High the RPM, Richer i get, NO BOOST LEAKS, Crazy Knock issues

LaN- · 08-02-2007, 08:08 PM

Mod Profile is up to date.

Problem is basically i get a lot of knock once i build full boost. (24-25psi on pump)

My timing is set to 18 degrees.

Biggest thing i've noticed is i get richer and richer the higher my RPM's go. For example, i start at 11:1 and it goes to 10:1 which is the lowest my wideband will read.

I've done a boost leak test and its good.

I checked my base timing and normal timing and they are both good.

At one point in time i had the car tuned at 25 psi with 23 degrees of timing on the meth injection. Now i can't even get 25 psi at 18 degrees.

I'll go to 75% thorttle and build up like 20 - 22 psi and have no knock but once i slam it down i start to get a lot.

I've done some 2nd gear pulls and its perfect, but then i do a 3rd and its all messed up.

I'm really confused. HELP!

Note: I had a few drinks tonight so i'll try to clean all this up later, but you should get the general idea.

arash15 · 08-08-2007, 03:50 PM

What type of mas are you using to tune thru your dsmlink? What type of fuel are you running? The case is usually due to Boostest not droping off after 6k since VE drops off at that time. This pretty much means that the injector duty cycle (IDC) is still increasing at a linear rate, even though the engine is not injesting air at a linear rate. This will cause the motor to run richer and richer as you get closer to redline, since VE is dropping and dropping further.Do you have a map sensor that is logged in dsmlink to cross reference to while tunning?

LaN- · 08-08-2007, 05:08 PM

Quote:

Originally Posted by arash15

What type of mas are you using to tune thru your dsmlink? What type of fuel are you running? The case is usually due to Boostest not droping off after 6k since VE drops off at that time. This pretty much means that the injector duty cycle (IDC) is still increasing at a linear rate, even though the engine is not injesting air at a linear rate. This will cause the motor to run richer and richer as you get closer to redline, since VE is dropping and dropping further.Do you have a map sensor that is logged in dsmlink to cross reference to while tunning?

It ended up being my head gasket. Under boost i was leaking into my coolant system. So more then likely at the higher RPM's i was smoking a little bit of oil and coolant to cause the knock.

Thanks for the advice tho.