Expert: Brad Sears - 11/21/2009

Question
QUESTION: Brad - I have a '57 T-Bird, 312 CI with Holley 4B Carb.  The car idles fine in Neutral at 500-600 RPM, but tries to stall when put in Drive or Reverse. The motor seems stressed and the generator and oil lights come on and it eventually goes dead.  Once you are underway, the car runs fine.  The problem is going from Neutral to Drive or Reverse.  When I set the idle with the car in gear, it is too high and causes the tranmission to jerk when going from Netural to Drive or Reverse.  The car has had alot of attention from reputable mechanics regarding this problem, but to no avail. Help!

ANSWER: has the transmission been rebuilt or the torque converter changed? let me know.
Brad

---------- FOLLOW-UP ----------

QUESTION: Yes. The transmission has been rebuilt, and the torque converter replaced. The problem existed prior to the rebuild. I was hopeful that the rebuild would fix the problem, but no change. I indicated that the idle was fine in neutral, but it has actually always been a little rough. Could that have any bearing on this problem?

Thanks for your help.


Answer
Ok time to attack the engine with some serious testing. The place to start is with a compression test. This will check the ability of the engine to build enough compression to fire the fuel with vigor. In the back of my mind there is the thought that perhaps the timing chain is getting a little sloppy but this should show up in the compression test as low but even compression on all cylinders. The roughness could be one or two cylinders with low compression. When doing the compression test take the spark plugs out and keep them in order. They should all be the same color, a light sand. If one or more are a different color then compare them with the compression test numbers. Keep me posted.
Brad