Check engine light came on after water intake in passenger side

everitt89 · 10 August 2011 07:39

Hi!

I own a Mazda MX-5 Phoenix 2002 1.8

need some advice urgently on why the check engine light has come on…

i noticed sloshing sounds coming from my passenger side and after a service i was told that there may be a build up of water somewhere as there was a rust issue. i then noticed that gradually, the floor on the passenger side was getting wet and the sloshing sound worsening after any period of rain. i kept mopping the water but the sloshing sound continued. then after a night of heavy rainfall, the car completely cut out on me when going round a right bend. When i started it again, the check engine light had come on. I carried on driving it to work, but again, when on a roundabout turning right, the car cut out again. so again, i pulled over, started the engine again and drove it to work. when i got to work i looked through the owners manual which indicated that i either had an emissions problem or electrical problem. when i checked the floor for dampness i noticed about an inch of water underneath the passenger seat. i have since found out that drainage holes on mx-5’s need to be regularly unblocked as they can get blocked with leaves, insects etc. i located the holes and unblocked them, water that was inside the car came out, i mopped up the inch of water that was in the car and started it up again. it took sometime to actually get the car going as initially, the engine would start but would cut out again when the car got below 1000revs. the revs were going up and down on there own and i had to drive the car for a bit in higher rev’s than normal to make sure it didnt cut out again. The car is now driving fine, although sometimes shuddery when initially pulling off.

the check engine light is still on even though the water problem has been solved and was hoping someone out there could tell me the likely cause, or if anyone has experienced a similar problem.

any help would be soooo much appreciated.

Drumtochty · 10 August 2011 11:43

Two problems here and you have fixed the blocked drain holes.

The electronic brain of the car (the ecu) sits on the floor of the passenger side of the car if I remeber correctly, which appears daft to me in a soft top that could get a flooded floor.

I assume your having problems there so lift the carpet and dry out the area around the ecu.

A friend in a 2004 Mk2.5 has the check engine light on and I attached a code reader and the ecu reported no faults so I charged the battery off the car as it was low on charge and put it back in and the engine check light went off!

everitt89 · 10 August 2011 12:07

oh that is clever of them putting it there! so your saying that if i completely dry off the area including underneath the carpet and maybe try charging the battery then that may well turn the check engine light back off? we did contemplate getting a diagnostics test but everyone i have spoken to said that can be a waste of time as the problem can be something easily solvable without forking out the cash!

i will try that though and see if we sort it. i did wonder if there was something electrical under the wet area, hence why the problems started when the puddles appeared!

thanks for your help!

Drumtochty · 10 August 2011 12:59

Watch out charging the battery. If it is one with vents that connect to tubes at the battery compartment they do not like a normal battery charger as they can give out too much current. Use one of the new fangled smart chargers or if you use a normal charger put it on low charge and put the battery in a basin and fill with water to half way up the battery to get rid of any possible heat caused by the charging.

Lets hop that fixes it.