Captain Obvious

Haha! Excellent! So in light of the additional info, I believe that those ring terminal grounds do NOT come from the EFI harness and I stand by my original claims: How do I know? Why do I care? Because my PO messed with the electrical system on my car, and I've spent some time trying to piece it back to the way it should be. And this thread is helping me a bunch because I've long known that he messed with the wiring up around the coil and AFM. Not quite sure yet exactly all of what he did, but I know it's not right. My car currently does NOT have a ground strap on the AFM, but I've got this misplaced ring lug groung coming off on one of the timing cover mounting bolts? I also have a completely unused foot long piece of wire with empty ring terminals on both ends (obviously is supposed to be a ground somewhere). I don't know where this stuff is supposed to go, but this thread is helping. So, keep discussing!! Please! And mgood... I third the comments about the beautiful engine compartment!!

Don't know if it's applicable or not, but I just went through something very similar with the butterfly on my FI throttle body. No linkage connected, blip the throttle, and doesn't always return to idle. Worse if you hold it above idle and then release it slowly (instead of a "blip"). Most interesting thing about mine was that it only did it when there was engine vacuum present. With the engine not running, it always snapped hard clean back to the adjustment screw stop. I think I have tracked mine down to worn through hard chrome plating on the throttle shaft which has exposed the gummy soft steel underneath. This soft steel of the shaft does not slide well against to the soft steel of the sleeve bushing pressed into the throttle body. I believe this soft steel to soft steel contact only occurs when engine vacuum pulls the butterfly towards the intake manifold and that's why it doesn't do it with the engine off. In the end, I wrapped my return spring another wind around the shaft and called it a day. Doesn't fix the problem, but seems to fix the symptom. If it gives me any more trouble, I'm going to mount hardened bearing surfaces on the shaft and maybe swap out the soft steel bushings for acetal. Anyway... Way too much about me... So does yours only stick while the engine is running, or is it at all times?

Actually... looking at the photos again, I want to enter an appeal... In mgoods photos, there are what appears to be TWO wiring harnesses going under that cable clamp near the AAR. There is a large diameter harness (which is clearly the EFI harness), and there's a small (1/2 inch) harness laying on top of it. That ground ring terminal connection actually comes out of the SMALL harness, not the EFI harness. So where does that other harness go? Does it actually tie into the large EFI harness somewhere out of frame, or is it in fact part of the engine bay harness and NOT the EFI harness. And what about the one at the AFM? Does that ring terminal actually emanate from the EFI harness, or does it come out of the bay harness? Huh? Huh? I'll take my lumps, but I want to double check first!

Haha! Me wrong? Completely plausible. Probable even! mgood's photos clearly show ring terminal grounds. :embarrass: I believe I have generalized and incorrectly assumed similarities between years. Please forgive me... Here's some input for my defense: 1) That ring terminal connection to ground near the AAR is not shown on the 76 wiring diagram. 2) That ring terminal connection to the AFM is not shown on the wiring diagram either. 3) I've got a 77 and I have verified that neither of those ring terminals exist on the 77 wiring harness. 4) My statement about ground connections holds true for 77. Unfortunately we weren't talking about 77! Do I get special dispensation since even though I spoke incorrectly due to my over generalization between years, I did nail the root cause of the problem!

I don't believe there are any "chassis" earth connections in the FI harness. I think the only connection to ground is that big wire which connects directly to the battery. From that connection, it splits within the harness to branch out to "provide a ground connection" to a bunch of locations within the system, but that sole connection to the battery is the ground for the whole system. There are no ring lugs coming out of the EFI harness, and the metal ECU case is not electrically connected to the circuit. Basically, if you have a problem with that main ground connection to the battery, there is no other backup which can share the load. And unless I'm missing something (which is completely possible!), the car will not run. That said, it's absolutely clear that you've got some kind of intermittent connection issue, but I don't think it's a grounding problem. The thermotime switch should be completely out of the picture unless the engine is cranking, so I wouldn't worry about that. Same goes for the CSV. Once the engine is running, the CSV is doing absolutely nothing. The AAR changes too slowly to react as you described. Even if you would disconnect it completely, you wouldn't see any effect for fifteen seconds or so. That leaves the temp sensor... If you have a shaky connection to the water temp sensor it will cause exactly what you're describing. Basically, if you open circuit the temp sensor, the ECU interprets that as an extremely cold engine and dumps in lots of extra fuel to account for the low temperature. If, by wiggling the wires, you are breaking the WTS connection, the engine will stall because you're flooding it.

Well I got a pretty good idea what you're going to be doing tomorrow. Don't tease Murphy... :laugh:

If the cap is free floating and isn't glued down, taking it out isn't bad at all. I don't remember if it's necessary, but taking the steering wheel off first makes it easier. A warm day helps too. If it's glued down, you're on your own.

