Thread: feel like Too rich mixture

44 viewers and no reply, too technical question?

What makes you think its too rich mixture? Can you see rolling clouds of black smoke in your rear vision mirror? Are your spark plugs all carboned up? Have you checked the air filter element?

Too lean from a nearly failed fuel pump or blocked fuel filter is more likely.

My first thought would also have been too rich. I had an old Audi with similar symptoms a while back. Turned out to be the injectors were stuffed, they were just chucking at much fuel as possible in whenever it felt like it!!

On that though, checking your spark plugs should give you a pretty good indication of what is going on, Black and stuffed up with carbon = rich, brown = lean, well put simply anyway. The rich condition could be caused by a number of things, though the first thing I would be looking into would be how it is breathing, things like the air filter, etc.

From there it becomes more complicated and more expensive usually. I try to start "optimistically" first with the cheap stuff and work my way in. Have you tried anything to fix the issue yet or investigated it in any way? If we know what you have done so far, people can give you some more things to look at.

As for the lack of response, no it's not too technical question, there has been a little less activity on AULRO lately I think as every seems to be pretty busy at the moment. I know I'm pretty busy at the moment, but I need my AULRO fix!

Chris

a friend came with his 3.9,so:
crossed: AFM,TPS,ECU,STEPPER MOTOR, O2 SENSORS
new:spark plugs and air filter.
nothing!!
thinking of replacing the injectors and if it will not help,i'll replace the timing chain.
i have the ECUmate and there is no code.
TPS - 0.3
AFM - 1.6 (should be 1.8 but i don't think this is the problem)
am i missing some things?

I agree with be utey, sounds more like low fuel pressure or supply. Did you checked the colour of the spark plugs while swapping over? Possibly fuel pump failing or blocked fuel filter.
Andy

the color was very pale brown.
fuel filter i have change a year and a half ago but if you say so, i'll replace it.
how i'm checking fuel pressure? can i do that with a vacuum gauge?
i'll buy one for better timing adjustment.

After hearing all that, would have to agree it's likely a fuel pressure issue now. I don't know what the recommendation is for the V8, but for the TDI's LR say you should replace the fuel filler every 10k km's. They must say that for a reason, it could be that it is all clogged up on yours.

Either way its the cheaper of the fixes. Can't help too much testing pressure though. Any time I have had a pump go it just died outright, no real warning, fairly simple issue to diagnose. No fuel coming from tank, hmmmm, what could it be?

Chris

I have replaced the spark plugs, but there wasn't any improvement, the engine still rev up and dawn almost from start, when trans. gear is at "P" "N" or in "D".
I think it's not electrical problem, maybe it's timing chain or worn camshaft.
I know timing chain can be checked by the distributor.
how much should the distributor rotate in order of determine if the timing chain is O.K or not?
how i'll check if the camshaft is worn without taking it off ?
i'll check the fuel pressure like recommended before.
what pressure should i'll expect for?
another thing from reading here, if the camshaft is worn, i should feel it not just when the trans. gear in "N", "P" or "D" while standing, but i should feel it working bed even in acceleration and high rev, don't i?
the problem is just when the car is standing no matter what the gear.