Adjusting Warm Up Regulator for 78 SC you gotta read this

[stormcrow]

Well, I have been having a problem with my fuel pressure. I noticed when the P-car has been sitting for awhile, it's hard to start.

That's not to say that it will not start, but it fires right up and then dies. Well, I put the gauge on it and found out that the pressure goes to 80 and the engine shuts down. Starts back up again and does this about four or five times before it stays running.

So, I decided I needed to check the pressure regulator. Now, I know there have been posts on installing a screw to adjust it, but looking at mine, I didn't think it would work. There is a recess in the bottom with a copper cap inserted.

I took the regulator apart but could not find any way to adjust it. I then drilled a hole in the copper cap and guess what I found.

There is a 4mm allen screw on the otherside of the copper cap. That screw is used to adjust the pressure on the system. If I hadn't drilled the hole in it, I wouldn't have known.

I made some adjustments and it works. So, if you have a pressure regulator similar to the one below, all you have to do is drill a hole in the bottom and you can adjust it.

Steve

"A Porsche does more then just go fast in a straight line"

[wckrause]

Does that adjustment effect cold temp pressures, or warm temp pressures. My guess is that it would effect warm pressures.

The adjustment modification described in the tech article is for adjusting cold pressures.

Make sure that your pressures are still within spec when warmed up. In other words, don't sacrifice optimum settings for a warmed up engine just to get the car to cold start correctly.

[stormcrow]

The warm up regulator does have an effect on cold starts. When the engine is cold, the warm up regulator allows more fuel to pass through so the engine has more fuel enrichment. As the engine continues to run, and 12v applied to the regulator, the fuel is slowly restricted allowing for more pressure on the fuel distributor and a leaner mixture.

If the pressure is low on the fuel distributor, then the air flow sensor will lift more thus allowing more fuel to enter the combustion chamber for a richer fuel mixture. As the pressure increases on the fuel distributor, the air flow sensor will lift less allowing for a leaner mixture and less fuel to enter the combustion chamber.

This in conjunction with your o2 adjusting screw along with the height of the air flow sensor allows for a proper mixture both cold and warm.

Steve

"A Porsche does more then just go fast in a straight line"

[Hladun]

I believe that the screw you're looking at holds the diaphragm assembly together. If you turn it you may tear the diaphragm and really screw things up! It is not an adjustment and you now have created a vacuum leak if you don’t plug the hole you’ve drilled. There is only one way to troubleshoot the WUR regulator and that's by doing the pressure tests properly using a tester (JC Whitney sells the CIS tester). Where are you reading the pressure? 80 sounds like the fuel pump, not WUR, pressure.

[stormcrow]

I'm going to post some pics later on this evening. I have a spare I will take apart to show you. The screw is locked on the diaphram with compound so it does not turn. I will have some good pics later to better explain

Steve

"A Porsche does more then just go fast in a straight line"