I have a 93 fd that runs and pulls great. My question is i have only 10in vac at idle. Any ideas

 

What rpm are you idling at?

Is the engine stock or ported?

 

Mine is the same way because my motor is on its way out.... I was wishing for the best but thats where I'm at........ Sucks......

 

my car has always pulled anywhere from 12-15" of vacuum at 750rpm. It has been consistent with the last 3 engines Ive put in the car. All motors were remans. I have never personally seen a rotary engine pull more than 16" at 750 rpm.

 

I've got a "2 idle speed" issue that I'm trying to sort out, but the only time I've seen less than 12 in/Hg on my boost gauge is when the car is in it's low idle mode (between 400-600 rpm) and I've got the fan on via the manual fan mod (which I believe puts some additional unexpected electrical load on the engine as it drops the idle rpm even further). Otherwise I see 16-18 in/Hg at the high idle 1,100-1,200 rpm, or 12-14 in/Hg on the low idle.

 

My idle is at 700 to 800 rpm I think the motor is stock but i dont know. It has 71000 miles on it when i got it, and has a acv boost controler and a aftermarket blowoff valve. and only 10psi vac at idle? Any ideas

 

What's your boost pattern like?

Considering where you are located, you will see a lower vacuum due to your altitude. I'm in Kansas City using a stock ported motor and I have around 19inHg at idle (idle rpm 1100). I'm running a Pettit ECU without the airpump so my idle is a little higher to make it smooth. When I did have the airpump, I was idling around 750rpms with a vacuum of 17-18inHg.

 

My boost pattern is 10-8-10 and my altitude is 5432 feet. Due you think thats why my idle vac is 10-11 psi at 800rpm?

 

If boost pattern is fine, it may just be low compression combined with the higher altitude.

You can go ahead and get a compression check just to see where you stand.