Click to view attachmentHello everyone, after being on the 914 club for almost a year, I finally decided to join the 914 world. I don't know what the story is but there has to be something in common here, other than the main topic of course...

Now to the main subject. I was driving on the highway at about 70-75mph for about a half hour yesterday and this is what my temperature gauge was showing. The outside temperature was about 80-85 SoCal.
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As a matter of fact, the guage takes the longest time to get up. So, I guess there is only two things that can be wrong, the guage or the sensor in the taco plate. Is there a simple way to verify them? Is there some measurement that I can do with a standard voltmeter?

Thank you

Well, yes, you can do an ohm reading on the sensor, but why is your volt gauge showing 10 volts? I know mine does if I have the lights on and step on the brakes without the car running, but does yours read there all the time? And it should read slowly, oil takes a while to warm up. Do you have an external cooler on the car?

OK, if I do an ohm reading, what am I suppose to be expecting for a certain position on the gauge and what should be the needle position at normal operating temperature (80 -85F outside temp).
I have a stock 2.0 FI, no mods except Bursch exhaust.
The volt gauge is sort of random. It does move with flasher (normal) but I don't think the ground is proper. BTW, isn't there a better way of wiring the voltmeter guage to get an accurate reading (flasher or no)?
Thanks

I live in Anaheim Hills and that temp reading is spot on in SoCal.

Should be about 240-252 at the heads. I have an infrared heat meter and at full temp, the gauge indicator never gets past the T in Temp in this area.

And you have your foot on the brake in the picture. I can see your leg, but the gas pedal is clearly visible.

Mine doesn't go down to 10 volts, but brakes and signals sure makes it move below 12.

What is it at when your foot is off the brake? Should be 13.5V.

John

Also remember that the temp travel is shorter on the wide-red-band temp guage - as opposed to the later ones with the short red zone. IIRC the red zone on yours starts at about 450 deg., so divide up about 60% of the gauge arc & I agree with avidfanjpl/John above - you're about right for a 80 degree SoCal drive.

that is an oil temp gauge, not a head temp gauge. Therefore, it will take a longish time to get up, as you have to wait for 4 quarts of oil to warm up.

Oil temps and head temps can be (but are not always) unrelated.

Oil temps go up with engine revs. So, if you are doing a lot of driving in 5th at 70 you are only barely turning 3K rpm. This will keep your oil cool. Doing the same 1/2 hour run in 4th will raise your revs about 1000rpm and you will see your oil temps rise too.

As an example, before I put my secondary oil cooler in...
my way to work in the morning is 45 miles, mostly freeway, and almost all of it is downhill. The trip takes about 45 minutes, and at the end of it my oil temps may only barely be 190 degrees. The trip is in 5 gear, and even though the car is moving quick, the engine is spinning slow.

on my way home, the same 45 mile drive is still freeway, but almost all uphill. I have to keep the car in 4th to keep head temps down, and this revs the engine to about 4K+ for the entire drive home. Even with the oil cooler, my OTs are pushing near 220 - though my head temps are very happy around 365 - even after 30 minutes of constant climbing at 70+ mph.

I'd say you are probably fine.

Zach

Also, if your cable is broken to the cooling flaps, it'll take longer for the engine to warm up.

On the later type Oil Temp Guages with the shorter red zone, where would you estimate the normal temp setting I am in Southern Florida which averages about 93 degrees with matching humidity. My guage is showing the needle over the E in Temp. Would that be considered normal?

Just checking as this is the first Summer this car has been running in 10 years.

Thanks,

Vysoc

I'm in Miami and I also have the shorter red gauge and my needle gets up to the P when I am on the expressway at 70mph, it moves down to the M in the city, but never goes below it. I have measured the taco plate temp with an infrared gauge and it's about 220-230 at the P. Not bad considering the heat here. Engine is a 2.0L with a cam, 40 dells and a bursch exhaust.

i have a short red gauge and mine stays up high but never gets to red but it still worries me when i see it that high. i just wanna cover it up so i dont' worry so much lol

Thanks for the information especially from the my neighbor in Miami, I will be sleeping better this evening. My set up is a 75 chassis with a '73 GA 2.0 engine
DJet FI car has run great since rebirth, just really did'nt know what to expect for engine temps etc.

