Topic: 1979 Trans Am

[Shakin]

Considering I'm relatively new to these forums, I'm going to start asking a lot of questions off the bat. I recently purchased a Dark Blue 1979 Trans Am 6.6L. The only thing stopping this car from awesomeness is the paint. It has several scabs and spider marks on the sail panel of the passenger side door. The underside is amazing. It was rust coated multiple times and when you peel back some of the coating over the floor panel, the origional paint is still there. Considering I live in Ohio, thats spectacular.

There is a few minor problems with the drivetrain and engine but nothing I can't fix. As for right now, I'm driving the car every day to and from school and it's been running great. Now onto my question. When I start moving I get a series of minor jolts from the engine. I also always seem to have a lot of exhaust clouds coming out, more than is considered normal anyways. This leads me to believe there is a problem with the fuel delivery, possibly too much fuel being dumped in and it's choking it. Would I be right in this assumption? If so, anything you guys could come up with to assist me would be greatly apprecaited. Here are a few more specs before I end this:

-403 Olds 6.6L
-Rochester Quadrajet Four Barrel (stock)
-Basically everything is stock on the car, no performance changes were made
-New Caps, Rotors, and Sparkplugs
-TH350 Transmission is leaking at the rear seal but thats about it

Thanks for the help in advance (hopefully)

[Rebel 5150]

Welcome to 78TA!  You may need to be a little more specific on waht your car is doing, and at what points on the throttle it does them.  ie:  Does the car try to die out?  Or does it 'surge'?  Is there a point on the throttle that things smooth out?  What color is the smoke?  White, blue, black?

[brian c]

Since the tranny is leaking is it possible you're low on fluid and getting jolts due to the tranny picking up fluid when it sloshes around in the pan?

Also have you (or the previous owner) rebuilt the carb recently? Might be a bad gasket in there. Might want to check/change the fuel filter while you're at it - cheap insurance. Finally you might want to check for vacuum leaks - either lack of gaskets or dry rotted hose(s).

[hdebo]

Welcome to the board Shakin 
Its great to see another 79 out there. Hope you get the car running good and we would love to see some pics of that bird.

[Shakin]

Thanks for the warm welcome guys. I do intend to post some pictures here in a couple of minutes, it isn't perfect but I'm sure you guys know how to look at these cars. I will post a link to the pictures when I'm done loading them.

In response to 78T/A:
The only time I've ever had the car die out is after a really cold start. Here is my scenario: I'll be idling at about 550 at the light, begin to roll forwards with a little pressure on the gas and the engine picks up to about 1000. Between about 5-18Mph I feel the car sort of jolting forwards until I hit 20Mph+ instead of a smooth acceleration and the jolts are in sync with the engine making exhaust "bumps" I guess as the speed increases. Sorry about the brute description but I know no other way to word this. Pertaining to the exhaust: to my friends eating my dust, it smells like something is burning. The smoke is white right now but it has been blue a few times in the winter after a night of sitting out.

In response to brian c:
The transmission appears to be at a safe fluid level for right now but I have experienced a slow shift or two. I believe the carb has been worked on sometime recently because the metal appears to be clean. My father found that the choke was shut after the car was running for a while but he fixed that. The bolts holding it on were loose so I tightened them with no results but I do think the gasket is relatively new. The only thing I don't know about is the vacuum. I'm in the process of acquiring a vacuum tester so thats the next thing to test. Could you point me to any specific locations to test first? Just looking under the hood it is blatant that the vacuum hoses are shot and need to be replaced but considering the cruise control was working even know the hose looks like garbage, I assumed they all must still be working. Dumb assumption.

Thanks again! 


Modified*

I uploaded quite a few pictures to the gallery pages here on 78ta. I'll post the link but I don't know if it's going to work though.

http://www.78ta.com/gallery2/main.php/v/TransAmTransAm/

[brian c]

I'd look for leaks anywhere in the vacuum path. Typically it'd be from dry rotted hoses running either to the emissions equipment, vacuum advance on the distributor, to/from the cruise control - think there's 4 or 5 lines there alone, etc. Might be best off just getting a very good length of hose (I bought a silicone set from Eastwood) and replace every vacuum line - I'd suggest doing one at a time so you don't mix up where they go.

