Hello all. I have a 2001 Toyota corolla, 108,000 miles, Automatic that i bought about 3 months ago. When i got it it had a system too lean code which through research and diagnosis i determined to be the MAF. Replaced with a new OEM sensor and the lean code hasnt come back since. I also had a code for the VVTi. Replaced the oil control valve and the little filter screen which eliminated that code. Ive done and oil change since i bought it, using castrol 5w-30 and a OEM toyota filter. Also changed spark plugs with high quality NGK Iridium plugs as per the sticker on the side of the valve cover. Took a look at my throttle body plate and cleaned that out a bit. It wasnt too bad to begin with.
Im in New jersey and this was most noticeable on the hotter days, but still happening now that its cooler.
I now have no engine codes at all. Have driven at least 500 miles since everything was replaced and the existing codes were cleared. Ive noticed pinging happening mostly when the engine is up to full operating temperature. It also seems to be most noticeable immediately after a gear change while accelerating. I now have gumout in my fuel, and planned on running that the next 2 or 3 tankfuls to see if that makes any difference. I logged my fuel trims over my roughly half hour drive home from work the other day and it seems that my long term fuel trim is always about +5%-9% which tells me the engine is running lean. Ive also checked TPS readings and they seem to be smoooth with no abnormalities. I'm not really sure where to go from here. Ive looked around for any obvious vacuum leaks but have not found any. Should i just continue running the gumout for the few tanks of gas and see what happens? What do i look at if that doesnt help?
Thanks for you time.
Just to clarify that +5% to +9% for long term fuel trim, wasnt sure how to edit my original post
Try some higher octane gas and see what happens. Your engine might have carbon build up issue.
This is what I expected. I believe the car was owned by an older gentleman it's whole life, and was driven pretty easy.
Get a live data scan to check that the ignition timing is correct and not too far advanced from specifications.
Have a source for the timing advance specification? Thanks
Any good scanner should be able to recognize the vehicle it is monitoring and provide the correct specifications and the live data.
Your engine has a timing chain that being 21 years old may have stretched a bit and advanced the timing too much, causing the pinging. @jfopps
Understood. Ive had Vw and Audis my entire life so im used to belts every 60,000miles or so with no adjustments needed. I do all my own work. I assume theres no quick adjustments that can be made here if needed or am i wrong?
You will have to do some research on that. Some of those early cars do have a timing adjustment on what appears to be a distributor of sorts. Follow the coil pack wires to their source to see if where they originate from has any kind of adjustment on it.