free hit
counters
temperature sensors - Engine/Ancilliaries - The Lotus Forums Jump to content


Recommended Posts

ok this issue has been going on years but need it sorted.

my temp gauge reads 70 degrees then in 1 second reads 50 degrees, (thinking that isnt possible lol), also it doesnt seem

to go over 72 degrees hardly ever.

i run a 1.2bar chip and that hasnt worked in about 2 years now, im assuming the issue is with the temp sensors not sending the

correct info to the ecu, it does however give my 1 bar on WOT sometimes when it feels like it. i havent really been using the car

and when i do i just go to work but i went on a little hoon the other day with alot of big big power supercars and 0.75 bar just was

a joke tbh.

i have changed the thermostat in the last 2 months as thought it was that and its still random on the gauge, are there 2 temp sensors

(1 for clocks, 1 for ecu?)

thanx in advance for any help

OUR CURRENT COLLECITON :- MODIFIED LOTUS ESPRIT, FULL VEILSIDE SUPRA (BEAST 409.3bhp), NEW ADDITON TO THE TROOP, 1996 S CLASS MERC (FULLY PIMPED OUT, DUB EDITION)

Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.
  • Replies 16
  • Created
  • Last Reply

Top Posters In This Topic

If the temperature gauge jumps, or is inconsistent, I'd suspect an earth, now whether that applies to also to the ECU I can't say, but it's where I'd start looking.

Edited by Roger the Dodger

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

Link to post
Share on other sites

thanx rodger

its stable and then goes down to say 50-60degrees and then back up etc, quite random. any clues where the earth is to the dash, or is it dash out time

OUR CURRENT COLLECITON :- MODIFIED LOTUS ESPRIT, FULL VEILSIDE SUPRA (BEAST 409.3bhp), NEW ADDITON TO THE TROOP, 1996 S CLASS MERC (FULLY PIMPED OUT, DUB EDITION)

Link to post
Share on other sites

think i need to buy freescan, ive been putting off for years lol

will look under the 'A' pillar aswell

OUR CURRENT COLLECITON :- MODIFIED LOTUS ESPRIT, FULL VEILSIDE SUPRA (BEAST 409.3bhp), NEW ADDITON TO THE TROOP, 1996 S CLASS MERC (FULLY PIMPED OUT, DUB EDITION)

Link to post
Share on other sites

You'll be wanting to change your sensor under the inlet manifold. It's a standard GM part. Enjoy!

British Ambassador to Florida, New York, Denmark and Newfoundland.  And Sweden.

Link to post
Share on other sites

You'll be wanting to change your sensor under the inlet manifold. It's a standard GM part. Enjoy!

I don't get it Sparky. He is having problems with the dash gauge, whose sensor is under the water pump. The one under the inlet manifold fees the ECU not the gauge. Sometimes the wire just gets lose on the sensor, so just have a look...

Well that's my knowledge for the SE, do you mean that the GT3 has a single temp sensor, unlike the pre-GT3 stevens cars, and that it feeds both the ECU and dash gauge ???

Edited by Vince
Link to post
Share on other sites

Worry ye not, Vince - I wasn't paying attention when I scanned this thread. You're right - it's his sender (or gauge maybe). GT3 is the same as SE. Sorry!

British Ambassador to Florida, New York, Denmark and Newfoundland.  And Sweden.

Link to post
Share on other sites

Just changed my sensor a couple of weeks ago after months without proper water T° at the dashboard. The cable connector was a bit rusty, but that was not the issue. Upon replacement of the sensor (at the water pump), water T° was reported back Ok. Yeeha!

The dash gauge is not the most accurate one but, at least, it's giving me about 75-85°C, where I was previously getting nothing at all. When I bought the car, the gauge would occasionnaly go beyond 70°C but sat most of the time at about 50°C max. Then after 3 or 4 months, it just went dead. It was just the sensor (also called the "water T° gauge sender") and I've read it's a fairly common issue.

Edited by RV_ABZ

1980 Peugeot 504 Coupé V6Ti

2000 Peugeot 406 Coupé V6SE

1996 Lotus Esprit S4s

Link to post
Share on other sites

thanx guys.

to recap on whats wrong as there seems some confusion LOL:-

the dash is reading wrong and goes up and down and only ever reads 71-71 degrees and the highest

i have replaced thermostat

i dont seem to be getting full boost (very very occasionally i get 1 bar on WOT, but i run chip 10 with is 1.2 bar)

i just wondered in a GT3 would i need to buy 1 sensor or is there 1 sensor for dash and 1 sensor for ecu

RV_ABZ - can you remember the part number or did you buy the:-

"WATER TEMP SENSOR (For ECM) (Charge cooled engine (in inlet manifold)) - £13.01 from SJ

and you never had issues with the ecu? and it only giving you 0.65bar warming up boost

OUR CURRENT COLLECITON :- MODIFIED LOTUS ESPRIT, FULL VEILSIDE SUPRA (BEAST 409.3bhp), NEW ADDITON TO THE TROOP, 1996 S CLASS MERC (FULLY PIMPED OUT, DUB EDITION)

Link to post
Share on other sites

I am investigating a similar low reading dash temperature gauge.

