Thread: Car cuts out under boost w/ vids

Ok guys finally got the car finished with all vac leaks fixed everything seems to be sealed. If you must know i verified the vac leaks by lowering my air compression regulator and with my homemade intake designed for this i shot air into the intake to listen for leaks and i finally got it all sealed. All the mods are in the signature below.

This i have tried.
-Changed pulleys to see if it was belt slip no change and scan showed that
-changed plugs and wires and didnt help
-thought MAYBE MAF tune was off so i changed back to stock and no change
-When i scan no misfires come up under load.
-Spark plugs are gapped at .042 and timing is at 24* (car has ran at this before hand with no issues)
-changed plug gap to .049-.050 nothing changed
-EGR is blocked off for intercooler
-Checked voltage to make sure alternator was keeping up and is at a steady 14.3v
-check vacuum at idle with the 3.0 i see approx -15-16
-Replaced fuel filter
-Changed fuel regulator still nothing changed
-Fuel pressure at idle is 60 and at wot when it starts to cut out is around 62-65
-Brought the ICM back down and made sure it was ground and still no change
-Took supercharger belt off and ran it that way and it still dies off at 5k rpm (can not do case relearn)
-Ran open cone on crank case to make sure i wasnt generating to much pressure

I dk if that has anything to do with it but could my PCV not be correct and create crank pressure and allow it to do this? Got it going from the TB (between MAF and blades) to the oil neck on the VC. The rear PCV is capped and block on the intercooler and s/c. I routed the rear pcv to the TB and ran open cone and seems to have gained a little more vacuum and idle a littler better.. Could it be possible that i might be loosing ground? My ipw dont get past 15. I does not indicate any misfires under load.

I cant even do a crank case relearn because it dies out under high rpm.

Im at a loss. Any ideas would help.

Video's

YouTube - Grand Prix GTP mods

YouTube - Grand Prix fuel pressure at idle

YouTube - GTP cutting out under boost

YouTube - Fuel pressure when cutting out under boost

YouTube - Vacuum when care cuts out under boost

YouTube - Grand Prix GTP Xp cam idle

The wideband needs to be fixed so DO NOT look at the gauge.

Nobody?

just throwing ideas here

did u replace the pump? how many miles on it? whats it sound like when you turn the key for pump prime?

fuel pump resistor?

could you post a picture of what u blocked off?

when i did my install on with my i/c and genV, i didn't block a hole, i ported a hole for rear pvc and use a breather

Originally Posted by 99prixgt

just throwing ideas here

did u replace the pump? how many miles on it? whats it sound like when you turn the key for pump prime?

fuel pump resistor?

could you post a picture of what u blocked off?

when i did my install on with my i/c and genV, i didn't block a hole, i ported a hole for rear pvc and use a breather

Fuel pump is pretty much new (PRJ fuel pump with re-wire) 200-300miles on it. With pressure being where its at i doubt its the fuel pump

I just blocked off the evap on the genV.

I also tried running the rear pcv to the TB like i did before the IC install and ran a open breather on the crank case and still does the same thing.

No where in there do I see that you checked the BBV...I had that issue...valve was toast.

Originally Posted by Ace

How much boost are/were you running? Are there any leaks on the line that goes to your MAP sensor? Since you're only reading 15 inches of vacuum, how's your intake manifold gaskets?

The Vac reading will be lower running a cam. But you're running a 3" on a GenV?

Originally Posted by KeithGTP03

The Vac reading will be lower running a cam. But you're running a 3" on a GenV?

E85 boss.

lol...thought it said EBS, and wasnt sure what it was

Double check your tune to ensure nothing is still disabling under TM or injectors, AFR etc.

When you hit certain calculated power levels, the pcm can hit these and drive a guy nuts.

Originally Posted by bluegtp91

No where in there do I see that you checked the BBV...I had that issue...valve was toast.

I have not checked that BUT the car still does its cut out thing with the supercharger belt off.

Double check your tune to ensure nothing is still disabling under TM or injectors, AFR etc.

When you hit certain calculated power levels, the pcm can hit these and drive a guy nuts.

I want to say its fine but i could be looking over something i dk.


DEMOD is sitting in the back of my mind

After doing heads and rockers on top of the rest..I started to cut out/lean out etc if I tried to hit any boost. It was odd.

Found the fuel injector disable and some other f'n thing about modes on fueling or TM tab. Next thing I knew...I wasn't think demod. I was thinking.. "here cobra cobra, corvette... " lol

Originally Posted by BillBoost37

After doing heads and rockers on top of the rest..I started to cut out/lean out etc if I tried to hit any boost. It was odd.

Found the fuel injector disable and some other f'n thing about modes on fueling or TM tab. Next thing I knew...I wasn't think demod. I was thinking.. "here cobra cobra, corvette... " lol

Im using the same file that i had in the car when i snapped the input shaft so i wouldnt think there would be anything in the TM tables but hell i dk anymore

Originally Posted by matt5112

hows it run at 5000 RPM +

It just dies off when in park and doing a case relearn.

Stop over with it..I'll take a look at it for ya.

Originally Posted by BillBoost37

Stop over with it..I'll take a look at it for ya.

Ya, he's only in South Dakota lulz.

Originally Posted by bluegtp91

Ya, he's only in South Dakota lulz.

Well CT isnt that far