87 XR-7 digital dash

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87 XR-7 digital dash

February 27, 2006, 06:33:24 PM

Hello,

I'm having a problem with my water temp gauge. It keeps going up and down on the scale and "dinging" when it shows hot. I have changed the water pump, thermostat, fan clutch, flushed the system and 50/50 water antifreeze mix, changed the sensor but to no avail. It shows the engine is hot when it isn't. Is it possible for the digital gauge to be faulty? Has anyone else had this problem? Thanks

87 XR-7 digital dash

Reply #1 – February 27, 2006, 06:47:08 PM

Yikes. Not sure on that one. It sounds like you have replaced everything that could be replaced, save for the instrument cluster itself. It would be possible to take the gauges module out of another V8 digital cluster and put it into yours since all three modules are separate. That way you could retain your mileage.

Out of curiousity, where did you find a new temperature sensor?

87 XR-7 digital dash

Reply #2 – February 27, 2006, 06:52:42 PM

I found the water temp sensor actually at advanced auto parts. It is a two wire design instead of the traditional one wire that the mustangs and marks have. I took the car to an automotive electrical place and they said that the gauges generally don't fail, but it could be possible. It was totally fine until we did the 89 GT engine and mass air swap. Is it possible I could have an air bubble?

87 XR-7 digital dash

Reply #3 – February 28, 2006, 11:48:24 AM

I don't think something like an air bubble would cause that kind of problem. You would think that it would eventually just work itself out if that were the case. Did you use your stock wiring harness when you swapped engines?

87 XR-7 digital dash

Reply #4 – February 28, 2006, 05:06:05 PM

My guage failed, however it was reading low, not high. As Jkirchman said, which harness are you using? Also which sending unit are you using? If you're not using the Digital dash specific sender, it may be reading backwards......

87 XR-7 digital dash

Reply #5 – February 28, 2006, 06:57:51 PM

To keep things simple I did go ahead and use the cougar 5.0 wiring harness and then of course the mustang mass air wiring. Interesting though, the cougar water temp wiring comes off of the driver fender and mustangs etc. have it on the engine harness. The cougar wiring harness DOES have a single wire connection to fit a single wire temp sensor, but it is not used. For fun I put a mustang water temp sensor in and used the other single wire connection, but the gauge had two bars on top and two on the bottom lit, so that didn't work.
I didn't think to specify about getting a sensor for the digital dash. That might be it, I'll check it out and keep you posted.

87 XR-7 digital dash

Reply #6 – February 28, 2006, 09:42:09 PM

Well.....................I checked out the sensor and I have the right one. I was hoping the wrong sensor was the problem.

Very frusturating. Would everyone agree that it is the gauge then? Does anyone sell just the module that fits in the back?

87 XR-7 digital dash

Reply #7 – March 01, 2006, 02:48:46 AM

I don't think you will be able to find just the module. You will probably have to purchase an entire gauge cluster from eBay, a salvage yard, or someone on this board; disassemble it, and remove the left module with the tach and gauges. Then do the same thing to your cluster and swap the other one in.

You could just swap clusters but, as I said before, you can retain your mileage if you just swap modules instead. It's not that difficult to do, you just have to be careful because the parts are fragile. I've had my digital cluster apart a few times now without any problems. While you've got yours apart you can do the W2 mod to enable your speedometer to read up to 199 MPH if you want. Just solder a wire to join the contacts labeled W2 together. Here are instructions: http://www.foxthundercats.com/199speedomod/

87 XR-7 digital dash

Reply #8 – March 01, 2006, 10:06:22 PM

I appreciate the help and advice everyone. I'll start looking around for a donor.

87 XR-7 digital dash

Reply #9 – March 04, 2006, 11:26:49 AM

Did you find anything yet?

87 XR-7 digital dash

Reply #10 – March 05, 2006, 07:26:37 PM

I had the same problem on my car, only it was the oil pressure gauge which read no pressure. I took it to several places and had the sensor changed and nothing worked. I ended up disconnecting the beeper thing from the dash because it got so annoying. I guess it could be the cluster (I have the digital one) I don't know. Eventually, I'm just going to run a separate buttstuffog oil pressure guage under the dash.

87 XR-7 digital dash

Reply #11 – March 08, 2006, 09:30:48 PM

I haven't found anything quite yet. I called a couple salvage yards and if they had the right year it was the wrong dash....of course. Plus I haven't had the time either to really do any exploring. In the mean time I also just disconnected the sensor so it wouldn't constantly "ding".

87 XR-7 digital dash

Reply #12 – October 31, 2006, 06:06:06 PM

where are you located in Kansas mechanized?

87 XR-7 digital dash

Reply #13 – November 04, 2006, 06:19:09 PM

Hey,

I'm located in Wichita. The pic of your car looks familiar, did you go to the Ark City "Rod Run"?

87 XR-7 digital dash

Reply #14 – November 10, 2006, 01:35:18 AM

Mechanized, were you able to fix the problem?

If not, I would check the resistance of the sender. At normal operating tempretaure, the resistance should be between 1770 and 4440 ohms (temp approximatly between 212 and 176 degrees). If it is less than 1770 ohms, and you know that the engine is not overheating, replace the sender. Use a Wells SU201. If the resistance is ok, I would check for an intermittent short in the red/white wire (do a wiggle test). If the sender you are using is old, it could be one of the faulty ones that had a bad crimp during manufacture. The sender is inexpensive, so changing it if it is old would not hurt and might fix your problem. Otherwise, it might be a fauly gauge module.

CaptHowdy178: Ground the wire at the pressure sender end to the engine. If you have 2 bars at the top and bottom of the oil pressure display and the can is blinking, grab a Wells PS4 Oil Pressure Sender. This should fix your problem. If the gauge still shows no pressure when the wire is grounded to the engine, or with the new sender, check the engine grounds and repair as needed. Also check for continuity from the sender terminal and the engine block. If the ground and continuity is good, and you still have no pressure reading form the gauge when the wire is grounded to the engine or connected to the sender, check continuity on the wire (wire end and pin 11A at the cluster). If the circuit is open, repair. If you have continuity, the gauge module is probably at fault.

Hope this helps!