Not building boost...

[Javi802]

So i recently put my sr back in my car after having been out of it for 2 months. Car had about 1/4 or less of a tank of gas in it while sitting that time.... 93 octane is what was in it

Well, i went to the gas station with a gas container and put two gallons in it. Im pretty sure i put 87 octane in the container because i know i paid $6.02...

93 octane where i live is never cheaper than $3.25 which would mean its not possible that i spent less than $6.50 for two gallons of 93 :picardfp:

I don't know what the fuck i was thinking.:rant2:


Would old gas and a mixture of different octane gas possibly cause my engine to not want to build boost?

Its only building up to -2mmhg


I do also have a knock sensor code, but i wouldn't think my car would not build boost due to that. I also checked mechanical timing while i had the engine out.

[Javi802]

Would the mixture of old gas/ different octane not burn correctly, that is, to build boost

[Dboyizmlg]

Do you have a boost gauge installed?

I'm assuming you do, if that's the case then you're gauge should read "0" or "- for vaccum".
Are you running internal actuator? There is a good chance that the flapper on the turbo snapped off and exit the back of the exhaust causing your motor to not build boost.

[Javi802]

Yessir i have a boost gauge.

Reads -20mmhg at idle

It "feels weak" too when i get rolling (from neutral to 1st) as well as in 2nd or 3rd.


And when i give more throttle, not wot...id say 50/70 % it won't build boost at all

Before having the engine out, a couple of months ago...with part throttle i could build boost

Now it just goes to -2mmhg. Builds no pressure at all.

I did check the wastegate and nothing seems to be wrong with it. I can move the arm and the little pin is still in tact

[Dboyizmlg]

I meant the "flapper" the little door inside on the back side next to the turbine wheel.
Take your elbow off and check if it's still there.

[Javi802]

The flapper was there before putting the engine in. I do not believe that is the problem.

[Dboyizmlg]

If your %100 sure "it's still there", then I could think of a few things.

-fuel pump
-TPS
-MAF
-air filter
-verify timing is correct

Most important before you get to all these things, do a Boost leak test!

p.s. Check all your silicone couplers

[Javi802]

I know that the mechanical timing is correct. When the engine was out i made sure that the dots on the timing chain lined up with the black links (11 links apart) as well as making sure the cas notch lined up with the dot its supposed to line up with. And the crank pulley being at the second line from the left ( 0 )

ECUTALK software shows my timing at idle to be at 15

TPS reads .46 volts at idle and 4.04 with the pedal all the way down. (tested that with car off)

MAF reads about 1.65 volts at idle

New A&N filter

fairly new fuel pump. Still primes and the gauge on my aeromotive fpr reads 36psi at idle.

Guess i should check for leaks.

I just figured id at least build some boost even with a leak, but I'm literally not building a single pound of pressure in the system.

I was running full rich on ( 10.00 afr) full throttle before pulling the engine to paint the bay. Was having boost issues too at that time, but was reaching 5psi. After pulling the eninge though i noticed that the manifold wasn't tightened all the way down. The bolts closest to the fire wall had loosened up

[Javi802]

I guess i should see what those values do throughout the RPMS

If i were to data log whats happening, via ecutalk, could anybody tell me whats going on?

See if its an actual electrical issue

[ghoti]

Take off the wastegate and pull it to see if it still has some resistance, could have crapped out. This happened to mine and car would take forever to boost and only get to 3psi