[Dr K]

Man this is a great board. Jazz, you're a resource, and not the only one on this board, either.

[73and88]

Jazzbass,

I just read your explanation of the DME Relay. The engine in my 1986 911 was starting intermittently. It would run for 4 or 5 minutes in idle, sometimes a little rough, then abruptly shut off. It would restart sometimes. I removed the DME relay. I noticed a white film of corrosion on pin 30. I removed the black plastic relay cover to expose the circuit board & two relays as you pictured.

Upon close scrutiny with a 7 power jewler's eyeloupe I was able to spot what may have been cracked solder connections on some of the circuit board. I reheated and added solder. Still no start after re-installing relay.

I noticed in your photo the copper braid on the relay furthest from the pins was discolored, probably from overheating. I see a similar discoloration on the braid of the same relay on my relay board. I'll call this relay (B). I also noticed a darkening of the coil winding wires on this relay. This usually indicates overheating of the wires.

There is a small resistor directly under the relay (B). It appears to be electrically across the coil of relay (B) yet this resistor is not shown in the diagram of the DME Relay you posted. It appears to have the color code of Blue, Green, Brown [ 650 ohms ]. I cannot make out the color of the tolerance band. When I measured across the coil of relay (B) with an ohmmeter I read 676 ohms which is in accord with the color bands and tolerance. The other relay nearest to the pins, I'll call relay (A) shows about 83 ohms across it's coil. This resistance is more in line with a 12 V relay of this size.

When applying 12 vdc across the coil of relay (A), relay (A) did indeed actuate. Applying 12 vdc across the coil of relay (B) had no effect. It did not activate. If the coil of relay (B) was indeed still good, I should have seen about 83 ohms or slightly less when measuring it's resistance. It seems that the coil of relay (B) is open.

I ordered 2 new relays that appear from the photo in the vendor's web site to be made in Hungary. My DME relay says made in W. Germany and it must be the original. It has 1986 date code.

That corrosion I spotted on pin #30 may have contributed to the early stages of poor starting. I plan to apply a thin film of silicone grease to all the pins of the new DME relay before installation in the socket. Over time I have found this reduces the risk of corrosion on electrical connectors.

Jazzbass, your posting was very helpful to me while trouble shooting. Photos excellent. Thank you for your concise info.

[73and88]

Here are some photos of the DME relay from a 1986 911. This appears to be the original unit. Note the area of corrosion on Pin #30.

Also see the areas of overheating on the copper braid of the relay on right and the discolored coil wiring. Compare colors of both coils.

The discolored coil appears to be "OPEN" when measured with ohmmeter. It reads the resistance of the 650 ohm resistor that is across the coil. Reading should be around 83 ohms.

[73and88]

Just received two DME Relays from Automotion/aka Eckler's. Their web site advertised it as a genuine Porsche part. The photo on the site shows the relay with the Porsche factory numbers and white lettering showing "MADE IN HUNGARY".

http://www.automotion.com/dme-relay-...1984-1989.html

The two relays I received from Eckler's have no factory numbers. It had a label marked uroparts. I found the company that imports them. APA in Simi Valley,CA.
I called them. Asked where this DME relay is made. They replied, "CHINA". In addition, there was no indication of the Country of Origin on the part or the package it was boxed in. This is possibly a violation of U.S. Customs regulations.

I refuse to knowingly use Chinese products in my car.

When I called Automotion/ aka Eckler's and complained about misrepresentation, the customer service rep claimed we don't go by the photos!

Moral of this story is: Be careful of where a part is manufactured before installing it in your car and don't assume the photo shown on a web site is what you will get. Especially if dealing with Automotion / aka Eckler's.

[BlackTalon]

This is pretty common these days. Not unique to Porsches, or to Automotion.

It's a chore to photo/ catalog a couple thousand parts; can't say I fault them for not having up-to-date pics of each and every part.

But the moral of the story is if you are intolerant of things from China, you may want to call and order your parts, and ask them to check each one.

[Lupin..the..3rd]

Originally Posted by 73and88

When I called Automotion/ aka Eckler's and complained about misrepresentation, the customer service rep claimed we don't go by the photos!

I'd be pissed too. Seems like false advertising. If you or I listed a part for sale on craigslist or ebay, and shipped something that wasn't the same as the photo, we'd be labeled as scammers.

But even if we ignore the photo, it is advertised as a "Genuine Porsche" part. What you received doesn't have a Porsche part number on it. And URO Parts isn't a supplier to Porsche. What you received is not a Genuine Porsche part. I'd complain and return it for a refund.

Also, URO parts has a poor reputation, at least in the MB world.

[Trak Ratt]

^ bet Porsche doesn't make their own relays or many other parts either. How about all the gen Porsche parts with VW and Audi emblems on them? Gen. Porsche parts can mean many things to many people. Global economy at it's best.

