DarkDrakeX

Starting yesterday when i went to start my car it starts fine and runs ROUGH and sounds super choppy for about the 1st 30 seconds to a min of idle,, I rev it a few X and then it goes back to running just fine..

Motor is a 84 12a in a 83 base model. Has about 90k miles on the motor (came out of my 2nd car) Emission deleted Nikki carb, RB header to custom exhaust, has never gone low on oil or overheated since i owned the car/motor (about 4 years on the motor). Dont rev it past redline wait till its warmed up to go over 3-4k rpms im pretty decent to the motor so im assuming its not a abuse thing. Is due for a oil change within the next 500 miles but idk how much that would have to do with it.

My only thought as to what it could be is when i shut the motor down and it sits for 6-8 hours while im at work and cools down its either getting coolant or oil into the combustion chamber?? Orr when it is cooling down the spring behind a side or apex seal gets stuck till it gets some gas/oil mix on it and starts working as advertised??

Any ideas or ne1 have had this happen to them before.. I am planning to eventually port/rebuild the motor but not within the next 6 months so im hoping its not like rebuild it now type of thing.

-Gamah

iTrader: (1)

Does it brap? Mine does that for a good minute or two from a cold start.

DivinDriver

iTrader: (15)

How fresh/clean are your plugs?

This could be a symptom of plugs running 'cold' due to fouling, or just electrode wear that has increased the gaps to the point that cold spark is marginal. Warm plugs fire better than cold plugs, so poor at-start behavior can show up when they are nearing end-of-life.

The other main thing that changes as the engine warms is that compression rises as the seals heat up and expand. 90k isn't excessive, but it's not young either.

Could be a combination of the two - compression starting to drop just a bit when cold due to age, and marginal plugs that need to get warm to fire reliably.

DarkDrakeX

yeah its pretty much sounds like a brap. I honestly dont know how long ago the spark plugs were replace.. not since ive been back from Germany the last 3 months. Ill change em out tonight and see if that helps the problem.

7aull

iTrader: (2)

Mine does the same on cold starts. New-last-year (summer driver) plugs. Its like the Trailing (or Leading??) plugs aren't firing so I was thinking (like _I_ know) one of the igniters isn't lighting up at first...
90K on my SA too....

maybe need to pull some plug wires when its doing this and see what/if anything changes...

Stu Aull
80GS
Alaska

85TIIDEVIL

iTrader: (2)

I get the same thing... It feels like it's running on one rotor until I feather the throttle a bit to raise the rpm's. As soon as she breaks 2K it smooths out even if it's just been started and COLD. I was thinking the ignition is not up to par somewhere and it feels almost as if something electrical has to jump a gap. Spark plugs sound like a good start. Mines also a 100K motor and compression is around 95 on each rotor.

DarkDrakeX

Yeah i changed the plugs and i havent had it so it as rough as it was yet but still does it. I tried to start it after 18 hrs of the car sitting and i was leaking coolant out of my intake gasket (little wetting on my header/ground) and it wouldent start for hell. So i think that has alot to do with it. once i replace my intake manifold gasket and install freeze plugs ill c if it changed this issue..

DarkDrakeX

when i went to start it this mornin it did the same thing but my RPM guage was going insane when the starter was engaged as soon as i let the key go once the car started it went back to normal.. Err this is such a weird problem.