I did some searching and saw this topic pop in in threads but didn't find a dedicated thread about it or a resolution. So we got a tropical storm passing through in Houston and its pouring rain on my way home in my 2020 RDX with 3500 miles. A van is lolligagging as we are about to get on the highway so I switch lanes and floor it to pass and the check engine light comes on and the power dies. Luckily I didn't get on the highway and pulled off into a business on the service road figuring I was about to get stranded. I turn the car off, open and close the door to reset the electronics, then turn it back on and its fine? Hopped back on the highway and drove the rest of the way home with no issue however I did notice the auto start/stop not engaging. Any thoughts? I'm curious how it'll react in the morning.

 

Sorry to hear it. You need to write a complaint to NHTSA, bring your car to dealer (they will not find codes, but get it on record), also open case with Acura corporate. If enough people complain, I am hoping for some kind of recall.

 

There is a whole thread on this. It DOES seem like rain is a contributor, as well as sudden acceleration. Not sure if we have seen it reported to clear itself like you experienced. I could be wrong. I haven't experienced it.

Limp mode

 

Flashing CEL is generally associated with a large misfire. Open up the air box and see if there's water pooled in the air box and snorkel. Also check to see if the air filter is damp or dry. If it was due to water getting sucked in, there will still be signs of moisture. I can't, in this day in age, believe that a company would have issues with water induction thru the intake. I'd wager it was likely due to an electrical issue brought about by poor water insulation, just add it to the list of poor Acura build quality.

 

I specifically did not whomp it in a Florida rain due to people’s experiences here.

Limp mode is no fun, either experienced or explained.

 

Exact same thing happened to me, except it wasn’t raining. Pulled the car over, turned it off for 30 sec, then it was ok. I was on a trip, and when I got back, I took it to Acura, who couldn’t find anything. Reported it to NHTSA and you should too.

 

was humidity really high?

 

Not particularly. It was the beginning of summer, but if I recall it was a beautiful day.

 

Hmn, the theory about the rain does not fully add up. I dont think you are the first person to say it happened without rain/moisture. For most it seems to coincide with heavy rain and sudden acceleration.

I dont know what progress Acura is making to fix it without codes, it sucks

 

No rain of high humidity, but definitely under acceleration. Like the other person, I had been following one of those annoying 5 mph under the limit people for 15minutes. When we both entered the highway, I pulled over a lane, hit the gas and expected to blow her doors off! Imagine my surprise when I topped out at 35mph in the middle lane with trucks barreling down on me. The thing that really got me is that was the speed she was going, and I had to actually brake to get behind her with said truck on my a$$!

 

I’ve had the same thing happen several times-was rainy both times- definitely had missfire
code both times-cleared code and was all good-
i do think I’ve found a fix as it’s been 10000 miles since last occurrence-
spark plugs- yup spark plugs

 

Not doubting you but I would think that with only 3500 miles my spark plugs would be good, most cars can go 100k miles on a set. Car worked fine today with the exception of auto start/stop. Kind of disheartening since being in a tropical environment, a heavy rain situation happens quite regularly I usually do my own oil changes but I may take it in for the first one. There are no codes to check but the auto start/stop not working is a symptom of something. Sigh.

 

Did you open the hood while the engine was running? If so...

Make sure the engine is warmed up
Shut off the vehicle.
Open the door and pull the hood release
Start the car, close the door, confirm the message center says hood open.
Turn off the vehicle then shut the hood.
Auto Start Stop (AIS) should again work

 

It's a very nonspecific symptom ( see below, from the fine Owner's Manual, page 432 ), and perhaps unrelated to the illness under investigation.

As for the water ingestion theory, I seem to recall Ford F150 with the "Ecoboost 3.5L V6" had a problem with water condensing in the intercooler for the turbocharger, under high humidity conditions. A sudden demand for power causes increased air flow and vacuums up the condensate. Cough, cough.

Our 2.0T RDX engines also have an intercooler, and I've yet to hear a better explanation for the problem. But apparently, the real issue is how gracefully ( or NOT ) the engine controller recovers from the transient misfire. RDX freaks out.

https://www.torquenews.com/106/feds-...-investigation

 

Tangentially related, but last year Honda issued a recall (only for China, oddly) for the 1.5T Accords to address a limp-mode issue related to the intercooler.

https://www.autonews.com/china/honda...-engine-glitch

I can't help but wonder if it's the same issue plaguing the 2.0T in the Accord and RDX, but Honda/Acura has decided it's not worth doing a recall in the US?

 

auto stop will not work with ck eng lite on or codes stored in history
if engine lite is flashing while driving it is an engine misfire of some sort
i replace the spark plugs because of something called spark plug “snuffing”
I used dilkar8a which is the same as factory only a smaller gap so under boost it’s much easier to fire the plug-and not missfire

 

That happened to me once, and only once. The RDX was still new - maybe 1,500 miles or so on the odometer. There is a stop sign on a certain rural Texas highway that is a favorite spot of mine to launch a 0-70 mph run from. The night was cool and humid, but no rain. I did a full pedal-to-the-metal launch, which went smoothly and beautifully until just before 70 mph, when the dash lights came on and the engine power went away. Limp mode. Like you, I thought I was about to be stranded and I pulled off on the side of the road already being chided by my wife for the way I was driving. Turned the hazards on, turned off the car. Took a few hopeful breaths and turned the car back on. Everything was fine like nothing happened. I continued on my journey driving cautiously assuming it would happen again but it didn't. I've got over 20k miles now and it's never happened again. I do regularly give it a hard launch but never any lights or problems. I hope you are as lucky as me.

