Car is cutting out under boost/high rpm

[Maltman]

I'm having problems getting smooth acceleration on this thing.....it almost feels like electrical.

Fuel pressure looks good (doesn't fall off), new coils, wires, plugs, spark module......but this thing had the same symptoms before I changed these....at least once I started running higher boost and bolted on more hp mods.

Is it possible that the plugs are "blowing out"? I'm really getting confused.....I know it must happen on other cars since a video I downloaded of a 10 sec. gn had the same sound once his boost and rpms climbed.

Could it be a semi-bad crank/cam sensor? I doesn't make since!

Anyone?

Mark

 

[blackbuick87]

Valve springs

 

[Maltman]

Valve springs are brand new....came with the roller cam kit from precision turbo....is that likely?

....and I can get good consistent power as long as I stay below about 75% throttle....problems start with full throttle

 

[blackbuick87]

If your O2 readings are high and cc's are cycling slowly it could be the O2 sensor.
The cheap things to change are:
O2 sensor
fuel filter
After that it could be MAF maybe
What are your O2 readings, scan tool readings, what type of fuel pressure gauge, etc? How do you know the FP is going up with the boost?

 

[Maltman]

I know the fp is going up w/ boost because I have an in-car elec. fp guage (the best available from autometer, so I know it is accurate). However, I can't verify the o2...although it is heated and fairly new, I wasn't able to have the scan tool hooked up.

I'll dbl. check the o2, but the MAF is the out of the impala and has a translator....but I'll check those values too.

Thanks,

Mark

 

[Lee Thompson]

miss at high boost

If not already in,--Try NGK-UR5--Gaped at .032

 

[REDS HOT AIR]

Re: miss at high boost

Originally posted by Lee Thompson
If not already in,--Try NGK-UR5--Gaped at .032

worked for meeeee

 

[Maltman]

will do....thanks

Mark

 

[TURBOZ]

Check your distrubitor. i had the same problem finally found the broken rotor and bad contacts.

 

[REDS HOT AIR]

Originally posted by TURBOZ
Check your distrubitor. i had the same problem finally found the broken rotor and bad contacts.

its not that..we have crank and cam sensors instead and a coilpack..

but i have had that problem on other cars..

 

[TurboBob]

Since you are not running an Extender chip, make sure switch #3 is ON in the translator.

How much boost? Those 42's may not be enough.

You REALLY need to hook the scantool....

How much spark advance? How much octane?

TurboBob

 

[Maltman]

TurboBob...

I'm running the ultrachip....and I switched between settings 2 & 3....I believe the timing is stock on #2 while #3 is lower?....but fuel recurved. Don't quote me, I don't have the sheet in front of me to check, but I don't think these things varied.

I'm running Mobil 100 octane/no lead...and have been for the last few tanks...however, the last tank (approx. 8 gals) was from last August

Turbo is new along with most everything else, so I haven't pushed boost more than 15-16 lbs. This is likely the reason for zero knock via the knock gauge....but like I mentioned, this identical problem plagued me when I had my old setup and started turning up the boost. (stock turbo, hydraulic cam) .....so basically, I know it isn't from the new additions.....

To note: This thing has tons of power up until 60-75% throttle....and until boost catches up to near the max.

Anything else I should look for?

Mark

I do wonder if the r43ts is not as good as the cr43ts...hmmm

 

[tazgn]

GROUNDS...

I had the same problem once before (actually many times with different things wrong), but one time it was as simple as I didn't tighten the nuts down that hold the front of the coil bracket to the manifold near the doghouse. I only tightened them finger tight and it did the exact same thing. So, grounds would be another thing I would look at. Those mounting points for the coil pack and from the motor to the battery and the chassis. I don't think it would be the O2 sensor as I believe that the ECM ignores that reading a WOT and goes to open loop (I'm probably wrong here). I'm not sure about the MAF sensor as when I had one go bad on me, it ran terrible at all throttle positions, but that may be a problem.

But I just wanted to throw out one of my embarrassing experiences with "self-induced" problems I've had.

Derrick

 

[Maltman]

hmmmm....probably a good idea to check and maybe add some more grounds.

Thanks,

Mark