GA gas used to make my 4.9 ping alot, I found running GA non ethanol eliminated it.

 

Headwinds, extra load and delta elevation all add up. And if you get crappy gas it doesn't help. Maybe mix in some higher octane with the remainder, why not? Might fix the pinging. But if you can run 87 with no pinging and you're timed correctly that would be the mo$t efficient

 

Non ethanol I buy here is 91 octane. I only use it in mowers, saws and other small engine equipment. It is usually a full dollar more expensive. Back in the day, I ran 89 octane all the time. Don't know when I switched to 87. Back then I probably used 89 octane to avoid pinging. I probably had a heavier foot then too.

 

I am timed by the book at 10° BTDC. I just checked over the weekend when I pulled the distributor out for a check up. Marks are lit up by the timing light.

 

10° at 600 rpm, how's the advance? Seems pinging occurred for you loaded and at higher rpm? Can it be solved by a bit more advance? Your mileage seems pretty good so you are probably close to the sweet spot.

 

If you have pinging you do not want to advance the timing you need to retard it as the spark is happening to soon.

I have also had a little pinging with my 300 six on a few different tank fulls.
I just think they are playing with the blends and why the pinging.
You know there is a winter & summer blend and now that it is getting colder we may still be on summer blend?
Dave ----

 

The ECU in this '86 EFI model is supposed to detect the pinging and retard timing in response. I have my doubts that it works though. I always get the knock sensor code. My original knock sensor was broken (apart) by my carelessness. All I can say for sure about the replacement sensor is that it screws into the proper hole in the manifold and the plug on the harness fits.

​​​​​​I am going to fill the mostly empty rear tank with mid grade 89 octane from Costco. See if that helps. It should.

 

Right Dave, I mispoke, I was thinking advance the advance which is really retard. Same as me a bit retarded and dyslexic.

 

The advance is controlled by the ECU. The pinging, in the past was generally at too much load at too little RPM. Right now it pings under modest load at all RPM.

Possibly would ping less higher speed.

Stock AOD, stock 3.55 gears and stock tire size.

 

Costco gas...Is it like BJ's gas... ? Every time over the years I've filled my tank with BJ's gas, I feel it gives less mpg, then other gas I get from say Gulf, Citgo, Shell...
Has anyone else noticed that kind of thing. The cars seem to run ok, but the mpg seems lower. Could that gas be causing the pinging in these older engines ?

I have noticed the lower mpg in my turbo Subaru's, and even the 18' Outback 3.6R.

 

ECU controls the advance curve. And you mentioned you lost your ping sensor. Are you able to pull any codes?

 

Yep that is when my truck also pings and I dont have a ECU
I think it has to do with the gas blend and the outside temp is what I am seeing.

I under stand some did not came with a knock sensor so there is no feed back to the ECU to kick back the advance.
All you can do is back out of the throttle and drop a gear to get the RPM up.
Dave ----

 

Had to Google BJ's. Don't know anything about BJ's quality. Costco, on the other hand, is "Top Tier", a recognized performance standard. Google Top Tier.

 

See this post

Yes, I always perform the goose test. I never hear knock during the test. Maybe one of these days, doing the test, I'll throw it in gear and goose it.

 

Great idea, Here's what google said. I kind of have already decided not to get BJ's gas again. Didn't realize there are no BJ's in your area. We have both locally. Used to have Sam's club too.

Is BJ's Wholesale Club Gas Good Quality? Right off the bat, BJ's gas is not Top Tier. This can be a dealbreaker for some people, especially when one of its main competitors, Costco, is a Top Tier gas retailer.