Flood Damage Caused Idle & Shifting Problems

1997 Pontiac Grand Am 3.1L 102,020 miles

Well anyone that lives in the New York Metro area knows just how bad the floods are in this area. There was actually a tornado in the Brooklyn borough of New York City, where I was working that day.

When it comes to my problems, I work during the night and when the rains started a few mornings ago, I tried to get home as soon as possible. The parking lot of my job was flooded more than I thought. My car wasn't flooded where it was parked, but there was an area that I "thought" I could drive through but ended up stalling out right in the middle of a huge puddle of water. After a couple of hours I was able to start my car and I noticed it idled between 1500 and 2500 rpms. I let it run for about 45 minutes and decided to drive home. When in drive, the engine idled at about 1100 rpms. Other than that driving was normal. The next day I noticed the idle was high still but I also noticed the trans was shifting very late. I changed the engine oil and filter, and trans fluid and filter, I also thought it would be a good idea to put some dry gas in my tank. Same problem, high idle and shifting late. My mechanic thought that the water may have damaged the throttle position sensor, so we changed that. Now everything seems to have returned to normal. So what I wanna know now, is there anything from anyone else's experience with flood damage that I should keep an eye on? My main concern is the long term effects the water may have had on the on-board computer.

Thanks All

Since you have changed the oil & trans fluid(filters) you shouldnt have any troubles with the ECU/Pcm as they are up high and should not have gotten wet.

As long as you keep it out of the water for a few days it should dry out pretty quick since its been so hot.
Most all of your wire connectors under the hood are protected with a rubber piece, but still can get wet.

If you floor boards got wet I'd air it out realy good or mold will start growing and it'll smell mustty.

I've driven my SE through some real deep water before, like over 2ft and my CAI sucked a bunch of water into the engine. I stay outta puddles if I can any more :lol:

just my :2cents:

Thanks xeroinfinity. I actually did notice something a little odd today. I had to take my mother to the train station, and oh yeah, it's raining again. I had to drive through some small puddles of water, but no big deal. Everything seemed normal until I got home and parked my car. I kept it running while I sat in the car for a few minutes reading a magazine, I noticed the electric fan turn on. The odd thing is it didn't turn off like usual. I did have the windshield defroster on, but my a/c compressor is empty so the compressor was never on. According to the temp. gauge the car was not overheating. I drove the car around the block and parked it again, and I noticed the fan finally did turn off. Is this something normal, or could this be a problem caused by the previous flood?

Thanks Again!!!

I'd suggest that ALL the electrical connections are going to be suspects in any future problems. All the ABS wheel sensors, the EVAP canister purge and vent valves are mounted very low, the fuel tank top unit (including the gauge sender, tank pressure sensor, and fuel pump connections) could have been submerged, the ABS modulator unit and control, and possibly the PCM are mounted low enough to have been submerged. In addition, the VSS, crank position sensor array, starter and solenoid, air conditioning compressor, oil level sensor, oxygen sensors (all of them), and probably a few other things I'm overlooking would have been submerged by driving through a pool as little as 13" deep.

Keep you eye on it, and be prepared to dry out and clean out lots of connectors. This is a major reason why flooded vehicles are frequently deemed a total loss by insurance company estimators in such situations.

IMO not all those sensors or connectors would get wet but yes thiers going to be problems thats for sure. Reason being you drive it in rain all the time and not every thing gets wet or has ill effects when it does get wet.

Best thing is to start hand drying everything and set it out in the sun or a very hot garage to dry things off.
Since it was just plain water vs. sea water damage which is much worse due to the salt corroiding things faster .

Good Luck

Perhaps not all those sensors are going to get wet in 13" of water, but a '97 Grand Am has the PCM located in the RF corner, between the outer fender skin and inner fender splash shield. The connectors are positioned on the lower end of the mounting arrangement, and would be under water in 13" of depth. Been there:

http://www.finemotorcars.org/files/1998N-BodyPCMLocation.jpg

http://www.finemotorcars.org/files/1998N-BodyPCMConnectors.jpg

Those are less than a foot off the roadway. The owner's manual advises against driving through standing water, and they weren't just making up reasons why.

There is a very good possibilty that some of these problems will rear their ugly head for a long time to come. One day when you get a chance it may not hurt to pull the connections apart and squirt some dielectric grease in there. I would even go so far as to get some QD (quick dry) electrical cleaner and clean up the connections before I put the grease on them. WD-40 will displace the water in the connections too. Make sure to hit up the spark plug connector with the WD or the grease, this will also make maintenence a lot easier!

I wouldnt recomend Wd-40 in those connectors it can cause the some plastics to degrade, and grease in the plug boots will make them swell up and get soft, ruining them. :grinyes:

Compressed air is usualy plenty to displace any remaining moisture :thumbsup:

WD-40 will not degrade the weather pack connectors. The dielectric grease is specifically made for those applications. What do you think the oems put in those weather pack connectors? I know some oils will damage plastics, WD-40 is not one that will degrade any kind of plastic in the lifetime of that car.

I guarantee wd40 will swell the spark plug boots, its petro based.
And I never let wd get onto plastics, it leaves behind an oily residue also.

IMO Wire drier is best to use for wet connectors,
or just compressed air.

just my :2cents:

If your going to clean connectors there are better cleaners than WD-40 I will agree to that. The dielectric grease on the other hand is what comes in your spark plug boots from the manufacturer. I have personally used WD-40 on the wires of several vehicles I have had, and I have owned 70 different vehicles so far. It has never causes the spark plug wires to swell (just my pesonal experience). The wire drier I'm sure is better no doubt, I used WD-40 because it was readily available and I was usually in a bind to get a car running right again. My point, the connectors should probably be cleaned and dried (with whatever works best) and should definately be repacked with dielectric grease.

I know about the dielectric grease.
WD wiping the wire part of the plug wires probly wont hurt to much, but getting it on the boot part will swell and get realy soft.

I think we've all mentioned that cleanin and drying of connectors is a must :D

Water damage sucks.... either way :grinyes:

Well said xeroinfinity. Your right about water damage sucking!