Good Timing

[RH77]

Originally Posted by Christ

Stop Stop Stop STOP.

I too am a huge SeaFoam fan. Every car I touch gets the vacuum suction treatment, etc -- usually twice a year. The replacement plugs are cooler and gapped to spec. I also have a PCV catch setup. So far, it's performing well at 140K miles.

As far as Intake Air goes, FE is optimal at 100-110F. Under high loads lately, the pinging is very noticeable -- so I filled to a mid-grade mix. The airflow is slower after the warm-air tube to the airbox. This was added later (when the Weather turned colder). I just changed the oil and trans fluid (synth ATF), so that should help. The pinging started after a dead battery cleared the ECU's memory. I may need to "re-train" the ignition system with the ECU bypass method.

I'll have some time to test it this week. It's getting a bit warmer before the next cold snap. Time will tell...

RH77

[Christ]

Originally Posted by RH77

I too am a huge SeaFoam fan. Every car I touch gets the vacuum suction treatment, etc -- usually twice a year. The replacement plugs are cooler and gapped to spec. I also have a PCV catch setup. So far, it's performing well at 140K miles.

As far as Intake Air goes, FE is optimal at 100-110F. Under high loads lately, the pinging is very noticeable -- so I filled to a mid-grade mix. The airflow is slower after the warm-air tube to the airbox. This was added later (when the Weather turned colder). I just changed the oil and trans fluid (synth ATF), so that should help. The pinging started after a dead battery cleared the ECU's memory. I may need to "re-train" the ignition system with the ECU bypass method. I'll have some time to test it this week. It's getting a bit warmer before the next cold snap. Time will tell...

RH77

Jeez... leave out the important stuff...

Drive for an oil change with OE timing settings, then re-adjust it back to what you have it at now... What's happening (for reference) is that the ECU is assuming the timing is at a factory setting, and it's trying to over-compensate, thus the pinging. Your timing is now further advanced than you think it is, after the electronic advance takes place.

Once you've done about 1k miles, you can slowly adjust the timing in 1-2* increments until you're max advanced... adjust each 1000 or so miles. This will manually train the ECU to under-correct the spark curves, allowing your timing to be run as optimal for your RPM range, instead of a broader RPM range.


I'm not positive, but if your car is anything like my Honda, I can just insert a jumper into a specific connector under my hood, and stop the electronic advance from taking place... this is how the service tech sets the initial timing, and how you reset it to whatever you want... on my car.

ECM's aren't stupid.. but they're better at being stupid than humans are.

[Whoops]

RH77: I had the timing on my 89 Honda advanced. However, what I noticed was starting about mid September the pinging went up dramatically. I know that here in California they adjust the fuel blend for smog reasons and the consequence on my car is that I had to back off the timing. You could go to a higher octane rating, but my expectation is that the mileage gain will be lost if you look at the costs.

[Christ]

Forgot about that... EPA reg suggests fuel blending in at least the winter months... perhaps you should try changing gas stations? Maybe get something that doesn't use ethanol, or uses very little of it.

[RH77]

Originally Posted by Christ

Forgot about that... EPA reg suggests fuel blending in at least the winter months... perhaps you should try changing gas stations? Maybe get something that doesn't use ethanol, or uses very little of it.

It's E10 everywhere here now instead of MTBE for Winter (mandated). But change stations [gasp] never! My QuikTrip station around the corner and Pump 13 have been there for me since I started hypermiling (and is one of the cheapest places in the Metro) Mostly for consistency in filling, but it's also a Tier-1 fuel.

I'll be headed to a work visit in town, then to the airport for a trip to DC, so we'll see what the SGII comes up with tomorrow evening.

Odd though, Ethanol has a higher octane rating, so it shouldn't ping -- in theory...

-Rick

[roflwaffle]

FWIW, based on what I've read it seems that advanced timing is only needed if the ratio of gearing/displacement given some power output isn't optimal. The lower the air&fuel to cylinder volume ratio, which corresponds to lower torque, the farther apart in the cylinder pockets of air/fuel can be, and the sooner ignition needs to start to get all the air/fuel burning up around TDC. W/ pockets that may be farther away, retarded ignition may not result in everything igniting until after TDC. W/ proper gearing and greater torque, the mixture is more or less homogeneous, and in this case even/consistent ignition of the whole mass in the cylinder is much more likely.