Shaking idle gets WORSE when put in reverse or drive

[oldblue]

Don't know if this is the right place to post but I'm in a pickle. I don't have a 4wd but I have a 1981 Toyota Corolla Tercel Automatic Trans with 2 barrel carb that has only 80,000 miles on it. I have had an incredibly rough shaky idle when cold but it had been going away once the temp needle moved up a bit. Now the whole car shakes noticeably when in park and when I put it in reverse or drive it gets much worse and I hear some knocking or clanking sound. No smoke, but I do have an intense exhaust or gas smell under the hood. I haven't had any problems with the transmission. I checked the oil and it looked clean and I checked the coolant and it looked clean. Had the tranny fluid changed 2,000 miles ago. I had thought maybe the aux accelerator pump needed replacing given what I read on your forum but I never messed with it and now the problem is different and worse. I know absolutely nothing about cars but have been reading posts on your forum that have given me some ideas. Any help would be greatly appreciated!

[dlb]

just to clarify, you said it's a corolla tercel but your info on the right says it's a corona tercel. i imagine it's the first and if that's the case, your car is actually a 1st generation tercel. toyota just threw the corolla badge on there initially to try to encourage tercel sales, as if the tercel was a corolla sub-model. that can be confusing so i wanted to clarify that.

there is one active member on here who has a 1st gen terc and i believe he has an automatic as well but am not sure. hopefully he will have some ideas. the older tercels have the same engine as the 4wd tercs but i'm not sure if the emissions packages are the same. i know that automatic tercs have very different emissions packages from the standard transmissions and most of us here have standard trans's so that makes things a bit more difficult.

all that being said, the problem could be related to your AAP if it goes away once warm and you smell gas. the test is easy, check the factory service manual. the link is at the top of every page. it's in the emissions section. from your description of the knocking/clanging sound though, it could be much worse--crank bearing, i would think. if the problem was only idle (when oil pressure is low, not lubricating as well) and/or when cold (when oil is thinner, not lubricating as well) and went away once the oil has warmed up (gotten thicker and increased oil pressure, lubricating better), and the problem has gotten worse to the point you are experiencing knocking or clanging, it's likely that a crank bearing has given up. not sure about your car but you might be able to do the job with the engine still in the car, if this is in fact the problem.

is the banging constant now? does it go away once you start driving? tell us more about the banging.

[oldblue]

Thanks for replying! The knocking sound isn't constant and doesn't sound like it's internal. In other words, it sounds like some external part of the engine is hitting something because it's shaking so much. It was shaking so bad that I haven't driven it more than a few feet. I was thinking that maybe the shaking on start up (which was intense) over the last couple of months from the AAP caused a motor mount to completely give out. I had the transmission mount replaced a few months ago.

[dlb]

I was thinking that maybe the shaking on start up (which was intense) over the last couple of months from the AAP caused a motor mount to completely give out.

haha, you beat me to it! that's easy to check, just put a floor jack with a block of lumber on it under the engine around where the engine bolts to the trans--not under the oil pan or you will damage it--and jack it up a bit. pop the hood and check the engine mounts (one on either side). they are a thick piece of hard rubber with a piece of metal on either side that bolts to the vehicle and engine. usually the rubber will separate from the metal on one side of the mount so you should be abe to see that once the engine is lifted a bit. if it's not obvious try rocking the engine by hand while it is elevated.

[Lil Beast]

Actually i think the first gen is a sub model of corolla my car shares more corolla features than a tercel espacially suspension wise and it as been built on a corolla platform! It was in introductory model for the front wheel drive bit hasnt quite got that popular on the market but got known for the fuel efficiamcy so toyota redesigned it to be more of a economy vehicle using the some of the factory left overs! The 2 gen do share a little of the corolla but not much other than the platform the suspension is totally different!
And i would need somewhat of a better description of your banging/lnocking thing! But as for the gas smell the aap diaphragm could be the thing and could cause your idle to be uneven due to too rich mixture with gas running straight thru the diaphragm into intake! And too low rpm once trans engage it would shake! How's your engine mounts if dry and cracked it could be part of your problem! To check aap it is kinda easy just to unscrew the 3 screws and examine the diaphragm for wear and cracks if doubtful replace it! But i dont know if they sell separatly from the carb kit! Or maybe you can bring the old one in and have the part store to match one!
Holy smoke goy beat twice lol

[Lil Beast]

Sounds like a blown crank bearings
Edit: sorry my bad i dis not notice the "NOT" before internal!

[Petros]

Welcome to the list,
Actually it might just be the cold idle cam out of adjustment. If it idles too low it will shake and rattle, adjust the cold idle up the problem might go away. Also, a vacuum leak could make it idle rough. Both are simple fixes, inspect all the vac lines for cracked lines or loose vac lines. If no vac leak than reset the cold idle setting bit higher.

[Lil Beast]

I forgot everything about the stock carb haven't learn much of it either as soon as mine failed , did rebuilded it but when it got time to adjust all these little linkage and never could got to run the way that like i just threw in the weber i had kicking around from an older 4x4 project! Simplier carb to deal with!

[Petros]

look for the simple answer first, if that does not work, than go on to look at the more costlier possibilities.

[marlinh]

You may have two problems, a fuel issue and something loose causing the rattle. What Rpm does the engine run at at idle? The clanking sound could be from loose torque converter bolts. Easy to check by removing the starter, (disconnect the battery negative terminal first) turning the engine over by hand at the front pulley and checking the four bolts that go through the ring gear. If it was blown crank bearings it wouldn't run for much longer. While you're there it wouldn't hurt to check that the bellhousing bolts are tight.