FI Owners: Keep an extra double relay in your emergency kit

[SunnySideUp]

There are several posts on the forum about the double relay for FI cars. I read on one of the posts where Csaba recommended keeping an extra double relay in your emergency kit "just in case." Today that advice paid off. I was getting ready to go to a meet-up and my car would turn over but not fire up. I know it could be one of 100 things that could keep my Spider from starting. It ran fine a week ago! Just on the off-chance I swapped out the double relay and tried again - BOOM Baby! Fired right up. Now I just need to replenish my spare double relay.

I know they are a bit pricey, but it beats being left out of the fun, or worse - stranded. I highly recommend having a spare double relay in your emergency kit "just in case."

[spider2081]

Did you put the original back in to prove the original relay is bad????

[SunnySideUp]

Did you put the original back in to prove the original relay is bad????

Sure did. I put the old relay back in and it would not start. I was kind of hoping that it was something more simple and that I wouldn't have to use my spare. Just lucky this time I guess.

[brackie1]

Not being a mechanic, I don't know what a double relay is and where it is located.

[4uall]

this might help

http://marketplaceadvisor.channeladviso ... 298-OE.jpg

[brackie1]

Since I have a 78 carb model I guess this dosen't apply to me.

[spider2081]

Sunnyside The reason I asked is: I read somewhere there is a resistor on the PC board in the double relay that over heats and fails. I opened 3 relays that were good and saw no evidence of any over heating. The cover comes off fairly easy if you haven't discarded it could you take a look inside?? If you do see a burnt part I could tell you what it is from one of my good ones. This might be good to know.

[bradartigue]

Sunnyside The reason I asked is: I read somewhere there is a resistor on the PC board in the double relay that over heats and fails. I opened 3 relays that were good and saw no evidence of any over heating. The cover comes off fairly easy if you haven't discarded it could you take a look inside?? If you do see a burnt part I could tell you what it is from one of my good ones. This might be good to know.

Whatever causes them fail is not the relay itself; they are extremely reliable in most cars - I've always suspected the flaky electrical system in our cars causes too much resistance (e.g. heat) and the switch overloads and fails. Or a component upstream of the switch overheats due to the switch having taken the brunt of resistance. Whatever it is, I don't think the switch is the culprit, I've always thought it might be the victim.

[spider2081]

agreed Brad
I think the article I read was in a Volkswagen site. It suggested the relay has an under rated resistor that should be a higher wattage. Over time the resistor overheats and fails. I have not seen any over heated or defective relays. I have seen failed relay connector contacts.
I think a failing fuel pump could draw more than designed current and cause premature failure of the relay, especially the relay contacts.
No part can last forever so the dual relay will fail however from reading the chat room posts I think some are replaced unnecessarily.

[SunnySideUp]

Reviving this thread specifically to obtain technical info on the resistor that spider2081 and bradartique mention.

A while back I took spider2081's suggestion and opened up the original relay I pulled. It had a burn marks on the contacts. Recently I had another double relay go bad - or so it seems. I had a no-start issue so pulled the double relay and popped its cover and found it clean with no burn marks. I had it tested by an automotive tech and he found that it was good. The action of removing the relay and reinstalling it seemed to solve the issue as the car started up and away I went. BTW - all the harness contacts are clean. Then several weeks later during a *hot* drive my Spider died like it was starved for fuel. Temps were in the upper 80's and I was going up a mountain pass doing some spirited driving with a local club. Car had 1/2 tank of fuel from a fresh fill up (Shell premium) and the temp gauge was reading a hair to the right of the "0" of the 190 mark. The cooling fan was running. The car had a new fuel tank and a new fuel pump installed prior to the run. I was fortunate to coast the car to a pull out. We did some trouble shooting and found that the fuel pump was not getting power. Out of curiosity I pulled the double relay which was very warm. While it was out it "clicked" meaning that the relay itself made a click sound. I reinstalled it and the car fired right up. It's been happy for the past few months. The really good driving weather is here in southern Arizona and I don't want to get stuck fiddling with the relay again while out on a drive.

My question is this: Where - specifically - is the resistor mentioned in the previous replies to my original post and what is the recommended upgrade/replacement? A link to another thread on the solution, a repair article, photos, etc. would be very helpful.

[spider2081]

Here is one of the links that discusses the dual relay

http://www.alfabb.com/bb/forums/alfetta ... et-al.html

If you have opened a relay and a visual inspection nothing looks overheated and the relay contacts look clean it may very well be ok.
The link mentions a need to unsolder one end of the resistor to measure the resistance. I don't believe this is necessary as long as the relay is unplugged from the car. When the dual relay is unplugged from the car one side of the resistor is not connected to anything. I opened a couple relays and the color code on the resistors was red,violet, gold ,gold. This should mean the resistor is a 2.7 ohm +/- 5% resistor.

It might be informative to remove the cover from the relay and then run the car. Watching the relay operation, That way you can see how the control relay and the fuel pump relay inside operate. Be sure you have the 2 plugs in the correct positions when doing this.

The fuel pump relay also powers the Aux Air Regulator. So a problem with the AAR or its wires could cause dual relay problems.
Hope this helps