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Fuel/temp problem


Sastis

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So today I started my Datsun 510 for a drive. I noticed the fuel and temp just would just shoot up to hot/temp and full/fuel. How the heck do I remedy this problem? Check the fuse, temperature sender was replaced along with the thermostat. I replace my radiator with a koyorad and no I did not keep the fan blades or shroud. I am running a electric Pusher fan. It was running fine before I park it. It's always at full. No the cluster I'm using doesn't have a regulator because it never came with one. Help?

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510 and 521 wiring is very similar. I only know 521. On the back of the 521 cluster there is a small voltage regulator box bolted. Removing, cleaning the connections and reinstalling the box has been a fix to issues similar to what you have described.

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Take the instrument pod out, turn it upside down.  Very carefully remove the fuel/temp gauges, clean up the contacts.  Put it back in and be sure that the 4 screws are tight, reinstall!

 

I replace the cluster a few months back, so when you say clean the contact with what Doctor 510? The temperature/fuel read fine with the key is on position, however when it's run it would slowly creep to full.
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510 and 521 wiring is very similar. I only know 521. On the back of the 521 cluster there is a small voltage regulator box bolted. Removing, cleaning the connections and reinstalling the box has been a fix to issues similar to what you have described.

hey HOGIE, well this 510 is the 3 pod clusters gauge and not the sweeper dash. It doesn't come with the voltage regulator. So when you guys say clean, clean it with what?
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Well this just for the 521 gauge cluster voltage reg then.....The female part of the spade connector, nothing, but it did crimp it down to make it a tight fit reinstalled. The male spade fine sand paper or wire bush. The you can it with electric terminal cleaner, aerosol, or just a little vinegar on a shop towel.

 

You might find a wire diagram then and look for a similar regulator for the 510

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Well this just for the 521 gauge cluster voltage reg then.....The female part of the spade connector, nothing, but it did crimp it down to make it a tight fit reinstalled. The male spade fine sand paper or wire bush. The you can it with electric terminal cleaner, aerosol, or just a little vinegar on a shop towel.

You might find a wire diagram then and look for a similar regulator for the 510

I'll pull my cluster out and clean/re-tight it I'll post back if the sun doesn't kill me first.
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I just went through this on my '72 510 - I'd turn on the key and the fuel gauge would go to full. The engine had to warm up some before the temp pinned on high.

I removed the gauge pod, then the three screws that hold the small fuel/temp board to the back of the main board. These are small, shallow cross-head screws so choose a small screw driver that fits them well and won't slip. Once the fuel/temp gauge cluster is removed from the pod, you will see a tiny set of points below the two gauges. I assume this is the regulator for the two gauges. My points looked rather dark and burnt. I planned to very gently stroke between the points with very fine grit sandpaper to try to clean them but since I had a spare gauge pod I swapped the gauge cluster from that. So far the "new" gauges are reading just fine. I'm tempted in the interest of science to try cleaning the regulator points on my old gauges and reinstalling just to see if it will work. But I have lots of other 510ish things I should do instead so I probably won't get around to it. If you are able to clean your points please post how you did it.

If you can't breathe life back into your stock regulator you might look at this post on converting to an electronic regulator for the gauges:

http://community.ratsun.net/topic/54598-bad-gauge-cluster-voltage-regulator-easy-2-fix/

If something is broken on your stock regulator this might be a lot easier than trying to find another gauge cluster.

 

Len

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I don't know the 510 at all, I am a 521 guy, but if it is fine with the key on but not running, then it goes crazy when you start it, the first thing I would check is how many volts the alternator is putting out.

your thinking the voltage regulator for alternator is going bad wayno? I will check it soon as possible among other things. Can you believe this all started when my sister boyfriend mom passed away on Monday? It's been bad news ever since....
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your thinking the voltage regulator for alternator is going bad wayno? I will check it soon as possible among other things. Can you believe this all started when my sister boyfriend mom passed away on Monday? It's been bad news ever since....

 

If your gauges don't have a voltage regulator for the fuel/temp gauges, then maybe if you alternator is putting out a high voltage, it might effect the gauges, but as I said, I know nothing about the 510 at all other than what one looks like.

I said that would be the first thing I would check as that is easy to do, you don't have to pull apart anything.

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So today I started my Datsun 510 for a drive. I noticed the fuel and temp just would just shoot up to hot/temp and full/fuel. How the heck do I remedy this problem? Check the fuse, temperature sender was replaced along with the thermostat. I replace my radiator with a koyorad and no I did not keep the fan blades or shroud. I am running a electric Pusher fan. It was running fine before I park it. It's always at full. No the cluster I'm using doesn't have a regulator because it never came with one. Help?

