Name this part and its function and win
 

Greetings all:

I'm fishing around the engine compartment and open the case on the left side towards the rear. Relay's and fuses seem to reside. Sitting there all by itself was a yellow relay with a ground wire attached... 91161511800 but not plugged into anything and no apparent home. The parts list call it a mass air flow boost something... what is it and where does it go?

The winner gets a shinny new nickel.

That is an over-boost protection relay. It cuts the fuel pumps when you over boost in a turbo car.

and it just lays there for no apparent reason? Not that I mind as the part costs $150... just checking.

Should be plugged in the panel in the engine compartment on the left.

The wire attached to it is not long enough to reach the only socket that is in the vicinity... there is a red and black relay already occupying the sockets. The only available socket is towards the drivers seat (on the side panel) in front of the fuel pump and some vented electrical box (looks scary with warnings all over it) god I'm such a novice... so please pardon my ignorance.

The yellow relay is for later turbos, the early ones used the red relay.

They are very expensive.

Here is an early red relay:

http://forums.pelicanparts.com/uploa...1141586239.jpg

and here is a later yellow relay:

http://img297.imageshack.us/img297/4222/mvc017s5lc.jpg

My 930 is a 1986 (first year back to the states) are you suggesting that I remove the red relay and plug the yellow in?

Relay
 

I have an 86, and mine is yellow.

I had heard that the yellow relay was to keep the CD box producing spark after the ignition was cut off for 30 seconds so that unburned fuel in the engine, manifold was combusted. Do you hear the ignition box humming for 30 seconds after the car is shut off?
Just guessing, but keep the nickel and use it towards a new relay they are expensive......

Fred

Mark,
I just noticed something, but your engine is missing in the photos, you ogt bigger problems than just the yellow relay, ha,ha.
Fred

Neither of those pics are my car. However, my engine is out of the car. Mine is a 1979 with a red relay. Sounds like maybe 1986 was the transition year.

Just kidding with ya, I wanted to add some comedy relief to the forums becaus ehtye get too serious sometimes.
So what is the diff in function between the yellow and red relay?
Why can't you just run the cheaper one unless they add an extra function to the system?

I don't know the answer to that. I've heard different theories but nothing conclusive. Some say the yellow one is a quicker acting relay since it has a pcb thereby doing some of the work with IC. Some say there is a reduction in arcing on the contacts. Some claim other functionality. I have never had the opportunity to look at the guts of a yellow one (not that I would understand it anyway) so everthing you get from me is from what others say. As a result, everything I'm saying should be taken with a grain of salt.

Another point to conside ris that not many of us are the original owners of our cars, so yo really don;t know what mods were made to the electrical systems or any other parts of the car for that matter by previous owners.
Moral of the story is find out what is supposed to be the function of the parts for your system, determine what is missing or there in your car, and then decide on how to cost effectively fix it.
The factory owners manual is a must read for do it yourselfers or have a good mechanic you trust tell you how to correct evreything.

OK, Now you got me curious. 87 930 here. I have the yellow relay.

Mine swivels freely. Is it supposed to be locked into place somehow?

So what do we win here?

a new nickel ;)

My '87 has the yellow one.
I tried a red one to see if it would work and the car woud not start.

I took the yellow cover off and resoldered the solder joints and put it back.

I worry it will leave me stranded on the side of the road someday..

I'd like to know which pins to jump on the relay socket to let the car run if it ever fails.
Anyone know?

On my red one you jump pin 30 and pin 87a

149 smackaroonies:
http://www.**********.com/ShowItem/1745%20Porsche%20Over%20Boost%20Protection%20Relay .aspx

Swiveling relay???
 

What do you mean it swivels? When it is in the socket the socket turns???

Mine flops... it's just laying there on the box tethered on by the ground wire... I have a red relay in the socket with a yellow floppy relay right next to it...

I offered up a shinny nickel and we haven't got very far...

How about some pics?

Was just a coincidence that I had the rear deck open yesterday and was looking at that yellow thingy and wondering what it was. When I was looking at it I kinda moved it around and was suprised at how "loose" it seemed to be in there. So loose that I wondered if it was seated properly. The car is put away in the storage facility for the week but if I recall the yellow relay was sitting vertically towards the bumper end of the box and possibly in a round hole which seemed odd since the relay itself is square.

I did not screw around with it too much for fear of making an OK situation a bad situation. I just accepted it for what it was. Thanks to this thread I now know what it is, what it does, and that the cover to this electrical area is MIA. Wonder how risky that is with water and such flying around?

No worries, already ordered the new cover from our host.

Here's a few pics that might shed some light..

http://forums.pelicanparts.com/uploa...1205803467.gif
http://forums.pelicanparts.com/uploa...1205803490.gif
http://forums.pelicanparts.com/uploa...1205803508.gif
http://forums.pelicanparts.com/uploa...1205803519.gif

That was my car without the engine one time. It feels better now...


http://forums.pelicanparts.com/uploa...1205804086.jpg

My relay area looks just like that. The overboost relay is vertical in the same spot. No cover in your engine bay either.

I have it, I just don't use it very often.

Want to part with it?

Swiveling relay
 

I have the same question. Any insight on whether the yellow relay socket can be/needs to be tightened from the underneath side of the fuse/relay tray? Being loose like that seems like it might cause some connectivity issues when the car is in motion and therefore causing the pumps to cut out and the car either stall or not start??