Guys, I need your help. Seems like the universe is conspiring against me,,, or my brain is fried. Or both.

I recently changed the coolant temp sensor in my 2002 (with a 2000my transplant engine) XK. Prior to changing the sensor I was AMAZED at how well and efficiently the (transplant) engine ran. Fuel trims were dead on, car purred. The CTS sensor was old (from original engine) so as regular service I decided to swap it, change coolant, oil and other stuff for spring cleaning. No good deed goes unpunished.

As it is now,,, my CTS connector has disintegrated and I will be needing to replace it. But with what connector?

After changing the sensor a couple of weeks ago the car seemed to run hotter (212 deg I've seen,,,, and as high as 220 on a 60degree day!) and the fuel trims were all over the place. High negative STFT sometimes in the 20+ range for reasons I struggled to understand. Never used to get over like 199, 204 tops on a hot day...

The CTS sensor I ordered, received and installed had/has a green connector - and the horizontal tabs on the connector are cocked - tab on one side higher than the other... It seemed to accept the crusty OE connector/plug on the car (unless the connector was so crumbly it seemed to take). I went to change the sensor today suspecting either a bumb sensor or incorrect part with a replacement CTS that has the familiar light grey male connector. Also, matching level placing tabs are level or equidistant on the horizon, I installed it and it seemed the connector didn't fit correctly, and in plugging it in the damn thing fell apart anyways, and now I am unsure WHAT to do...

I was able to get the damaged CTS plug/connector (without any surrounding connector walls) over the pins on the new GREY CTS and started the car, just to see.... The car started and ran HORRIBLY. Maybe because the car had come to base map and running on the old CTS? Maybe there is right polarity on the two wires that I reversed???? I don't know.

I have read that the AJ26 and 27 cars have a different CTS...? Is this right? And shouldn't the 2000 engine, as well as the 2002 XK8, take a CTS for the AJ27? Also, now that the connector is trashed I don't know what connector to by to replace it.

Could someone PLEASE straighten me out here!? Talk some sense to me,,, it's crazy but I am not sure what's next...

What connector and CTS goes with the 2000/2002 Jaguar XK8? Does it matter which wire goes to which pins on the CTS? What's the correct plug?

Heeeelp.

 

I have had all this $hit . The one with the offset slots is the correct one . The other one is a fuel temp sensor and not used on the XK8.Personally, I would either solder the wires onto the pins or locate individual slide on connectors or destruct the original connector to remove the female connectors and push in with long pliers. ..does not matter which way around the wires are .The cause of your problems is probably a bad connection. Correct sensor is LNA 1600AA often confused with LRA 1600BA-R which does not have the offset pins and is wrong length.

Correct

 

Hey Man, Good Morning... TY. Need all the help I can git!

Feeling a BIT refreshed this AM... If ya can call it that. Was messing around with this yesterday in a very cold rain. No good for an ol man, lol
​​​​​
I guess I'll start with the reason I was suspecting (I have what appears to be the same green LNA sensor you listed) I have/had the wrong sensor installed - but maybe my issues are a problem other than the sensor??? I'll try another sensor like this as the one I have my be bad out of the box.

With the green LNA sensor I had been getting higher than usual readings for temperature and strange negative STFT/LTFTs after swapping in the sensor in. I took readings with an inferred thermometer and got nothing over 190 at any surface on the cooling system. I know IR thermometers can be a bit off, but the DTC reader app on my phone was reading 206 as high as 212, and I've seen 220 more than once on cool days. Big difference. Also, on both my XKs, 02 and 04 the head of the sensor is/was grey (not that that actually identifies a sensor) not this super bright green.

I've been thru 3 180degree thermostats. The original,,, the new one, then a second new one - all 180degree stats, jiggle pins on top and a new thermostat aluminum hosing trying to see if it was a thermostat thing... Fresh coolant went in at the beginning of spring.

STFT with new green LNA sensor are all over the place where previously they were PERFECT. With new sensor, especially thru warm up, I see -25s and all kinds of high negative numbers. After a bit of driving things calm down some but the numbers are nothing like they used to be PRE new sensor. LTFTs are up around 10pts - honestly I can't remember if they are positive or negative. Negative I think. Crazy making...

