sussex

PostPost by: prezoom » Mon May 07, 2018 3:50 pm

On my home built water rail, I placed a Smiths sensor directly behind the thermostat. It picks up the coolant temperature where is should be the warmest. Not advocating building your own rail, but like the TC's, that is where the sensor is located.
Rob Walker
26-4889
50-0315N
1964 Sabra GT
1964 Elva Mk4T Coupe (awaiting restoration)
1965 Ford Falcon Ranchero, 302,AOD,9",rack and pinion,disc,etc,etc,etc
1954 Nash Healey LeMans Coupe

Owning a Lotus will get you off the couch
prezoom
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1257
Joined: 16 Mar 2009
Location: Escondido, California

PostPost by: TAS » Mon May 07, 2018 4:14 pm

334BADE7-D72A-45B8-8915-36DD2A93DF20.jpeg and
334BADE7-D72A-45B8-8915-36DD2A93DF20.jpeg and


These are the senders I have. I believe the water rail one has an emerald sensor in it. The other side is oil pressure and what I believe to be the water temp one. It had a cable attached prior to the photo.
Attachments
439093FB-D32E-431C-AF50-F4F4969BAC55.jpeg and
TAS
First Gear
First Gear
 
Posts: 22
Joined: 09 Apr 2018
Location: Sussex

PostPost by: Bud English » Mon May 07, 2018 5:00 pm

That must be an added coolant sensor in the block, not the head temp sensor, obviously. The forward sensor is the oil pressure sender. On my block, I have a threaded plug in the position of your coolant sensor, that I assumed was an oil gallery plug. Shouldn't assume, but it will be interesting what you find when you pull the sensor. Oil or coolant??

In Work 1.jpg and

In this old pic of my motor mount fabrication, you can see the plug in the position of your sensor. The oil pressure sender in behind the pigtails (one of the pigtails is from the cylinder head temp sender, the other from the knock detection sender).
Last edited by Bud English on Mon May 07, 2018 5:11 pm, edited 1 time in total.
Bud
1970 +2S Fed
"Every Lotus that an owner modifies makes yours worth that much more." - You're welcome!
User avatar
Bud English
Fourth Gear
Fourth Gear
 
Posts: 933
Joined: 05 Nov 2011
Location: Winnemucca, NV, USA

PostPost by: TAS » Mon May 07, 2018 5:10 pm

Bud English wrote:That must be an added coolant sensor in the block, not the head temp sensor, obviously. The forward sensor is the oil pressure sender. On my block I have a threaded plug, that I assumed was an oil gallery plug. Shouldn't assume, but it will be interesting what you find when you pull the sensor. Oil or coolant??

I?ll find out tomorrow, I thought I read somewhere that the fan switch lived there on some cars.
TAS
First Gear
First Gear
 
Posts: 22
Joined: 09 Apr 2018
Location: Sussex

PostPost by: TAS » Tue May 08, 2018 12:19 pm

The mystery deepens. I unplugged what I thought was the temp sender and my gauge still works..

I've no idea how it's getting a signal unless it's piggy backed off the ECU temp sender which is a modern one. I've just take it to my local Caterham specialist who couldn't see where its plumbed in either.

I'm going to rewire the gauge to a smiths sender in the top hose.
TAS
First Gear
First Gear
 
Posts: 22
Joined: 09 Apr 2018
Location: Sussex

PostPost by: Bud English » Tue May 08, 2018 2:31 pm

After another look at your water rail photo (enlarged) it looks like the water rail has two temp sensors in it. One is coming straight out the front under the filler cap and the other is threaded into the boss about four inches back from the cap. I can't tell from the photo if both have two wires connected, but the smiths gauge should have just one.

What I thought was the sender that you were talking about in the exhaust side photo looks like a connection for a mechanical oil pressure gauge, the other is a sender for an electric oil pressure gauge or an oil pressure switch.
Bud
1970 +2S Fed
"Every Lotus that an owner modifies makes yours worth that much more." - You're welcome!
User avatar
Bud English
Fourth Gear
Fourth Gear
 
Posts: 933
Joined: 05 Nov 2011
Location: Winnemucca, NV, USA

PostPost by: TAS » Tue May 08, 2018 3:26 pm

Bud English wrote:After another look at your water rail photo (enlarged) it looks like the water rail has two temp sensors in it. One is coming straight out the front under the filler cap and the other is threaded into the boss about four inches back from the cap. I can't tell from the photo if both have two wires connected, but the smiths gauge should have just one.

What I thought was the sender that you were talking about in the exhaust side photo looks like a connection for a mechanical oil pressure gauge, the other is a sender for an electric oil pressure gauge or an oil pressure switch.

The one under the filler cap is a fan switch, and the other one is for the ECU, if I pull it off the engine changes maps and the mechanic confirmed it was the ECU sensor.

The wiring to it is wrapped so I cant see how many wires connect to the plug, I think it may be connected to the gauge as well.
TAS
First Gear
First Gear
 
Posts: 22
Joined: 09 Apr 2018
Location: Sussex

PostPost by: pauljones » Tue May 08, 2018 4:32 pm

Is your gauge feed an input from an ecu output? Can you confirm what voltage is sitting at the gauge, maybe you are getting a constant 12v feed.

Im just about to look at my zetec block, ill let you know what i have.
Kick the tyres and light them fires...!!!!!!!
pauljones
Fourth Gear
Fourth Gear
 
Posts: 968
Joined: 09 Feb 2008
Location: Gosport sur la mer,South hants

PostPost by: Spyder fan » Tue May 08, 2018 4:57 pm

The temperature sender is tight against the bulkhead on the head on the LH side.
Kindest regards

Alan Thomas
User avatar
Spyder fan
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2541
Joined: 11 Jun 2009
Location: Kent country & Sussex seaside UK
Next

Total Online:

Users browsing this forum: No registered users and 7 guests