Looking for a Service Station in the Worcester, MA area that has extensive knowledge to troubleshoot a 305 carburated engine from my 86 Trans-AM. I've been to a few but not comfortable with any so far. Any recommendations would be appreciated.

Thanks.

 

Welcome Aboard!

Yes, there is a place close to you. Owned and operated by a newly famous "Mass-Hole". I think it's called "Drew's ThirdGen Performance", and shares the same address as you. It's supported by ThirdGen.org, so you KNOW it has the resources to get it done right.

In short, get a good manual, a few simple tools, and hang by your PC. Anything you can get yourself into, we can likely bail you out of or talk you through. There are quite a few GM certified and ASE certified Techs within our membership. Unless your favorite shop has a few hundred qualified Techs and thousands of years of experience, you may want to think twice about turning your car over to them. Most of the decent Techs that ever knew much about these cars have probably forgotten most of it, and likely never really knew any of it as well as many of the members here.

You'll never learn anything by handing over the project, except how to open your wallet wider.

So, what exactly are the problems you are experiencing?

 

Chicken's Customs out in Auburn (maybe shrewsbury) on rt 20 does ALOT of 3rd gen work.

 

Funny!

I already bought the manual and spent some time in the garage over the weekend replacing sensors (EGR, PCV) and tune up (rotor, dist, plugs, wires), replaced smog pump (seized), plus checked all hoses for vacuum leaks.
Here's the problem, runs a tad bit rough and occationally the check engine light will come on or off or when the car is cold it will stay on until you drive it. However, the big problem is that it did not pass inspection because of high NOx and what concerned me was that when it sat at idle for 20 minutes at the gas station it started to blow more and more smoke out the end. When the guy put it on the Dyno, it was smoking pretty bad but not the color you would associate with burning oil...I think. Now, when I drive it on the highway or first start it up, with the exception of the valve seal leak, it does not blow any smoke. It seems to only occur when at idle for a period if time. Any thoughts?

 

O2 sensor would be my first guess if it blows black smoke.

Have you ever tried getting the code while the check engine light was on?

 

No. Can I do that without the use of a computer. I also forgot to mention that I pulled all the plugs (bitch) ans the tips were white in color as if it were running hot.

 

Yea, you use a paperclip to check the codes. You have an old car, the most complex tool you'll need will be a multimeter.

do a search on the "paperclip trick".

 

I checked the codes and I got the following: O2 sensor (lean) and VSS (vehicle speed sensor). Any suggestions?

Thanks.

Drew

 

Replace the O2 sensor.

 

Yeh deffinantly change the o2 sensor it could be as simple as that if your lucky,(I wasnt, still getting a code 44) the sensor is around 20 bucks if iam not mistakened, dont forget a o2 sensor socket and your probably gonna need alot of lube to get it out mine was cooked on the exhaust it was a real pain to get out even when I cracked it loose it fought me all the way until it was completely out. And if that doesnt get rid of the lean code do a search, Iam in the process of researching the board for that same problem, you'd be surprised at the amount of info covered on this board. gooduck

 

I was thinking what if it doesn't go away. My thought would be to perform a contnuity check from the O2 sensor wire to the ECM terminal to see if there is a break or bad connection. The manual shown a single wire connection straight back to the ECM. If that's fiine, then the only thing it could be is a bad ECM? Your thoughts.

 

It could be alot of different things, but why troubleshoot ahead of time. See what the 02 sensor does first.

 

Well, guess what? Replaced the O2 sensor and the code went away. However, now runs at lower idle and when I accelerate it jerks at low rpm and when I rev it up it or wind out and lay off the gas it seems to backfire. Any definite solutions or should I give up at this point and bring it to a garage?

 

I would never give up. It's not an incredibly complicated system.

has the carb ever been rebuilt? might be time.

chances are it just needs to be tuned, but it sounds most like timing. Not enough i'd guess.... Do you have a timing light?
Or you could just try to do it by ear, adjust your timing advanced a bit, then try driving it, see if it runs better.

 

Trust me I wish I had the time to fix it myself. Doesn't it seem strange that it runs like **** after replacing the defective part? It is possible maybe with the now richer mixture of gas I could have fouled a plug? Why the timing now? Doesn't make sense.

 

Since the oxygen sensor is again functioning, the ECM should be trying to control the mixture. In order to do that, the TPS voltage must be set correctly, and the lean- and rich-stops on the carburetor mixture control solenoid must be adjusted properly. It's not a difficult nor really time-consuming procedure. My guess is that you may find something amiss with the TPS voltage.

 

Time to call up Chicken's then.