Emissions Fan (pump) Relay Description/ Help?

FChat

Aurrrrgh.

Long night staring at the dread laptop.

As I work to make the Ferrari emission system function perfectly, I have been figuring out the evaporative side of things. I repaired the flap that closes off the airbox, and figured out the wiring for the little fan/pump that pulls air from the closed off airbox and pumps it through the charcoal cannister. The pump now works (I had to hit it with a hammer, lightly!). But the pump never shuts off. It is supposed to turn on after the ignition is switched off, and then run for about 15 minutes. I feel this is a LONG time, but ...

The pump turns on now, but doesn't shut off. I let it run for about 20+ minutes to see. the commone failure mode reported seems to be pump runs until battery death, so people unplug the relay. My relay was unplugged, and for good reason.

Replacement relay? I doubit it. I can't find it on the microfiche. I can find the pump, but no mention of the relay. There's a number on the plastic case that houses the relay, 111736 but I can't find that on the main part supplier websites I checked, and I really couldn't stomach paying 150$ for it if I found it (the small airpump seems to list from 200-350$ -it's a good thing it just needed a Lucas type repair with the hammer). I am somewhat cheap and poorish. The only two mentions of this on Fchat don't describe the system.

The relay is inside a small plastic box labelled Ferrari and 111736. Inside is a sipea relay connected to a circuit board with a chip. In 1979! A chip. To run a fan! The numbers on the chip lead me to a Raytheon clock timer (RV555NB). I can't tell what's wrong with the circuit board - bad chip? Who knows. It has 11 resistors, 1 chip, 3 capacitors, and a small silver cylinder I can not id and can't read the numbers off of. It is a sipea relay, but has no Sipea numbers on it. The circuit board reads 8066B but that doesn't google anything useful. I see no loose connections, loose solder, cracks in the solder. IT appears ok but does not work properly. This seems like the general failure mode of old relays.

As far as I can tell, the system works like this - ignition switch to off position sends 12V to relay via blue wire and 8A fuse seperate from the fuse box. This activates the relay for 15 minutes, at which time the chip should shut off the relay's output. The unit resets itself when the ignition switch gets turned back on and the blue wire no longer has 12V. This jibes perfectly with the wiring diagram that Paul has posted here before and his fabulous 308 wiring webpage.

I believe the proper name for this is a delay-off relay. I have searched and searched for delay off relays. It seems that Volvo uses them on a car but the wiring looks very different. There's one for Saab radiator fans, but I also found a Saab service letter from approx '85 that says to replace them with normal relays bc the delay relay of the day kept draining batteries overnight. Similar problem there in Saabville as at Ferrari. It seems that time delay relays of the 1970s and 1980s were not too reliable.

Many modern cars seem to have circuit boards to control electric radiator fans (ala Acura). I want to make my system work, but not go about building hugely complex

There's a company in Australia called Auto Electrical Imports that makes a very nice looking adjustable delay-off relay, but their catalog does not list prices & they appear to be a wholesaler only. They call their parts Ionnic and their TIM05 looks like what I need.

This modern relay is made with solid state stuff, so no moving parts to wear out. I have written them to see if they have a US distributor, or can put me in touch with an Austrailian company that will sell to me. Of course the car works just fine without the little fan, but it would be nice if these things could be sourced. Harder to find than those fancy cad plated ribbon clamps for my airbox bellows.

I may have to appeal to the Australian contingent if I can't buy them from here.

Has anyone sourced a delay-off modern relay (not a NOS Sipea from 1979 that will fail!) for this application?

I'll add photos when i borrow a camera (alas, still no camera)

Jonathan
Denver, CO
GT4 15302

 

Voicey
If the fan/pump runs while the car is on, it won't really do anything. Now, I have no idea how much pollution this actually saves, but the theory is that after shut down, some fuel evaporates from the carbs. You can smell this. With modern fuels, it seems more prevalent than just a couple years ago (I hate E10).

Instead of these fumes just leaking out into my garage and atmosphere, this pump will put the evaporative emissions into the charcoal canister. Upon restart, the charcoal canister feeds back into the air-box via a vacuum line. The bottom of the charcoal canister inhales hot air from near the headers - the hot air causes the charcoal to release the evap fumes it earlier sequestered, and those fumes get burned in the running engine. It actually seems quite clever, assuming the system works. But the fan must run while the engine is off to perform this, but surely can't run all night!

While the engine is running that little pump could never overcome the vacuum of the engine and would be even more worthless than it is.

Since the system costs no horsepower and does not change drivability I have decided to repair it to proper working order - if I can!

Jonathan