Car: '85 12A

A while back I was having problems with the the car just dieing.. So I figured it was the fuel pump.
To test, I bought a fuel pressure guage, installed it, and later found out that the problem was a bunch of rust and **** in the gas tank.
Fixed that problem!

Now: I had installed that fuel pressure guage just before the carb, and it gives me odd readings.

It seems like when its really cold out, there is 3-5 psi of fuel pressure before the carb.
When its really hot, theres next to 0 psi.
When driving it when its cold, it stays around 3-5, dropping when I really floor it, but when its hot out, it drops down to 0.

Is this normal, or is something wrong with the carb/fuel pump/etc?
It seems to run normal, I just find it odd to hold more pressure before the carb in colder temps.

 

Just a simple ? What line did you tap into?

 

yes, the stock fuel pumps are JUUUUUUNK! when they heat up they sorta die out and don't flow. most rotary vane style pumps will do this with age. go ahead and upgrade and get a regulator to bring down the higher pressure. your car will thank you

 

I have found many of the fpgs will not give consistant readings, liquid filled or not. I have had the same problem with good fuel pumps, the stock one only makes it worse.

 

T hit the nail on the head. Don't trust any guage that is not specifically designed to give accurate readings at those low levels. Also, I will agree that the stock fuel pump is junk, and barely adequate when brand new for a completely stock RX7 that is driven moderately. If you need to upgrade, check out this thread for instructions and suggestions; https://www.rx7club.com//showthread.php?t=529605

 

The guage is actually rather nice, meant for a carb. 0 to 15 psi.

And I suppose it makes sense the stock pump is crap. I suppose this means its running real lean when the pressure is at 0.

I shall upgrade immediatly!