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Hey everyone,
I have a 72 f100 with a C4 in it. Just had it rebuilt and would like to confirm that the switch in the pic on the trans is for the emission system (which I plan to delete).
Do you know if it's a pressure or temp sensor and can it just be plugged off? My trans builder believes I can plug it off and be done with it.
Hope someone here can confirm
Thanks for the reply...
What is strange about it is the wire from it goes up to the engine where there is a vacuum control switch for allowing vacuum to the distributor which made me think it was a factory deal with emissions.
I plan to delete all that too. Just never seen one on a trans like that before
I would’ve thought the same thing. Looks more factory than aftermarket, and most aftermarket gauges recommend putting the sender in the transmission pan anyway.
Didn’t know there was a fitting there in the case for that, but if it’s common to all C4’s, I can see where an aftermarket sender could be used there too.
And because it’s a 72, I would’ve equated it with the Ambient Switch.
Which is a thing that some 72 and 73 model trucks came with from the factory. At least they did with manual transmissions.
The broncos of those two years had a switch on the manual transmission and a sensor up in the door post that senses what gear it was in, what temperature (or pressure?) and changed timing or something of the sort.
Does your truck happen to have a trapezoidal shaped doohickey sensor (metal plate thingy) screwed to the driver’s A-pillar?
I would’ve thought the same thing. Looks more factory than aftermarket, and most aftermarket gauges recommend putting the sender in the transmission pan anyway.
Didn’t know there was a fitting there in the case for that, but if it’s common to all C4’s, I can see where an aftermarket sender could be used there too.
And because it’s a 72, I would’ve equated it with the Ambient Switch.
Which is a thing that some 72 and 73 model trucks came with from the factory. At least they did with manual transmissions.
The broncos of those two years had a switch on the manual transmission and a sensor up in the door post that senses what gear it was in, what temperature (or pressure?) and changed timing or something of the sort.
Does your truck happen to have a trapezoidal shaped doohickey sensor (metal plate thingy) screwed to the driver’s A-pillar?
yes it does. Best i can tell it works in conjunction with that thing and a vacuum control switch located on intake.
If it's easily removed, you can tell if it's a pressure/temperature "sensor" or if it's a mechanical switch.
Or maybe we can look up replacement ambient-switches and see how they're made. I don't know what type of sensor it is, that can tell gear position in an automatic, unless it's either sensing a linkage location internally, or if it's got a port into an area that only flows pressurized fluid when in a certain gear?
It sure looks like a pressure sender, rather than an electro-mechanical switch, but I have never laid eyes on the business end of one before. And the ones in the Bronco manual transmissions seemed smaller.
Or it's just my memory getting smaller!
Of course, it comes back down to the bottom line that if you're removing your smog compliance equipment anyway, you don't need it connected.
Most leave the ambient switch sensor in the door pillar so there isn't a hole there. And most would probably leave their ambient switch in the transmission. Again, because there's a hole there!
So how are you connecting things back up in the engine compartment? Using all the vacuum lines and timed thermal vacuum switches and such? Or eliminating all that?
If so, I'd leave it in the transmission case and leave it disconnected.
Thanks 1Ton, I do agree that it is for the emissions stuff. I do plan to delete all that including the vacuum lines that are not needed. The end result will be the vacuum from the carb to the distributor and that's it.
Appreciate the comments and advice from folks here. Such a wealth of knowledge here.
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