[Diy_efi] Air fuel meters

[James Seabolt]

At 07:23 PM 4/12/05, Lee M. Lemoine wrote:
>Hey James,
>
>I've seen this before also with my car -- are you using the correct
>heat range o2 sensor?  My car ran funky before i went out and got the
>O2 sensor for a turbocharged car.  Apparantly, like spark plugs, there
>are heat range indexes for turbos too -- even if you riched out the o2
>sensor, you can usually get it to come back to life with a propane
>torch...
>
>I'd be glad to elaborate, but my first question is:  what color is the
>tip of your O2 sensor.  Let me know, i'm on AIM as well


I haven't pull the O2 sensor to see. I'll check that out. I have a spare 
sensor from another motor that I know is good (the Spider that had dual 
Webers on it) I could swap just to see what happens.

As far as being different heat ranges for turbos and non turbos I did not 
know this.

I ran this same meter on my turbocharged Fiat Spider with the original O2 
sensor and it seemed to work just fine for months. However the constant 
cycling from rich to lean got on my nerves so I removed the meter. Also 
this meter gave me a false sense of security. It was telling me my fuel 
mixture was pegged out but the car still pinged. I finally figured out I 
did not have enough fuel. If the dynojet was properly calibrated, I have a 
12.5:1 fuel mixture under boost. The meter showed the mixture was higher 
yet was probably closed to 12:1.

As a matter of fact these cars have the following in common:

1) Same part number on O2 sensor
2) Location the same (directly after the turbo)
3) Same meter (K&N)

I forgot to mention that during the first few times the meter seemed to 
work just fine. At idle it was showing stoich but strangely enough once I 
hit boost, the meter would peg out and stay that way. As if a hugh amount 
of fuel was dumped into the engine under boost which contaminated the sensor.

Now after like 100 miles, the meter starts off at lean and as the engine 
warms up gradually shows a richer mixture then eventually pegs out after a 
few minutes.





James Seabolt
Tennessee, United States
Homepage --->>> http://users.chartertn.net/jseabolt/

2003 Subaru Baja
1980 FIAT 2000 "turbo" Spider
1968 Ford Fairlane 500 (Not a Ford Galaxie!!)
1987 Yugo GV 1500cc also turbocharged









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