And don't assume anything with these cars. It's very easy to wipe grease/grime off the exterior of the carb and not do a single thing to the internals. A rebuild kit for the Quadrajet is cheap and easy to swap in - heck I did it and I had no clue what I was doing. Just follow the diagrams and take your time in a well lit area.

If you don't have a manual for the car I'd recommend picking one up from Brett on CD format here:

http://www.78ta.com/store/product.php?productid=16150&cat=255&page=2

[Shakin]

When I said the carb looked clean, I meant it was metalic before I wiped it like someone was recently working on it and there was a new gasket installed in it too. Also, what is the vacuum solenoid on the carb for? By the way, I just found out my choke was stuck shut >_< and it was basically dumping gas into the engine. I took off that control coil and froze it then put it back in the carb and adjusted it accordingly. It was always starting so easily and I wondered why, well the fact that it was primed like a bomb every time I started it may have helped. Now it takes a while longer to start but I have come across another issue.

After I pump the gas fully twice after the car has been sitting about 2 hours, it makes a strange attempt to start. I'll get it cranking and after the first couple of turns if it doesn't start I'll start hitting the gas in 2 sec intervals. Usually 2-3 pumps later it sounds like it's starting and makes like a half-assed cycle then cuts out and winds down. Of course I immediately try to start it while it's spinning again and I raped the saftey clutch on the starter. But when I goto start it again, I keep the starter going and keep pumping the gas as it starts to do that half start thing but the longer I crank the shorter the time between the half starts is until it starts. If you could understand anything I just said, I'd apprecaite some help in preventing it from doing that because it's bad for the starter according to my father and I really don't want to try and replace that now after I've seen where it's hidden.

[brian c]

For the first part I understand what you're saying with the outside of the carb looking clean before you did anything to it. But again, its very, very easy to wipe down the outside of the carb without every touching the internals which *could* cause some of your issues. Better safe then sorry as far as I'm concerned and again its a very cheap kit to buy for peace of mind.

Sounds like the typical heat soak issue - you run it for a while, let it sit, and it then sounds weird trying to start again. Couple options: 1. Wrap the starter in a heat shield - Jeg's, Summit carry them, 2. Switch to a high torque mini starter - I'm running an IMI unit on my Pontiac 455 but I still have a minor issue with heat soak, 3. Let it sit longer to cool down and go from there.

[Shakin]

So basically it's just a starter issue or not being too cold enough? The starter stays at the starting RPM the whole time I'm cranking it, it doesn't waiver or anything. I figured the plugs must be getting fouled and not sustaining combustion. Would a heat shield really help it that much? What is it doing to help ease the start? Retaining heat or shielding it?

[toqwik]

Check your timing.  Mine started easily, but after warming, hard to crank.  Adjusted timing, and cranks the same everytime.  As far as smoking..
Black- Car is rich, choke stuck, out of adjustment, needs rebuilt, etc
Blue-oil, most noticeable after sitting a few days
White-codensation, common for us cold weather guys, but should dissapate after a few minutes.  If white smoke continues, maeans you have bigger problems. 

Sounds like a nice car you have....Happy learning, and don't be afraid to ask questions !!!!!

[Shakin]

Thanks for the help. I sadly drive it in the snow, but it is my only means of transportation. About the smoke, it's really thick and white. I can tell you the problems I know so far about the car and if you could point me towards which problem I should correct first to fix it, I'd sure appreciate it. By the way, http://www.78ta.com/gallery2/main.php/v/TransAmTransAm/
Thats my car.

-Exhaust leak
-Catalytic converter is shot and could have a hole in it
-Rear seal on transmission is gone and it's leaking pretty good

-I replaced caps, rotor, sparkplugs, and radiator