Motor Vehicle Maintenance & Repair Stack Exchange
Motor Vehicle Maintenance & Repair Stack Exchange

Questions tagged [rich]

A condition where the air fuel ratio is not optimal and the engine is receiving too much fuel from the fuel system

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Symptoms of Lean or Rich carb settings on a motorcycle

I have a 1981 Yamaha XS650. I recently put in K&N stock replacement filter (ie, they are in the airbox and conform to the size of the original), however they may be leading to a leaner mixture because they purportedly let through more air. I want to…
user460
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What's the meaning of a "lean" vs "rich" air fuel mixture

I'm learning about vacuum leaks on engine intakes and I'm hearing this terminology of lean air fuel mixture. I thought I heard of a rich mixture before too. What's a normal mixture referred to as? A balanced mixture? Also just for clarity, this…
jxramos
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Exhaust Backpressure and Its Impact on LTFT Values

This is a follow-up from my initial question which can be found here : LTFT and STFT values are off and don't make sense. Car : BMW 2015 F10 M5 Modifications : Eisenmann Race Catback Exhaust, MSR Cold Air Intake. Everything else stock. The summary…
DerStig
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Is there a chemical limitation to the mixture an engine can maintain?

I know that the question/title is a bit ambiguous, but I couldn't wrap it in a single sentence, so please let me elaborate. You can change the mixture of an engine for whatever reason. Because of multiple reasons, it's unwise to go either too lean…
Bart
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Hard warm start + low long-term fuel trim (mixture too rich) DTC. How to diagnose?

Just wondering what my next steps are here. Vehicle is '05 Volvo V50 2.4i. Initially had two misfiring cylinders, which was tentatively diagnosed as a blown head gasket by the shop. I changed it myself, but the old gasket appeared in serviceable…
cob
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Black water from exhaust, cylinder misfire and rought idle

It is a Skoda Fabia 2006, petrol, 3cylinders 1.2L. Main problem: Rough idle. Misfire at random cylindners. Steam, Water and black carbon from exhaust. (I'm sure it is not normal). Undrivable. Question: what is wrong with it? Diagnoses: Coolant…
user24053
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25%/70ms dropouts in fuel pressure in Cummins ISL 07

The first picture is low idle, the second is high idle. With the exception of the spikes, the high idle looks more normal to me. Anyone know what this signifies? I just replaced the PRV which was dribbling, and am thinking metering valve next under…
Milford Trout
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Subaru Forester - petrol coming out unlit in bursts out exhaust. Ideas on what could cause it?

I've got a Subaru Forester '02 2.5L that I push kind of hard off road on New Zealand beaches. I had a near dead battery recently so bought a new one but on replacing it I must have wiped the ECU because it has no clue how to run the engine now. It…
Jesse Reza Khorasanee
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Spark Plug Deposits

So, I pulled the spark plugs today to check to see how the engine is running. After pulling all 6 spark plugs, I've noticed there is a white deposit caked onto the spark plugs. I doubt this is normal operation, if anything this should indicate that…
James Vargan
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Engine feels like it will stall after Air/Fuel ratio sensor changed?

Got an 04 Acura TSX that's been baffling me for the couple of weeks. Accidentally bought an Upstream Oxygen sensor instead of the downstream so I thought might as well replace it since I have it (keep in mind the Upstream (Air/Fuel) Oxygen sensor…
Noah
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BMW M140i showing P0172

Details of the car: BMW M140i (F20) B58 engine - 3.0L petrol, inline 6, turbocharged Year of manufacturer: 2016 Mileage: ~13000 miles (3000 of which are mine) The majority of my use is short trips (< 5 miles, < 10 minutes), but I try and give it a…
BadAtMaths
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p0140 and p0172

I have a 2005 Elantra (205K miles). I replaced the second o2 sensor (downstream; after cat), added a defouler to second o2, replaced cylinder # 2 injector, air filter, tune-up. If the car is at idle in park, the second o2 data looks normal. That is,…
Paul
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Unexplained Low LTFT on my Mazda cx7 2.3 turbocharged

So, it started when i got CEL with code p0172: system too rich bank1. I took the car to the mazda dealer, they said you need to replace MAF sensor. I agreed and got the new sensor installed. Now CEL is off but I still have low ltft readings…
EmpMak
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2 Stroke 70CC Scooter Engine

I own a scooter which I blew the engine in Dec 2016. I since replaced the defective parts in it and it now runs great aside of one thing: Bottom end of the throttle is slugish (I'll elaborate) It appears that I'm running fine on Idling and top end…
Samuel Goulet TechnoSam
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Recurring code P2196, but seemingly OK oxygen sensor, on 2012 Volvo C30

My 2012 Volvo C30 T5 has been having a recurring engine code P2196 (O2 Sensor Stuck/Biased Rich) for some time now. It has popped up on four or five separate occasions. I usually clear it, but one time it went away by itself during a 2-hour drive…
ivorysoap
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