Sniper and O2 Sensor

[Randy's]

I have the Holley Sniper EFI on my Blueprint 347 and am very pleased with the performance. For those of you that have an EFI system, you know the placement of the O2 sensor is not ideal. Like most others, I have it in the side pipe just after the four pipes merge into one and it is angled up from parallel as much as possible. The issue is that my original Holley O2 sensor went bad at about 700 miles. I replaced it with a comparable Bosch sensor. Now, at about 2,500 miles, it has gone bad. Is it just my bad luck or does anyone have any theories on why these sensors are going bad? Anyone else having similar issues? Can anyone recommend another brand of sensor to try?

[phileas_fogg]

I thought the Holley O2 sensors were impedance matched to their system such that a regular (cheaper) O2 sensor wasn't compatible; at least, that's what the instructions for my Terminator system says.

As for going bad, no one to my knowledge has studied the root cause - certainly not for our cars. Anecdotally, I know that if you get Permatex Copper (or any other sealant) on the tip of the sensor they will fail prematurely.


John

[bobl]

The Bosch unit is what Holley uses. The reason they fail is contamination. Usually moisture, but also rich fuel mixture and oil can cause them to fail. Most often it's cold start condensation that does it. Being in a cold climate you probably have a bigger problem with this. You can try raising the cold idle speed quite a bit. That will get it warm faster and decrease the amount of moisture. That's why they say to mount the sensor on top of the pipe. There is a heat sink extender you can get that helps some also. There is no better 02 sensor you can get for that system.

[rich grsc]

Do you cold start and idle the car a bunch?

[Randy's]

Thanks to everyone for the replies/suggestions. I do not cold start and idle the car per Blueprints instructions. They say that, in addition to the O2 sensor, it can foul the plugs. They suggest that anytime you start the car you at least let it get up to the normal operating temperature. I may try the heat sink extender. I'm not real comfortable manually "tuning" the Sniper so i will likely not raise the cold idle speed.