rfortier

Hello all,

I have an '84 Trans-Am with a 305HO, manual trans mission... All original.

I did a tune up a month ago and reset the timing and adjusted the carb, even compression was perfect but the carb smelled like gas, looked like it was leaking and hard start-up when hot.

I decided to rebuild the carb, I did the minimum and only removed 3 screws out of adjustment. Just put it back on with an extra 1/4" spacer and now its blowing white rich smelling smoke, idles at 3500 rpm and choke not coming off. The idle screws are at 5.5 turns each, just like when I tunes it.

Any help would be appreciated. THANKS.

1987L69

post a video. or PM me with questions

rfortier

Sorry for the delay, I'm not home until tomorrow, what kind of video do you want?

I found a vacuum hose not connected, it brought down the RPM to 2500 but still blowing white smoke. Can I remove the choke sensor to see if this is the problem?

naf

iTrader: (7)

Go thru it and figure out what went wrong. I'd probably look at the mcs first. You did ensure it had 1/8 in of travel after reassembly?

What's a choke sensor?

rfortier

what is mcs?

on a video, it said to put the power piston at 4 turns but for a different car. mine was at 5.5 turns, I decided to keep it at 5.5 turns from bottom.

I meant the choke itself. can I remove the 3 screws for the choke and remove it and start the car?

rfortier

found what mcs is? mixture control selenoid.

mine is fully mechanical with no selenoids attached or wires exept for the choke's since wire.

dlinger

iTrader: (4)

Maybe post of picture of your carb? Our 84 HO Z28 has two additional wire connections.

navy02ws6

All '84s sold in the U.S. had a mixture control solenoid when new. Sounds like someone swapped your carb out.

rfortier

Here are the pictures of my carb. One with the air horn removed

rfortier

This is a Canadian version TA. I believe the carb and computer are the only difference, dont have either.

zed-028

i pulled the choke on mine ages ago, yes you can just unscrew the 3 screws, then there should be one or 2 inside the body itself. if you do this then get rid of the choke plate off the primary too and the choke rods, high vacuum can suck these things closed.

there will be a hole int he body that you should plug when you remove it.

but yes your carb from those photos is a mech carb with no TPS or MCS so you should be all sweet in that regard. are your secondaries opening? to test out that operation just remove that secondary door rod that runs across the choke and the vac cylinder. theres also a little tang that locks out the secondaries at the bottom of the body behind the choke, get rid of that little piece if its still there.

rfortier

Thanks for the help guys, my neighbour came over today, made a few adjustments and seems to be running good now. I may need to replace the choke but will see tomorrow. Idle is perfect now.

Will know more in the spring since it's now winter here and the car is up on jacks for the next 5 months.

Next winter will be the big job. Pulling the engine and replacing all the seals and exhaust.

Thana again,

rfortier

Hello again,

I didn't realize right away but I finally got the choke up to par and the idle down to were its suppose to be.

I now have a new problem I didn't notice. My choke pull-off pulls in when I start the engine locking in me secondary barrels, after 5 minutes of warm up, it still does not release, by this time, my choke has been open for at least 3 minutes.

Doing some research, I didn't find anything online about this, but a picture of another carb with the linkage removed and another complaining it would take over 30 minutes of driving before it opens up.

My car is on stands for the winter which means I cant drive it around for the next 5 months or so, how long does it take to disengage usually and do I need to drive around to fully warm up for it to disengage?

Thanks again

naf

iTrader: (7)

the choke pull off performs two functions:

it cracks open the throttle slightly upon cold start in order to allow enough airflow to cold idle after the motor starts.

it delays opening of the secondary air flaps. under heavy throttle the pull off is no longer under vacuum and disengages allowing the air flaps to open.

rfortier

Thanks NAF,

how do I test it, do I just give it a good shot of gas and look if it opens or is there a different way to check it?

zed-028

Yeah once shes warmed up and that choke flap opens, give it a decent rev - watch the cloud of smoke go out the rear, then the idle should drop down, at that point that thing should release.

If you dont want this feature (i didnt when i had a choke) you can pull the rod out that is attached to the secondaries, and also pull the little lockout tab on the bottom passenger side of the carb.

naf

iTrader: (7)

the secondary airflaps will only open when there is enough airflow through them. Won't happen in the garage revving it.

Two things control the airflap opening: the choke pull off and a spring set screw. there's an article here in the tech section on adjusting the set screw tension for best performance.

the choke pull off should not need any adjustment for a near stock or mildly modified motor. as long as it holds in under vacuum and releases when the vacuum source is removed it has passed a basic function check. next thing is to ensure that all of the linkage is clean and moves freely.