Yup. The tap from the ign switch gets the pump running, then it's up to the AFM and trailing coil signal to keep it running.

"Still, the pump should run when the key is on, so assuming all else is good the engine should catch, and if it were the AFM door the engine would die as soon as I released the key. Is that right?"
The pump will not run with the key at "on" unless the engine is already running. Because of the tapped wire from the ign switch, it does run in the Start position.
If the problem was the AFM door, I would still expect it to start and run until it ran out of pressure: the pressure it built up while you were trying to start it because of the fact that the pump runs when the key is in Start. But it wouldn't die as soon as you released the key, it would run on the residual pressure for a few seconds. At a minimum, it would start, then die.

The relay for the fuel pump on the SE has two coils, not one as in the 12A. One coil is activated by the AFM switch; the other is activated by the computer (as on the '84/'85 12A), but is also activated during cranking by a wire tapped into the ignition switch Start position going to the wire from the ECU to the second coil. During cranking, if it's going to start it won't be from a lack of fuel: the wire from the ign switch will start the pump.

One way to eliminate any question, is to jump the fuel test connector and try to start. Now, you know you have fuel.

-John.

Just read your last post, and as it's not the AFM switch, and the fuel is circulating, it should start with a push. It will. Good luck.

 

It's not the same, as I mentioned in the previous post, but I would tend to agree with you as the 12A has fuel in the bowls for starting. It doesn't need the tap off of the ign switch to start the pump as the SE has. But what happens when the bowls run dry after prolonged starting attempts?
If the trailing coil signal, during cranking, does not start the pump then what feeds the fuel when the bowls become dry? Is the suction enough to draw the fuel into the carb?
Don't mean to ask silly questions: I'm just not very familiar with carbs, although I've rebuilt a few.

-John.

 

Sorry to bring up an old thread, but I was wondering if there was any progress on the mound. I am wondering because my SE is experiencing the exact same problems after I just rebuilt it. I have fuel, spark, and it sounds like my compression is good. The only things I can think of that are left to test is compression, fuel pressure, and the voltages at the computer. It is getting a little frustrating, but I am sure that I will figure it out soon (hopefully).

Kent

 

I replaced the fuel regulator. Still no start. After that I've been lazy or busy or it's been 100+ degrees out, too hot to work on the Mound.

I'm getting fuel vaporization coming from the front spark plugs but nothing from the rear. Suspect injector or connection I guess...still yet to be determined.

Rest assured I will update you when I get her going!

Right on!

 

Awww dooood..... the Mound still ain't run'n? Man that sux!

--Bob

 

Well, I know my injectors are working because I pulled them off and tested them. Should they inject at the same time? Mine do. I am going to try to check fuel pressure and compression this weekend. I will let you know if I find anything out. Good luck on the mound, she is looking good.

Kent