I'm not sure if this is a typo or not, but you've said it twice now... You're happy with 5-10 minutes of clock error per DAY? To each his own, but I would not be happy with that. I'm thinking you meant per week, or month?

Yes, in theory, if you never loosened up either of the tie rod ends, then the alignment should not have been affected. Steering wheel position could shift, but basic alignment should still hold. That said, if I replaced my bushings, I would not be surprised at all to find I changed the alignment some. "Shouldn't" change, but...

Oh, and Yes... There are some high impedance points in the ECU design... Like MegOhms high. So it's perfectly conceivable that dust and/or other contaminants which have accumulated in these areas over the years could slightly affect operation. :bulb:

As a matter of fact, way back when at the factory, they probably were cleaned with water or alcohol after soldering. Back then? Probably alcohol. Just make sure they're thoroughly dry after cleaning before you put power on anything. (And I would not recommend compressed air to speed the drying process...)

Haha! Bring it on! That would be excellent.

I've thought the exact same thing. I suspect that if you take it off there and put it back on there you run the risk of changing the door alignment. But, if you take it off at the "normal" location, I can guarantee that you'll mess with the door alignment. So, I'm hoping someone has the answer...

*Cough* *Cough* Why limit yourself? *Cough* LM317 *Cough* *Cough*

I know you have said it's not a fuel issue, but I'm having trouble coming up with any situation that would be strictly confined to just the front three cylinders. Everything else would be common to all six cyls. Humor us? Try what FastWoman suggested:

What carbs do you have on the car? The original flat tops, or has it been converted to round tops? Also, how did you ensure that the carb(s) were getting fuel?

There should be one plastic washer on each carb, and best as I can tell, that washer exists simply to prevent metal to metal contact when and if the piston rises all the way to the very top. When the piston reaches end of travel in the upwards direction, that's where contact is made. About the sizes... I don't think the thickness is that critical. If you've got one in the other carb, can't you just measure the thickness of that one?

Right... I was just talking about the temperature of the air that was exiting, not the location of the exiting air. It is normal for the air that comes out of the dash and center vent to be unheated. However, it may not be normal for there to be air coming out of the dash and center vent at all. That depends on the position of the slider on heater controls.

Stuff like that burns me up. Sometimes you buy stuff and everyone knows it's a "kit", and part of the fun is the finish work. But I'm assuming those manifolds aren't marketed like that... Anyway, it sounds like the changing of the mounting hole threads went well. Let's hope that a stiffer linkage and better end bearings make the necessity for a center mount a moot point. Get the torsion springs on for the return and you may not miss the center point at all.

That's normal. The air that comes out of the vents in the dash is not heated. With some of the air conditioning set-ups, those vents may be cooled, but they are never heated.

So about that third center mount... I assume that the direction of "problem" you were originally having was fore/aft (as opposed to up and down), since the rod ends have adjustable height. I would HOPE (and assume) that the manifold manufacturer located and drilled all those holes on a machine capable of holding a suitable tolerance to use all three mounting points. You are threading a non-precision shaft into a (hopefully) precisely located hole, and then locking it in place with a non-precision nut which may or may not pull straight up on the shaft. I'm not surprised you can't get three of them in enough of a line to have the shaft rotate smoothly. How about a thin tapered washer under the center mount lock nut to cant the rod a little in the direction of your choosing? You could test the concept using by slipping a feeler gauge under the nut on one side and snugging up the nut. But before you do any of that... It looks like they did not machine the top surface of the mounting bosses? Make sure there isn't simply a thread burr kicked up or something that is preventing a perpendicular face. Me? I would have machined the tops of those mounting bosses normal to the threads. Just throwing out some ideas... Maybe something will stick?

How about modifying the threaded portion of the new 3/8 rod ends down to 5/16 instead? Drilling & retapping the manifold is hard to undo, and you could always buy another set of 3/8 rod ends. Lathe would make quick work of that. In a pinch without access to machine tools, you could probably even use a file to cut them down to size before running a 5/16-24 tap over them. How good is your eye? Nice pics of the linkage BTW.

I don't get any pics... Just this: I'm assuming there's a problem on my end?

Yup. There they are! Thanks Blue. I gotta assume from the lack of input that these aren't highly thought of?

Getting an accurate reading with those IR guns can be difficult. Not only the distance from the target, but the accuracy also depends a whole lot on the emissivity of the material being scanned. Shiny stuff like intake manifolds, aluminum head, or stainless headers can be trouble. You can read a bunch here about how to take more accurate measurements: Noncontact Infrared Temperature Measurement | Emissivity Measurement ? Raytek.com Emissivity of Materials | Thermal Emissivity*? Raytek.com