Don't see how you can say this Paul when the operation of the coolant thermoswitch ("sensitive switch 7 Fig 44") is described in opposite ways on pages D59 and D60 in WSM 281/83 -- can both be "right"? Also, if you re-review the wiring diagram in either the 186/80 or 216/81 OMs, you'll find that one side of the cold-running warning light 48 is always at ground. The other side of cold-running warning light 48 is connected to the SN wire that has the following behavior: When cold (and the coolant thermoswitch 73 is open), the SN wire is at a positive voltage via the electrovalve coils and the R wire on their other terminal (even though the electrovalves are unenergized) -- this causes the cold-running warning light to illuminate, and no vacuum reaches the cold start air valve so it is open and raises the engine idle RPM. When warm, the coolant thermoswitch 73 closes which connects the SN wire to ground, this extinguishes the cold-running warning light and energizes the electrovalves (putting vacuum on the cold start air valve to close it). If you want to argue about this, please explain how the cold-running warning light 48 can be illuminated, if the coolant thermoswitch 73 is closed during cold-running, and both terminals on the cold-running warning light 48 are at ground.
Steve, that is correct ... and exactly what happened on my fast cold idle system (before I modified it) as soon as I connected the two wires of the coolant thermoswitch, (which says nothing short of: "hello, I´m warm already" ) ...consequently I never had any "fast idle" and the "cold running warning light" never iluminated again....which of course was intended by this mod . Image Unavailable, Please Login
Anyone have a coolant thermoswitch (open when cold) they would like to sell? The one on my 83 308 QV is toast.
All, The early carb cars at least the GT4 seem to have a coolant mechanism which seems to act on the carb throttle shaft. Mine was disengaged from when I bought the car. Rob Image Unavailable, Please Login
In the 1983 there were both lambda and non-lambda US cars on the line. Some cars had an 'open' thermoswitch. Some had a 'closed' thermoswitch. And some had TWO thermoswitches. This was documented in several threads a few years back. Here is one of them. http://www.ferrarichat.com/forum/showpost.php?p=139019601&postcount=1 During this cross-over period of adding lambda to US cars, Ferrari switched to the newer thermoswitch, removed the 'cool engine' dash light, and reversed the fast idle electrovalve vacuum plumbing. Image Unavailable, Please Login
Paul, My Mondial has two thermoswitches, but the other one is a vacuum switch, not an electrical switch. It has two hose ports on it just like the one you show (except one of your hose nipples is broken off). I forget now what the vacuum switch was for...either the EGR or the air injection, but not the cold start. It is safe to say though, based on your description of the thermoswitch being changed over to a cold=closed design in '83 at the crossover to the lambda system, there are a lot more cars that have the cold=open switch. And if they have a cold=closed switch, they also must have a different electrovalve, or at least an electrovalve where you can connect to all three ports because you need it closed when the engine is cold so there is no vacuum at the cold start valve and it will be open. If that is the case, the electrovalve would have to be closed when energized. Robert, don't muddy the issue man, leave the carb cars outta this!! Birdman
Just checked my 1980 and it is also OPEN when cold. Damn. I still need to spend more time with the Mondial WSM section D. I still think it is right but it does have some theory ambiguities with the abundance of 'sensitive' switches. The circuit below is from that WSM, I find helpful and it does agree with the other 308 wiring diagrams. With me out of your way yelling 'closed', there won't be much to finish your article. Suggestion for maximum clarity, please make certain the multitude of pronouns are well antecedented. This was a great exercise J, in fleshing out the puzzle details, I expect there will be more. I always think about the blind men describing the elephant, you have 2 cars, most of us have only one to hug, plus the manuals (which I lean on heavily), to gain the great 308 understanding, so articles like yours, plus FChat, do spread the experience. Image Unavailable, Please Login
Bird, Thanx. Appreciate your afferming my old 1K doughnut memory banks. But why IYO, pointless? By doing this you keep the warm-up reves down and keep: 1) The system working and, 2) The car looking unmolsted. Is it Not the "Best of Both Worlds?"
My 86 Mondial 3.2 could not start the other day. And I mean, it would not even crank. On a hunch, I looked at the fuse box, and saw a fuse labeled "Cold Start Electro Valve." I removed the fuse. It did not look to be blown. Then I cranked the car, and it started fine. Since the Mondial 3.2 basically has the engine as a 328, could one of you do a simple diagnosis and/or give me a recommendation for the next step to take? If the car is starting now, should I simply disregard the issue and simply not put the fuse back in? - Sam in Saratoga
Sam, I had the same issue happen to me on the same day shortly after I got my 1988 Mondial. I had an appointment to drop it off the Greensboro dealership. I picked up a buddy of mine who would give me a ride back. I drove to his place turned off the ignition because he was not ready and when we wanted to leave...nothing. I tried to start the car a couple of times and the car started. At the dealership I pulled to the drop off place and did the paperwork. Then their service person said that the car would not start ...nothing happening. I told them to check this too while it was there. When the car was ready they said they checked the ignition and also checked it when the car was at warm/hot/running temperature and they could not find anything wrong with it. My car has started since but I just don’t trust it so I will be following this thread. Stephen Sent from my iPhone using FerrariChat.com mobile app
I know this is an old thread, but as an update, my 1985 308 QV WITH Lambda (and o2 sensor): The Thermoswitch is CLOSED below 57 Degrees C (~ 135 F). It OPENS when heated to above 57 Degrees C (its 35 years old, so its more line 54 C when it opens). Ive verified this in my kitchen in a heated pot of water. Note, these switches are IMPOSSIBLE to find! And if you do find one, make darn sure its the correct open/closed as described above, if you have a 308QV with Lamda. Mine is stamped: 57/33. The others Open/Closed look identical (not sure about the stampings). So you need to verify in a hot water test. As a workaround, there is a company that sells thermoswitches that work nearly the same as described able, for about $35: BiMetal Immersion Temp Switch: TSW-TT-F3B-130R/WL (130 Degree F) https://www.omega.com/pptst/TSW-TT.html The only gotcha is the threads are different: OEM Thermoswitch: M8 Thread Omega Thread: 1/4 NPT You could either drill a new hole in the tank and weld a new 1/4 NPT Bung for it, or drill and tap the existing hole to 1/4 NPT... I never needed to go that far, but that was my plan... I ordered mine as a future replacement, if I ever need it. Ive verified that it operates nearly identically as the OEM switch from Ferrari with the hot water test. Remember, this part number is for a 308 QV with Lamda (Closed below 57 C, Open above 57 C). They do have other parts that should replace other thermoswitches on other 308s and temp combos... Great company, I also got a Thermocoupler for my Cat from them (Part #: TJ36-CASS-18U-6-SB), you have to do a little bending so it matches the original, but it works. Ill post pics later in a separate thread for both of these workarounds. I need some time to organize the 1000's of pics Im taking through this journey...