I plan on running it up to Sebring on the back road highways to see how she will handle a hour and forty minute run.

Thank you for your input and I apologize for the hijack on the thread.

Vysoc

I'm glad to see that this is a good reading on my temperature gauge but this one is for the oil.
For the voltmeter, it is at about 12V and I did a reading with a digital meter on the connectors on the back of the gauge and got 12.3V. I have no poblem starting the car. The battery doesn't seem to be low. I even parked my car the other day with the left blinker on (the left blinker stays continously on even without the key) and after my days work, the car started right away.

Thank you for this information, what kind of head temperature gauge do you have. 20 years ago, I had a vw beetle with a 1776cc dual dellortos and had installed the VDO one with the ring that goes under the spark plug. Do you feel this gauge is a must? Do 2.0 heads typically run hot?

The PO has removed the thermostat for some reason. I would like to reinstall it. Haven't look yet to see if the flaps are still there. I assume this is not a big job to do. I first need to find a good deal on a used unit.

That's why I'm told on the later models they moved the red mark further to the right.
That gives you an idea as to how much information the temp gauge actually gives you.

these gages need to run with the correct matching sendor, there are several ranges fo sendors an d gages that might have been swapped out, so confirm that they are a mtached set.


for the stock gage, the middle or range is nearly 240F, which is too hot for my oil temp.
note that the early gages had a larger (ie lower) red zone. since these car would run too hot in hot climates, under hard driving, the temp gage often read in the red zone, so rumor has it, the factory fixed the probelm by painting a high temp red zone, so as to not continue freaking out the customers.

I wish my oil would run at 180F all day without teh need for an auxilary cooler.

I suspect the original poster has an innacurate gage. in my climate on a 70-80F ambiaent temp day, after 15 minutes at 65 mph I can see 220F, even more if I am pusshing a grade. that is why i suspect your temp gage reading is not right. (unless you have a very very cool motor!!)

I would calibrate that gage by sticking a known good thermocouple wire into teh sump of a hot engine, via the dipstick hole,and calibrate yoru dash gage to that. they you know what temp yoru really at. a nice target is 180F for sump temp. the temps of north of 230 f are not good for the oil/enigne.

make sure your temp gage is reading right, note with a magic marker or colored tape a true red zone and normal zone for your gage verses a calibration gage. set yoru red line at 240F (that means slow down, pull over cool it off, that is Too hot!!!!) or maybe a bit prior to that. set yoru green happy happy zone for 180-210F.

dont ignore the gage just becuase it dont have numbers, find out what the calibration is, mark the gage, and live within the temp ranges set. if your oil is too hot, chack engine conditon for fualts, failing to fix then you might want to add an auxilary cooler.



for the voltage gage, I really like to read the spark coil voltage, that one is imortant to me. so that is how my volt gage is reading, right off the coil.


have fun, stay cool, be cool, keep your oil cool. thats cool!!!!!!!!

I changed out all of the console gauges to 2 1/16" VDO gauges, instead of the larger stock types.

For my OT gauge, I bought a 2 1/16 inch VDO calibrated gauge AND sender. I like calibrated gauges, I don't like guessing.

For my head temps I did not buy VDO. The Dakota Digital head temp gauge with a spark plug type sender came very highly recommended from several different sources. It is the only gauge on my car that is not VDO and looks a little out of place, but it is also the easiest gauge to read in my car, and I know in a glance EXACTLY how hot my heads are, to the degree. I like it a LOT.

I have a VDO voltage gauge, but I do not trust it. Many many people have commented on how the wire path to the gauge is too attenuated to give an accurate view of your charging system. I only use it to be sure that the charging system is charging properly and that I am not one day making 18 volts out of the alternator and boiling my battery. Turning on the lights and the windshield wipers at the same time causes the gauge to read at 10 volts, which is silly.

