Ok, so I've been beating around the bush for awhile now, afraid of what everyone is going to tell me. But for some reason, my car pulls 9" of vac at idle, which leads me to believe that its blown...or that I have the most severe vac leak in history. My motor is a rebuild with 30k on it. It IS a turbo 6 port. But has never seen boost due to various fuel related issues, and the reading was 9" the first time I started the car after the conversion. I've never heard any detonation, and the car starts and idles fine. I've checked and rechecked the intake for leaks, even going so far as to pressurize the manifold, no hissing. Also, it is a steady 9", no pulsing, if that matters. I havn't done a proper compression test yet, but pulling the plugs and turning her over nets 3 very strong pulses from each rotor. So what the hell? 9" seems like the motor should be dead, what am I overlooking?

 

did you try another vacuum port?

 

Have you tried another gauge?

 

+1. I would try another gauge.

 

no and...no. I'll def try both in the morning. Any other ideas for me to try tomorrow?

 

might be a leak somewhere between your guage and source.

 

It's really dependant upon your idle-speed. At what RPM are you seeing the "9"?

For example, with my street-ported/rebuild TII I see around "16" at 1000RPM's, but "11" at 600 or so. Do you have hot-start issues etc? Also, a compression test would tell you what you need to know. Oh, and a 30k mile rebuild doesn't mean that much if you didn't use new/almost new housings. If you use 150k mile housings on your rebuild, you can't expect them to last forever (for example).

 

the 9" is at ~750. I dont know about the housings. The previous owner said he bought the engine from a rebuilder ( i dont remember who, it was almost a year ago),

 

But yeah; no hot-start or compression issues? You should just check your compresssion since they're "related" numbers.

 

if you can see the needle on your vacuum gauge
it's not blown

if it's bouncing around like crazy, it's dead.

it'll bounce between 9 and 0 so fast you can't see the needle stay in one spot, it'll just look like a blur. If you hit the gas it will be worse and when you let off it will be better.

Your motor isn't blown! check your compression if you still think it is, I bet it's fine.

 

Is your ignition timing dead on?
Having the ignition timing outside of stock spec will mess with idle vacuum.

AND THIS BETTER NOT BE OFF A PIECE-OF-**** AUTOMETER BOOST GAUGE.


-Ted

 

I know where you are coming from, but there are some exceptions, my phantom autometer is dead on with the E6K, over one year without a problem (knock on wood, and I hope I don't jinx myself )

 

Defi for the win...

 

woah...hatin on the autometer............. I'll try another guage i guess before ted rips off my head :/....I totally didn't mean to rhyme..

 

what is wrong with Autometer? They have been making gauges alot longer than I can remember. I sell alot of autometer gauges to the local tuners and race car drivers (we have a track here in town) that all swear by Autometer.

 

There's a reason people call them the Guess-o-Meter's...

 

I have never had a problem with autometer.

 

Their boost gauges are pieces of ****.
Ever wonder why Autometer doesn't have a tick mark for ZERO?
It's a RANGE!?!?!

I've seen Autometers which are 2psi off at ambient, and I've seen Autometer gauges off by as much as 5psi (Autometer showing 10psi, but other gauges showed 15psi!)!!!

MY experience tells me not to trust those blasted things, period.
If it works for you then fine.
Just don't tell me to use them.


-Ted