The car had a REAL rough time and wouldn't really idle with the LRA type sensor below. Was real bad.

I'm frustrated and at a loss.


This is the sensor I have that DID NOT work.

JLC lists this.

 

Put the old sensor back ....

 

Ha... I did something I never do (which is why the attic in my NYC apartment is filling with ol parts from 5 different vehicles) I tossed it. I almost never do that.

Listen to this... The last time I started the car the other day in the cold rain, my lower trans cooler hose BLEW spraying (unbenounced to me) trans fluid all over the LH side of the engine and engine bay. Lots. So, yesterday I spent the entire day cleaning up and replacing that line (small section of oil grade hose in the last section between the rad and last soft section),,, great fun. All's left is leveling the fluid. OMG

But, after that I found my problem. Partly. As part of spring cleaning I had also replaced the alternator with a nice remain denso unit. In the area is the loom for the MAF. The cause of my strange trims were a result of a pinched wire in the MAF loom. Repaired that and my MAF readings (which I hadn't noticed hovering around 5.9 to 6.1 at idle until this weekend) to about 4.9 to 5.2 or 3. Trims completely leveled out both LT and ST and, unless I'm mistaken, the temps look better as well. Is that a thing? The ECU had been trying to subtract fuel based on false MAF readings, car was thinking a rich running condition - or something like that. O2 sensor results and MAF readings weren't jiving. I need to understand these ideas better. Anyways,,,

I have a pigtail and another CTS due today. I'll solder in the pigtail and try the new CTS. See what kind of temperature readings I get. The IR thermometer says nothing over 190 in any area of the coolant system - on both sides of the thermostat. I can't see how it could be 20+ degrees off. Strange. Bad CTS out of the box?

This ain't been fun, but I guess it's what I signed up for, lol. I don't own a vehicle younger than 18yrs old. Oldest is 36yrs, (104yrs all added up) And all of them are complex (for me) cars. Maybe I should have started falling in love with 60s Ford's and Chevys...?

 

Hi Jay,
I *think* that the ECU defaults to internal fuelling tables if the MAF doesn't give sensible readings.

I got burnt a couple of times too so now I never let go of an old part until its replacement is fitted and confirmed.

It's easy to remove the pins from the connector, so you might be abler to dismantle the pigtail and re-use the existing connector pins. Easier than breaking out the soldering iron and neater than a pigtail:
https://www.jaguarforums.com/forum/x...4/#post2261542

 

Hi. GM Michael.

Lol, I do basically the same EXCEPT I never actually get rid of the old,,,, it's becoming an issue (lol). These NYC apartments are famously small. I struggle with the ability to keep things remotely organized. I need a three car garage - would be heavenly.

The MAF was sending readings that were at and around 1pt high. I think maybe sometimes that would trigger a default to base logic, but not all the time. The brains of the car seems to have a mind of its own sometimes.

Q: if the ECU was intentionally RICHENING the fuel thinking the car was getting more air than it actually was, while the O2 sensors were saying something else (telling the ECU to reduce fuel - maybe even creating a lean condition), would that create a hotter running car? I'm not even sure my thinking is right about the ECUs reaction to a false more air from MAF and O2 sensor readings that tell the ECU to reduce fuel,,, but is there something to this?

The second CTS never showed up (still in process) so I have no new news. I have the GREEN sensor, supposedly the right sensor, in the car now and the STUMP of the old plug/connector. Car idles hotter than usual but not as bad as it seemed. Trims are very normal. I won't and haven't been actually driving it this way - also need to reSET the trans fluid level after the hose fiasco. Jeeeeeze Louise.

Also, like on the 928 for example (and the XJS for that matter), is there a correct RESISTANCE one can expect out of these coolant temp sensors??? My OBD says the car is at 204+ degrees and the 180degree thermostat hasn't even opened yet... The bottom hose from the rad will still be cool to the touch after startup,,, while the temp reading is 205degrees... Is there a running range one can expect and can confirm thru a temperature range measuring resistance off the sensor - back probing? It would be nice to test back probing in the car AND, now, when a sensor comes out of the box. What a thing. Duff new parts. The INCORRECT temp sensor I received actually shows ZERO resistance, no continuity, when probing the pins. That can't be right. Nothing at all.

