overheating problem after serp engine cam change - help!
Discussion
TVR life is exciting...
I think you have a faulty reading due to connecting the wrong sensor. No way the temp is coming up so quickly. If it was an air lock the temp sender is most likely to be in air and would never gain such temp in such short time. If you have Rovergauge you can see what the other temp. sensor reads.
Did you put the wire at the right temp sender ?
Mine has three senders in the manifold and only two are used.
There's one at the top with a dual connection -> temp input for the ECU
The other one is mounted lower behind the distributor, this is a very small one. The sender is vertical mounted. Not of any use...
The last one is horizontally mounted at the front side of the manifold. Its behind the distributor and hard to spot.
This is the one that you need to connect to your temp. gauge.
Maybe tonight I can provide a picture.
Ronald
I think you have a faulty reading due to connecting the wrong sensor. No way the temp is coming up so quickly. If it was an air lock the temp sender is most likely to be in air and would never gain such temp in such short time. If you have Rovergauge you can see what the other temp. sensor reads.
Did you put the wire at the right temp sender ?
Mine has three senders in the manifold and only two are used.
There's one at the top with a dual connection -> temp input for the ECU
The other one is mounted lower behind the distributor, this is a very small one. The sender is vertical mounted. Not of any use...
The last one is horizontally mounted at the front side of the manifold. Its behind the distributor and hard to spot.
This is the one that you need to connect to your temp. gauge.
Maybe tonight I can provide a picture.
Ronald
Rovergauge is free software but you'll need a laptop to run it on and a cable to connect it to the ecu
https://code.google.com/p/rovergauge/
http://www.pistonheads.com/classifieds/parts-and-p...
https://code.google.com/p/rovergauge/
http://www.pistonheads.com/classifieds/parts-and-p...
Thanks for the photos Ronald. I am absolutely positive my temp lead was connected by bullet connector to the 'unused' connector and not the one on the front face of the inlet manifold.
I'm now wondering whether the sensor on the front of the inlet manifold was found faulty in the past and rather than change it someone previously connected the wire to the 'unused'sensor as it was easier to access. I'm going to add a fly lead with spade connector to the temp lead and attach it to front of manifold connector and see if it works, I've also purchased a Maplin infrared thermometer to try and monitor the real temperature.
I also wondered if the original lead had a resistor in it (as mentioned previously) to compensate for less resistance of the unused sensor thereby giving a acceptable 90C gauge reading when engine has warmed up.
Do pre seeps use the 'unused' sensor with a resistor in the lead?
The saga continues but not until the weekend now.
I'm now wondering whether the sensor on the front of the inlet manifold was found faulty in the past and rather than change it someone previously connected the wire to the 'unused'sensor as it was easier to access. I'm going to add a fly lead with spade connector to the temp lead and attach it to front of manifold connector and see if it works, I've also purchased a Maplin infrared thermometer to try and monitor the real temperature.
I also wondered if the original lead had a resistor in it (as mentioned previously) to compensate for less resistance of the unused sensor thereby giving a acceptable 90C gauge reading when engine has warmed up.
Do pre seeps use the 'unused' sensor with a resistor in the lead?
The saga continues but not until the weekend now.
The sensor with the bullet connector on it, is the one that Rover fitted and used in the original engine.
TVR added the other one presumably as it was matched to gauge. I've seen a few posts on here about people using the original rover sensor but yes it does need a resistor. No idea about the value required. If you do a search with google on the site you should be able to find one of the threads.
TVR added the other one presumably as it was matched to gauge. I've seen a few posts on here about people using the original rover sensor but yes it does need a resistor. No idea about the value required. If you do a search with google on the site you should be able to find one of the threads.
Can you take a pic of the aux belt as the water pump can slip if fitted in the wrong orientation.
Also is the swirl tank (the larger one) getting hot and if so keep running until the fans kick in and the temp should hover about 95. It's normal for the temp to rise very quick when bedding the cam.
