Looks like you’re on the wrong sensor. The sender for the temp gauge on the dash is a single wire, Probably red/white stripe.
The one you want looks similiar, but has 2 wires typically light green/red stripe & gray/red stripe.
Connect your ohm meter directly to the 2 terminals on the sensor.
87 Ranger has it correct. If you look at the wiring diagram, you see that the gray/red wire joins the circuit to terminal 91 of the PCM. It is not common ground.
You want to put your digital multimeter probes on the engine coolant temperature sensor terminals. Set to read ohms. Guesstimate the temperature of the ECT It will be above ambient. [The ECT terminals connect to the gray/red wire and the light green/red wire. I’m trusting the wiring colors on the wiring diagram.)
Here is Auto Zone, again, with photographs, drawings, and instructions for taking ohm reading on the engine coolant temperature sensor. http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c1528003aabf
Read above paragraphs, again.
You are all correct, I was testing that sensor instead of the ECT… Doh.
I will try again tonight!
Hellokit, just wanted to say how very nice it is of you to post the links to these wiring diagrams.
My only gripe is that my high buck/state of the art (LOL)$49.95 internet browser wont pull the diagrams up. I only get a blankscreen.
One of these days i’m going to have to bite the bullet & invest in a real computer.
OK, I found the correct sensor this time. It’s very hard to get to, the metal pipe that it attaches to angles back towards the cars’ cabin and I am not able to see the business end of it at all… However, I’m pretty sure I was able to get the leads in there and on the prongs correctly (I also noted that the cable connector did not have any corrosion in it). The meter read 3.82k ohms. Which may or may not be OK. I had just finished driving it about a half hour after it had sat in the sun in 95F weather all day. Tomorrow morning, before I drive it, I’ll meter it again when I know what the temperature of everything is.
Hey, 87_Ranger, I had that exact same problem with the pictures. I do not know what the reason is, but they do not show up at all on my work computer (which is a great computer) in either Internet Explorer or FireFox. However, they appear just fine on my home computer with is much older!
Regardless, I DID find an alternate link to Autozone’s wiring diagram webpages where the images DID work… but I left it at work, so I’ll post what I found tomorrow.
If you look at the temperature/resistance chart in Fig. 3 for the ECT (Engine Coolant Temperature) sensor, you’ll see that the ECTS resistance is correct at that temperature. Nothing says that it can’t go haywire at higher temperatures, though.
Next, measure ECTS and the wiring resistance. Connect the plug to the ECTS. Turn ignition OFF. Pull fuse #19 (15A). Disconnect the big electrical plug from the PCM (Powertrain Control Module). Touch a multimeter probe to plug terminal 38 (LG/R wire). Touch the other probe to plug terminal 91 (GY/R). Whatcha got? The ohms should be the same as directly across the ECTS terminals. If way different, you gotta find the open, or shorted, place in the wire.
You NEED backprobe pins to go on the tip(s) of your multimeter probes, such as these http://www.sjdiscounttools.com/thx490.html One does NOT stick pins, or probe tips into (puncture) wires! It’s just not cricket (and, problems resulting therefrom can come back to haint you).
Sliding straight pins along the wire to touch the metal terminal is ok. Then, touch pins with multimeter probes.
Glad to see that you found the sensor. Looks like your starting to zero in on this thing.
Theres a lot of times such as this when i’d like to be able to look at a set of wiring diagrams, so please do post that link.
For my own cars I always buy the paperback versions of the factory wiring diagrams which ae worth their weight in gold.
Knowing the temperature this morning (75F), I checked the ohms on the ECT sensor again, it read 26.48kohms, which according to the chart here: http://www.autozone.com/az/cds/en_us/0900823d/80/1a/f7/5b/0900823d801af75b/repairInfoPages.htm is correct. (This is the multimeter I have: http://www.kmart.com/shc/s/p_10151_10104_9990000031937411P?keyword=31937411&sid=K-on-Sx20k061224x0000001)
I’ll pick up a back-probe kit on the way home tonight and report back. How does those probes that you linked to attach to the multimeter leads? Looking at the picture it is not clear… So the point of this test is to test the very end of the ECT sensor wires that connect to the PCM in order to determine if the wires are damaged anywhere, right? Boy I hope that’s the problem… I’m not looking forward to taking about the PCM…
SIDE NOTE: My radiator fan is NOT staying on when the car is off after driving a half hour when the car has been in the sun in 95F weather all day. Is this a clue?
