Pierre, Accel is gone. It is Mega Squirt now. Dropping the fuel pressure down required raising the REQ-FUEL from 15.5 to around 16.5. This is just a constant that is applied in the fueling formulas. You can change the entire map at once by adjusting this number. Then I had to adjust the VE tables to make them richer. But, it all works right now. That is the key.
I feel fabulous right now! I feel more confident, and more optimistic, and more gratified with this car project than I have felt since I took the carburetor off of it. I want to jump up and kick my heals. I could hardly sleep last night I was so excited by the direction things are going now. Any problems I encounter at this point will pale in comparison to what I have been through. You cannot imagine the heart aches this challenge created when I would think I had a solution to this ongoing problem, and it would simply come right back. Maybe it is a little too early to celebrate, but I am going out on a limb, and having my own personal, internal victory party. All the money and time I have put into this car are suddenly seeming like a worthwhile thing. I am no longer feeling defeated by it. Do you get my drift here? Before yesterday I felt like this project was never going to be right. I felt like a failure. I did not feel like I could drive long distances with it. I could drive it to work, but not across country. And now the missing link has been uncovered. It is a real car once again. Am I being melodramatic here? I just don;t want you to miss the point. Come celebrate with me.
Now on to the gauge saga. It will help you understand why I trust this mechanical gauge (aside from the fact that it runs right now). Gauge number one was a 0-60 psi one and was ordered from Summit. When it arrived, I screwed it in and started the engine. It leaked, and APPEARED to read 0 psi on its face. Without any careful checking I sent it back, and they dutifully sent me another one. I screwed it in: This one didn't leak, but it APPEARED to read 0 on it 0-60 face. I cut the engine off, and .......wait a minute....the needle is falling slowly down to through the numbers. It had been pegged all the way around to the bottom of the gauge. So, logical me, I assumed (you know what they say about that), the gauge had the wrong face on it, and it was really a 0-15 gauge. O me of little faith. After all my expensive Autometer in-dash gauge couldn't be wrong could it?
So, I trekked up to Frederick Maryland, where our local speed shop had moved to ( a distance of 25 miles now) and bought one over the counter. This one was liquid filled(what does that liquid do anyway?) and cost twice as much. Maybe that is retail markup, but Summit had more expensive ones also. So when I screwed this 0-100 psi one in and it read 80 PSI, my lightning fast mind began to put 2 and 2 together and it no longer added up to 43psi. And I realized for the first time that the first gauge was probably not bad except for the leak, and dollars to donuts was pegged as well. If three mechanical gauges (I know it is only 2 I can be certain of) all read over 60 psi I think my expensive in-dash gauge is likely the bad guy here.
Here is the bottom line: at least for now, the fuel pressure and AF ratios seem to be reliable across varying temperature ranges. Here is another observation that is germain. When you kick the throttle now, the pressure jumps from the vacuum referenced input from 37 to 43 on the mechanical gauge. That is what it is supposed to do. My electronic gauge was not showing that relationship. Now maybe that was because it simply could not pump over 80 PSI and had no room to rise when vacuum dropped off.
In fact, I think maybe that explains the loss of pressure when hot. I think the FPR regulator was doing nothing before. I had to turn up on the adjuster a long way before I saw pressure start to drop. The pressure was simply whatever the pump was able to put out. And it obviously dropped off when warm. Which was only a problem because the tuning was for 80 PSI and got too lean at 50 or 60 PSI or where ever it was going when hot. In fact when I lowered the pressure from out under the hood, I had to do it in stages, because the engine wanted to die as I was lowering it. So I lowered it to 60 PSI, kicked up the REQ_FUEL number, lowered it some more, kicked up the REQ_FUEL number ETC. until I had it reading 43 PSI with the vacuum reference unplugged. Plugged in the vacuum line, and voila, 37 PSI just as advertised.
I do not think I have to change the fuel return line now. If I change my mind later, I will do it. But for now, this seems to have been the magic bullet. I have been chasing this ghost for 3 years. I switched to ACcel because of it. I switched back to MS because of it. I feel the car is no longer haunted. As my GRandfather used to say, "It is not what you don;t know that hurts you, it is what you know for sure" That makes more and more sense to me as I age. Now, on to other problems. And, you will hear about them. 
Sam
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