Hotwiring makes a big difference...

[Welby]

I've had my 340 in the car for a few days, and finally got my hotwire in last night. I checked my line off pressure after starting it up, and it was almost 51 lbs, where before it was 43
I knocked it back down to 43lbs and concluded "Yeah, hotwiring makes a difference ". Took off down the road and swear I could feel a difference in how the car was running, too

Final Analysis: Hotwire = good

One serious question though; when I first put on the Accufab regulator, I set the FP to 43lbs with the engine cold, then went out for awhile. When I came back, with the enine fully warmed up, the FP was only around 39. I reset it to 43 when the motor is hot. Is that normal for the FP to rise or drop depending on engine temp?

 

[turbobuickman]

Was this before or after the hotwire? Maybe when you first started it up, the engine was racing and alternator making more power, then when the idle settled down(warm), there was less power to the pump...

 

[Welby]

This was before I did the hotwire, with the idle at normal levels. But even now, the pressure reads differently when cold and hot *shrug*

I'm just going to set it right when "hot", but it puzzles me.

 

[crownvic96]

the regulator needs to be set when everything is up to operating temp.

 

[turbosam6]

Its going to change with engine temperature because your vacuum changes with engine temperature. You set the psi with the line off anyway, then check it with the line off. If it changes alot then, you have a problem.

 

[mgmshar]

For what it's worth,

I've had an Accufab and somebody else's adjustable regulator on my car. For both of them, the fuel pressure, as shown on my underhood gauge, would drop a couple of psi when the car is fully hot versus when it's cool. This is the pressure with the line off, so I know it has nothing to do with engine vacuum.

I'm not sure if the gauge is moving when it gets hot, or if the regulator spring is relaxing a bit when it's hot.

HTH...