hi! less than a week ago i purchased a 1970 250CE. we flew interstate to pick her up and drvie her home. she is in mint condition, second owner. 2 and a half hours out of town we stopped for rest and when switched off the 'gener' light came on the dash. the alternater was red hot. an auto electrician found that when the mechanic serviced it prior to my pick up he had left the earth strap to the block loose. after replacing the old alternater we found she starts, runs smoothly for 3-5 seconds thens stops. if started with the accelerator pedal flat to tha floor shell start and rev high then if you feather tha throttle real quickly and build the fluttering revs up to about half throttle you can rev her from half to full throttle position cleanly. anything below and shell struggle to idle and eventually stall.
please help me! wot else could have been fried by the earth leak in the alternater???
she ran soooooo smoothly and so powerful when we picked her up. i cant believe tha transformation. hopefully its somethign real simple
wot is that? isnt the regulator part of the alternater? i had it professionally installed and tested by an auto electrician. unfortunately the auto lekky was not a mercedes mechanic so he could not diagnose the fault with it not running. she starts so effortlessly and then snuffs out. after researching i am suspecting the fried alternater may have shorted my thermo time switch or my pressure sensor or my overload relay(if my model has 1)
ok, update. i have checked the pump line out and it is clear. no signs off rusty residue or rubbish blocking it. but, i decided to try disconnecting the fuel return line at the regulater and close it off, hence forcing maximum oressure to the injectors... presto! it runs.
can any1 tell me which of the two diaphram looking units is the regulater that could be causing this problem???
Ah, did we forget to tell you to check the pressure in the system? There are two small cans in the system, one to control pressure and the other is a damper. The one with three lines can/should be adjusted to get the fuel pressure to 32psi (2 atu) and when the motor is shut off, the pressure should hold a while. If these things don't happen, replace it with another from any d-jet donor car you can find. It doesn't have to be a 250ce and it doesn't have to be new.
ok, had a tamper with that, unassisted by any sort of pressure guage to no avail. i screwed it in plenty but could not increase the pressure enough to make it run like it was when i completely blocked the return line. i have replaced it to the postiton it was when i picked the car up. keeping in mind, before any electrical issue, the car ran for 2 hours beautifully. it is only since the alternater fried that it has had trouble running. even when i had blocked the fuel system she still didnt move up off idle smoothly. a quick touch on the throttle and it coughs before miss firing then firing smoothly right up thru the rev range.
i must say, the plastic casing of my tps is all bubble like its been cooked with a blow torch. im not certain it is fresh but if it was, could the earth leakage from the alternater have cooked it?
in my nissan s14 drift car i have had similar tps trouble in the past... although the whole efi system is a little different.
also can any1 tell me wot voltage the injectors should be running? my auto lekky says its surprisingly low like 2 or 3 volts? would that close the duty cycle, mimicing low fuel pressure? if so, why would it have dropped since the alternater trouble??
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