87_Ranger: OK, do NOT ask me why this is the case but as an example, here is the version of the AutoZone 98’ Ford Taurus Wiring Diagram page that seems to work for everyone: http://www.autozone.com/az/cds/en_us/0900823d/80/1a/ff/4a/0900823d801aff4a/repairInfoPages.htm . And here is the version that does not: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c1528003ad27 . If you back-navigate from within the first link, I think you could find the repair guide for your car with images that appear for you.
On your way home from work, after you get that six-pack of stout, and stop at an auto parts store, an elecroncis supply store, or Radio Shack for the multimeter backprobes (“Huh?” - store clerk), stop at your public library. Also, you’ll need banana probes for the backprobes to fit on.
Ask the librarian to help you go to the library’s web link to alldata.com. Go to something like, “Electronic Data Base”; then, “Reference”.
Once on alldata.com, go to: Vehicle Level > Powertrain Management > Computers and Control Systems > Testing and Inspection > Pinpoint Tests > H-Fuel Control > Hxx. Click on the small, blue-ringed, H-xx. Print out 5 pages: H26, H27,H28,H30,H31,H32,H33,H34,H35,H36,H37,H40,H42. Go home and apply.
Give me a hint, what are those pages going to be telling me to do? Poke around in the PCM?
If you were in the area, I’d give YOU the six-pack for all of your help.
You need the Hxx charts to tell you where to do voltage and ohm checks (and their values) for the DTCs (Diagnostic Trouble Codes) which have been set in the PCM (engine computer). You need the backprobes, for your multimeter, to take voltage readings at the PCM terminal, and other points, without disconnecting terminals, and without damaging wiring. PCM terminal 91 is “signal return”. “(non-FFV)” is: non-Flex Fuel Vehicle.
Thanks for the link, but could’nt get that one to work either.
Not sure on your 98, but the fan on my 95 Taurus would not run key off. I suspect thats normal on yours also.
Which diagram(s) would you like to be able to see?
The Cat has been following the trail here. Sorry to just pounce in here but I have to wonder about something. I noticed that the results of the scanner showed the CTS temp at 181deg-C, as you fellas did also. After looking at the results of the testing that was done on the sensor it looks to me the CTS sensor is fine. It looks to me the scanner may be incorrect on the display units. The temperature it showed would be perfect if the display was in Fahrenheit instead Celceus. I have to think the scanner display was showing the wrong units. From all the previous testing it looks to me there is nothing wrong with the sensor or the circuit to it. If the circuit had a problem there should have been a code for that.
The circuit to the O2 heater circuit in bank 2 has a problem or it is within the PCM itself. I would check to see if voltage for the heater is getting to it and if the PCM is turning it on as it should.
The P1131 code had me puzzled a little. I did a little research and found this info real quick. It is pretty interesting. Perhaps the fuel pressure regulator is the problem here and the fuel is so rich the O2 sensor can’t compensate for it. Here are the links you can check out and see what you think.
http://www.fordscorpio.co.uk/ho2smonitor.htm
http://www.fordscorpio.co.uk/maftest.htm
Hey thanks Cougar. I have thought the exact same thing about the scanner after reading the detailed real-time results as well. I’m working on the car now and will post later.
Side note, something has recently been leaking on my driveway… The small (4"x3") puddles are brown, oily and not particularly smelly. I’m going to try to locate it, but this is not typical; and my driveway is new, fresh concrete.
http://www.knizefamily.net/minimopar/fuelsystem.html
"Fuel Regulator Failures:
Fuel regulators don’t often fail, but if they do, it may result in low pressure. You can verify this by pinching off the fuel return line to see if the pressure rises. More often the diaphragm will develop a leak and while the fuel pressure is not effected, fuel finds its way into the vacuum lines causing any number of problems (usually MAP sensor related)."
Also: http://www.youtube.com/watch?v=UHTV3W5VI5w
I’m looking into this now as well. And Cougar, don’t apologize, I REALLY appreciate it!
Those are interesting links you provided. Let us know what you find out.
Well, my engine oil level is is just fine. But I DID figure out where the oily leak is coming from. This is my expert artist representation of the thing that is leaking from a view of under the car:
http://badsushi.net/images/leak.gif
Looks like all I have to do is tighten the bolt to stop it…
I THINK I FIGURED IT ALL OUT
Very quickly as I do more research: My PCV valve is oily!!! And there is a VERY good reason for it! If you read back to one of my first posts, a state inspection guy showed me a little section of vacuum hose that had completely collapsed. So I replaced it. Well, it turns out that that little section of hose connects DIRECTLY to my PCV valve, and I’m holding the valve right now, and it’s VERY oily! Which, from what I’ve read, is exactly what you would expect if there is a hole in the hose, it will get clogged up.
Wouldn’t that account for everything??