 

The limp mode is doing what it’s supposed to do-
if there is an active missfire the ecu want to protect the cat converter from melting-so it will give u idle only

 

that's a shame that a brand new vehicle is having active misfires.

 

Is it real misfire, or computer gets confused and thinks there is a misfire, but its not?

 

Either way, something ain't right, and either Acura doesn't care enough to address it, or is incapable of doing so. Neither is a good look for them. This same issue plagues the 2.0T in the Accord too, and I suspect we are going to see some cases come shortly out of the TLX as well, especially with the rainy season upon us.

Now that I think about it, it's very possibly that Acura has passed the ball to Honda since it's their engine, and Honda is the one dragging their feet on this. It'd be a very Honda thing to do; while they've historically built very reliable engines, they've also historically been very stubborn at not admitting that something could be wrong with said engines. While problems are few and far between, good luck trying to get them make things right when something goes wrong. The R18 cracked block issue only got acknowledged after a class action lawsuit was filed.

 

It is a real missfire
my theory on what happens-
under high boost conditions with the humidity level up the spark plug gap is to big to fire and gets snuffed out- even just 1 missfire will cause the ecu to see it and go into protection mode-
i am running a custom tune with 24 psi boost and 10000 miles without a hiccup with the new style spark plugs

 

please expound!
what new style spark plug?

 

Iirc it’s a DILKAR8a8
just like in a Nissan GT-R

same plug as stock just has a tighter gap

 

DILKAR8a8 - https://www.ngk.com/product.aspx?zpid=9718 - gap = .031"

SILKR8A-S - https://www.ngk.com/product.aspx?zpid=10147 - gap =.031"


interesting as they both have the same gap.
Same heat range as well.

the only difference is the hex size.

 

DILKAR8P8SY

this is the factory rdx 2020 spark plug

dilkar8a8 is what u replace them with

 

Spark plug fix? Hmn, cant be so simple

 

Cant seem to find the specs from NGK on the stock plug...
I admittedly pulled up the wrong plug in my previous post. Pulled the 1st gen RDX.

interesting that NGK doesn't list the honda plug...or it's specs. curious on finding out the gap and heat range of the stock plug.
one could use the 1st gen plugs as a replacement as well, as it has the same exact specs of the gtr plug

 

Heat range is an 8
im trying to remember where I found the specs for factory spark plug- it’s made for Honda by ngk and I’m pretty sure the gap was larger all else being the same

 

Thank you, Rob!

 

Seems like there is already a class action for this https://www.classaction.org/acura-rd...oblems-lawsuit
not sure if it’s the same

 

Got some resolution. I did the hood poppin' hokey pokey the day after, and although it didn't fix it immediately, on my drive home the the RDX was back to normal. The last couple days its been normal too. So on the bright side it seems to be self healing which is good because I don't have time to be making trips to the dealership. With it running totally normal now I don't know what the dealership could even diagnose. But I'm going to be very nervous during the next big rain storm and I'm really scared of it happening on the highway traveling at high speed, fortunately I was able to abort my highway entrance and limp into a nearby parking lot. Time will tell I guess.....

 

I had this happen twice, had my car in for service today, b 1 2, and they replaced my spark plugs as a remedy to this issue lol... I'll take it, but we know this is not the cause. I have 25k miles on my car. Also, for creaking sunroof, they are replacing wind deflector???? It's on back order, so bringing it back for that. All warranty work, so whatevever. Paid $175 for oil change, air filter, cabin filter, tire rotation and wiper inserts, not horrible by any means.

 

it could very well be the cause, as rob pointed out..

Higher combustion chamber pressure increases the amount of voltage to jump the spark gap. The higher pressure has a more insulative property. Decreasing the gap reduces the amount of voltage required to jump the gap. The alternative would be to use a higher voltage spark coil.

 

This happened to me today.

Could it be bad gad? I was far from home and forced to buy no name gas. 45 minutes later, I pulled out to pass someone and my car went limp. Engine light flashing yellow. I pulled over, turned off the car, turned it back on, the light was gone and the car drove fine. I even tried some acceleration pulls just to make sure.

I topped it off with premium from Esso later that day, so at least 25% of my tank is high octane premium gas which will hopefully average out any bad gas.

Im bringing it in for service next week and will see what they say. My car is a 2020… so evidently not just a problem with ‘19s. Heck, I don’t think anything was fixed from 19 to 20, as I also have a creaking sunroof, a rattling hud, constant Apple CarPlay failures to connect at startup, squeaky brakes and a trip computer system and HUD that feels like it was designed and coded by a high school student.

 

demand them to do TSB, be prepared they will tell you they have no codes.

what apple car play connect failures you have, I posted about it, mine is related to hitting reverse before system fully boots

 

Was it raining? Mine went limp but only when raining. Had the Turbo fix done and no more problems in same conditions. High confidence it’s fixed for good.

 

I thought it was an intercooler issue, not the turbo. Did they replace your turbo?

 

It was raining! Though not particularly hard. I didn’t even know there was a turbo fix… thanks for the tip. I will be politely demanding this at my next service appointment which is next week.

 

Yes it was the intercooler fix, my bad.