dr.jones63

My 83 is smoking at start up and at intersections. The cooling system seems solid, the idle is solid. The car is going through ATF, but there ain't any leaks. The ground is clean where I park it. Anyone have any experience with this?

kenn_chan

front (most likely) or rear seal (possible B/not probable) on the tranny is going.

When have the car in gear on an automatic, there is a pump in the tranny that is constatly makeing pressure, when the front seal goesit can force oil out. so, your front seal leaks a little (primarily when you are moving, becasue there is more pressure from the pump (engine RPM's are tied to pumps rpm's) oil leaks out, splashs on exhaust pipe, or catalytic converter, Voila: smoking at standstill at intersections, no puddles under car at home. (oh and I bet it smokes while driving also, just not as much cause the wind blows it away when you are moving)

kenn

dr.jones63

That wouldn't explain how it gets inside the tail pipe. A mechanic told me that there is a vaccum line that connects to a diphram valve in the tranny and the diaphram can deteriorate so that the vac line then sucks ATF into the intake manifold. Higher vac at start and at idle. Im going to check the manual, I just thought someone may have had the same problem.

kenn_chan

thats a possibility also, the diaphram the wrench told you about was the one that controls the downshifting/upshifting and things like that, but if it were that I would think it would smoke whenever the engine was running as it would be in a vacumn state all the time for a NA (obviously a higher vacumn at certain throttle positions)


Also you didn't mention wheather there was oil in the tailpipe or not, being that you didn't I assumed that there wasn't, but this is just like arm chair Quarterbacking, without the car right in front of any of the forum members, its rather hard to diagnose, and that diagnosis will rest solely upon the input you give



kenn

Jeff20B

iTrader: (13)

Modulator? Is that what it's called?

numan2

Yes it's called a vacuum modulator make sure that you compare the spring tension in the replacement to the original because there are several different ones and you may have to adjust the replacement to get the shift timing where it needs to be turn the screw in raises shift speed out lowers it 1 turn = 2 1/2 MPH also don't loose the pin that goes from the modulator to the valvebody.

vipernicus42

iTrader: (4)

Or, you could do what GlazedHam42 did and switch to manual hehe...

Good luck fixing it. I don't know anything about Autos, I just had to make my smartass remark

Jon

Edit: Heck, I went to go look it up, just because it bugs me when I don't know something about these cars. Then I realized that I never bothered printing the Auto Tranny part of the factory workshop manual because I didn't think I'd ever need it... oh well.

dr.jones63

http://rotarynews.com/node/view/164 edit - find on this page - vacuum modulator

Now I just need to find it.

dr.jones63

quote from http://usatransdoctor.com/foreignmazda.htm
" You have a modulator on the driver's side of the vehicle pointing towards the driver's door. Pull the rubber line off the modulator and see it trans fluid comes out of the line. Now, if it does your modulator is no good. It can cause any of the above symptoms."

dr.jones63

Ok just for future reference. If someone else has the same problem in the future. I found the vacuum modulator, pulled the line lose and ATF poored out. Traced the line to 2x check I had the right one and it goes to the intake below the carb. Thanks for pointing me in the right direction

dr.jones63

Put the new transmission vacuum modulator on and the problem is solved. It was a pita getting the old on off, I couldn't find any information in my hayes manual. It is not very acessable unless you want to remove the shift linkage, I didn't. Tried a large channel locks but the top spun without unscrewing the threaded connection so I finally had to use the old hammer and screw driver to gently tap counter clockwise on the edge to break it loose. Glad I had a pan under it because ATF poored out the opening after I removed it. Put the new one in as tight as I could by hand and gently snugged it up with the channel locks. Hope I did it right, if it developes a leak I will reinstall it with some copper gaskest sealer. So far so good, no more smoke.