1980 308 GTSI LOW TEMP LIGHT NOT ON.

Are you sure that you have the right logic thermoswitch? IIRC, on the 308 using K-Jet without Lambda injection it should be:

cold = open
warm = closed

(which is the opposite of the coolant thermoswitch on 328 and TR)

Alternatively, if you just unplug the thermoswitch in the coolant tank (simulating the "open" condition), and do a cold start, does your fast idle then work OK?

 

Is this light only triggered by the coolant temp?

 

I had a real wacky cold start problem which turned out to be one of the electrovalves pulling too much resistance . . . they're in series with the bulb if I'm remembering right . . .


Good luck . . . glad to see someone down here in SD that's a tinkerer.



Sean

 

OK Phil, here we go :

1. Check fuse #2 and the general conditions of the terminals, rivets, etc.. -- there should be a R (red) wire in the mess leaving the bottom of fuse #2 that should always be +12V with the key "on",

2. (When cold or with the thermo switch unplugged) Unplug the two ECUs and turn the key "on" (the engine need not be running ) --

If the low temp light then comes "on", this might not be a good sign. Try plugging the ECUs back in one at a time and see if one causes the light to go "out" and the other one doesn't.

If the low temp light stays "off" -- plug the ECUs back in and go to step 3

3. Find the fast idle electrovalve as shown in the jpeg. It will have a 2-wire connector -- one SN (pink/black) wire and one R (red wire). If you measure the voltages on these wires (relative to ground), when plugged in and the engine's running, it might be helpful:

The R (red) wire is the same R wire as the one leaving the bottom of fuse #2 -- it should always be at +12V with the key "on" (or the engine running) whether cold (thermoswitch open) or hot (thermoswitch closed).

The SN (pink/black) wire is the same wire connected to the plus side of the bulb, pins 6 on the ECUs, and the floating side of the themoswitch -- when cold (thermoswitch open or unplugged) it should be a reasonable positive voltage (I'm not sure exactly what, but high enough to cause the bulb to be "on" and the electrovalve to not actuate, which causes the fast idle device to be "on"); when hot (thermoswitch closed) it should be ground.

Sean's advice is also related -- (key "off") unplug the fast start electrovalve and the air diverter electrovalve and measure the DC resistances of their internal coils -- should have reasonable continuity (e.g., if one is "open", the voltage on the SN wire when cold will not get high enough as described above).

Try some of those and we'll go from there...
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Trying not to be dumb, but....

I've got an 80 as well and I have no clue as to what you guys are talking about....

Low temp light?? Where, what, how??

I switched out all my "small" gauges to VDO. Are you talking about some low temp light on the OEM H20 gauge?

 

This forum's a blessing thanks to those like Steve.

 

Scott -- On a 1980 US version 308i, item 20 in this jpeg is the low temp warning light (on a standard version, item 20 is present but not used -- i.e., a "spare indicator"). However, many of these cars have had the cold start air valve (fast idle) system disabled, and, depending on how this is done, it could also disable the low temp warning light too.

Phil -- Just curious -- is your 308i unmodified in all other respects? (e.g., is the air diverter electrovalve also still present -- or was that your "spare" electrovalve?)
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On the very early North American GTBs, such as mine (#19399), #20 is a "spare indicator" too. One of the 308 GTB manuals downloadable from the Ferrari Owners Site indicates the change to a "choke on" light with chassis #20109.

I'm not sure when it became a "cold engine" light. Most probably with fuel injection.

 

It is a cold engine light in the 81 and 82 US owner's manual.

It is a rear defog warning light in 84 and 85.

 

Thanks, Tommy.

 

On my '77 (#22393) it's a choke indicator.

Steve M--you rock!

Birdman

 

Thanks for the additional info Phil -- with only the one wire, both of those other electrovalves are "open" electrically, so it makes perfect sense that when your fast idle electrovalve went "open", you lost the +V power to turn on the low temp light.

 

Good to see you guys can help each other through problems like these. I have a smaller problem but the switch in my 85 308qv that controls my rear window defog is broken. I am only asking because we are in that general area of the car somewhat. The light stays on all the time. Can anyone tell me the best place to buy that little switch? You know the ones that look like Mickey Mouse ears attached? Also any trick to removing the ring that holds the switch tight? Thanks, Eddie

 

Thanks for the info!

In 6 years of ownership, that light has never come on. All my emmisions stuff has been removed and I'm sure the car has (as you said) a dissabled fast idle system.

Thanks for all the tech info you provide to the site and owners!

 

sean, can you email or pm me. anyone know how to get hold of sean?