Running lean issues update

Okey dokey to clarify thats a MAP sensor!

why do you think it is weak?

Sorry mrc if wha is weak *brain like a doodah today*

running lean and running weak are the same thing.

Doh right I'm woth you now. Basically a few months ago I do a engine check light, I did a diagnostic scan and showed the Pre-cat lambda at fault which was changed last year and is less than 20k old. I cleared the fault and it didn't come back. So I did my usual routine scan and it says its running lean on b1 s1 fuel trim. Also the colour of the plugs are a whitish colour.

So basically ot answer the question becuase of the error codes, and the condition of the spark plugs really. Other than that the car drives great as usual.

He also said if I keep driving the car I could risk damaging the CAT which will be costly to replace.

He said he had a "hunch" it could be the MAP and then mentioned something about a speed sensor ...?

But said to drive it for about a week and re-scan it and then bring it back if the plugs are still white and the error code returns.

well it is the usual : check for inlet or exhaust leaks, check fuel pressure, replace lambda sensors, replace injectors.

Do you have a standard car or are there any mods?

Do you use good quality or supermarket fuel?

If it runs well ignore it till it develops (as my neighbour advises !)

Dubber pretended :

Rather than checking the Flow (MAFlow), it works on Pressure (MAPressure). The MAP will have some small bore pipes leading to it from the manifold, so it can measure the pressure in the manifold and cables feeding to the ECU.

I guess if I have to ask how to check for exhaust leaks and fuel pressure might be best left to the man who can although I've learned to do so much over the years frm a bit of research and am willing to get my hands dirty so might give diagnosing this lot a go myself. I know you top of the game round here how would I start with checking the exhaust leaks and fuel pressure ? and faulty injectors. Although touching injector is that not likely it will be leaky afterwards ? (justsomething I remember reading many moons ago)

No mods.

Usually supermarket fuel, tesco stuff, or shell rarely.

I think I'll try that first. I might replace the MAP (not MAF) sensor and see if that improves things first after a week or so of driving.

Front lambda was done last year, butI guess a possibility its gone. But I'll hold off on changing that as its over a £100 :-s

If it's dieing then your driveability will go to pot, if it's got decent throttle response then ignore it.

If it's gone that quickly then something else is probably wrong.

exhaust leaks are easiest found by blocking the exhaust (with the engine running) and listening.

inlet leaks are found by listening with a tube and spraying round every engine bit that could possibly leak air in with carb cleaner, any change in engine speed would indicate a fault.

try good fuel for a tank or three.