Built engine - GEN-2 GTX3076r

[GsxrMe]

My car idles from 19-20 vacuum at idle. Hows the 2 barbs under the plastic cover on your intake? Do you got those pigs clamped?

[Kris86]

Originally Posted by GsxrMe

My car idles from 19-20 vacuum at idle. Hows the 2 barbs under the plastic cover on your intake? Do you got those pigs clamped?

so I assume I should be seeing around the same reading as you on my boost gauge?


yes we have all hoses secured with hose clamps

[Kris86]

i was told to make sure i have the one under the intake manifold and behind the aircon compressor secured properly.


thing is that hose runs to one of my radium catch cans and is vented to atmosphere

[Amputechture]

Originally Posted by Kris86

i was told to make sure i have the one under the intake manifold and behind the aircon compressor secured properly.


thing is that hose runs to one of my radium catch cans and is vented to atmosphere

You're talking about the crankcase vent. He's talking about the EVAP purge shits;

http://www.ft86club.com/forums/showthread.php?t=109444

[FRS Justin]

Hey Kris didn't you lower the compression?


for the EXACT same combination of parts...a higher compression motor draws harder on the intake, and thus has more vacuum.

the bigger the difference in compression...the bigger the difference in vacuum...

1-2 inches of vacuum per point seems realistic...


I would check fuel trims for signs of a vacuum leak not the gauge

[Kris86]

Originally Posted by FRS Justin

Hey Kris didn't you lower the compression?


for the EXACT same combination of parts...a higher compression motor draws harder on the intake, and thus has more vacuum.

the bigger the difference in compression...the bigger the difference in vacuum...

1-2 inches of vacuum per point seems realistic...


I would check fuel trims for signs of a vacuum leak not the gauge

Hey Justin, thanks for the info !

This is what my tuner sent me letting me know I have a vacuum leak

"I can see that manifold absolute pressure is at .52 BAR and 18% short term fuel trims. Trims should be close to 0%, and manifold absolute pressure at unassisted idle should be .27-.35 or so with no vacuum leaks."

[GsxrMe]

Originally Posted by FRS Justin

Hey Kris didn't you lower the compression?


for the EXACT same combination of parts...a higher compression motor draws harder on the intake, and thus has more vacuum.

the bigger the difference in compression...the bigger the difference in vacuum...

1-2 inches of vacuum per point seems realistic...


I would check fuel trims for signs of a vacuum leak not the gauge

You beat me to it. I thought of this yesterday while working on the jeep. He changed his comp so 14-15 sounds about right.

I know your looking at fuel trims but hows the MAF? Is it solid readings when at idle or is it all over the place?

[FRS Justin]

Originally Posted by Kris86

Hey Justin, thanks for the info !

This is what my tuner sent me letting me know I have a vacuum leak

"I can see that manifold absolute pressure is at .52 BAR and 18% short term fuel trims. Trims should be close to 0%, and manifold absolute pressure at unassisted idle should be .27-.35 or so with no vacuum leaks."

The only thing I can think of left would be the orings on the bottom of the intake flange, that bolts to the heads.

[Kris86]

Originally Posted by GsxrMe

You beat me to it. I thought of this yesterday while working on the jeep. He changed his comp so 14-15 sounds about right.

I know your looking at fuel trims but hows the MAF? Is it solid readings when at idle or is it all over the place?

so I was just checking my logs


when I turn the ignition and engine speed at "0" rpms. my MAF reads 0.76 volts.


once started and idling on its own it jumps between 1.3 V - 1.4 V


the g/s for the MAF jumps between 2.9 g/s - 4.3g/s


( don't know what the hell all that is supposed to mean but hoping you guys will see something unusual



@GsxrMe

[Kris86]

Originally Posted by FRS Justin

The only thing I can think of left would be the orings on the bottom of the intake flange, that bolts to the heads.

had to take my oil pan off to get the turbo feed re welded


the issues with living on a island in the Caribbean, u cant even get a proper weld done.


so tomorrow when the oil pan is back on im gonna be doing what u suggested with the carb cleaner and spraying the said areas

[GsxrMe]

At hooters atm, once im home ill pull some logs to compare.

[FRS Justin]

Originally Posted by Kris86

had to take my oil pan off to get the turbo feed re welded


the issues with living on a island in the Caribbean, u cant even get a proper weld done.


so tomorrow when the oil pan is back on im gonna be doing what u suggested with the carb cleaner and spraying the said areas

cool keep me posted

[Kris86]

So we did the vacuum test with the fancy smoke machine last night, found out my turbo has a very small leaking through the front cover on one particular section, possibly the o-ring that seals the cover. This tho, I don't think will cause my issue at idle. No other leaks anywhere what so ever. USED THE VACUUM FROM THE BRAKE BOOSTER TO DO VACUUM TEST

My tuner sent me this

"your manifold absolute pressure at a stable idle should be between .28 and .36 at most. Yours was around .5 or higher, with correspondingly high fuel trims. This indicates a leak. "

[Kris86]

The tuner also stated that if I do not find any vacuum leaks, then my motor isn't holding compression.


what I find weird is that the car has a wont idle once is cold, I have to keep my foot on the throttle to prevent it from stalling, but once it warms up, it idles perfectly, if I shut off the engine and start back when its hot I don't need to apply any throttle


my mechanic is saying that the piston rings need some more time to be seated and then my compression will go up.


whats you guy thoughts on this?