My car really hates the rain
12-08-2011, 09:56 PM
#1
My car really hates the rain It rained pretty hard on my way back from campus yesterday and a number of roads had some fairly large puddles. I made sure to take it slow through the pools (probably about 4 inches of water max) but I guess that wasn't slow enough. The throttle response changed further down the road and the car began to stumble, getting more and more sluggish with each mile. I made it home minutes later and feared the worst... I thought my Opti was drenched.
I jacked the car up earlier today to inspect my distributor. I pulled the vacuum hose on the bottom of the vented Opti expecting water to leak out... but it was bone dry. I also had a friend force compressed air through the blue elbow vent and out the bottom but there was still no moisture which seemed odd.
I also pulled the plastic top from my Moroso CAI to check for any water that may have seeped into the filter. Everything seemed dry except the clamped section of hose right above the metal plate which was damp.
The car started up fine while cold but began to miss (SES flashing) and stumble after warming up. I think that eliminates the Opti as a suspect. I borrowed a scanner and got these new codes:
P0300 -- Misfire, to be expected from flashing SES
P0174 -- System too lean (Bank 2)
P0133 -- O2 (Bank 1 Sensor 1) "circuit slow response"
The damp band on my CAI makes me think that water made its way into my intake and possibly damaged my MAF, resulting in the P0174... but why am I only getting a DTC for one bank? How much water does it take to damage a MAF?
The car has LONG TUBES meaning the O2's sit significantly lower than on stock manifolds. I soldered in my own extensions months ago and have driven in the rain numerous times, but is it likely that water made its way into my wiring and shorted the sensors? They seem pretty dry. I made sure to insulate my connections with tons of electrical tape and wire wrap but maybe that wasn't enough. Also, aren't there vents on the backs of the sensors? Water would damage those, right? I've tried testing the sensors using the propane torch + multimeter method but I get nothing. Can someone walk me through the procedure?
I jacked the car up earlier today to inspect my distributor. I pulled the vacuum hose on the bottom of the vented Opti expecting water to leak out... but it was bone dry. I also had a friend force compressed air through the blue elbow vent and out the bottom but there was still no moisture which seemed odd.
I also pulled the plastic top from my Moroso CAI to check for any water that may have seeped into the filter. Everything seemed dry except the clamped section of hose right above the metal plate which was damp.
The car started up fine while cold but began to miss (SES flashing) and stumble after warming up. I think that eliminates the Opti as a suspect. I borrowed a scanner and got these new codes:
P0300 -- Misfire, to be expected from flashing SES
P0174 -- System too lean (Bank 2)
P0133 -- O2 (Bank 1 Sensor 1) "circuit slow response"
The damp band on my CAI makes me think that water made its way into my intake and possibly damaged my MAF, resulting in the P0174... but why am I only getting a DTC for one bank? How much water does it take to damage a MAF?
The car has LONG TUBES meaning the O2's sit significantly lower than on stock manifolds. I soldered in my own extensions months ago and have driven in the rain numerous times, but is it likely that water made its way into my wiring and shorted the sensors? They seem pretty dry. I made sure to insulate my connections with tons of electrical tape and wire wrap but maybe that wasn't enough. Also, aren't there vents on the backs of the sensors? Water would damage those, right? I've tried testing the sensors using the propane torch + multimeter method but I get nothing. Can someone walk me through the procedure?
12-08-2011, 10:35 PM
#2
I did a bit of testing...
The passenger side (bank 2) reads about 4.1 ohms at room temp (70F).
The drivers side (bank 1) reads about 4.6 ohms at room temp (70F).
http://www.freeautomechanic.com/ho2s...en-sensor.html
"If the reading is approximately 6 ohms at 68°F (20°C), the sensor's heater element is in good condition." My multimeter isn't the most accurate tool, but that seems in the ballpark. If the element was bad from a short or something else I'd expect close to 0.
EDIT:
Tested the O2 voltage readings with a multimeter and propane torch. I hooked the positive on the purple wire (O2 high) and negative on the O2 casing or ground.
Driver side (bank 1): Slow change when heat was applied, climbed to .10 after 20 seconds... Defective (proven by P0133)
Passenger side (bank 2): Working well, climbs to .8 to .9 in seconds and returns to .1 after about two seconds of cooling
The passenger side (bank 2) reads about 4.1 ohms at room temp (70F).
The drivers side (bank 1) reads about 4.6 ohms at room temp (70F).
http://www.freeautomechanic.com/ho2s...en-sensor.html
"If the reading is approximately 6 ohms at 68°F (20°C), the sensor's heater element is in good condition." My multimeter isn't the most accurate tool, but that seems in the ballpark. If the element was bad from a short or something else I'd expect close to 0.
EDIT:
Tested the O2 voltage readings with a multimeter and propane torch. I hooked the positive on the purple wire (O2 high) and negative on the O2 casing or ground.
Driver side (bank 1): Slow change when heat was applied, climbed to .10 after 20 seconds... Defective (proven by P0133)
Passenger side (bank 2): Working well, climbs to .8 to .9 in seconds and returns to .1 after about two seconds of cooling
Last edited by Catmaigne; 12-08-2011 at 11:53 PM.
12-09-2011, 10:33 AM
#4
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Did you watch any live data to see what the o2 sensors were doing? One the car heats up you have an issue would tell me that when the car goes into closed loop(starts reading the o2 sensors ) would point me toward watching live data to make sure the o2 is cycling correctly and also reading where it should. i would also pull them and look at them.
12-09-2011, 05:08 PM
#5
It's a random misfire w/ the P0300 code, not cylinder specific. Plugs and wires are fine but the car is missing because of a lean fuel mixture.
I don't have anything to datalog or scan for more than trouble codes.
The driver side O2 was faulty so I replaced it. Now I'm going to clean and test the MAF before starting it back up again.
I don't have anything to datalog or scan for more than trouble codes.
The driver side O2 was faulty so I replaced it. Now I'm going to clean and test the MAF before starting it back up again.
