[njsteve]

I had a separate post looking for TCS info so I thought I'd co-post it here, with the results. Here was the original link: http://forums.maxperformanceinc.com/...d.php?t=508684

Here was my question:

"I am trying to make sure I have everything on my car that should be on my car. (1972 T/A 4550 HO 4 speed). In checking the 72 repair manual it says that there should be a TCS (temperature controlled spark) two pronged temperature switch on the passenger side cylinder head. Mine does not have one (could have been removed by a previous owner) but it does have the single lead (green wire) temp gauge sensor on the driver's side head. The reproduction harness has this blue and yellow lead connector that reaches to the exact spot where the switch would be. My question is this: Should there be a two pronged temp switch on the pass side? and if so does anyone have a part number for it? (I would imagine it is different than the idiot light switch as the TCS switch works as an on/off switch for the TCS system once the engine hits a certain temp range."


Thank you to everyone who assisted me in this quest. I love this website!


I just found an NOS three pronged TCS sender unit #6490384 on ebay for $30. The guy had it listed as a regular auction under the part number only, with no application identified, so it slid under the radar of most Poncho guys I guess. I emailed him to see if he had a buy it now price and he said OK to $30. I installed it today and the wiring harness is now complete for the whole TCS system. Oh, happy day!

[72formula400]

NOS three pronged TCS sender unit #6490384


I have a 72 and im getting it back to factory under the hood, but had a lot of the wiring cut off when i bought it. i have the 3 prong sender unit but noticed you have only 2 being used? 1 from the TCS (blue wire) and 2 yellow, is this right? does the bottom middle not get used..Also do you or anyone know where they come from. Looking at the wiring diagrams and other 72's ive seen it 1 seems to come from loom and 1 goes to idle solenoid? although GM book doesn't show them as 2 yellow wires..Thanks,

[njsteve]

The 72's used the three-prong sending unit but only had wires running to two of the prongs in the three terminal female connector. I would recommed buying a new engine wiring harness. The two-wired/three-outlet connector on the new harness will connect to the correct two prongs on the sending unit.

[72formula400]

[QUOTE=njsteve;3977968]The 72's used the three-prong sending unit but only had wires running to two of the prongs in the three terminal female connector. I would recommed buying a new engine wiring harness. The two-wired/three-outlet connector on the new harness will connect to the correct two prongs on the sending unit.[/QUOTE


Sounds good.. Looks like i'll have to go elsewhere though as PY dont seem to stock any..
Some help needed on which one to get though. Did all 72 formula 400's come with a unitized distributer? also when they say (gauges) does it mean rev counter?

[njsteve]

Gauges means it has the tachometer and the oil pressure and water temp gauges versus just the empty round idiot light bezel that was the same size as the speedometer. In 1972 the 455HO Formula came with the unitized distributor as a mandatory option but the T/A came with the points distributor standard, with the unitized distributor as an extra cost option. I dont know about the 400 engine, though, on the Formulas.

Do you have the PHS invoice sheet on your car? It would show the unitized option on it.

For harnesses check out these guys:

http://www.lectriclimited.com/mainpage.htm

[72formula400]

Went on there web site, looks like thats sorted , thanks..
Checked the PHS and nothing on there mentioning a unitized Dist..

[njsteve]

Good. Then what you need is the harness for the V8 (non-455HO) with gauges and non-unitized distributor. Dont know if your car has a/c or not, so that would be the only other addition.

(The 455HO harness had a different starter wire routing).