Tuning for Colder Spark Plugs

[TalonJohn94]

Since I'm no good at tuning for Lo-Throttle conditions, I think I'm still running pig rich on decel and possibly cruising. I am currently running the factory recommended NGK's. (6's?) I want to run cooler plugs and higher boost before shoot out.

My question is: How do people usually tune their car for cooler plugs, I'm afraid I'll foul the cooler plugs right away with current fuel maps?

Are the cooler plugs that sensitive to fouling?

 

[1992awdlaser]

You tune the same way as you would with the factory plugs. What does your wideband or o2 voltage read when crusing and on decel? The only time to tune for colder plugs is if the hotter plugs caused pre-ignition. This would have caused the tune to be less agressive than with the colder heat range plug. Now with the colder plugs it would be possible to make the tune more agressive.

 

[JayRolla]

Just tune them normally. I would also like to know the afr you are seeing while crusing. Im still running ngk 6es plugs at 30psi with no misfire.

 

[Defiant]

You don't really tune "for" plugs, you select whatever plug best fits your tune. If you're already flooding the thing with too much gas, cooler plugs probably won't be happy.

 

[steve]

I think I'm still running pig rich on decel and possibly cruising.

On decel the ECU should be cutting fuel and going max lean if the Idle Position Switch and Vehicle Speed Sensor are working. At cruise you should be seeing closed loop dithering fuel for a 14.7:1 AFR like at idle unless your talking about cruising at 80+ MPH.

These are some basic functions, if they are not working correctly then it's hard to tune the rest.

 

[TalonJohn94]

On decel the ECU should be cutting fuel and going max lean if the Idle Position Switch and Vehicle Speed Sensor are working. At cruise you should be seeing closed loop dithering fuel for a 14.7:1 AFR like at idle unless your talking about cruising at 80+ MPH.

These are some basic functions, if they are not working correctly then it's hard to tune the rest.

Well, I have yet to log the car since I've speculated this condition. The main sign seems to be that when decelerating in the first 3 gears you can hear a deep exhaust tone and sort of a random popping. This only happens when left in gear and not when in neutral. I guess I don't know about the Idle Position Switch (the car idles as good as any DSM) but I know the Speed Sensor works fine. But no I wasn't talking about when the vehicle is cruising at 80+ mph.

So, I was just going to tune for lo-throttle conditions first because I haven't touched it much since I dropped 650's, 2g MAS, and 3-stage Keydiver chip into it. Then I was going to see if the problem persisted.

 

[1992awdlaser]

Well, I have yet to log the car since I've speculated this condition. The main sign seems to be that when decelerating in the first 3 gears you can hear a deep exhaust tone and sort of a random popping. This only happens when left in gear and not when in neutral. I guess I don't know about the Idle Position Switch (the car idles as good as any DSM) but I know the Speed Sensor works fine. But no I wasn't talking about when the vehicle is cruising at 80+ mph.

So, I was just going to tune for lo-throttle conditions first because I haven't touched it much since I dropped 650's, 2g MAS, and 3-stage Keydiver chip into it. Then I was going to see if the problem persisted.

When on decel with the car in gear the engine is basically off. The injector duty cycle will read 0 and the air/fuel ratio should read as lean as the wideband will allow. The 02 voltage should also read 0.00volts. The only thing keeping the engine turning is the wheels turning the transmission and the transmission turning the engine.

 

[TalonJohn94]

the air/fuel ratio should read as lean as the wideband will allow.

I've hear a couple people refer to a wideband o2 setup, but I don't have that instrument on my car.

 

[TalonJohn94]

On decel the ECU should be cutting fuel and going max lean if the Idle Position Switch and Vehicle Speed Sensor are working. At cruise you should be seeing closed loop dithering fuel for a 14.7:1 AFR like at idle unless your talking about cruising at 80+ MPH.

These are some basic functions, if they are not working correctly then it's hard to tune the rest.

I did a quick log yesterday to see what my trims were. When I first installed the injectors and keydiver chip and 2g mas - I was at exactly 100% on all 3 fuel trims. Now when I logged it said 81% for all 3. So I leaned it out a few points on the SAFC and checked a few hours later, in which it was then 81% on Hi, 82% on Med, and 83% on Low.

Is this good, should I be leaning out the low-throttle this much?

What exactly is happening here?

Do you think I'm slightly overrunning the stock FPR with my rewired 190 Walbro?

 

[steve]

I did a quick log yesterday to see what my trims were. When I first installed the injectors and keydiver chip and 2g mas - I was at exactly 100% on all 3 fuel trims. Now when I logged it said 81% for all 3. So I leaned it out a few points on the SAFC and checked a few hours later, in which it was then 81% on Hi, 82% on Med, and 83% on Low.

Is this good, should I be leaning out the low-throttle this much?

What exactly is happening here?

Do you think I'm slightly overrunning the stock FPR with my rewired 190 Walbro?

Keep going. Your still rich.

Considering that your richer still in the high trims than low it doesn't look like FRP overrun.

 

[TalonJohn94]

Thanks. I'll keep tuning for lo-throttle. It would be great if I could get rid of the backfire and black muffler tip.

1g lo-throttle tuning seems to take forever to set in.

 

[steve]

The Mid fuel trim is the hardest since so little driving falls in it's range. The Low trims update just sitting in the driveway but often don't reflect actual trims under load because of deadtime issues.

It sounds like you need to read the SAFC tuning guide Kyle Terry wrote. I think it's in the Tech Archives.

You'll never get rid of the black muffler tip unless you start running leaded, then it will be gray, but you shouldn't have any soot on the bumper.

 

[TalonJohn94]

Well, I think I'm going to get the AEM UEGO to make things a lot easier. It seems so easy to install - like maybe I'm missin something.