Dave WM

second what ZH said. Plugs give an excellent insight as to what is going on in an engine. new ones in, drive around for a while, check and see how they look.

no rain, the problem was noticed before getting on the dirt road, just a lot worse when on dirt. Drove yesterday, no issues. Will continue to monitor and report back If something new happens.

Not sure which this belongs to. I seem to have an intermittent problem. Out yesterday I noticed for the 1st time a pronounced pull to the right when when braking moderate to hard. was on some dirt roads and it was even worse, hands off the steering wheel would very quickly turn right with even light braking. later on in the day it seemed to stop (not on dirt road did not get to try that again). tire pressure even. Jacked up the front and had helper apply brakes. could not determine any noticeable difference when trying to turn wheels against braking force. Granted this would be only a test of the lightest braking loads, but mainly I just waned to make sure the left was working at all. The intermittent issue is going to be hard since the above test was when they seemed to be working again. The only thing I can think of is a hung up caliper on the left, if that is possible. I suppose it would be a good idea to rebuild the calipers anyway since I have not service history on the vehicle.

agree with the throttle cut is prob what I am experiencing (seems to be the RPM ranges I am feeling the effect in). I am pretty sure the BCDD is doing nothing at this time, but at least its stuck in the no bypass mode.

really hard to tell, I know it is different now that when I 1st got the car, it used to hang up on idle until right at 10mph then it would drop off. Anyway I took it out for a spin and honestly I could not tell the diff with the wire on vs off. Rev up to 4k in 1st the suddenly get off the throttle, plenty of engine braking for a second or two, then it would relax just a bit. Before it would just sail along slowing down very little until 10 mph then it would drop of fast. rev up with car still and connect the wire and no wire, again no real difference in drop off from 3k to 800 I can hear the solenoid clicking away when I connect and disconnect so I am pretty sure that part is working. Maybe there is a hole in the chamber that is suppose to react to the high vac and pull the bypass open?

Re read the FSM for 75 and 76. going to try this start car get up to operating temp (so the AAR is no longer bleeding air) with BCDD wire attached rev engine up to 3k and then quickly shut throttle. Since the car is no moving the solenoid should be on and the BCDD not active allowing RPM to quickly drop. Next with the BCDD wire off (simulating above 10mph) do the same, I am expecting the quick shut off of the throttle to generate a high vacuum, activating the BCDD and bypassing some air, there by keeping the RPM up at least a bit (with the car not moving the vacuum will not sustain long anyway so I don't think it would hold it up very long).

some notes: BCDD coil resistance 30ohms tested out of circuit power at wire disconnected KOEO approx. 11v meter used simpson 260 analog

I recently put new foam on from one of the kits out there, that and the repro seat bottom (too lazy to do the top, besides it looks fine), anyway the new foam was thicker that the old, and the seat is fine for at least the 150mile trips I have been making. One thing if you get the repro cover you will need to get new foam or at least add to what is there, the seat cover is too big if you use the old stock foam.

so disconnecting the wire simulates above 10 mph, could I test the function but idling (maybe not high enough vacuum to test) and then there should be an increase in RPM due to bypass?

does the little S light come on when you press it? mine would hang up and not toggle from S to not S. you can start by just touching a screw driver to the volume pots, center tap, there should be two ganged up on the volume, one is left one is right, see if the signal (60hz hum) gets thru on both. that will clear the amp as the issue.

good point about not piping in water into a possible leak point in the cabin. Less there to go wrong the better.

I had the same problem, but mine manifested as intermittent sound, twisting the case would activate the amp portion. That's when I realized the screws were not installed. Glad that was of help to you. Those sure are fun to work on eh? Like a puzzle getting them apart and then the constant fear of popping some wire loose and not knowing where it went.

I also assume that if we have a working good temp control valve some pre bent hose would allow a replacement of just the core with no other mods?

make sure you have all the screws installed and tight when testing, some are used for grounding thru heat sinks. IIRC there are two screws on the back, you have to have at least one in making firm contact with the case.

good thinking of deleting the metal piping! how does the valving work?

Would not hurt and could prevent forgetting to keep the key off.

Since its the easiest thing to do, just unplug the ECU 35 pin and then plug it back in. Key off of course. Never unplug with the power on.

new plugs see if it drives ok, then pull them after a short while to read.

and with that stud prob the engine hoist mount.

spark is easy, pull a plug attach the wire, lay it on the valve cover and look for a good strong spark while cranking.

ZH mentioned ECU, that can cause a sudden issue, I had the same thing happen, Sudden loss of power then it just died. I replace the ECU and all was good, then put the old one back in and all was good, pointing to an intermittent ECU issue (or connector). Agree 1st thing to try would be to just remove and reconnect the 35 pin connector.

second the temp sensor, need to check the resistance AT the 35 pin plug for the ambient temps. you should replace the plugs as well. Lastly a check of the cold start valve (not likely but still something that should be checked). 1st thing to do would be a pressure test of the fuel. All the above assumes you are having fuel mixture issues based on the plug observations. New plugs will help with the diagnosis since if they quickly foul again then is almost for sure a mixture issue and not an ignition issue.

Well actually the plastic parts are in good condition which is why I decided to keep them vs trying to connect new ones. If the metal bits or the plastic was not in good shape I would have just replaced with the new ones. Oh and I did have a few spare plastic shells gotten from donor cars just in case I find a busted one.

here you go..

So you think the idea as to minimize the use of rubber (therefore rupture possible with fuel leakage) around the hot exhaust manifold? Perhaps one of the reasons they went with the solid hard line fuel rail later (vs the two section connected with hose).