P0172 Running rich
- Thread starter slybunda
- Start date
Yes the code returned after replacing the thermostat.
Drove today to work and no code yet.
Guess I could pull injectors next. Very easy in this car since they are at the front.
Only issue is it's cold weather 3c here and I don't like doing car work in the cold.
Looking into ways to clean or lubricate injectors incase it's sticking open. But got to test them first I guess before I spend any money.
Can a dodgy pcv valve cause a rich condition?
I know the primary 02 sensor looks like its working - but that is the primary input into fuel trims. I might consider changing it before pulling injectors and such - more to rule it out than anything.
Guess I can go that route which is cheaper.
Car is 25 years old and done 96k miles dunno what the lifespan of the O2 sensor usually is
Then there is the other thing. Iv Googled this issue and only time someone has to replace an O2 sensor was due to a lean condition and never rich.
Car is 25 years old and done 96k miles dunno what the lifespan of the O2 sensor usually is
Then there is the other thing. Iv Googled this issue and only time someone has to replace an O2 sensor was due to a lean condition and never rich.
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Been thinking about this some more and looking at the readings the O2 sensor is probably correct, it's voltage reading is as it should be and a fouled O2 sensor would under read rather than over read.
If the sensor was faulty and thinks it's over fueling and cutting fuel then car would end up running lean but I don't get any symptoms of lean running , car starts and drives fine.
Dont want to turn this into a parts cannon job so want to test things out properly and learn stuff along the way.
Since ECU is cutting less on the fuel at higher revs it does seem there could be more fuel or less air going into the mix.
https://www.ebay.com/itm/2569650957...i7YxJbL9sxdEQteqv7rM-SEHJDJT4BWnMDM27BhLyqpxU
This is a picture (off ebay) of the fuel rail. I wonder if the vacuum module at the left of the fuel rail could be the culprit. Does anyone know what it does?
This is a picture (off ebay) of the fuel rail. I wonder if the vacuum module at the left of the fuel rail could be the culprit. Does anyone know what it does?
His Celica doesn't use this setup. This is the older generation.
That vacuum module you are calling is the fuel pressure regulator that is operated via vacuum.
thats cool to know, but does that rule apply regardless of engine size? mine is 1.8L engine naturally aspirated, would the 1g/s per cylinder be the same on a 3L engine too?
I have always been told 1g/s per liter at idle.
For example my 4 liter pulls around 4 g/s pretty consistently. My 2.5 pulls about 2.5. Give or take - altitude obviously has an affect.
I don't think there is a way to track by RPM - because air is based on loading as well as rpm.
Completely agree. The numbers I gave were what I would roughly look for in park/neutral, engine unloaded.
Shouldn't my 1.8L be pulling 1.8g/s at idle then? but my reading is 2.7g/s so it's over reading?
It actually goes both ways - can be lean or rich both banks. Without known good data, it would be hard to interpret.
On the hot wire type like yours, you can clean them no problem. Just use the CRC MAF Sensor cleaner.
Also clamp the purge valve hose see if it changes the fuel trims.
sounds like a job for the weekend. will see if i can get this CRC maf cleaner here in the UK.
would regular electrical contact cleaner work?
https://www.toolstation.com/holts-electrical-contact-cleaner-aerosol/pAE193
would regular electrical contact cleaner work?
https://www.toolstation.com/holts-electrical-contact-cleaner-aerosol/pAE193
Looks fine to me.