VDO style combo gauge questions

914 or replica 356 gauges?  Photo? Are you sure the second sender is not for dash oil pressure idiot light?  (some solve both with a sender with dual connections.  Remember no teflon tape on senders - they must ground to engine block.  Temp sender is often in one of the oil pressure relief valves or the sump drain - at least they work better there. 

See the pics below.

Miss-matched sender would be my guess.

Who sells the correct sender for the gauge I have? Can you tell by the pic what type of gauge I have? VDO replica or authentic out of a 914? Thanks in advance.

Looks like your multi-gauge is an Asian reproduction.  They are supposed to work with regular VDO senders.

The senders work by providing different resistance to ground, depending on fuel level or temperature, respectively.  

If you go to each sender, remove the wire from it and ground the wire to something either under the hood or on the engine, the respective gauge needle should go from zero (left side) to full scale.  When you remove the wire on the fuel sender or engine sender from ground, the needles should return to zero.  You will not break the gauge by doing this (it's how they are supposed to work) and it will tell you if the gauge is working properly.  I suspect it is, and you have a sender issues as Bill mentioned.

Once you know that, then we can probably help you with the right senders (in a confusing way, of course!)    

Thanks for the help. I will get back with the results of your suggestion.

The oil temp gauge needle pegs to the right when the wire is grounded. So the sending unit is bad? How do I find the correct replacement?

Replica gauge - did it come from Beck SE recently?  Does it says Made in China or Brazil on back? 

The car was assembled in 2002 and then parked. So the gauges were not purchased recently. I have not been able to see any  made in marks. I would need to move a bit of wiring to see the backs of the gauges.

The temp range, resistance, on the sender will determine how much and where the needle moves in your Chinese gauge. 

If you look at your sender, there should be some #s engraved along the rim, that will tell you the model number, brand, and temp range.   See picture #1 bellow.  The numbers written in pencil were all taken from the engravings you can see on the sender.  The last line of numbers is the model number... which you can then use to find the " replacement part number on the VDO site. ( I attached at TH bottom of this post.)

 The attached information that may also be useful to you;

· For stock Type 1 VW engine cases/ and 356s, many engine builders are using OEM VW temperature senders because the are short, don't block oil flow, and will not trigger the pressure sender when installed in the same T fitting.

See picture #2 bellow - for reference to notes 1, 2, 3;

1- On the left is the VDO sender 323-427b, 300f, M10 x 1 thread, 22mm, long.

2- In the center is the OEM VW German made sender of the the same M10 x 1 thread, SHORT 10mm, 150c/300F. VW OEM part number #1H0 919 563 - oil temp sender, 0-150c range, used on for a bunch of 70s to late 90s VW cars. Also Audi cars.

They, both ( 1 and 2), have the same 10-180 Ohm range... The OEM VW short one can replace the M10 thread sender for the aftermarket VDO oil temp gauge with 150c/300f range. The short sender will not protrude into the oil passage like the longer VDO unit. The longer VDO unit can trigger the oil pressure sender.

3 - To the right is the more common and cheaper OEM VW sender part #049 919 501 - oil temp sender, short 10mm, 0-120c range also used for mid-70s to mid-90s VW stuff. And commonly used now for small aircooled engines.   I have the VDO version of this one installed in the car, part number 323-088.

4- not pictured, Then there's OEM VW #049 919 563A - oil temp sender, 0-180c range. Same M10 thread and looks just like the sender on the right but used in modern water cooled engines.

Picture #1

picture #2

Also,  you can find VDO senders at most local Autozones, NAPA, O'Reilleys, etc...  plus Amazon stores... but can also order them on line from many places at discounted prices.

Here is a useful store, witch includes great details- thread, resistance, temp range, and a picture...

-  http://www.egauges.com/VDO-Tem...-Senders-s/35438.htm

- https://www.vdo-instruments.co...sensor-only.html?p=1

- https://vdo-webshop.nl/en/34-t...ategory=34&n=125

Hope this helps...

2002 - You might be lucky and have the Brazilian replica gauge which is better than the Chinese ones that followed.  I'd pull the sender and look for a number on it.  This is one that goes in place of the drain plug but they all should have a number on them.