I plan to add a wideband to my exhaust maybe over the winter and will need to run a wire for it, and find a place to put another gauge. Dunno where the gauge is going to go. maybe replace the clock?

Zach

Click to view attachment
This morning after my ride to work(15 min on hway) here is the reading. Outside temperature is 65-68F. I probed my battery at Idle at the end of the ride and it was at 13V , next I probed the coil and it was at 12V. I guess I should have reved the engine to get the alternator kiking, will do that later today.

I will try to measure the oil temp with a thermocouple.

BTW how do I confirm that the sender and gauge are a match set? Is there an identification somewhere or part number?

Thanks.

[quote name='Vacca Rabite' date='Aug 13 2010, 06:41 AM' post='1355865']
I changed out all of the console gauges to 2 1/16" VDO gauges, instead of the larger stock types.

For my OT gauge, I bought a 2 1/16 inch VDO calibrated gauge AND sender. I like calibrated gauges, I don't like guessing.

For my head temps I did not buy VDO. The Dakota Digital head temp gauge with a spark plug type sender came very highly recommended from several different sources. It is the only gauge on my car that is not VDO and looks a little out of place, but it is also the easiest gauge to read in my car, and I know in a glance EXACTLY how hot my heads are, to the degree. I like it a LOT.

I have a VDO voltage gauge, but I do not trust it. Many many people have commented on how the wire path to the gauge is too attenuated to give an accurate view of your charging system. I only use it to be sure that the charging system is charging properly and that I am not one day making 18 volts out of the alternator and boiling my battery. Turning on the lights and the windshield wipers at the same time causes the gauge to read at 10 volts, which is silly.

I plan to add a wideband to my exhaust maybe over the winter and will need to run a wire for it, and find a place to put another gauge. Dunno where the gauge is going to go. maybe replace the clock?

Zach



just wonder how you buy a calibrated gage and sendor???? how can you trust the calibration if it is not wired all togther and working in your car????

to assure you got calibration, the gage should be installed with sendor, then tested aginst a known good standard, then it can be calibrated with your own marks on the gage. if you change the wiring (with assosiacted resistances) such when installing, you cant be sure the calibration done outside of the car is still correct.

i suggest for best results to calibrate once installed. then you can be assured it is right.

Or, use a dipstick thermometer (as I have installed on my car) to verify that the OT gauge/sender I installed with stock wiring was accurate. It was 5 degrees off what the Mainley dipstick thermometer was reading, but that is close enough for my uses. Its still more accurate then using the stock gauge with no graduation marks.

For the head temp gauge, I used a dedicated thermocouple and wire combo made precisely for the head temp gauge. It does not run through any of the stock 914 wires.

Zach

[quote name='realred914' date='Aug 13 2010, 09:24 AM' post='1355930']
[quote name='Vacca Rabite' date='Aug 13 2010, 06:41 AM' post='1355865']
I changed out all of the console gauges to 2 1/16" VDO gauges, instead of the larger stock types.

For my OT gauge, I bought a 2 1/16 inch VDO calibrated gauge AND sender. I like calibrated gauges, I don't like guessing.

For my head temps I did not buy VDO. The Dakota Digital head temp gauge with a spark plug type sender came very highly recommended from several different sources. It is the only gauge on my car that is not VDO and looks a little out of place, but it is also the easiest gauge to read in my car, and I know in a glance EXACTLY how hot my heads are, to the degree. I like it a LOT.

I have a VDO voltage gauge, but I do not trust it. Many many people have commented on how the wire path to the gauge is too attenuated to give an accurate view of your charging system. I only use it to be sure that the charging system is charging properly and that I am not one day making 18 volts out of the alternator and boiling my battery. Turning on the lights and the windshield wipers at the same time causes the gauge to read at 10 volts, which is silly.

I plan to add a wideband to my exhaust maybe over the winter and will need to run a wire for it, and find a place to put another gauge. Dunno where the gauge is going to go. maybe replace the clock?

