Water over engine - Mazda MX5 - sputtering and revving high.

Wilde_37

Mazda MX5 (Eunos) 2001 1.6 Manual. 95,000km

Washed my car the other day and stupidly ran the garden hose (low pressure) over the engine bay. May have gotten water somewhere!

Car restarted but revs idle at 1500rpm. This settles back to 900 rmp after a few minutes. But there is a constant growling or sputtering from the engine now. Sounds like something is misfiring.

Brought to my mechanic - he couldn't resolve the issue.

• No lights on the dash.
• No codes showing on the computer.
• Spark plugs / coils removed and checked for water - nothing.
• All connectors disconnected and reconnected.
• All sensors appear ok.
• Car only recently serviced.

Took the car for a drive and felt it "shuddering". Feels like it is ready to cut out all the time - but never does.

Am due for NCT in a few days. Now I expect it to fail - but will be interested to see what fails it. Maybe the NCT will help diagnose the problem.

Any ideas?

biko

The water must have shorted something? Have a mech check each sparkplug but I'd go with a bad alternator.

Tbh, others and I do this all the time (hose the engine bay down) without issue so you must have been unlucky.

Wilde_37

Brought the car for the NCT. Sputtered all the way there and home - still felt like it was about to cut out a few times. Expected the car to fail and assumed the tester would give some indication of what was wrong but it PASSED!!! Still sputtering though. So not sure what the purpose of the NCT is now also!!:rolleyes:

biko

Nct don't give a toss about your car as long as it's not a safety hazard.
Get yourself to a mechanic before it gets worse.

H3llR4iser

Really odd, just like other posters already said, I often get quite a bit of water in the engine bay when washing the car - never had a single problem. Afterall, a car is engineered to work in almost all weather conditions.

My speculation here is that the problem might or might not be related to the water - afterall, the water would have evaporated by now.
It could be that an ignition coil decided to give up the ghost right around the time of your wash, and it might be completely unrelated to the water. Did the mechanic try to replace the ignition coils one by one, or did he just check for water?

dharn

Stange that a misfiring car passed the emissions test

101sean

My father's old dog of 1.4 AUA Polo passed emissions with a misfire and a dash light on.

I'd go with what H3llr4iser says, possibly coil related or water trapped in the elecrical connections to the coils.