There are 2 sensors. Next to the thermostat is the dash gauge sensor with a single spade connector.

Under the intake manifold (not visible from on top) is the sensor that feeds the ECU.

It sounds as if both are bad in your case, though it may not be the temperature that is holding down your peak boost pressure.

In my case, I get a full bar of boost while the dash gauge is showing 70C, so I expect its my dash sensor that is fouled (I cleaned the connector).

Link to post
Share on other sites

karluk29, it's clear you have got two different problems but there is no evidence (just yet) that they are linked.

So best to treat them separately, this will make things clearer... TO start with, fix your temp gauge. The fact that is drop rapidly to 50 is clearly unrelated to the engine temp, of course. The terminal on the sensor, or the sensor itself, must be faulty in some way. This is easy to investigate, depending what hardware you have at hand. So first fix your dash gage reading. Once this is sorted, you canthen move on to the low boost problem... can be a number of things, not necessarily a defective coolant reading. Freescan or Espritmon (which seems to be more popular theses days) will be a great help !

So, first you should fix your dash gauge reading. I don't have my workshop manual handy unfortunately, but IIRC you will find in there the sensor response (resistivity vs temperature data), so you can easily check that the sensor gives the correct resistance for a given temperature. To know the temperature, just stick a thermometer in the coolant header tank as you live the engine idling/warming up. You can also do it another way: engine stopped, replace the temp sensor by an adjustable resistor/potentiometer, to "simulate" whatever engine temperature, and see how the dash gauge reacts to that.

Of course before you do anything, pull the wire from the sensor and make sure it's tight enough an that both sides are clean. As I said, on a friends SE, the gauge was starting to misbehave, and it was simply the wire getting lose, pushing it back into place was all it took to fix it proper !

TO start simple: pull the wire, the gauge needle should flight to the roof (or stay at the bottom, can't remember which way around it is), and stay there firmly. Then short the wire onto the engine/ground: needle should fly to the other side of the scale instantly.

Once this is fixed, move onto the ECU temp sensor and hook Freescan or Espritmon to the ALDL plug to see where the problem comes from. Could be engine temp sensor as you suspect, but might as well be a throttle position sensor/TPS not reliably reporting wide open throttle, or could be the MAT sensor as IIRC it's involved too (?) or might just be located at the end of the chain: the actuators rather than the sensors -> boost control

Soooo.... just start with your dash gauge sensor, simple things first ;-)

Edited by Vince
Link to post
Share on other sites

To clarify Vincent's point about dash gauge checkup, having done it myself prior to sensor replacement, simply disconnect the wire from the "gauge sender" (sensor near water pump) and put that wire to ground (connect it to engine block for example). The needle of the dash gauge should then go all the way to the right, to the maximum reading. This is how I verified that my dauge was Ok or not.

The part I bought from SJ was was Temp Gauge Sender (95-98), A082N4040F, £21.75

However, on receiving the part, it actually looks exactly like the Sender for VDO instrument (I've got Caerbont in my S4s) pictured on SJ's web site. SJ912E0008, £16.00

So which is it, I don't know, it just appears to work Ok to me...

1980 Peugeot 504 Coupé V6Ti

2000 Peugeot 406 Coupé V6SE

1996 Lotus Esprit S4s

Link to post
Share on other sites

wow thanx guys for all the info

i have know purchased both temp sensors to make sure (inc some clutch gear, different post in other section lol)

im going to replace them both and then check the WOT position like you suggested vince but i think that is ok as i got 1 bar the other day

which is standard, im thinking as i had a battery problem for ages its messed with the ecu and in turn needs to be run in for 100 miles

again. BUT as the temp sensors have been messing up even though the car has done 100miles it hasnt thought it was at temperature all this time

and only occasionally. my boost should be 1.25bar.

OUR CURRENT COLLECITON :- MODIFIED LOTUS ESPRIT, FULL VEILSIDE SUPRA (BEAST 409.3bhp), NEW ADDITON TO THE TROOP, 1996 S CLASS MERC (FULLY PIMPED OUT, DUB EDITION)

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.




×
×
  • Create New...