o2’s keep failing in the rain
Thread Starter
TECH Apprentice
Joined: Sep 2011
Posts: 301
Likes: 5
From: Miami Beach, Florida
o2’s keep failing in the rain So posted a thread about 3 weeks ago about how my car was running like crap with the BLM’s and fuel trims all over the place. Found out that it was my AFS75 AC Delco O2 sensor. Realized due to it raining hard that day that it got wet. So I replaced it with the same part number. Today it rained again. The same exact thing happened. Ended up replacing with the same part number. My car has long tubes. Question is what is the fix, how are we water proofing O2 sensors. It rains a lot in Florida. It rains 3 out of 7 days here on average.
Thanks guys
Thanks guys
Last edited by LTX; Sep 21, 2023 at 09:32 PM.
Thread Starter
TECH Apprentice
Joined: Sep 2011
Posts: 301
Likes: 5
From: Miami Beach, Florida
Last edited by LTX; Sep 21, 2023 at 11:37 PM.
TECH Resident
Joined: Oct 2006
Posts: 993
Likes: 173
From: Euless, TX
I had new Bosch O2’s in mine and drove through heavy downpour and they both went wonky. Put in Densos and all was right with the world. That was almost 8 years ago so who knows if Densos these days are any better than any other brand.
Thread Starter
TECH Apprentice
Joined: Sep 2011
Posts: 301
Likes: 5
From: Miami Beach, Florida
So after some investigation remembered the wire look was burnt from the newly installed headers but never burned through into the wire. I’m thinking on putting suram wrap on the connecter. Noticed no water inside the connector when I replaced it eatch time but hey I’m lost. Throwing out ideas. Find it hard to believe it’s the male and model O2 sensor since it always happens when it rains heavy.
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TECH Resident
Joined: Jun 2013
Posts: 853
Likes: 32
From: Kernersville, NC
A gentleman in this thread...
https://ls1tech.com/forums/general-l...ep-puddle.html
...mentioned the following.....I would give this a try.
"I had a similar issue when it rains really hard, car bucks and simply wont perform. I unplugged all my O2 sensors and sealed the connectors with die-electric grease= Problem solved"
Just thinking about where pre cat o2s are generally located from OEMs, they are close to engine under hood. Post cat o2s are further downstream and are more likely subject to water. I suppose that it's possible that pre cat o2s are not as waterproof as post cat o2s. Just from my memory....I think they are sealed the same.
Could it be a case where water is getting into the collector where the Y pipe connect to it? I'd find it hard to believe that the exhaust would let it run upstream to the o2 in the collector.
Back in '05 my Z28 went from a daily driver to a fair weather machine(daily drove it for 6 years). I've not really had it out repeatedly in heavy downpours with my headers. That said, I've been caught a few times in the rain, but have suffered no o2 issues because of it.
https://ls1tech.com/forums/general-l...ep-puddle.html
...mentioned the following.....I would give this a try.
"I had a similar issue when it rains really hard, car bucks and simply wont perform. I unplugged all my O2 sensors and sealed the connectors with die-electric grease= Problem solved"
Just thinking about where pre cat o2s are generally located from OEMs, they are close to engine under hood. Post cat o2s are further downstream and are more likely subject to water. I suppose that it's possible that pre cat o2s are not as waterproof as post cat o2s. Just from my memory....I think they are sealed the same.
Could it be a case where water is getting into the collector where the Y pipe connect to it? I'd find it hard to believe that the exhaust would let it run upstream to the o2 in the collector.
Back in '05 my Z28 went from a daily driver to a fair weather machine(daily drove it for 6 years). I've not really had it out repeatedly in heavy downpours with my headers. That said, I've been caught a few times in the rain, but have suffered no o2 issues because of it.
Last edited by ACE1252; Sep 26, 2023 at 07:01 PM.
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Verdad Gallardo Thread Starter
TECH Apprentice
Joined: Sep 2011
Posts: 301
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From: Miami Beach, Florida
Opinion on Delphi ES20317 sensors? AC Delco’s are too expensive nowadays. I hear Densos are geared more towards Japanese vehicles. Been running in safe mode for sometime now and thinking on heat shrinking everything from the sensor all the way to the damn PCM or wherever it goes. Both AFS75 fail when it rains still. No broken wires.
TECH Resident
Joined: Oct 2006
Posts: 993
Likes: 173
From: Euless, TX
Opinion on Delphi ES20317 sensors? AC Delco’s are too expensive nowadays. I hear Densos are geared more towards Japanese vehicles. Been running in safe mode for sometime now and thinking on heat shrinking everything from the sensor all the way to the damn PCM or wherever it goes. Both AFS75 fail when it rains still. No broken wires.