93 rough idle and code 26 after water crossing

Joined
Aug 1, 2017
Messages
35
Location
Seattle, WA
Hey everyone.

Got a pesky issue going on that I'm hoping someone has an idea about. Two days ago I took my 93 cruiser through a water crossing that turned out to be deeper than I expected. Water was almost up to the engine latch. drove out of it fine and without issue. I stopped to inspect the engine and it was wet but the air filter was dry so I figured I was in the clear. 15 minutes later the check engine light came on. I pulled the code and it’s a 26: running rich. Idle is also rough.

everything I’ve seen on this forum suggests that it has something to do with the vacuum hoses so i did a visual inspection of them and don’t see any visible cracks. Doesn’t mean there aren’t any, but is it just a coincidence that this happened after going through some deep water? Any thoughts on how this issue might be related to a water crossing or do I just need to start replacing vacuum hoses?

Side note: oxygen sensor were replaced just one month ago with new NTK sensors.

Thanks for the help
 

Tachycardic

SILVER Star
Joined
Nov 3, 2019
Messages
319
Location
Nevada
Just some thoughts, so don't flame me too much...I would consider an engine flush (a bottle of MMO into the oil maybe?), then change the oil and filter, and replace the spark plugs. Hopefully your issues will resolve.
 

93yotasr5

Molon Labe
Joined
Oct 15, 2010
Messages
3,293
Location
sacramento, ca
 
Pull the connectors to the O2 sensors apart and blow them out with compressed air then use some dielectric grease to protect the connections.
This and check other connectors in the engine bay to ensure they didn’t get moisture inside of them. This happened to me a while back and water somehow got into the VAFM connector and was causing the same issue.
 
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ppc

M Go Blue
Joined
Aug 18, 2003
Messages
3,029
Location
Nashville, TN
 
 
 
This and check other connectors in the engine bay to ensure they didn’t get moisture inside of them. This happened to me a while back and water somehow got into the VAFM connector and was causing the same issue.
Just don't touch the screws on the VAF connector. There is a metal clip that releases that connector.
 
Joined
Aug 1, 2017
Messages
35
Location
Seattle, WA
Hey thanks your all your help! We fixed a slightly cracked air intake hose, undid most electrical connections and sprayed with compressed air then applied dielectric grease to all connectors, pulled the spark plugs out and cranked the engine (though no water came out) then replaced with new iridium plugs. This appears to have fixed it, the idle is normal and the check engine light is gone. Thanks again for all of your replies so glad this worked.
 
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