I wanted to re-experience what Thumper3322 had gone through this fall when his car just refused to start after an Esso automatic car wash.

To test the theory, I used the Sunoco car wash instead which is similar to the Esso one.

The theory held back then was that water from the powerful jets and "undercarriage" washes at automatic car washes would soak past the rain-shield on the Mazdaspeed Cold Air Intake (MS CAI) and cause erratic engine behaviour afterwards. It could get even to the point where the engine is flooded with water.

Before going further, I want to say this has been confirmed TRUE. I have detailed below what happened, and how I fixed it.


1) I ran through EcoBrilliant wash at Sunoco. Ambient temperature -7 C.
2) Exited car wash and drove home at moderate engine speeds not exceeding 6000 rpm.
3) After a 5 minute drive, the rushing cold air most likely froze a lot of the water on the rain-shield and left a layer of thin ice over top.
4) I floored it, and at around 6500 rpm, engine sputtered... DCS light flashes... CEL starts flashing.
5) I back off the throttle, shift to neutral and let the car coast at 110kph down to about 70kph... CEL continues to flash and then disappears.
6) Continue driving at engine speeds below 6000rpm for another 20 minutes, never stopping though (highway)
7) As the car slows down to traffic jam speeds (around idle --> 2000rpm).. I start to notice engine problems, hesistations, hiccups. The car would not stabily maintain idle rpms. It would go up and down, and feel like it's stalling. At certain intersections, I had to give it gas to hold it around 1200 - 1500rpm while the light was red just to prevent it from shutting off (looked like a jackass by the way)
8) Managed to stutter my way back home. As long as the car was in motion and above 2000rpm, there was very little stuttering.
9) Got home, read the code. It was P0171 System too LEAN. Whatever.. onto the diagnosis.


***Repair***

1) Examine CAI rain-shield. As suspected, it was very wet, and had several layers of thin ice all around it.
2) Scraped the ice off... used microfibre towels (very absorbent) and kept padding at the rainshield until it was dry.
3) Remove electrical connector on MAF sensor, and unscrew MAF using 9/64" hex screw.
4) As suspected, there were several drops of water on the lower section of the MAF sensor. I took a flash light to examine the interior. The walls were damp. Near the edge of the screen closest to the engine, there was a tiny pool of water formed.
5) Insert microfibre cloth inside hole, twist and twirl around to leave inside for several minutes to absorb water/moisture.
6) Use "CRC brand" MAF cleaner and spray clean the MAF sensor. Allow to dry.
7) While waiting, I topped off with Castrol GTX 5W20. Re-filled my windshield washer fluid with Rain-X. Replaced both my drivers and passenger side wipers with Rain-X Latitude series wipers (Excellent performance, used it in my old car)
8) While waiting, also do a quick detail on the car exterior hehehehehe
9) Re-assemble MAF sensor. Started the car. Used scangauge to clear the code.
10) All repaired. No stuttering.. allowed engine to idle till warm up.. no sputtering, awkward knocking sounds nothing. Just smoothness again.


Lesson learned:
A) Keep microfibre towels in your trunk at ALL TIMES.

B) After an automatic car wash, pull to the side, use microfibre towel and pat dry the rain-shield and surrounding area in the intake. *Extremely important*

C) Refrain from high-revs beyond 6000rpm for the next 24 hours to allow everything else to dry thoroughly in the undercarriage where the intake is. *Also extremely important*

D) If you cannot refrain yourself from doing that in 24 hours, be prepared by keeping CRC MAF CLEANER, and a 9/64" Hex screw (if you used the supplied AEM/MS CAI mounting screws for the MAF sensor). Some people have re-used the stock MAF sensor screw and it is NOT a 9/64" hex screw. I believe Thief is using the stock screw?

 

Thanks for using your own car to test out the theory. For the <2hp gain, extra sound and the trouble compare to the exhaust, the MS CAI is really not my thing.

But I really respect your relentness pursuit of knowledge...cheers!

 

There is another option.. have them tape plastic over the lower grill when the car goes in.

 

Pizza box still my theory to prevent. Med. sized pizza box rip in half and fit in, in front of the CAI should shield all the water Haven't had the chance to try it yet tho.

Good write up!!

 

I don't often use Esso (I usually use washbays and do it myself -- even then, it's hard not to get it wet) but I have used it a few times last year and never had a problem.

To top it off, I have the Veilside kit which doesn't fit flush with the underbody plastic shield. Also, the CAI is 100% exposed behind the grill in the Veilside front bumper!

