Allgas24

Hello Everyone,


I'm building my first car with my 10 year old son, with us both hoping we can have a street /strip car built by his 16th birthday doing all the work ourselves. We are current in the process of labeling all the wires and parts before disassembling anything. I've purchased countless manuals and collected aids from the internet, its the engineer back ground and career.


Here where I need help looked every where can someone tell me what these wires go to in the attached picture and if this is the DTVS


Thanks for help

Fun71

The wires go to the transmission to prevent vacuum advance in the lower gears. Also, it has a thermal switch to prevent vacuum advance until the coolant is up to temp; then if overheating occurs, it switches from ported vacuum to manifold vacuum in order to promote cooling. It's an early emission control device and can be removed on a performance oriented street/strip car.

oldcutlass

Welcome to the site, its great that you and your son can share the experience together.

2blu442

Welcome to the site! I agree with Eric that its cool your doing a father/son project. I'd encourage you to get a Chassis Service Manual for the year of car your working on. I find these manuals really helpful with many of the questions that come up regarding these cars. Attached is a link to an ebay ad showing what I'm describing. There's several on ebay all the time so you should be able to find one at a reasonable price. John

http://www.ebay.com/itm/1971-Oldsmob...VZVm5k&vxp=mtr

CRUZN 66

Welcome to the group... Good luck with your father/son project, it's an experience you both will never forget...

joe_padavano

Welcome and congrats on the purchase. Yes, that is the combines solenoid and vacuum switch that operates the Transmission Controlled Spark system, which is described in the Chassis Service Manual. As discussed above, the wires connect to power and a switch on the trans that operate a solenoid valve that blocks vacuum to the distributor vacuum advance in all but high gear. This is a very early emissions control system to lower NOx emissions. Unfortunately, by retarding the timing at low speeds, the TCS can cause the car to overheat in traffic.

In addition to the TCS, the car also uses ported vacuum that provides no vacuum advance at idle. The purpose of the lower part of the switch is a thermal sensor in the cooling passage that will bypass both the TCS and the ported vacuum connections and send straight manifold vacuum to the distributor. This advances timing at idle and low speeds, lowering engine operating temps.

Unless you care about a totally correct restoration, most people simply bypass or delete this system and run the distributor directly from manifold vacuum all the time.