still having problems with my 240
My 1990 245 still has a problem. It was running a bit rough, but
getting good mileage and had good power and response. Then one morning
it had a problem. It hesitates at throttle opening and is low on
power, but runs fair above about 2000 rpm, but still hesitates a
little when throttle is increased in that range, but responds better
than at off-idle. The off-idle peformance is really poor, and with a
cold engine I can nearly get it to die by slowly opening the throttle.
It feels to me like an overly-lean situation- no popping, backfiring,
or any such symptoms that would indicate an overly-rich state. When I
"pump" the throttle I can get it to not hesitate quiite so badly
off-idle, so it would seem, again, to point to an lean mixture (I
realize it does not have an accelerator pump).
At first I thought Throttle Position Switch, but the hesitation and
low-power is at least somewhat evident throughout the normal operating
I have checked a LOT of things, including (but not limited to):
-OBD socket 2 and socket 6 codes (none displayed for some time, but
originally was getting a 1-2-1, "no signal to/from AMM").
-OBD socket 2, test 2 and 3. Everything checked out fine.
-Cleaned and reinstalled throttle body
-Cleaned and reinstalled Idle Air Control (this car has the 2 wire
-Readjusted Throttle Position Switch (three times)
-Readjusted throttle cable and linkage
-Adjusted idle stop
-Checked for any air leaks between AMM and throttle body.
-Replaced Plugs, ignition wires, and dist cap (rotor on the way).
-Checked every vac line I could find, made sure that they were tight,
and trimmed the ends of those that felt even a little loose.
-Checked all the intake manifold bolts.
-Cleaned all vac fittings on manifold to be sure they were clear.
-Cleaned flame trap and related lines. (good vac at oil cap and no
significant oil leaks).
-Removed all under-hood connectors I could find, cleaned contacts,
silicone greased, and reconnected/disconnected a few times before
Another oddity (maybe) is that the "Check Engine" light never came on.
It illuminates when the switch is in P-II and goes out when the cars
is started, but even when the AMM code was set, the light did not come
on... if that means anything... I hope not.
I have a few guesses as to what it might be, but to just start
replacing parts until I get lucky can get expensive, particularly with
what one or two of the suspects cost! I also have a few more things to
check, but thought I would ask here to see if I am heading in the
right direction before I give up and take it to an independent service
I am going to try the "Spray something on all vac leak suspected
places to see if the RPM or behavior changes" trick (use WD-40?), but
if you have any thoughts or any directions to send me beyond all this
please feel free to share them. I would much rather be driving my car
than washing my hands three or four times a day with mechanics' hand
cleaner, if you know what I mean..
It is (or seems to be) idling a bit smoother (roughness mostly gone, I
think) but the hesitation is fairly severe and needs to be taken care
When started cold, it goes to about 2000 RPM, drops to about 700-800
or so, goes back up to about 1100, then settles in at around 1000,
slowly dropping to around the correct idle speed as it warms up.
.... and thanks!
Randy & \ \/ /alerie's
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"