So it continues 😐

 

Oh and,,, thanks for the link. Considering the luck I've had with "NEW" parts lately I won't get my hopes up. The new pigtail should come with wires and clips all set.

Did I mention, my first "new" alternator, a remain denso unit from RockAuto installed beautifully a couple of weeks ago. Put the thing in, bolted it up, added a new serpentine belt, fired her UP and the alternator basically FRIED in the car. For 30min after a 2, 3 minute (if even that) start up, the alternator was toooooo hot to touch. Thankfully, they honored the warranty and sent a replacement overnight (I do like RA)... Installed the 2nd "new" alternator and all was right in the world...

When things like this happen it makes it very very difficult to enjoy a long drive... But clinching.

 

Zero resistance is full continuity........

 

Mis-spoke... No reading,,, no beep from my DMM.
thanks

 

So thats open circuit ..infinity resistance .. let's not spread crap on the internet.

 

and the converse ; little to no resistance, as in two ends of a copper wire , is full and complete continuity. ( as previously stated )

Z

 

This is just me,,, folks need to take it easy. Anyways.

I was wrong. I'm not very good with electrical stuff. I've never been trained, or educated in, nor have I studied enough.... It's been that way since, well, ever since. I try, but struggle.

Anyways, I was wrong, and still could be. I set my DMM to 2K ohms and got a reading of 1.830 at room temperature. If I put my hand around the business end of the sensor the resistance dropped slowly but immediately. This was the "new" green URO parts sensor. The one I replaced with a denso part which (y'all can yell at me again, or imply that I am stupid compared to you) I didn't take a measurement on before installing. Now that I know how to set the DMM, I'd be interested in knowing (and will) what it reads while in the water rail at different temps.

Ya know,,, I come here because there are a LOT of things I don't know and need help... But the TONE here from the folks that know EVERYTHING keeps me away. Jus say'n.

 

I'd imagine that if and when the temperature got up to around 180 - and +, the resistance would fall to near zero? Is that how the sensor would work and communicate engine temp to the ECU?

 

Nobody is getting at you at all ...but its amazing how bad information spreads on the internet.
Everyone here wants to help anyone.
If you want to know what the resistances are you need to suspend the sensor in a pan of water with a thermometer and make a list . Remember its NTC ... negative temperature coefficient which means as the temp goes up the resistance drops ie 20 deg C its 1800 ohms and at 100c its 200 ohms ( just giving some typical figures not specific to this unit) Thats how it would communicate with the ECU. BUT thats an analogue signal..smooth variation with temp and the ECU converts it to digital to do its processing
People in Europe could not even tell you what Farenheight is if they are under 40 ha ha

 

I should also mention (got caught up reacting to responses) that I forgot to tell the good news...

With the Denso CTS things are back to normal, thank goodness... That and, working on the wiring and plug to the MAF... I simply removed the section I chinked and pinched between the body of the new alternator (or the old one when removing) and soldered the two ends together and shrink wrapped. It took a drive to work and back for the trims to fall back to normal (amazing how these cars will adjust or try to adjust to changes in conditions when things go out of wack). Good.

Also, for the damn trans fluid line and resetting the level of the trans fluid,,, the way I do it is to JACK the car up on the RH rear and place a jack stand, crawl under the car to get to the plug and get the plug close to it's last theads,,, lower it and start the car to get up to or close to temp (40c or so) measuring with car down. When close to 40, jack the car up again, hot and running, wearing gloves, remove the plug (nothing comes out of the plug hole with car on jack) shove in the hose, place a small shallow 2inch walled aluminum baking sheet (1$ at American dollar stores) then LOWER the car. From there, I start pumping. As soon as fluid starts to trickle, I take temp (constantly taking temps) and go around and shift the car into and thru gears with nice long pauses. Then, little little bit more with the pump. When I am satisfied, the fun part. I JACK the RH rear side up again. Place JACK STAND and get back under the car. DUE TO LEVEL AND ANGLES,,,, fluid COMPLETELY stops running. Which is GOOD... Remove the hose and reinstall the plug, and drop the car... Really it just takes about 20 minutes. Or less. Shifting smooth as butter now.

Anyways. Crisis averted.
Thank ya once again for your help, support and attention!
Be well.