Are these the stock gauges? After market??

 

How do you know there is no regulator?

 

The regulator produces a steady 6-8 volt supply for both gauges. This avoids the 12 volt with the engine off and the full 14.3(ish) at full charge fluctuation of the gauges.. Like reading low when you pull to a stop light with headlights and or heater on. The stock gauges are calibrated for this 8? volt supply and will read about 70% higher without it.

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Are these the stock gauges? After market??

How do you know there is no regulator?

The regulator produces a steady 6-8 volt supply for both gauges. This avoids the 12 volt with the engine off and the full 14.3(ish) at full charge fluctuation of the gauges.. Like reading low when you pull to a stop light with headlights and or heater on. The stock gauges are calibrated for this 8? volt supply and will read about 70% higher without it.

these are stock gauges mike and yes you are right. The gauge do come with a regulator built inside like the 620. I could be wrong because there are 3 different cluster that I'm aware of. The sweeper, 3 pod cluster and the none-us cluster one.
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Link to Dropbox with quicky pics I did this morning of my '72 520 gauge cluster. I want to re-shoot these when I have more time. What I guess is the voltage regulator is the set of points with the green wire, located behind the two gauges. If I'm wrong about this being the regulator, someone please let me know.

 

https://www.dropbox.com/sh/2y93icaof58g1q0/AABPhTfw_a88r8xfohSZVEGCa?dl=0

 

Leaving for Spokane right now or I would post more (and better pics).

 

Len

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If the regulator is missing how are you supplying power to the fuel/temp gauges??????

Mike there are two or three different cluster/gauge for 510, I could be wrong. There is a sweeper dash that looks like a 521 that use a regulator on the outside board. I have the 3 pod gauge that has a regulator on the built on inside gauge like the 620. Can someone please correct me!
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Racerx, it's a 1970 and I also clean it out with vinegar over night. Replace fuse 2 times already. Replace temperature sender, I will be replacing my thermostat on my days off. Again the temperature​ and fuel gauge creep to full blast when I give it gas. Head gasket blown maybe? I also let it warm up with the cap off. No bubbles that I see off. Upper radiator hose is soft and hot, lower radiator hole is cold. Compression check after the thermostat. It's a lz24 and z24 are prone to head gasket failure from years of lurking. Help

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You sure it does not have a voltage regulator on the cluster?  Mine is a 71 and fairly sure it's like a 70 and has a voltage regulator. Google Datsun 510 fuel/temp cluster voltage regulator and you should see a picture of it.

 

when you checked the fuse did you take it out and ohmed it out? Don't think it's a head gasket since both temp and fuel is going up.  You can check your dipstick and/or oil filler cap and if oil looks like chocolate milk and smoking white smoke then head gasket.

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You sure it does not have a voltage regulator on the cluster?  Mine is a 71 and fairly sure it's like a 70 and has a voltage regulator. Google Datsun 510 fuel/temp cluster voltage regulator and you should see a picture of it.

 

when you checked the fuse did you take it out and ohmed it out? Don't think it's a head gasket since both temp and fuel is going up.  You can check your dipstick and/or oil filler cap and if oil looks like chocolate milk and smoking white smoke then head gasket.

not chocolate milk or smoking white smoke, but I could be wrong again I'll check and recheck it again on my day off. Sadly don't have a ohm reader I'll go buy one asap, at what ohm should it be reading?
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Since you posted that both the temp and fuel gauges are reading high, I wouldn't think very much about a blown head gasket. Not to say it isn't possible, but why would the fuel gauge read high too (unless your tank is completely full - in which case I would siphon out a few gallons so you know the gauge should read a partial tankful)?

 

I'm still thinking this is a faulty regulator for the gauges. I briefly played with the gauge cluster I posted the Dropbox pics of. I used jumper wires from the gauges to the battery. When the regulator points are closed the fuel gauge climbs to "Full". When the points are held open, the gauges don't move. I get the idea that by opening and closing, these points maintain approx. 8 volts to the gauges. If your regulator points aren't opening when they should, the gauges are getting a constant 12V and pinning on high. But I don't have a fix (yet). I'm going to try cleaning my gauge regulator points (I finally found fine sandpaper late this afternoon) and re-install them.

 

If the gauges don't get power (say from a bad fuse) they won't read at all.

 

Len

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