More likely something to do with the air / fuel ratio being too lean.
Either a significant vacuum leak - air entering the engine without being
metered by the MAS - or, more likely, a defective MAS - mass air sensor.
A vacuum leak can occur at the juncture of the intake manifold and
cylinderhead, also a split or disconnected vacuum hose. Look for that if
this came on suddenly rather than gradually.
I have just had a MAS fitted, and I had a similar problem before it being
fitted, except that it run poor at low temp, and not too bad at high temp.
Just seems to have flipped. It cost me nearly ?300 just before christmas,
and after an expensive christmas, I cant afford to have it checked out again
without really knowing whats wrong with it. The merc garage wants ?80 hour
just to find out whats wrong, nevermind any more repairs.
Could it be a faulty MAS fitted ?
paul
> More likely something to do with the air / fuel ratio being too lean.
> Either a significant vacuum leak - air entering the engine without being
[quoted text clipped - 3 lines]
> cylinderhead, also a split or disconnected vacuum hose. Look for that if
> this came on suddenly rather than gradually.
Al Bolton - 19 Jan 2005 22:11 GMT
Don't pay the ridiculous amount the Mercedes dealer wants! Use a good
independent. Where are you, as I keep an up-to-date list of these here, so
could point you in the right direction? Independents typically charge 30-40
pounds per hour and are often far more competent as well...
Al Bolton
Caversham, UK
1990 500SE 139,000 miles
1988 260E 160,000 miles FOR SALE
===========================.
>I have just had a MAS fitted, and I had a similar problem before it being
> fitted, except that it run poor at low temp, and not too bad at high temp.
[quoted text clipped - 15 lines]
>> cylinderhead, also a split or disconnected vacuum hose. Look for that if
>> this came on suddenly rather than gradually.
to@d - 20 Jan 2005 14:25 GMT
Hi Al
I live in Worcester, and would apreiciate any pointers in the right
direction. The Merc garage over here doesn't give me any confidence.
paul
> Don't pay the ridiculous amount the Mercedes dealer wants! Use a good
> independent. Where are you, as I keep an up-to-date list of these here, so
[quoted text clipped - 25 lines]
> >> cylinderhead, also a split or disconnected vacuum hose. Look for that if
> >> this came on suddenly rather than gradually.
Al Bolton - 25 Jan 2005 19:05 GMT
If you don't mind travelling a bit, I would suggest Andy Gayle in Smethwick,
not desperately far from you. He is excellent and should be able to help
you.
Check out his web site, which is at:
http://www.aimpronet.com/andygayle/index.htm
To be honest, the web site isn't great but it has the contact details!
Let me know how you get on. Call Andy and he can give you an idea what needs
doing.
Al
=================================
> Hi Al
>
[quoted text clipped - 40 lines]
> if
>> >> this came on suddenly rather than gradually.
T.G. Lambach - 19 Jan 2005 22:45 GMT
Of course the new MAS COULD be defective but since it's new let's assume
for the moment that it's OK.
I'm sure you will scream, I would in your position of now being an
unwilling captive of the "let's try this" prison, but has anyone checked
the crank position sensor?
If it gives the computer the wrong crank position the spark will not be
correctly timed. Badly retarded the engine will start easily, run
smoothly but lack power and acceleration, too far advanced it will buck
and may backfire as yours does.
You wanted ideas, that's mine.
Henry Kolesnik - 23 Jan 2005 15:52 GMT
In the old days you could make just about any car backfire by turning the
key off while moving letting gasoline to get into the exhaust system and
muffler and then turning the iginiton back on., boom. I the muffler was
weak you ended up with repair job. So if your car is backfiring, it must be
getting fuel inot the exhast system and being iginite. Now to find out how?

Signature
73
Hank WD5JFR
> Of course the new MAS COULD be defective but since it's new let's assume
> for the moment that it's OK.
[quoted text clipped - 9 lines]
>
> You wanted ideas, that's mine.