texas67coupe

hi guys,

I just installed these gauges from summit:

http://www.summitracing.com/parts/SUM-G2980

I am having issues with the readings.

The volts gauge is reading about 12.6V's, so no issues there.

The oil pressure gauge reads 0 with just key on, then stays at 45psi when car is on???? It doesn't move at all from there, car off 0, car on 45. I replaced the pressure sender and same thing.

the temp gauge reads 100 with car off (which is the minimum reading), and about 220 once i start the car (cold) and then it creaps into around 300 with the car running.

Any ideas on what i should check. I have checked all the wiring about 5 times. It isn't rocket science, 12V switched wire, a signal wire, and a ground. Thanks for any help.

MustangFTW

i dont think oil pressure should change much. the temp should never get to 300! could be faulty product.

texas67coupe

i could see if one gauge was bad, but 2 out of 3? I hope not. How would I even test that?

I don't think I should be getting 45 PSI at idle, or 220 or so degrees starting a cold engine. There is definately something wrong, I just don't know what it is.

The gauges did come with some sending units, but they don't fit the mustang. Any chance this could be the issue?

Gun Jam

I run a mech oil pressure gauge.. Oil pressure is very dynamic I get like 55psi cold idle and about 83psi cold above 2200 rpm. I get about 45 psi idle warm and about 70 psi warm above 2200...So point being is the oil pressure should be changing whenever the RPMs are changing and below 1800 rpm above there not much change. Same for volts I get about 12.6 at 700 rpm and about 14.3 above 1500.

You should at least see the volts change when you rap on the throttle. Thats the simplest gauge and if you cant get that to do anything (always reads 12.6) then I would send it back

kalli

you can't do much wrong measuring voltage. there is no difference the way it's measured no matter what gauge.

however for the oil pressure and temperature (I assume they are electric) there's a reason they send the sensors with it (so that it matches).

the sensor is nothing but a resistor that changes it's resistance depending n what it's supposed to measure.

example (this is valid for fuel level, water temperature, oil pressure etc).

stock sensor in fuel tank:
- when full it's 0 ohm
- when half empty 30 ohm
- when empty 60 ohm
(this is just an example, not real values)

you but a gauge with a different sensor that gives
- 30 when full
- 15 when half full
- 0 when empty
well the gauge will be going backwards, and only moving for half the sweep.

so from this, you could unplug your water temperature sensor, measure the engine temperature with an infrared thermometer (or siply guess it with outside temperature when cold). measure resistance over the tip of sensor agaist the thread of sensor and do the same with the new sensor in water. does that match?

a lot easier, simply attach the new water temperature sender to the new gauge, put it into a glass of cold water, check what gauges says
then add some boiling water and see if the gauge goes up, and finally shove the gauge into the boiling water and see what it says.

if that's all ok, you could try the same with your old gauge.
I just believe the old senders might be incompatible with the new gauges. at least there's a chance of that

tcrote5516

You need to use the senders that came with the gauges. A couple of adapters will solve the fitment issues.

texas67coupe

Thanks for all the replies. I will definately try the water dip test for the temp sensor. If that seems to make a big difference, I will go look at getting fitment adapters for the senders that came with the gauges. I will work on this one today.

scootchu

Yep the senders designed for the gauges will give accurate readings. If you are using the existing senders then you will have different resistance calibrated for the old gauges.

texas67coupe

well,

after staring at the fitting section at Lowe's for 30 minutes, i finally found the right ones. (they really need to have a better system) Came home, swaped it all out and it worked. temp reading 170ish after warming up in the driveway and oil pressure reading around 73 at idle and goes up and down with the press of the throttle. Thanks for all the help.

I can truly say nothing is ever an easy bolt on. Thanks for the help.

The gauges look great under the stereo in my 67 coupe. Who needs the old dash gauges anyway. I left the old wiring there to switch back if ever need to, but this is a world of difference and relief to know what the car is actually doing.