Sensors Question

[gladie]

Dear,

I have 2 sensors on my Intake manifold, for my E21 318 carb y1978.
I found that one is a 17°C air temp sensor and the other is 45°C water temp sensor.
Please could you tell me exactly what these are for ?? I suspect they are used for water auto choke, but can you confirm ?
My wish is to remove the auto system and replace with a manual, so I would remove all the related items to it (including both sensors that are already broken, and also all water pipes connected to intake if they are only used for auto choke system) ?
Thanks in advance

[gladie]

No one knows ? :-(

[cgifool]

I can't think what else a carbed engine might do with a temp sensor...

[320iAman]

Engine temperature switch 17C is used with Bosch K Jetronic and O2 sensor when below open-loop, above closed loop , in open loop there is no fuel adjustment-so its part of the warm up system, when closed loop O2 sensor signal the ECU for fuel adjustment or not. Not used in Carburetor fueling systems

Randy

[epmedia]

There appears to possibly be Two electric components on the carburetor. #7 and #14 (shaded out). Now all that's needed is an electrical diagram.

Real OEM

[GDAus]

Dear,

I have 2 sensors on my Intake manifold, for my E21 318 carb y1978.
I found that one is a 17°C air temp sensor and the other is 45°C water temp sensor.
Please could you tell me exactly what these are for ?? I suspect they are used for water auto choke, but can you confirm ?
My wish is to remove the auto system and replace with a manual, so I would remove all the related items to it (including both sensors that are already broken, and also all water pipes connected to intake if they are only used for auto choke system) ?
Thanks in advance

Hi .... when I first got my e21 years ago I copied big chunks out of the Haynes Manual I found in the local library and I read the entire chapter on the carb and fuel injection systems. The copy is buried somewhere in a filing cabinet
and I don't have time at the moment to go searching.
So ... this is from memory ....

They are part of the choke system.
They are hooked together in series so that when the air temperature is above 17^o C and the water temperature is above 45^o C they kick in heating elements in the choke mechanism that stops it from operating.

But ... I think there is also an electrically operated enrichment valve on the side of the carb that is affected too.

So .. converting the choke to a manual operation may not be that easy.
It will be couple of days at least before I can hunt down the info I copied.

Cheers

[320iAman]

Okay wait a second, I thought it was a conversion... from K-Jet to Carb.. the two switches are on the intake manifold,,17C switch 80-83 is front engine hoist.





It been a while since I had a carb car yet it seems to me the two temperature switches #7-17C and # 13-45C would involve enrichment on start up when cold and warm.

The electric idle valve #7-45C-different diagram- Robert is referring to is on the carburetor .

So so far there 3 temperature switches involved in enrich startup or not-- could be multi adjustment as well depend on the sophistication of the startup system , eg full closed-total enrichment start up- below 17C , from 17C to 45C partially open, after 45C mostly open-after startup fully open- it seems plausible. Internal combustion cars like rich degree startups whether they are cold, warm or hot.

The last time I had a carb'ed bmw many moons ago, I got it for a song and a dance-no one had the electric start valve for it, I bought it and found a company that made them-it would not want start up installed new start valve-bingo started right up. As I recall the electric idle valve was stuck wide open--too lean start up and run right.

Randy

[gladie]

Thanks all for your replies, very appreciated !

My car is an original carb model, not a conversion or injection one.
All there, is stock and not modified ever.

[gladie]

So in addition, I confirm that I have a "idle electro-magnetic jet", to enrich the idle which I guess is also related to both sensors...
So, do you also beleive that switching to manual choke would allow me not to connect back all those 3 electric items (they are more or less already faulty) ?
And do you think I would better let the water system still going through the intake manifold or also remove it (during manual choke installation) ?
Thanks :-)

[320iAman]

If you can just replace the items that are stock to it sometimes its a little slow to find the items yet in Europe companies that make auto parts are generally job order, they wait till there is a an order then make the items except basic tune up parts for which they carry an inventory of.

Randy

[gladie]

My desire is to remove all that is related (and then unnecesary) to the auto choke (and possibly faulty) to swap to manual choke kit.
So if I remove the 17° + 45° (on the intake) + electro-magnetic jet (on the carb), with all corresponding cabling, am-I sure not to mess up with anything esle than the auto-choke ?

Thanks

[cgifool]

I would not remove the jet on the carb. Just the wire to it. Otherwise won't it leave a hole?

[gladie]

I would not remove the jet on the carb. Just the wire to it. Otherwise won't it leave a hole?

Yes, sorry, completely, by "remove" I meant not to wire it, as I would have holes. I intend to leave all the censors/jet in place but not wired.
But you confirm they are all 3 related to auto-choke ?

Thanks

[cgifool]

I can't, but it does make sense.