'87 GM A/C Issues

[sly]

Best one I can find... should be the same system as in any box panther with ATC.
http://www.lincolnlandinc.com/blog/2..._concerns.html

[miamibob]

Best one I can find... should be the same system as in any box panther with ATC.
http://www.lincolnlandinc.com/blog/2..._concerns.html

Cool and thanks! I will try to get a larger diagram as I couldn't read it or make it larger.

[sly]

I know I have an easier to read one around here somewhere, but I can't find it.

[miamibob]

I know I have an easier to read one around here somewhere, but I can't find it.

I think I have the original EVTM schematics here so I'll also see what I have. It is LARGE paper work that opens up to the size of a kitchen table!! ONE of us will find something!!!

[sly]

I cleaned up most of the needed text on that link I posted...

[miamibob]

Now THAT even I can read! Thank you for taking the time to provide this!!!

[miamibob]

If I needed to run a new "black" vacuum line, from the check valve, should I run it directly to the ATC Control Panel or elsewhere? Would like to know if that is the issue before all that work. Wonder if the sensor is good? I think it is like an $80 part...

[sly]

There's a T in the black line about a foot or so inside the firewall and you'll have to tap into the line before that T as the section through the firewall will be cut loose.

Definitely worth diagnosing that line first to make sure.

[miamibob]

The issue, as I see it, is there can be an issue anywhere along that black line - from under the hood to the control unit, ATC sensor or TBL. Guess one would need to check vacuum to each part to narrow it down?

[sly]

Pretty much

[gadget73]

if its anywhere, I'll bet you a buck its either the soup can is bad or the TBL is leaking. The vast majority of the time, the stuff in the dashboard is fine. Handy, since its all hard to access.

[miamibob]

if its anywhere, I'll bet you a buck its either the soup can is bad or the TBL is leaking. The vast majority of the time, the stuff in the dashboard is fine. Handy, since its all hard to access.

TBL can easily be replaced - I gave it a "quick" look and didn't see a leak but I will give it a real good look soon. What can that "soup can" be replaced with?

[gadget73]

vacuum test them first before you throw parts at it. The TBL can be a bit trickier to test, but unhooking it and plugging the lines will answer that question. If the problem goes away, then you're done.

the soup can can be replaced with pretty much any vacuum reservoir. Most newer things have plastic ones. Mostly its a junkyard shopping sort of thing, you find a gee-gaw that looks useful and grab it. If I was ebay shopping, I might use something like this:

http://www.ebay.com/itm/Dorman-47077...e53c51&vxp=mtr

looks like the Chevy S10 vacuum ball. Probably is. There are others that are similarly inexpensive.

[miamibob]

vacuum test them first before you throw parts at it. The TBL can be a bit trickier to test, but unhooking it and plugging the lines will answer that question. If the problem goes away, then you're done.

the soup can can be replaced with pretty much any vacuum reservoir. Most newer things have plastic ones. Mostly its a junkyard shopping sort of thing, you find a gee-gaw that looks useful and grab it. If I was ebay shopping, I might use something like this:

http://www.ebay.com/itm/Dorman-47077...e53c51&vxp=mtr

looks like the Chevy S10 vacuum ball. Probably is. There are others that are similarly inexpensive.

Thanks for the leads and info - I'll check the TBL first and see where I am at!

[miamibob]

Took a quick look today and BOTH vacuum lines to the TBL were broken. I capped them both and removed the electrical connector and the car got REAL cold! Not sure if it will cut in and out, like before (I doubt it) because I did not drive it. We'll see on Thursday! Does anyone sell vacuum lines that small?? Perhaps I can put a larger size on, if not, and zip tie them (NOT my first choice for a repair)? Of course, I could just leave the lines capped and unit unplugged as I have a bypassed heater core anyway and don't really need heat.