Water 1, Z4 0?

[Capa]

Short version: Car had an argument with a puddle. Lost. Is now running like a bag of arse. Video & INPA readouts below.

Recently I was driving along the M40 in lousy weather - somewhat surprisingly, I ended up getting absolutely showered by an arctic truck next to me as it drove into what was presumably quite a deep puddle.

Next thing I knew, it felt like the car had lost a couple of cylinders. After half a mile or so the car and all its cylinders came back to life - given there were no check engine lights displayed, I decided to try to nurse the car back home.
Ten miles or so later, I drove through a small, yet ultimately unavoidable puddle once more, and a similar thing happened, albeit to a much lesser extent. Fortunately enough the weather soon improved and I got home without incident, although the car wasn’t running particularly well.

Upon my return I fired up INPA and found the following:



The first fault code - 2F45 appears to be related to an immobiliser, yet I’ve never really been able to find anymore information on it. I have seen this code when the car has been running well mind, so I’ve never been quite so bothered about it.

The second is new - 2C7F. From what I can tell, this appears to be a problem with bank 2 post cat lambda sensor reading too lean.

I then cleared the codes and disconnected the battery under the proviso that the ECU might have learned some naff settings somewhere along the line.

However, this hasn’t yielded much in the way of results, though the 2C7F code is no longer present after taking the car for a short drive.

Ever since the first puddle incident, the car has not been happy. It’s somewhat tough to describe, but the engine’s response isn’t there and it’s making a bit of a din to my ears, although didn’t passenger didn’t notice anything.

Again, I’ve resorted to INPA and youtube:

https://www.youtube.com/watch?v=R09X5lP2y2o
Hearing it in person, it sounds like the ‘injector tick’ is very loud to me - almost diesel-esc. I had the cam cover off to see if there was any water in the spark plug tubes or similar, but the noise it’s making leads me to think it might be something different...

In terms of the monitoring views within the diagnostics:




















I won’t pertain to know what I’m talking about with the above INPA readings - to my eyes they look alright, but that engine does not sound happy.

Has anyone experienced anything similar to this previously or can provide some ideas on what might be going on?

 

[Marlon]

Dont want to be the voice of doom but I drove my Mondeo ST through a deep 'puddle' - engine cut out, towed to a garage, dried out but water had entered the cylinders and the car ended up a write-off. Hope you have a better ending

Engines don't like water:
https://enginelaboftampa.com/water-sucked-into-engine-water-ingestion-hydro-lock/

 

[Capa]

God I hope so too!

About the only positive is that the car didn't cut out entirely. I'm now resoundingly less upbeat than I was, however.

 

[biojo]

Dont want to be the voice of doom but I drove my Mondeo ST through a deep 'puddle' - engine cut out, towed to a garage, dried out but water had entered the cylinders and the car ended up a write-off. Hope you have a better ending

Engines don't like water:
https://enginelaboftampa.com/water-sucked-into-engine-water-ingestion-hydro-lock/

I too had this on my clio, going down a dual carriage way in queuing traffic, but all engine locked, bent everything inside, on plus side insurance was willing to pay for new engine and fitting. when police towed me out yes they was already there, their was 2 other cars done same (one was a brand new loan car whilst his was beed fixed) council changed all that road since, so it doesnt happen.

i never thiught this would be an issue with the z4, intakes quite high. how long have you left since it got wet?

 

[firebobby]

Sounds more like water has entered an electrical component causing a short somewhere. Fingers crossed for you :|

 

[Chris_D]

Sounds like beginnings of the dreaded hydrolocking phenomenon?
Have u had the engine running again since the incident?

 

[Marlon]

Dont want to be the voice of doom but I drove my Mondeo ST through a deep 'puddle' - engine cut out, towed to a garage, dried out but water had entered the cylinders and the car ended up a write-off. Hope you have a better ending

Engines don't like water:
https://enginelaboftampa.com/water-sucked-into-engine-water-ingestion-hydro-lock/

. . . . .
i never thought this would be an issue with the z4, intakes quite high

True, the intake is high - I've seen video of E85s driving though deep water on a local Bowland fells run. The Mondeo ST apparently had a low intake, I followed a fiesta through a dip in the road thinking if that little car can drive through then so can I - big mistake. Insurance paid out without any issues.

 

[Mike6]

I would try running a hand held hair dryer over all the electrical connections in the hope it may just be water causing a short.

 

[obewan]

I had a similar experience years ago albeit in a different car.
Young and daft and I thought it would be good to go flying through a partial flooded road (Lesson now learnt)

After several days of rough running it turned out the air intake had sucked water up in to the air box and the filter was soaked
Put a new one in and dried the box out and all was fine again. Luckily for me the water hadn't got any further

 

[biojo]

Yeah this is when you know your definetly f**ked it,

cylinder 1 water upto top, 2nd is half full.

Tbh with yours, check all filter housing, and any signs of water at front of engine where electrics are, If its still turning over its not hydro locked like mine was

 

[dhobbs]

What does your air filter look like?
I assume if it’s ingested water the filter will be absolutely knackered. If it looks fine then you may be lucky

 

[Capa]

Thanks for the replies gents.

I’ve checked the air filter and it’s bone dry, as is the housing. Indeed - there were even some dry leaves/detritus in the bottom of the plastic container. These have since gone in the bin, but they do show that no water entered here to my mind.

Water having entered an electrical component sounds a pretty valid idea - I’ve checked the coils over and there’s no obvious cracking or similar, does anyone know anything else that might cause this kind of symptom should it get wet?
Prime culprit might be the lambda sensor given that it was throwing a code, so next weekend’s task is going to be to get the car on axle stands and see if there’s any kind of dodgy connection around there.

I also had a look at the plugs this afternoon - they aren’t in the best of health being somewhat black and sooty. I’ve ordered up a new set as they were due for a change anyway, but I’m not convinced that they’re the source of the problem.

I have some doubts (hopes) about the engine being (not) hydrolocked - the car is still running, it's didn't cut out entirely at the time, and I've done a good number of gentle miles on it since the puddle incident in order to get home. The cars starts, pretty much as it would normally at present, there’s just this rather unpleasant noise that sounds like a very loud injector tick.

 

[ph001]

I think you would be very unlucky for it to have pulled enough water in through the filter to have caused hydrolock damage. It will be the first i’ve ever heard of on a Z4. Compression and leakdown test would be the next step I would have thought. More likely some moisture has got into a sensor somewhere.