Audible ping @ low RPMs > bad gas?!
08-19-2002, 09:04 PM
#1
On The Tree
Thread Starter
Join Date: Feb 2002
Location: Plano, TX
Posts: 111
Likes: 0
Received 0 Likes
on
0 Posts
Audible ping @ low RPMs > bad gas?! After a fillup yesterday evening, I noticed a strange noise on my way home. With all of the problems I've had with my exhaust system lately, I passed it off as another rattle. What piqued my interest is that the noise was only audible under load (40% throttle or greater)and ONLY between 1500-2000 RPMs in fifth or sixth gear. I just started buying gas from this place... a Shell station near my office and sold at a surprisingly decent price for a central location just off a major highway in Dallas, TX. I ONLY fill with 93 octane fuel and have done so with the past two cars I've owned.
I crawled under my car before leaving just to check everything out. I looked for loose shields and rapped on the Y-pipe but found nothing. It wasn't until I was halfway home tonight and experimenting with the noise that I suspected detonation. But why, with a fresh tank of 93-octane fuel and ONLY at low RPMs? I've never had a problem with this before.
I came home and hooked up the Autotap just to make sure my SES light wasn't due to the cam (P0300). Sure enough, I found a P0327 (knock sensor 1 circuit) mixed in with the P0300. I took off for a drive and simulated the same driving conditions. When I gave the car more than half-throttle at over 1500 RPM in 6th, I heard the knock again. Autotap registered between 6 and 9 degrees of KR when the knock was audible.
I immediately drove to Wal-Mart to purchase a bottle of Super 104+ octane booster, then over to the closest gas station. I was able to add 7 gallons of gas with the 104+ booster added. I still heard the knock on my way home but I discounted this because the fuel mixture probably didn't have enough time to dilute.
I WISH I could pull my plugs tonight (TR55s with 10K on them) but I really don't have the experience nor tools to get to #7 and 8. What actions should I take at this point? I'm going to continue to drive carefully, monitor the PCM and hopefully get rid of this gas by the end of the week. Should I pull these plugs right away? Anything else I need to look for? What action should I take with the gas station? Any advice is appreciated.
I crawled under my car before leaving just to check everything out. I looked for loose shields and rapped on the Y-pipe but found nothing. It wasn't until I was halfway home tonight and experimenting with the noise that I suspected detonation. But why, with a fresh tank of 93-octane fuel and ONLY at low RPMs? I've never had a problem with this before.
I came home and hooked up the Autotap just to make sure my SES light wasn't due to the cam (P0300). Sure enough, I found a P0327 (knock sensor 1 circuit) mixed in with the P0300. I took off for a drive and simulated the same driving conditions. When I gave the car more than half-throttle at over 1500 RPM in 6th, I heard the knock again. Autotap registered between 6 and 9 degrees of KR when the knock was audible.
I immediately drove to Wal-Mart to purchase a bottle of Super 104+ octane booster, then over to the closest gas station. I was able to add 7 gallons of gas with the 104+ booster added. I still heard the knock on my way home but I discounted this because the fuel mixture probably didn't have enough time to dilute.
I WISH I could pull my plugs tonight (TR55s with 10K on them) but I really don't have the experience nor tools to get to #7 and 8. What actions should I take at this point? I'm going to continue to drive carefully, monitor the PCM and hopefully get rid of this gas by the end of the week. Should I pull these plugs right away? Anything else I need to look for? What action should I take with the gas station? Any advice is appreciated.
08-19-2002, 09:32 PM
#2
Re: Audible ping @ low RPMs > bad gas?! Your car is probably doing all that you can do right now. Hopefully, you will have shifted to the "Bad Gas Table" and your timing will be significantly lower. To check this (I don't advise you do <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> ), your timing will be around 19 (if I remember correctly at WOT).
Just make sure you haven't clogged something in your gas line, and that you are getting the amount of fuel that you use to. Are your Lterms what they normally are?
You may have gotten the goop that sits on the bottom of dirty gas tanks (bacteria and stuff). This junk can clog all kinds of stuff.
Try to burn if off safely, and put in a tank of 'good' gas. If the problems persist, you know you have bigger issues.
Just make sure you haven't clogged something in your gas line, and that you are getting the amount of fuel that you use to. Are your Lterms what they normally are?
You may have gotten the goop that sits on the bottom of dirty gas tanks (bacteria and stuff). This junk can clog all kinds of stuff.
Try to burn if off safely, and put in a tank of 'good' gas. If the problems persist, you know you have bigger issues.
