> The Chilton manual that I have isn't very helpful
>in that regard. And when I located the Bosch Jetronic control, it
>didn't have any label to indicate 2.2 or II...
I HIGHLY recommend the Bentley manual for anyone working on a 240.
Choice number two is the Haynes. If you have a wobbly table, get the
Chilton. Actually I have not seen the Chilton 240 manual, but if it is
anything like the 960 manual it's only positive feature is that it is
flammable and easily ignited.
>I pulled out the air mass meter last night. At least physically, it
>looks OK. The three filament wires are intact. If it's really
>non-functional, would I be able to bring the car (while in Park) from
>idle to very high rpm, albeit only with very slow pedal movement?
>(don't know what the rpm was, without tachometer.
They don't always fail totally, and when not working properly the car
will still run but poorly. There is virtually no way to check it
visually. Even if the wires are intact it means nothing. If they were
not intact the car would be in limp mode. There are a couple of basic
voltmeter tests but they are just abut useless because they can show
that the AMM is good when it is not (BTDT got the shirt). This is a
very sensitive and precise piece of equipment and if it is feeding the
wrong signal to the computer the car will run poorly... downright
crappy, really. For some documentation, look at these threads:
save me from running around
still having problems with my 240
Still trying to get it running right
AMM - more Q's
As you will see, I played with mine for about two weeks before I broke
down, got a used AMM and tried it. The car immediately ran great. If
you intend to keep the car for any length of time, pick up a used AMM
on eBay or at the local Pick 'n Pull. Worst case, you can always sell
it later on eBay.
>If it is truly bad, and causes running very rich due to "limp mode",
>would this explain the sooty exhaust?
Just disconnect it and start the car. You will know what limp mode is
immediately. Low power, poor throttle response, exceedingly rich
mixture, and no more than about 3500 RPM. As I have said, there is all
kinds of bad with AMMs. A slightly incorrect signal (which cannot be
detected any wa I know) will cause a poor running car. The symptoms
can be wide-ranging and can even change from day to day. it will make
you think that, at any given time, one or more of the things have
-Idle air control valve
-throttle position switch failure
-clogged fuel injector
-low fuel pressure
-high fuel pressure
-stuck open cold-start injector
etc., etc., etc., ... did I mention "etc."?
>If Very rich, I would expect to
>smell a lot of gasoline from the tailpipe., and see condensation, as
>you describe, not so much soot.
There are a lot of levels of rich, and if your car has a catalytic
convertor there may not be as much gas smell as you might normally
expect. With the computer controlled systems, if the car is a little
rich the O2 sensor tells the computer and the computer tries to
compensate. In the meantime the AMM is telling the computer that X
amount of air is passing by when in actuality (X + Y) or maybe even (X
- Y) is passing by. So the computer, much like a married man, is
trying to please the wife and Motherinlaw at the same time, and we all
know that NEVER works if both are living! ;-)
The computer depends on accurate signals from a lot of places, and one
of the most critical is the amount of air passing into the motor. That
is what the AMM senses. When it is just a little off the computer has
a really difficult time getting things to run correctly.
>Reading other posts, I was also suspicious of the in-tank pump and
>filter & hoses, as well as fuel pump relay.
If you can get it up to about 3,000 rpm and hold it there, then the
pumps should be OK. There are pressure and volume tests that can be
done to verify this. You can also try removing and plugging the vac
line to the pressure regulator at the end of the fuel rail (don't run
it too long that way as it boosts pressure to the injectors at certain
times beyond what they need).
>Fuel pump relay looks OK, no broken solder connections, as others have
I carry a spare, just in case...
>I located the leads to the in-tank pump. There are 3 leads going ito
> Brown: attached to chassis GND just before entering tank pump.
> Grey: fuel tank gauge sender (confirmed by test with ignition key
>to Run posn, and connecting the wires one at a time to see which made
>the gauge move)
> Black: + lead for fuel-tank pump -- must be, it's the only
>The black wire connects to a red-yellow wire. Sound right for the
>I measured open circuit between GND and Black. Should see something, if
>it's a DC motor on the other end! About 500 Ohm between GND and Grey.
>12 V on the Black wire appears to do nothing -- no pump noise. Should I
>hear the tank pump? I removed tank cap, and opened the flap with a
>screwdriver, with ear close to it. Still no noise. Should have tried
>the ampmeter, will check tonight.
Someone else more experienced and knowledgeable will have to comment
on the specifics of this. Someone tell my wife that there _IS_
something I don't know. She would never believe it from me... ;-)
The pump would be difficult to hear with the motor running. When you
turn the key on (from P-I to P-II) the pump should run for about two
seconds or so, then shut off. If you can get the motor to run at about
2500-3500 RPM and stay there, then there is a good supply of fuel-
whether it is sufficient or not takes a pressure gauge to test.
You need to get the Bentley manual! It has a number of tests that can
be done with a good volt/ohm meter. it is a very useful book to have.
>Thank you again for your helpful comments.
Air mass Meter... That's my vote, but read my previous posts and see
what my car was doing to be sure.
Randy & \ \/ /alerie's
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"