LOW (0-3psi) BOOST (HELP, I'm new!)


New Member
I have a low boost condition that I tried to correct by having the very sloppy stock turbo rebuild by a local reputable turbo/injector house. The still has low boost. I have adjusted the puck (it was a little loose), I cannot find any exhaust leaks or intake leaks. I have original cat converter that could be plugged but the car revs fine. Readings at idle: MAF-6 (WOT-183), O2-.45, Coolant-185 deg, Spark advance-37, Block Learn-129, Integrator-124, LV8-36, Air Temp-122, Cross Counts-16(12-18, it varies), TPS-.39v, IAC-66, Fuel Pressure-28psi (25-32 per engine speed). Idles high at 1000rpm. Seams to run rough at lower rpm and smooth and torquey at 60mph, about 2000rpm.


Well-Known Member
I think being new and low boost is a great thing. Read all you can and post more info. What year car? Any modifications? If you don't know, post pics


New Member
1987 Grand national all stock. Bought it to learn on then sell. It had undergone a complete frame-off restoration but the engine didn't run and the parts didn't all make it back on the right way :nailbiting:. So I have another 87' GN that I plan to build to modest power (400-450 hp) and keep as a daily driver.

Gene Van Horn

Active Member
Agree with Pronto,fuel pressure way to low, half those scanmaster numbers out of whack. Do your reading, check all your vacumn hoses, does the car have a boost contoller? Looks like it needs all basic " bring me into this century parts". Ls maff, hotwire kit, new chip and possibly injecters ect. Take it real easy until you find out why no boost. Start by adjusting the fuel pressure reg.


Active Member
you say you adjusted the puck. You want to make sure you have a good 1/8 to 1/4 inch past flush. another words, pull the rod off the puck lever, hold it tightly closed, then go another 1/8 to 1/4" . that will make sure your exhaust is not inadvertently opening the puck limiting your boost. easy on it till you get it tuned properly. use the search function here for adjusting those scanmaster settings.


New Member
Great advice guys! I plan to adjust the puck tighter and test the fuel pump pressure straight out of the tank tomorrow. The pump and regulator are new. The car sat for 8 years and the fuel lines had a lot of debris. I cleaned it out several time but maybe it is still plugged up somewhere.


Believe nothing you hear and half of what you see.
Yup, injectors are now full of that crud, they'll need to come out and get cleaned, if you're staying stock with this one. The O2 sensor might be failing. The cc should move in a fair pace from 0 to 255 and start over again while driving around normal. If is real slow moving or stuck while driving it's done. Do you know what chip and injectors it has?
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Chuck Leeper

Toxic old bastard
Staff member
Hi idle = IAC at 66.
Check the t body for "ring around the collar". AKA, dirty around the blade, causing it to stick.