[Jazzbass]

Originally Posted by Trak Ratt

Gen. Porsche parts can mean many things to many people. Global economy at it's best.

Regardless of who the OEM is, "Genuine Porsche" does mean something - it means the part has passed Porsche's QC. Like Lupin said, it should be in a Porsche bag with a Porsche part number on it. What you see with a lot of places like Pelican, Automotion, etc, is that they buy parts directly from the OEM and not from Porsche. Sometimes this leads to the issue that the parts they get from the OEM are not quite up to the standards that the parts they sell to Porsche.

I learned this lesson the hard way with some OEM Lemforder ball joints I bought shortly after I got my car. Supposedly the exact same part that was on my car. The car at the time was 20 yrs old and while the ball joints were worn the boots were still intact. Within a year of installing, the boots on the replacements were cracked and torn.

If someone sold you a "Genuine Porsche" part and it wasn't in Porsche's packaging, send it back. Pelican is usually pretty good about letting you know the difference on their website.

[73and88]

I carefully examined the DME relay received from Eckler's. It is marked Uroparts. I could see some differences in the construction of the board and layout of components as compared with the original genuine Porsche DME relay board. More on this Uroparts DME Relay later.

I removed the defective relay from the original genuine Porsche DME Relay P.C. board. The coil was indeed "open". No connection. The other relay on the board is still operational. Looking at the white plastic molded parts of this defective relay I could see the plastic had darkened from what I think was overheating.

I have seen many postings in a few forums talking about DME Relay failures with some suggesting we all carry a spare in our glove box. There must be a reason for all these failures.

I had a few similar relays around that are made in Germany. Same coil resistance, physical size and shape and ratings as the original, now defective relay. For simplicity I'll call this relay (C). I applied 13.0 VDC to this relay's coil for 10 minutes. Each minute I checked the temperature of the relay coil (C) with an infrared temperature sensor. After 10 minutes elapsed the temperature reading was 173 degrees F. Impossible to touch for more than a split second. I then lowered the voltage to 12 VDC and after 10 minutes the temperature of the relay coil held at 152 degrees. Then I dropped voltage to 11 VDC and after 10 minutes the relay coil temperature dropped to about 125 degrees F. Bear in mind, this test was done in a room with 70 degree ambient temperature.

Based on the resistance of the coil, I calculated a current draw at 13.4 VDC of 161 milliamps. That equates to 2.16 watts. Since there are two of these relays in the black plastic box that house the "DME Relay" we are looking at a total wattage of 4.32 watts. That is a lot of heat that is being dissipated into a tiny box , 1"x 1"x 1.7". With no place for the heat to go those relay coils are probably reaching temperatures well over 173 degrees. It is no wonder the soldering connections on some failed DME Relay boards have been found to be cracked. It is also no surprise that the fine coil wires can eventually open and fail from this excessive heat. I'm certain the discoloration or darkening of the coil wiring and the surrounding components is from this extremely high heat being trapped inside that black 'dust' cover.

Possibly Porsche engineering realized this heat problem and tried to reduce the voltage going to one of the relay coils by putting a diode in series with the coil. Or they may have used the diode to reduce inductive spikes on the 12V line. In any case, the diode lowers the voltage around 7/10 of a volt. If the battery supply voltage getting to the DME Relay box is 13.4 VDC, which is a typical voltage it could see when the engine is running, the actual voltage to the relay with the diode in series with the coil would be 12.7 VDC. 12.7 VDC is only 3/10 of a volt less than the 13.0 VDC I used in my temperature test of the relay.

What can be done to lower the voltage to a point where the temperature of the coils would be at least 25 degrees or more cooler. And how can we get rid of some of that heat being generated by the both relay coils?

One method of cooling those coils would be by inserting 2 more diodes in series with the relay coil. That will give a voltage drop of 2.1 volts. With a supply voltage of 13.4, a 2.1 volt drop would leave us 11.3 volts. This would reduce operating temperatures by at least 25 degrees.

These relays will activate from 7 volts and up. Running them on 11 to 11.3 volts should not be cause for concern.

I recently replaced the bad relay in my DME Relay housing with one of those German Relays. I plan to install 2 additional diodes or use a Zener diode if I can find one that would be suitable for the proper voltage drop and current.

I have also drilled six 3/16" diameter holes in the upper part of the black DME Relay dust cover. Three on the top and 3 on the bottom. The top being the surface that faces up when the relay box is installed under the seat. This series of holes should allow some of that heat to flow out of the black housing which should reduce the internal temperatures.

I'll post more about the use of additional diodes after I install them and then try the complete assembly in my 1986 911.

[Dr K]

73and88,
That's an awful lot of posting, detail, testing, and labor on your relays, but I really want to know - did the car run with the new (Chinese) relays???