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Old 02-04-2014, 03:39 AM   #1
cigar-
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wiring and relays

Again back on this getting my 71 truck running. The truck I bought was an inline 250 ci six cylinder. That was swapped out for a 350 some time ago. I pulled it due to a wrist pin knock and slid in a new 300 hp crate motor. All good so far.

Some previous individual cut many wires and re-routed others to make the 350 with and HEI distributor work. How well it worked I do not know. The truck ran when I bought it (yes I test drove it) so the wiring was operational/ I am trying to get it back to original by replacing old six cylinder wiring with V8 wiring.

There is a four wire harness that ran over the top of the firewall and went to who knows where. It has a black nylon clip that was holding the wiring up there. I bought the CR-ROM showing the wiring harnesses but am unable to determine where these wires went to. That's one problem.

The second problem are the two relays(?) mounted on the firewall, drivers side right near the hood hinge. The photos show them. Does anyone have any idea what they are for? Can I remove them without affecting the operation of anything, including the truck itself?

My hope is that on this site is someone that is REAL good with wiring issues that can offer help.

Please help and thank you!!

Michael
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Old 02-07-2014, 03:16 PM   #2
MagmaJct
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Re: wiring and relays

Those are time delay relays. They were part of an emission control technique that (if I recall correctly) delayed spark advance until the engine warmed up and/or the transmission was in the right gear and/or time elapsed. I'll see what I can pull up for you.
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I own 3 classic vehicles. 1971 LWB C10 Deluxe. 1974 VW Super Beetle. 1971 VW Fastback.

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Old 02-07-2014, 03:21 PM   #3
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Re: wiring and relays

Okay, I got it a little backward. Check out the true story here: It's called the TCS or "Transmission Controlled Spark".

http://www.autozone.com/autozone/rep...00c15280081fe1
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I own 3 classic vehicles. 1971 LWB C10 Deluxe. 1974 VW Super Beetle. 1971 VW Fastback.

The C10 and the Super Beetle run, the Fastback is just not there yet!

Please visit my Super Beetle and Fastback profile on TheSamba.
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Old 02-10-2014, 03:33 PM   #4
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Talking Re: wiring and relays

I can't thank you enough for the reply. I have been tearing out my hair asking around and finding nothing. All I have is a copy of the Chevrolet wiring schematic for the truck and it does show relays. The problem with that is the abbreviations don't mean much to me....until now!!

Again....a HUGE thanks.

Michael
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