I would think that if anyone had a problem, it would be me. That said, I think that contributing factors would be

- Cold weather creates icy surfaces on the rain shield, reducing air flow
- Some people hitting the throttle too hard, sucking in water while in the car wash
- Inadequate protection -- missing rain shield or underbody cover

The water should bounce right off the rain shield... very little residue should be left.

Also -- I am re-using the stock screw... fits well?

 

I'm never taking my car through the car wash. The mesh on the MS bumper is definitely not gonna keep the water out.

 

i drive through the rain all the time. ms bumper, nothing protecting the intake. haven't had issues.

 

You did all of that in -7C weather? Impressive :P

I'd like to add that I also haven't had any problems with auto carwashes.

 

I dunno.. I guess this is hit or miss. I don't think it's the under carrage that's the issue.. rather the jets that wrap around the car... when it's at the front it's forcing the water through the grill straight onto the filter itself... the force of this is MUCH greater then just driving through heavy rain.

In any case... good on ya Footman for doing such a test.. in fact you might have been a bit lucky with it being so cold out... having the water turn to ice would have prevented more from being sucked in.. though it is also a more likely cause of suffication as it would effectively block air from coming in as well.

AEM normally offers a by-pass to collect any water that makes it pass the filter.. but that doesn't seem to be an option for the 8 for some reason... guess there's no where to put it due to the tubing they use.

 

Hi all,
Been to the Sunoco touchless wash twice in the last 2 weeks and not had any issues yet. But, the fact you tested out the theory means that this is possible. So, I have duly noted your suggestions.

Thanks!

 

You know, for the heck of it, just clean your MAF SENSOR

 

Thing is, if you take a look at the shape of the intake, you would have to get a LOT of water in it -- likely sucking it in pretty hard -- to make it past the rain shield, a 2 ft horizontal pipe, a 1 ft vertical climb, and then a few more feet into the TB. I find it highly unlikely that we need the bypass as it would be pretty tough to get enough water up there to justify it. I've driven to some thick storms and car washes, with my CAI 100% exposed through the front grill of the Veilside kit, and it's a non-issue.

I still don't know how you guys manage to do that... I have a feeling something else is going on here. As I mentioned before, the temperature may have something to do with ice blocking the intake, but that should simply restrict airflow...

 

It's pretty amazing how much volume of air is sucked into the engine at high RPMs. Regardless of what any of your experiences have had, I have validated proof that water can indeed make it past all those barriers.

Take it easy on the throttle after an automatic car wash people...

 

yeah, instead of being silly and driving the car (and sucking up water), drive for about a mile in reverse so that you blow all the water out of the intake.

 

TheWulf - it happened to me in the summer which started this whole thing. If you haven't had any problems yet awesome! I did as a group on here found out the hard way it sucked lol. I didn't rev during the car wash, came out going down the street, not hard reving problems started. I then (stupidly) reved it up higher thinking getting the engine hot burn it off. In short, engined died, until we could dry it out. Thx to the peeps that helped got her going again in about 45min., but what a pain in the ***!!

 

Yes that would suck... but I am still interested in figuring out why it only happens to some people. I'm pretty sure there's another factor in here somewhere!

 

i pour a gallon of distilled water directly into the intake manifold to clean it out, and it runs fine. Of course I need to keep the rpms over 3k and it idles like **** for a few miles...

 

yeah... but that's the thing.. you're pouring something down there yourself.. rather then sucking up water, soap and god knows what else into the engine while you're not expecting it. Would come as a bit of a shock to someone who didn't know what the hell was going on...

 

I have the AEM cai as well, does anyone know where I can find or build a water shield for this intake? I have the stock fender which allows water to get in, and we get some pretty heavy rain storms where I live.

 

Racing Beat for the win!

 

Emmm... honestly.. it really shouldn't be too hard to make one... a quick trip to Home Depot or the like and you should be able to buy everything you'd need to make a splash gaurd.

haha... that's 1/2 the way I'm going. Have a RB duct to channel the air.. going with a short ram sealed to the end of that... haven't figured out what I'm going to use for the ram... might just make my own.

 

i experience only CELs, and DSC/TRACTION OFF temporarily (a couples miles, then off/on ignition resets CEL) after any car wash with AEM CAI, no stalling

 

Another reason not to waste money on an intake.

 

Water gets in from your fender to the air intake?

I'll assume you meant "bumper"

FWIW My AEM is going on 2 years and no problems... and I have a Veilside bumper with a cheap mesh so my filter is completely exposed (though I have the sock on it).

 

It really depends on your driving style and the road conditions and what type of vehicles you are following.

I had so many runups with the MS CAI, where I physically inspected the MAF sensor and the hole in there, and there was water inside it!