Motor drops out under high boost

[Razor]

Posting for a friend...His 87 GN if you mash the pedal to the floor takes off and when the needle hits under 15 lbs..duh..duh..like sputters.

If the pedal is half way floored 15 lbs can be gotten too and no problem.Only problem is with WOT.

Swapped out ecm w/chip,coilpack ign mod,MAF,replaced vacuum lines at turbo.MAF does max out.TPS is at .46 at idle.

I saw BLM as high 140..its like if the car had a blowoff valve.Or kinds like when you blow an IC hose hose...that kind of dying.
Driveability is great on the car.cept for high load/boost.

Any ideas would be appreciated.Spent 4 hours tonight..

 

[Sleeper87]

This almost sounds like my problem.....Does it studder? Or keep sort of revving but not go anywhere when at WOT but feels or is faster under 1/2 throttle...sounds like my problem wich i have not figured out yet..
Sleeper87

 

[Whitettype86]

What are the plugs gapped too? And what plugs is he running?
Thats the first thing to look at.

 

[Razor]

Studder..like if it was a huge detonation..but no knock.dah..dah..dah..if lift the pedal..idles and runs normal.

Pulls strong until it hits 13-15lbs from a launch..or 18-20 rolling into the throttle.

We'll swap plugs out.Cant hurt.

It has an ATR ext gate.Could a waste gate cuase this?

When it studders it drops the boost off too.

Thanks all.Trying to get the car ready for the track Sunday.

 

[cjp69]

Razor,

These are the same symptoms I am experiencing after doing an injector swap and bstc installation.

What ended being the problem?

Thanks, Chris

 

[87national]

ttt

 

[Brian Mc]

Sounds like not enough fuel, maybe injector size or fuel pump or filter clogged. Part throttle boost should show up an ignition problem.

 

[Turtle TR]

does he use a scanmaster? is he getting a crap load of KR?

 

[1of1547]

Try another chip. My Regal did the same thing. Something about the fuel curve was off. It was basically running out of gas on the top end. I sent my original chip back to have it touched up. But it did the same thing. So I sent it back again and they are going to try another fuel curve.

 

[Quick6'n'-K.C.]

im sure the problems is fixed now,
the thread is 357 days old!!!

 

[Turtle TR]

Originally posted by Quick6'n'-K.C.
im sure the problems is fixed now,
the thread is 357 days old!!!

*LOL*

 

[cjp69]

True, but I just experienced the same problems on Saturday, which is why I revived the post.

Here is what happened on the "1 year old" post, which I am hopeful is not the problem with mine:

"Replaced the headgasket, it was the number 4 cylinder. It had started to blow..In other words the gasket was 10 percent
there. It was breaching torwards the intake. And under
high boost..poof right by..but no puff puff at idle
since it hadn't blown completely through..make sense.

Perform a leak down on the motor..may show up on a
compression test as well.

No antifreeze in oil.No plug problems."

Thanks to all for your advice and for assisting in troubleshooting.

Chris

 

[billsgn]

sigh....




hehe....Chris, Ted and I will pickup the car on Monday and get it fixed for you.