...When I changed the spark plugs, I noticed they were clean of oil or carbon deposits, but they looked burnt white with a tinge of orange here and there near the electrode. My friend says the car is running too lean, yet I just have your basic mods (I/H/E) as Street Touring doesn't allow major changes. What can I do to make it run a little richer without going nuts with new fuel pumps and injectors and other class illegal stuff???

93 Civic with the D15B7 engine. 106,500 miles, excellent condition, and I intend on keeping it that way.


Anthony "Mario" Crea

 

Honda's run on the lean side from the factory, but possibly adding a fuel pressure regulator will help at WOT, or if re-programmed ECU's are allowed in street touring (i cant remember if they are) that would certainly help. I do know that a piggy back computer is allowed, such as the Apex VAFC - this could correct this if it is indeed a problem. I would do a baseline run on a dyno that can use an A/F meter (widh a wide band O2 sensor) to see where the engine is running at.

-Ryan

 

Have you check your ignition timming, it might be to advanced....

 

Hondas run rich from the factory.

 

According to my a/f guage, my car usually is around 14.7-14.6. Goes a little rich on exceleration (14.5-14.2). Goes dead rich initially when it hit the vtec (12.5) with the pedal to the floor. Settles @ around 14.5 near the top. The only time it really goes lean was under coast down situation. These are with a 10 segment Split Second A/F guage. It was run with the stock O2 sensor so it wasn't as accurate as a wideband O2 sensor. FYI, the level fluctuates almost continously under most driving conditions because of different engine loads & the computer trying to make adjustments.

 

Good info. Yes if you watch the AF during idle or normal driving, the car is constantly going way lean, then way rich to try to make the mix stioch.

 

The autometer air/fuel gauges are horribly inaccurate - as well as the stock 02 sensor as it moves away from stoich conditions. Also, the sensitivity of the autometer gauge isnt so good either - 10 lights for a rance of 1 V - thats .10V per light, which, on a high strung engine could mean the difference between making good power and blowing it up. To know what its doing, you gotta put it on a dyno with a wideband O2 sensor. As you said, it bounces around and fluctuates under varying loads...

-Ryan

 

Ryan, those are good points. I guess I should have been more specific when I pointed out that I was using a stock sensor,i.e. explained those facts for those who might not know. If anyone out there wants or needs a really good system, you might consider a J&S (using a wideband sensor). For FI engines, they also make a combo unit with a a/f & knock sensor. I would also caution against using the dyno for 'absolute' tuning. You can not exactly duplicate real world conditions on the dyno. HTH. Mike

 

good stuff

-R-

 

Tell me more about these wideband sensors...

Anthony "Mario" Crea

 

The allow for a more precise measure of a/f ratio, as they are accurate over a much wider band than the stock o2 sensor (which will just bounce back and forth between slightly rich and slightly lean), hence a 'wideband' o2 sensor. A shop with a dyno should have one that you can use for dyno testing.

-Ryan