So, went to the track today and didn't even get one run in due to detonation

[baller760]

I've been preparing this car for the track for one month now and got it running really good. All numbers were within spec minus my idle BLM which is 142. Car was running great yesterday boosting 18.5 psi with no knock at all. Today the car began to idle sporadically from 600 to 1400 rpms and was detonating like crazy with 100 octane fuel. My first run I had to let go after the top of first gear because my scanmaster showed 19.9 degrees of knock around 25 mph. So, I added fuel by upping the fuel pressure and adding the maximum amount of fuel possible on my turbotweak chip, which is 20%. Next run it detonates about 3.2 degrees in 1st but then hits 19.9 degrees of knock again in 2nd gear, so I let out and cruise to the end. After this I just packed up and went home and now will conduct a compression and leakdown test next week to see what's going on.

Yesterday the car was running perfect and the only thing I changed were two things. I put on a heavy duty wastegate to boost at 20 psi and installed a homemade CAI and re-oiled my K&N filter. Timing was left at stock 91 octane levels of 18/17. My guess is it must be my MAF was fouled by the K&N oil although it shows 05 AF on my scanmaster at idle.

Things I've noticed:

At idle the 02's are now under 100 but I'm not sure if it is literally under 100 or over 1000 and running rich. The O2's go up to about 340 after the car has been idling for a while. The Int is running between 153 and 160 all of a sudden until the car warms up to about 200 degrees and then it drops into the high 130's low 140's. My BLM's at idle are 142 and never change until I get on the throttle and they are about 128-135. IAC values are between 22-25 and I only have about 11 inches of vacuum (always have) and I think it is due to the front tube on my passenger side header. It might be leaking.

It's just crazy to think that the car would change so drastically after running beautifully yesterday afternoon.

What can I do in regards to the ridiculously bad idle and my horrific detonation issues? How do I fix the Int and BLM values to bring them back down to normal?

This just pisses me off because I have been waiting for this day for one month since the track is only open once per month out here in southern California.

 

[djj624]

What comes to mind right away is

My guess is it must be my MAF was fouled by the K&N oil

Iv seen many people do this to their cars its only supposed to be a light coat and let it sit for a while. Try to find a good one from a buddy or somewhere throw it on and see what happens, and or at idle tap the mass air lightly with the end of a screwdriver and listen for changes in idle. Another way is to pull the mass air plug and see if idle gets any better. Second would be fuel pressure, make your pump didnt take a dump use a gauge to make you fp is rising with boost. My bet is on mass air though.

 

[salvageV6]

Check your motormounts too, maybe they are strained a bit causing false knock.

If you actually heard the detonation and KR then nevermind, if it's off a scantool check for stuff that's hitting something, downpipe, motor torquing over, exhaust hitting etc.

My car ran just fine WOT with high idle BLM's until I got around to getting a new chip with more idle and tip in fuel.

Lots to check but it might be false KR.

 

[bison]

Buy a wideband and get some a/f numbers

 

[baller760]

I appreciate all the comments. The motor mounts are brand new like the rest of the suspension.

I'm pretty sure I heard knock at the top of the rev range.

And I just installed an upgraded fuel pump last week. It's the new replacement for the Walboro 340.

I tapped the MAF with my hand a couple of times and didn't notice any difference but I'll go out and try to tap it with the end of a screwdriver right now to see if there is any difference.

What would cause the INT's to be pegged near 160?

 

[baller760]

Okay, just did the tap test with the screwdriver and noticed absolutely no change in idle. My O2's were around 300 this time.

Btw, I also have really bad tip in stumble when I take off from a stop. It's like the car almost dies from too much fuel at once but kicks back in.

 

[Eric Stage I]

The upper BLM limit in your chip is 142. The computer thinks it's lean, so it added as much fuel as it could (by increasing the BLM and INT), but it's still lean. This is usually caused by airflow getting into the engine that is not metered by the MAF. In other words, there may be a big vacuum leak after the MAF, or the MAF itself is reading incorrectly. Tapping it won't tell you if it's reading wrong, and a scantool may not help either, since it won't show if it's reading 5.1 or 5.9, it just shows '5'.

The other possibility is that there is an exhaust leak before the O2 sensor, making it look lean (when it really isn't). However, if it's stumbling on tip in, and idling bad, etc, my best guess is that it actually is too lean.

 

[baller760]

That is exactly what I'm thinking. If I remember correctly, the last time I used Seafoam and ran it through the upper intake I noticed some smoke coming out where the header goes into the turbo, and that is right where the O2 sensor is.

This would make a lot of sense since I only have 11-12 inches of vacuum in park despite replacing all of the vacuum hoses and zip-tie-ing them. So, how difficult is it to get the passenger side header off and get it re-welded? Or am I better of buying some new headers that cost a million bucks? What is the cheaper route?

And do I need a copper gasket to go between the header and the turbo?

 

[baller760]

I just noticed I have a clicking or ticking noise coming from the driver's side near the intake plenum. Could it be one of my injectors or some form of a misfire? It's definitely not coming from the head to suggest a valve train issue.

 

[BlackBandit]

I would do a compression check and also check the cam lobes.