Help Please
 

Okay So I Just Washed My Car At The Car Wash And When I Got Home As Soon As I Pull In The Driveway The Car Dies And Wont Start It Cranks But Wont Start Now I Checked All The Fuses I Think??? But The Nb Rspeed Af Meter I Have Is Powered By The Ecu And It Doesnt Turn On So What Happened How Do I Fix?????? is there a fuse or something for the ecu?

If you washed your engine and you didn't cover the spark plug holes your problem could be there. Water gets down in the spark plug holes and causes your spark plugs to short out. Sometimes they won't run at all sometimes they just run like crap. DO NOT PULL YOUR PLUGS, stick a rag down there or something to see if the holes are full of water. Then the best thing to do is pull your plug wires and let it dry. You can let it air dry or blow it out with an air compressor.

no i didnt wash the engine bay and why wouldnt my gauge have power with the key on??? it used to! i has to be something to did with this cuz it worked while i was driving home

Yeap, he's right. If they are full of water, here's another way to get out the water. Take a spary bottle of glass cleaner or something and take off the pump and stick the pickup tube of the pump into the hole where the sparkplugs are and pump that water out. You can get most of it out, and use a rag to get the rest.

I had to do this at the car wast after I washed my engine and it wouldn't start and this is all i had in the car. Worked well.

theres not a drop of water in the engine bay

okay so i just took my voltmeter and checked the power wire the the ecu and nothing no power to the ecu so thats why it doesnt run! is there a fuse that controls it or is the ecu fried?????

Does anything work (electrically that is)? - power at the battery ? All you did was wash the car ? A/F meter powered by ECU ? Sounds scary - they usually draw a good bit of power to heat up the O2 sensor - when did you add this ?

the af meteverything electrical except af gauge and car running loler instructions say to use the ecu power supply to power it and its been on the car for 4+ months but if the ecu has no power to it is there a fuse to it i would think??? the interior lights work i dont know what to do???? its been running fine and stuff i guess i shorted something how somehow??? but y would it affect my car starting?

just go through and check all your fuses.

im pretty sure i checked all the fuses i could pull but nothing they all tested good???? unless there are some hidden osne that i cant see or know where they are i checked both the fuse panels underdash and under hood anyone know which fuse is specifically the ECU one?????

what year is your car, I've got a manual for miata's to 97

It is a 91! think you could help?

Look for a fuse labeled 'room fuse' 10 Amp. I think that's the one for the ECU. How did you check all the fuses? I would use a test light to be certain.
Engine guages fuse is labeled 'meter fuse' it's a 10 Amp. Both fuses are under the dash.

i checked em all with a fuse puller/light

check the fuses in the engine bay. the fuseable ones.

i already checked those to except the ones with airbag on them cuz i figured they wouldnt have anything to do with it

so yea i just rechecked all the fuses underhood and in car and they all test okay so what now is the Ecu screwed?

Now it wouldn't hurt to check the gound points - theres one in the engine bay, one next to the battery (which since the lights work I would assume that one is ok but the one in the engine bay may be bad). Also for the ecu fuse and the power you tapped for the gauge make sure there is power running there with your volt meter (meter to fuse and meter to ground should show power - same for gauge power)- you could also test disconnecting the wideband sensor cable - this may have rubbed somewhere on the way to the O2 sensor and could be shorting..

The problem is that i have no power reaching the ECU!!

So the good news - if no power reaching ecu then ECU may not be fried.. Now ya gotta trace the wires back to where they get power and check the ground straps. There's a wiring diagram in the archives on this forum should cover your car - follow the power and check it at each relay/fuse/ground point. Seriously if you had a questionable ground which is very possible given the year of the car the moisture from the car wash may have been enough to make it not make contact. Not sure on NA but NB has a big ground strap at the motor on the driver's side near the exhaust mani which I believe is the ground for everything ecu related. I'd start there.