Thanks to getting my mitts on a Shop Manual, I now have definitive answers to these questions
xanthias said:
QUESTION 1:
Now, here is a question - a momentary toggle was installed as a button-start by taking the yellow wire pictured at 5 o'clock here:
which comes out of one of the two starter switch connectors to one pole and the other pole was spliced to the purple wire pictured at 9 o'clock, which was apparently pulled out of the starter switch connector. I'm restoring this to the factory setup and eliminating the button start. Does anyone have a pic of how these connectors are wired from the factory?
The answer is as I was thinking the post above - the yellow lead comes from the blue ignition connector and feeds the neutral safety switch. The purple lead then goes from the neutral safety switch to the starter solenoid. This should work fine and retain my neutral safety feature using the supplied switch with my B&M floor shifter.
xanthias said:
QUESTION 2:
The red box you see at 6 o'clock in this pic:
Was this part of a factory cruise control? It appears connected to a harness that went to the cruise on the old column and it is nothing more than a circuit board inside - it is labeled "AC Delco" on the side. It mounts on a bracket right next to the accelerator pedal?
The answer is, it used to be part of factory cruise control but tied in, as you might expect, with the brake light switch circuit, etc. so the cruise would know when to disengage. The factory engine in this truck was a carbureted 305 and the cruise control worked via a servo. I can eliminate this and will have to tease out its harness.
Engine Chit-Chat
More interestingly, the vehicle VIN, which you can decode at
http://www.decodethis.com/ specs out for a 305, which also jives with the option code on the original window sticker (LE9). So, I pulled the block casting number (14010207) and it's a 350, so we've had an engine swap in this rig, which explains some of the harness dead-ends. Further, the 350 had an aftermarket Edelbrock intake and carb. You can check your block castings at
http://www.mortec.com/
The engine swap creates some new questions in my wiring research. Apparently, the LE9 305 from the factory had an "electronic spark control" module. This was a closed-loop system that controlled detonation by modifying advance and then returning control to the "EST" or electronic spark timing distributor. EST distributors did not have vacuum advance. It worked from two sensors, a piezoelectric knock sensor on the passenger side of the block, (which is also present on this 350, curiously) and a vacuum switch on the firewall that provided a signal at throttle tip-in to retard timing to reduce knock - this vacuum switch is still left over on my firewall. Inside the cab, the ESC module itself was supposed to be mounted on the brake pedal bracket and it is gone. Someone bothered to hook up the knock sensor on this 350 and to hook up the harness to the vacuum switch, but not a vacuum line. Here's what the EST HEI Distributors looked like:
Transmission Chit-Chat
Now, here's where things get weird. According to the shop manual, only California rigs had an ECM and I did remove one from above the glove box in this rig. However, the original 305 engine VIN code (H) for this truck is wrong for a California (F) engine (yay CA emissions). Further, if you had an ECM, you didn't have vacuum advance, which really tells me nothing here since this is a swapped engine. The distributor on the 350 is a vacuum-advance HEI unit that does not have EST ("electronic spark timing", which would be signified by a 4-prong connector coming out of the distributor, with brown, black, white and green wire leads to connect to the ECM).
So, how does a rig that does not have a California VIN have what appears to have been an ECM?
The plot thickens a bit more with the 700R4 transmission, which was originally spec'd to this rig according to the sticker (option code MXO). As you know, the 700R4's have lockup torque convertors. I had wondered if the ECM, or the no-longer-a-mystery red box, controlled it. According to the manual, on "F" VIN units (i.e. California units with an ECM and a 305) the ECM did control what GM calls the "TCC" or torque convertor clutch. I haven't crawled under and traced the transmission's harness yet, but that's next up. I think I see a lockup kit in my future, such as those offered by:
Bowtie Overdrives:
http://www.bowtieoverdrives.com/catalog/catalog.php?Action=GETSUBCAT&CATID=OA1
Summit Racing:
http://store.summitracing.com/egnse...+lockup+700r4&searchinresults=false&N=700+115
I wonder if the old ECM I pulled was still performing that function, even if all or most of its other functions were disabled by the 350 swap . . .