84 Tercel sudden jerkiness

I'm the original owner of an 84 Tercel hatchback that is at 151000 miles and 8 days away from its 20th birthday. A few days ago the car suddenly started to run very rough with mild body jerking and loss of power especially at low speed. It seemed to me like loss of a cylinder although I'm guessing because such a thing never happened to me before. I used a timing light to determine that the all plugs were firing and I also replaced the distributor cap, ignition wires, and plugs to no effect. After removal, the tips of the #1 and #2 plugs were shiny black on one side. There is also a smell of gas after the engine is on a short time. Could this be a valve problem preventing one of the cylinders from combusting properly? Please help this car reach antique status which is defined as 20+ in my state.

Roger

Reply to
news.bellatlantic.net
Loading thread data ...

Shiny black plugs points to missfire. Hopefully, its not from low compression.

Reply to
MDT Tech®

It could be a vacuum leak, that would cause exactly what you're describing. Lots of things on your engine use vacuum from the intake manifold and are connected with a complicated system of hoses. Usually it's a hose that's cracked or come off that causes the leak.

Reply to
Jon Dalton

Reply to
AZGuy

...and then you unloaded on some unsuspecting kid, who used his life savings to purchase it?

jak

Reply to
jakdedert

i *just* bought a little 95 Neon for $600. It had these same symptoms. A flashlight and some crawling under it - and sure enough - cracked exhaust manifold, just like the previous Dodge Clot I had.

$100 fix at most or DIY for $30. Engine will run like new.

Neons and Tercels and Mazda 323s(dodge colt/etc) and the like - they all have this problem with age. Simple fix and you're on your way.

The giveaway is the purring like faint pops that sound like loud pinging and when you stomp on the accelerator, it makes a sound like a miss or backfire(bogs down, right then, as well). Once it gets going and up to speed - it smooths out.

That means a leak in the exhaust or intake. Fixable.

Reply to
Joseph Oberlander

I'm not familiar with the 84, does it have a carb? If so, you might check to see if it uses the auxiliary acceleration pump (AAP) system. My '80 Tercel developed a similar problem to what you described. I noticed the problem on mine mostly within the first few minutes of operation. Mainly rough idle and it stumbled upon acceleration. After a few minutes the car started running better, but still seemed to be running too rich. There is a diaphragm in the carb that becomes leaky and allows an extra shot of raw gasoline into the number 1 cylinder. That is the source of the strong gas smell. The "good" news is, you don't have to have a good diaphragm in place for the car to run ok. I just removed and plugged the vacuum line on mine and plugged the hole on the carb and it now runs great. I've heard that doing this causes them to run a bit more cold natured, but it hasn't been a problem for me.

If yours doesn't use a carb then none of this will probably apply.

Good luck! Mac

Reply to
Mac

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.