... continuing trouble shooting of why my '89 sometimes just cuts out. Then
accelerates perfectly again. I'd like to check my crankshaft position
sensor as 'one' possible reason for this. Where the heck is it exactly?
Hate crawling around under the car in winter.
ps anything else I should check while I'm at it?
Ah hem... you don't want to change that... You won't believe where it is
located.... it is located back of the engine by the tranny with almost no
space to work on it.
My friend has a 93 tha tdid the same darn thing... Drove both of us nuts...
I would start out with overload protection relay... common cause.
There is one more thing I want you to check. Pull out both carpet by the
driver seat. I want you to look at the big bundle of wires going to engine
compartment... does it seems like been rubbing, cut, etc? I want you to find
any exposed wire in engine compartment and give it a good rub to see if
insulation falls off or something.
Sounds like a classic symptom of the biodegradeble wire insulation
problem... but I can't recall your model year.
thanks, tigerm it's a '89 300E. Pulled out the carpet. finally
managed to open the plastic latches on the plastic case that protects the
wire bundle. they look perfect. Moved them around to see if there were
rub marks.... nothing. the insulation (electrician tape... cloth type)
looks as good and is as solid as the day it was put on. Next I used the
propane torch on the engine compartment (carefully at first) no fireball
and no difference in idle. Next I moved/lifted from car body, the wire
bundle going from compyter to the infectors etc (runs along a little
plastic 'tray'). No effect. tomorrow I intend to open up the distributor
again and recheck points rotor etc.
....puzzling. Car runs great and am waiting for it to act up again.
Idle is 'lumpy' definitely, but not horrible.
- cheers, guenter
89 would not have the wire problem... at this point, I would suspect the
distributor cap and rotor... if not also the coil.
Other thing is the OVP which I am not sure if you changed it already.
Check your charging system voltage...
Thanks for that Tiger. Actually I did exchange the OVP with that from
another car whose engine is working well (a 190E) and there is no change
in either car. Haven't done the cap and rotor yet but will do asap. Meanwhile
I've decided to acquire a Code reader. I assume an '89 will use OBD 1. In
fact, I noticed in MBShop that the reader is quite trivial. Power from
2 pins (forget which off hand) and then read codes from either one of two
pins 8 or 14. Might tell something useful. At the moment the car is
running and idling perfect.... geeesh I hate that. As soon as my wife takes
it somewhere with her mother I 'know' it'll stop working...
- cheers, guenter
I thought a bad crankshaft position sensor will completely kill the
engine, meaning no start at all. Also, I though this kind of 'hall'
sensors (camshaft, crankshaft, ABS speed sensors, etc.) are long lasting
due to the simple operation (no moving parts, simple/reliable physic).
The only things that can kill them are the rust metal and cut wire. Is
my understanding correct?
Guenter Scholz wrote:
I don't know. that 'would' be a useful piece of information though. My
engine does not cut out, it goes into (I don't know though) what appears to
be the 'limp home mode' that I've read about but don't know anything about.
In short, the engine will not rev up for a few seconds or so, and then it
will motor on as if nothing had happend. Typically it 'appears' to help to
take the foot of the gas and nudge it's rev's up gently.
ps I was thinking a lose connection to the crank position sensor.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.