72 TA : New Project

[njsteve]

Thanks! I've been trying to put some miles on the car before winter. Started the whole project when the car had 114,163 on it. Put about 80 miles on her today and finally got the odometer to 115,000, so thats about 850 miles on the car since finished. Another 150 or so before the magic 1,000 mile mark. Plugs are still burning perfectly clean.

The one thing I've learned about Pontiacs is that they are very cold-natured when it comes to needing a warm up. You really have to let this car warm up to operating temperature before driving it. Once that choke pull off engages, she's good to go, but very cranky if you try to drive her before she's ready.

I've also finally run out of little noises and bugs to get rid of, from the squeeking front shock bushings, to the tach reading wrong, to the lean secondary rods and bad accellerator pump, to the steering column/clutch rod ringing, to the bad o-ring in the proportioning valve. I guess it never really ends.

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[njsteve]

BTW, I did actually notice that the TCS system works. I was sitting in the driveway after returning from the Sunday drive and was just shifting through the four gears and reverse, with the clutch engaged. When I put the shifter into fourth, the rpms dropped by several hundred. Pulled it out of fourth and the rpms rose back to the idle position. Very interesting. I guess in fourth, they didn't want any vacuum advance, so once it hits fourth gear the vacuum signal gets interrupted by the TCS solenoid.

[njsteve]

Spoke with Dave from the Performance Years website (necb3) who has the 72 4-speed T/A that parked with me at the MusclePalooza show back in September. He mentioned that my TCS emissions system seems to be running backwards. I checked the manual and he was right.

This was from page 6D-9 of the 1972 repair manual:

&quot;TCS solenoid energized, providing no vacuum advance in all transmission ranges but high gear during normal operating temperature (between 85 degrees and 220 degrees).&quot;

&quot;TCS solenoid de-energized, allowing for full vaccuum advance in high gear during normal operating temperature and all modes of transmission operation. (below 85 degrees and above 220 degrees).&quot;

So I checked the wiring and it turns out I had the two-prong wiring clip hooked up the wrong way, of the two possible ways to connect it to the TCS solenoid. So I flipped the wiring terminal over and reconnected it.

The good news is that the TCS then worked properly as designed.

The bad news is that the engine ran like crap with no vacuum advance within the above factory parameters. Couldn't even get the car out of the garage for a test drive.


What the heck were they thinking back then? I guess it was their drastic attempts at making these monsters somehow emissions friendly. Gotta love the early 1970s - the engineers figured if they could make the tailpipe emissions somehow cleaner, then all was wonderful in the world. They didn't care that the cars barely ran, they just had to make the EPA happy and the customer be damned.

Anyway, I rerouted the vacuum line from the carb T directly to the distributor and then reset the timing as per another 455HO guys' recommendations (Lloyd: 12 degrees initial with the vacuum disconnected and plugged). The car definitely picked up some power and wasn't falling so flat in the upper mid-range anymore. Currently waiting on some new jets and primary rods to arrive.