Exhaust popping

[RedogOnyx]

Hey guys

Been a while since I've been on here, then again I haven't really had a probelm is a while.

I had a nasty exhaust leak at the headers so I repaired that with the gaskets from WOT-Tech and that's good now. My exhaust used to pop at the header (mainly 2, 4, and 6) but now it's still popping under heavy load, but the popping either under the car or out of the tail pipes.

Ben was helping me a lot with tuning and said in order to go futher, I would need a WB A/F gauge. I was waiting on Autometer's 4970 gauge for a year, but they are not making in now so I got a regular gauge with the ditigal readout.

Drops as low as 10.2 when I get on it and when I stop after that, I've seen it go as high as 17.4. I do have HP tuners, but I'm really a tuning novice.

Any help, I would be very greatful

[RedogOnyx]

Nobody knows?

[Driver_10]

Do you still have provisions for air injection with your new headers? If it were disabled, then that would make it backfire. (mind you, this is just a guess since Ive never really owned one of these cars)

[RedogOnyx]

Still have the EGR valve in place. I had Cali emissions on the heads, but that when away with the P&P heads I put on about a year ago.

As far as I know, there is nothing missing from the headers.

[Schmieder]

17 AFR when in decel isn't too bad but hitting 10.2 AFR while in WOT is hellish rich man. Are you boosting or N/A? I'm pushing anywhere from 5-10 psi and I go as low as 11.4 and slide into 10.8 after several seconds of boost.

What is your cam? Stock or modified....I won't pretend to be an expert, I'm on my way though. But I can say running an AFR of 10.2 is WAY rich. Your exhaust heats up dramatically the richer the AFR gets. My guess is your combustion is slower under richer AFR's and the combustion process isn't complete when the exhaust valve opens, making that pop sound.

I found simply changing the spark degree at idle will change the engine exhaust sound. Less advance makes it louder.

You need to get your WOT AFR under control. I don't know the history of the tuning done, so I can't really suggest what to do. BUT, if your tune is good and your fuel trims are good, then go into the ENGINE > FUEL > POWER ENRICH tab and open up the Base AFR vs. ECT and Add vs. RPM tables.

Base AFR vs. ECT is the base fueling AFR while under WOT. This table should remain untouched but you need the info in there. Mine says 13 AFR for example.

Open the Add vs. RPM table and now you can subtract these values from the base AFR to see what your AFR's are at specific RPM's over time. To make it simple, focus on the top row only for now. If your boosting, you want the AFR to be in the low 11's when boost kicks in, usually 3600 rpm and up. If you are N/A then 12-12.5 would be good power producing AFR's. But do NOT just jump 2 AFR points like that. Take away in smaller increments to be safe.

Try adding 0.5 to the tables (mine are negative as it is an AFR subtractor) we want to get your WOT AFR's up a little. Because 10.2 is just TOO freaking rich for N/A and even too rich for moderate boost, like 5-12 psi.

Post up your HPT file if you can and an good log file would really help. Any info you can give me about your tune will help.

Tuning w/ HPT is something I can do well, so I can help there.

[RedogOnyx]

I'm running a stock cam and I'm NA

here are a few screen shots of those charts