Rogue_Ant

Ryan, what is your altitude?


-Rogue

Lorax

~1000 - 1200ft above sea level

black944 turbo

I have driven mine and one other car in the Atlanta area and both mine and his were getting around 14-16 in hg. I have done the same pressure tested, all new vacume lines, new vacme pod on vapor canister, No leaks. I had a leakdown test done recently and was told there was none to speak of (meaning less than 1%). I think you are fine.

turbo8

whats everyone getting on decel in gear? im getting 16" at idle on decel I get 19 or 20" doesnt seem right used to be getting 25-30"

TurboTommy

If you're at 1,200 ft the max vacuum you could get can easily drop off 1 or 2 inhg; so you're not really comparing to the 20 inch guys.
Also what is your engine speed at idle? Once you go below the 850 - 900 RPM mark, vacuum drops off quickly, even if everything is healthy.

Mike Lindsey

Several things can make your vacuum vary from car to car. 16 is fine. If you cannot find
any leaks, then don't worry about it. Since vacuum is created between your throttle blade
and the piston going down, your leak your looking for could simply be the position of
the throttle blade. Maybe yours is further open then the next guy.

Lorax

Well I have a few other issues that are all possibly related. I have a bit of a rough idle on cold start (just for a few seconds) and I have a hesitation when going from vacuum to heavy throttle.

I'm going to be replacing my TPS shortly. Oh, I wanted to say thank you for sponsoring 944Fest, especialy since I won the $500 gift certificate in the drawing!

ausgeflippt951

Don't worry about it. 16 seems to be fine. Mine gets -0.6-0.7 bar (around 18") at idle and around -0.8-0.9 bar (25" or so) on decel. I have Vitesse St. III running 15 lbs at 2000 ft elevation.

If you're at 8" at sea level then I might start to worry...

black944 turbo

Ryan have you always had this hesitation? I had the same problem when I had my maf and a custom chip. Never could get it corrected after chasing my tail and $2000 down the tubes, I went back to stalk with only a chip (low and behold it runs great). You may be looking at the wrong things here, don't just buy a new TPS, test it.

Lorax

I have always had the problem with this car.

Going back to stock is not an option for me..

6ocyclehum

I get 15 warm. Idle at 850. I checked my vac at the brake booster hose and it's 19.

BGA9512

Also in the Atlanta area (800 feet MSL) I get 18" Hg on an '88 with 80,000 miles and stock except for a LBE.

flosho

I would be more worried if the vacuum reading fluctuated up and down or was not steady in general. If its rock solid at 16 then I wouldn't worry about it.

Keithr726

+1 16 is not bad, fix the other problems and drive it

Lorax

I was just out playing with the car and had a thought come to me.

I think that the throttle stop may be adjusted too far closed... and that could be causing my low vac and possibly my hesitation going from vac to throttle. It makes sense if you think about it

So I will need to adjust the trhottle stop to a point where it is slightly further open, then adjust the TPS to that point as well. If my throttle is sitting too far closed on vac, could that cause the minute hesitation going to WOT?