And make sure to remove any Teflon tape! It might just be as easy as  that...

Can you get a camera phone up behind your dash?

I wish I could see up under the dash. I will need to move a lot of wiring which I will do. I just hate working on under dash issues. Not an easy area for my to get to. The speedo worked for 5 minutes and quit also. Is it usually an issue at the wheel or at the speedo?. I assume the cable isn't being spun or has come undone some how. The car is very very nice with a strong 2276 engine with dual 44 Webers.  Just need to address these detail issues. The car was built and parked with 110 miles on it  in a temp. controlled building in a plastic inflatable cocoon.

Speedo driven off front left wheel hub - cable in square hole in bearing cap held by usually a c clip.  Check for C clip and cable sticking out.  

And or the gauge end next. Mine had the plastic collar that attaches the cable to the gauge split. Easy $1.00 fix.

I pulled the oil temp sender out. Wish I would have taken a picture of it. It is very short with no markings. I placed my voltmeter across it set to resistance. ( not sure the scale)It shows 1.2 ohms resistance cold and drop to zero when I heat it. As it cools the resistance climbs back to 1.2. I assume the thing is working. Not sure why I don't get gauge movement as oil heats. Maybe it is so short it isn't getting to the oil? I will continue to work on this and let you all know.

I've not seen a case tapped like yours. Usually there is a brass T fitting in the side area. The T's generally aren't big enough to hold a temp sender.  The oil pressure sender (black one) looks melted?? Same for the wire where the tape is.  Could the oil pressure sender be blocking flow to temp sender? The wire from front to rear could be bad.  Gauge might not be adequately grounded too.  If you can get to wire on back of temp gauge - you could check it for open front to rear or run wire from sender to gauge outside the vehicle. 

If your only getting a 1.2 ohms the sender could be bad.,.. most vdo 120c (250C) temperature senders have a resistance of 287ohm to 22.7ohm.... but it's also imortant to check the wiring/ ground on the gauge to eliminate possible sources of problems.

refernece for testing senders.  One of the links I posted earlier had ohm ranges for the senders asreference;

How to Troubleshoot VDO Sending Units- by Quinten Plummer-

VDO produces a third-party line of automotive gauges, ranging from temperature gauges to pressure gauges. VDO sending units monitor your automobile's components and processes and then report this information to your automobile's gauges. If you start to notice odd readings on your gauges, your automobile's components may not be at fault -- there may be a problem with your VDO senders.

1 Test a VDO temperature sender using a multimeter. Switch the multimeter to "Ohms." Touch the temperature sender with the multimeter positive lead, or clamp the positive lead to the sender. Touch or clamp the multimeter black lead to a solid metal portion of your car. The temperature sender ( at room temperature) should register 700 Ohms - 287 Ohm ( spending on sender model) when cold, and 22 Ohms after the car has warmed up.

2 Test the Ohm output of a VDO pressure sender using a multimeter. -- Set the multimeter to "Ohms." Touch or clamp the multimeter black lead to a solid metal portion of the car. Touch the sender with the multimeter positive lead. The sender should register 10 Ohms with the engine off. Start the engine and test the pressure sender again. For engines with 40 psi oil pumps, the sender should register 105 Ohms. It should register 152 Ohms for engines with 60 psi oil pumps.

3 Test your VDO fuel sender with a multimeter. Disconnect the fuel sender positive wire from the fuel gauge; disconnect the negative wire. Touch the negative lead of the multimeter to the negative wire and the positive lead to the positive wire. The fuel sender should show between 10 and 180 Ohms, depending on how much fuel is in the tank. It should register 10 Ohms on a full tank and 180 Ohms on a full tank. If your fuel level falls between full and empty, the Ohm output should register between 10 and 180 Ohms.

Also,  it's much easier to work on the gauges if you push them out of their sockets... from behind just push gently... the rubber gasket will release wth the right amount of pushing.  They will dangle from the cables through the hole, but enough for you to see, work and test all connections...

if your car is a VS I can send you their wiring diagram they sent me when they built the car... but always best to make your own, as not all cars are consistent.  The files i have are PDF... I can email, but don't know how to post PDF files on the site.

Remember, when touching the black ground leads, to metal, it must be clean unpainted metal to insure a good connection.