cant get it over 4000rpm

[crazygn]

Can any one tell me why this car will not get over 3800-4000 rpm and gets bad knock when it get there. I will take any ideas and check them, i have checked every thing. It seems to build good power but does not last, it builds it at about 3000-3500 and then dies at 3800-4000. I cant beat a school bus.

 

[turbowrenchhead]

Bad coil?

 

[crazygn]

I tryed my brothers coil and the same thing, I found a some what bad leak, i cant tell how bad it is yet , if i blow in the pipe and hold myhand over the other side i can fell a little air coming from the nos nossle on the up pipe. This would help my boost problem but would it help the rpm problem.

 

[turbowrenchhead]

Think it is getting to lean and misfiring? Can you monitor the O2's?

 

[crazygn]

i had my brother sit in the car and read the scan tool when i was driving and the o2's where 800-820 wot at 15psi and nothing over 4000rpm.

 

[turbowrenchhead]

So the O2 voltage is droping to zero when you go over 4000 rpm?

 

[crazygn]

no the o2's stay at 800's when it dies out and seems to not want to rev any more , 3800- 4000 and i pick up knock on the knock gauge and the car seems to slow up like its pulling timimg for the car.

 

[Buick From Hell]

Check the cam sensor adjustment!

 

[turbowrenchhead]

put some race gas in it and disconnect the knock sensor, maybe false knock

 

[crazygn]

maybe it came lose , i'll check it after work. Any more help would be great guys thanks

 

[turbowrenchhead]

Friend of mine was having the same kind of problems with false knock. He ended up disconneting it all the time. He thinks that he is getting it from the aluminum heads, having to much vavletrain noise. He also runs 110 ocatane in it all the time. So he is safe.

 

[crazygn]

I guess fulse knock will pull timimg to and slow the car up. I'll try the cam sensor and fix the intercooler leak and see how it does. I'll try to get some money up and get some cam2 its about 3.75 a gal now.

 

[turbowrenchhead]

What happens if you back off the actuator and run less boost?

 

[crazygn]

Thanks bud i'll check it out and post back.my turbo link should tell me when i am getting knock right. If i unhook my knock sensor will it just not pull and timing , just unplug it

 

[turbowrenchhead]

Yeah just unplug it and the cant pull timing then. Listen for auidable knock. You might hear a ping or feel a slight hesitation. If you do you are getting real knock. If it pulls like a raped ape then it is false. I have heard of a bad O2 sensor causes false knock as well.
Sure got this thread alot of posts in a short time.

 

[crazygn]

not sure , i wanted to try that today and forgot about it. last week it was pulling like a 11'sec car and now a 15 sec car i just dont get it. I'll check it all and see what happens .

 

[crazygn]

Cool i'll check it out, yea i got alot of post in a short time , thats pretty cool maybe i will post something else it fun when you have nothing to do.

 

[FJM568]

Oh boy, disconnecting knock sensors...

BOOOOMMMM!!!!!

See my previous post about ranting... enough said...

 

[REDS HOT AIR]

Originally posted by FJM568
Oh boy, disconnecting knock sensors...

BOOOOMMMM!!!!!

See my previous post about ranting... enough said...

i had mine undone whole time i had hotair motor in my car ..knocked so bad a few times thought i ran over the whole front clip but motor looks good still bearings look great and the hypo pistons still look new..

car ran like **** with it hooked up

personally i didnt care if it blew up but im sure others do..

 

[turbo6x2]

Did you figure out the issue and if so, what was it?