The truck is running well now. I found that the VSV connections were not correct. Here is how everything is connected now.
White goes to distributor.
Red goes to carb base (manifold vacuum)
Black goes to manifold connection under air cleaner
Green goes to throttle position diaphragm
The...
For a vacuum retarding distributor, how can the VSV apply vacuum at WOT? The source vacuum from the manifold has dropped. I guess it works because according to the Haynes manual, during acceleration between 13-41 mph, the VSV is energized to retard timing. I assume then that I shouldn’t have...
Now that is a new one, I would like to learn more. You are saying my timing should advance up to a point and then retard under high output? And this would be accomplished in my 1972 distributor how? Here is another thread where someone mapped timing advance against rpm. No where do you see a...
The main issue seems to be my VSV isn't working properly. To bypass that for now, I connected my distributor vacuum directly to the base of the carburetor (manifold vacuum) and reset the timing. A retarding distributor cannot be timed to the bulb without manifold vacuum or it will be too...
In the video I am parked in neutral and there is some hesitation. I’ll try it again and see if I can get the idle down. I brought the timing back down, and with the VSV disconnected, I am not seeing the carb backfire like I was. That vacuum loss through the VSV appears to be at least part of my...
I believe I have a retarding distributor and its vacuum is hooked to the VSV. I’m not measuring any vacuum at that port.
Edit: I connected the distributor directly to the port at the bottom of the carb and it started to run rough. So vacuum does seem to retarding the timing.
Did some more testing.
1. Disconnecting fuel solenoid wire causes the engine to die immediately.
2. Vacuum I measured before was teed into the manifold port that went to the VSV. If I measure directly from manifold I get a good 21 in. So I’m losing vacuum inside the VSV. Not sure if that is a...
At 7 BTDC it will idle ok, but backfire/sputter as soon as it is revved. Pretty much not driveable. At 20 BTDC it seems to run fine with no backfire or sputter. The only issue is the idle is high and it may not be good to run long term with that much advance.
I have pretty solid vacuum numbers so I don’t think there is a intake leak. Would the sight glass have fuel if there was a fuel starvation problem? I can manually rev it and watch the glass, it will backfire but the glass still shows fuel. The idle speed screw is currently not doing anything...
I also took some vacuum measurements.
vacuum at the brake booster is 21in
vacuum from VSV to the bottom of the carb is 14in
vacuum from the manifold to VSV is 14in
vacuum to distributor from VSV is 0 - revving has no effect
vacuum to top of carburetor (actuator) from VSV is 0 - (only opens at...
Couldn't agree more! The idle is ok at 7 BTDC but it stumbles and backfires as soon as you take off. Fuel pump looks relatively new, I am going to replace the fuel filter next. I'll check the advance and see if the timing changes at higher RPMs.
I did attempt to use the Fel pro gasket but I didn’t like the fit. The gasket they are selling is like a combo gasket for both F and 2F. Notice the bolt holes on each end...
Pin_Head, did you see my first post about the missing weight? Have you seen that before. I suspect someone lost the weight and just threw a ball in there. I wonder how that is affecting function.
Thank you all. I checked with the brake booster line plugged, didn't seem to help. I put a new hose on the booster anyway because the old one was cracking. I did notice an RPM increase when I sprayed WD-40 directly where the intake manifold meets the head. The manifold nuts and bolts are...