Zach



just wonder how you buy a calibrated gage and sendor???? how can you trust the calibration if it is not wired all togther and working in your car????

to assure you got calibration, the gage should be installed with sendor, then tested aginst a known good standard, then it can be calibrated with your own marks on the gage. if you change the wiring (with assosiacted resistances) such when installing, you cant be sure the calibration done outside of the car is still correct.

i suggest for best results to calibrate once installed. then you can be assured it is right.
[/quote]

Actually, I think what you want is temperature compesating gauges. Check this link out. These are meant for aircraft, so I would assume the calibration standards are rigid.

http://www.aircraftspruce.com/menus/in/cht..._micro1000.html

[quote name='jeffdon' date='Aug 13 2010, 09:44 AM' post='1355936']
[quote name='realred914' date='Aug 13 2010, 09:24 AM' post='1355930']
[quote name='Vacca Rabite' date='Aug 13 2010, 06:41 AM' post='1355865']
I changed out all of the console gauges to 2 1/16" VDO gauges, instead of the larger stock types.

For my OT gauge, I bought a 2 1/16 inch VDO calibrated gauge AND sender. I like calibrated gauges, I don't like guessing.

For my head temps I did not buy VDO. The Dakota Digital head temp gauge with a spark plug type sender came very highly recommended from several different sources. It is the only gauge on my car that is not VDO and looks a little out of place, but it is also the easiest gauge to read in my car, and I know in a glance EXACTLY how hot my heads are, to the degree. I like it a LOT.

I have a VDO voltage gauge, but I do not trust it. Many many people have commented on how the wire path to the gauge is too attenuated to give an accurate view of your charging system. I only use it to be sure that the charging system is charging properly and that I am not one day making 18 volts out of the alternator and boiling my battery. Turning on the lights and the windshield wipers at the same time causes the gauge to read at 10 volts, which is silly.

I plan to add a wideband to my exhaust maybe over the winter and will need to run a wire for it, and find a place to put another gauge. Dunno where the gauge is going to go. maybe replace the clock?

Zach



just wonder how you buy a calibrated gage and sendor???? how can you trust the calibration if it is not wired all togther and working in your car????

to assure you got calibration, the gage should be installed with sendor, then tested aginst a known good standard, then it can be calibrated with your own marks on the gage. if you change the wiring (with assosiacted resistances) such when installing, you cant be sure the calibration done outside of the car is still correct.

i suggest for best results to calibrate once installed. then you can be assured it is right.
[/quote]

Actually, I think what you want is temperature compesating gauges. Check this link out. These are meant for aircraft, so I would assume the calibration standards are rigid.

http://www.aircraftspruce.com/menus/in/cht..._micro1000.html
[/quote]


a compensting gage is usually done with thermocouple (TC) gages, as they read the difference in temps (millivolt signal) between the thermocouple junction and the gage itself. so on a hot day your gage may be at 90F and on a cold day the cockpit gage might be 40F tyhat would result in a 50F difference in the same junction temperature. hence the need for compensation for thermocouple based systems. (ie head temps and exhuast temps are often Thermocouple based.) my head temp gage reads cooler on a hot day than a cold day! all becuase of the differances in the cockpit (gage) ambient temp! I dont have this temp comnpensated.

the resistance type gage (used for oil temp) does not require temp compensation as the TC gage does. in this system you not measuring millivolt signals generated by the TC junction, instead your reading the resistance at the sendor this will not change much with amibeint temp chnages at teh gage, hence temp compensation is not generally needed for a resistance gage.

the compensating TC type of system uses a resistance type temp sensor inside the gage (in the cockpit) to get the cockpit temp, then uses that value to compensate the TC reading from the sendor.

remember a TC systemn actually generates a voltage (two disimular metal wires when tied togterh tat one end, will genertate a small voltage if there is a temperature differeance between teh junction end and the measurement end. that voltage is dependant on the temp differance from the junction end (sendor) and the meter (gage) hence compensation is needed for the most accurate readings with a thermocouple.

however final calibration should be done with the gage(s) installed, so that all voltage drops and wire resistance is taken into account and then the scale on the gage can be corrected as needed.