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Questions tagged [lean]

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

5
votes
1answer
68 views

Engine lean issues

Vehicle is a 2006 Ford Courier, started having hesitation/loss of power after fill up at a gas station that I'd never been to before. I depend on it for transport so I'm forced to still drive it, ...
3
votes
2answers
4k views

Help on diagnosing positive Long term fuel trim

My vehicle (Ford Fiesta 2014 Petrol) always have a positive long term fuel trim, which means its running lean mostly. The log data that I recorded using torque pro can be downloaded here : Torque Pro ...
1
vote
0answers
110 views

Help me diagnose my lack of power & lean condition

I have a 2000 Mercedes CLK 320 with the M112 V6 engine at 125 000 kms. The car has rough unsteady idle and is lacking a lot of its power - to illustrate, 0-100 km/h takes exactly 10 seconds, while ...
24
votes
4answers
355k views

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 ...
1
vote
0answers
353 views

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 ...
9
votes
2answers
4k views

Strange surging and like it's going to stall, hesitant whilst idling

I have been having an issue with my Peugeot 207 (2008 model) 1.6L VTI petrol engine. The cam cover was replaced by the garage but hasn't fixed the problem. I have lost faith in them. I have managed ...
5
votes
2answers
91 views

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 ...
2
votes
0answers
111 views

Emissions per mile of high MPG lean-burn gas-powered cars versus standard gas-powered cars

I am wondering if there have been studies or calculations of the NOx emissions per mile of high MPG lean-burn gas-powered cars versus standard gas-powered cars. Honda made some great lean-burn cars ...
7
votes
1answer
2k views

Fuel Trim Readings

I have a 2002 Toyota Corolla (1ZZ-FE engine) and I am trying to understand the fuel trim values I am getting in real driving conditions from my scan tool. I have P0171 code (lean condition) that comes ...
5
votes
1answer
103 views

How much leaner can you responsibly run an old engine?

I've got a '76 Triumph TR7 and I was wondering this after I got its carbs tuned after its restoration. As many of you may know, old engines are initially not capable of running as lean as modern ...
5
votes
2answers
2k views

Can a permanently stoich or lean running engine ruin a catalytic converter?

It's known a cat can be burned by an engine running too rich for too long, but i wonder what the effects are of constantly running lean. Will the cat just be uneffective because of the lack of CO, or ...
12
votes
2answers
38k views

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 ...
6
votes
1answer
176 views

2009 Aprilia RSV1000 - Piggy Back ECU, Should I get one?

I have an Aprilia Tuono, 2009. It seems to run lean after putting an Akrapovic exhaust on it. It makes exhaust popping sounds on deceleration. My boyfriend said I need a power commander on it to ...