Mark
Also is the swirl tank (the larger one) getting hot and if so keep running until the fans kick in and the temp should hover about 95. It's normal for the temp to rise very quick when bedding the cam.
Mark
Apologies if I missed it.......but have you said whether the fans are kicking in or not when it goes over 90 degrees?
Your rad fans should have kicked in well before 100 degrees C.
You can test they are potentially working by shorting out the otter switch - pull the leads back a little off the terminals so you can get a small screwdriver in to connect the two terminals together, ignition on, no need to start the engine. Both fans should come on. Otter switch is either on the bottom of the swirl pot, or bottom left of the rad looking from by the tax disc.
Your rad fans should have kicked in well before 100 degrees C.
You can test they are potentially working by shorting out the otter switch - pull the leads back a little off the terminals so you can get a small screwdriver in to connect the two terminals together, ignition on, no need to start the engine. Both fans should come on. Otter switch is either on the bottom of the swirl pot, or bottom left of the rad looking from by the tax disc.
Hallelujah, problem fixed!
A previous owner had connected to the rover temp sensor (usually unused on a serp) on top of manifold next to the ecu temp connector rather than the one on the front of the manifold behind the distributor.
As I suspected when I snipped off the manky knackered last 4 inches of the wire and insulation I also unwittingly removed the resistor with it.
I then spliced/soldered in a new wire tail and connector minus resistor, resulting in a worrying but false gauge reading going into 100C+.
So the solution was to connect a 160 ohm resistor from Maplins (didn't have a 170 ohm one as suggested on forum post) in the wire, this resulted in a gauge indicated running temperature of 82C. Checked temps around the engine with an infrared temp gun all over the cooling system, in particular at the hose connected to the bottom of the header tank, this gave a reading of 89C. At last, problem resolved although I will try a 170 ohm or maybe a variable resistor to tweak up the normal engine running gauge indicated temp to 90C.
Finally, I would like to thank everyone who contributed to this thread and to say what a great forum this is. Along with bringing to my attention TVR's little resistor trick (the bu@@ers!), I also received some great advice on bleeding the cooling system.
Looking forward to a long run out tomorrow to try out the stealth cam http://www.pistonheads.com/gassing/imgs/2.gif
Thanks again guys
A previous owner had connected to the rover temp sensor (usually unused on a serp) on top of manifold next to the ecu temp connector rather than the one on the front of the manifold behind the distributor.
As I suspected when I snipped off the manky knackered last 4 inches of the wire and insulation I also unwittingly removed the resistor with it.
I then spliced/soldered in a new wire tail and connector minus resistor, resulting in a worrying but false gauge reading going into 100C+.
So the solution was to connect a 160 ohm resistor from Maplins (didn't have a 170 ohm one as suggested on forum post) in the wire, this resulted in a gauge indicated running temperature of 82C. Checked temps around the engine with an infrared temp gun all over the cooling system, in particular at the hose connected to the bottom of the header tank, this gave a reading of 89C. At last, problem resolved although I will try a 170 ohm or maybe a variable resistor to tweak up the normal engine running gauge indicated temp to 90C.
Finally, I would like to thank everyone who contributed to this thread and to say what a great forum this is. Along with bringing to my attention TVR's little resistor trick (the bu@@ers!), I also received some great advice on bleeding the cooling system.
Looking forward to a long run out tomorrow to try out the stealth cam http://www.pistonheads.com/gassing/imgs/2.gif
Thanks again guys
No problems Pete, you were very close but at the time of your valued response I wasn't aware of the significance of the sensor switch from TVR to Rover and the associated resistance difference. Thanks anyway, I've quite enjoyed this 'journey' of learning in a masochistic way! TVRs don't you just love 'em.
No problems Pete, you were very close but at the time of your valued response I wasn't aware of the significance of the sensor switch from TVR to Rover and the associated resistance difference. Thanks anyway, I've quite enjoyed this 'journey' of learning in a masochistic way! TVRs don't you just love 'em.
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