C180: engine turns but does not start please help

benlauren

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I left my car on the road for about two weeks with petrol tank full and everything working fine, but when I got back It just won't start. The engine turns but it won't start. It is not the immobiliser as I have set and re set it many times but still won't work. I get all the lghts in the dash come on as well.
The mechanic says there is 12.5 volts on both contacts (earth as well) of the connector to the fuel injector. He also believes that the problem is with ecu and not sure if it is repairable.

What is going on? does anyone know?

Thanks
 

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Its worth checking the crankshaft sensor for this
 

television

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They measure 1 k ohm when good and open circuit when bad.

Is there fuel coming up, with the circuit your guy should be able to work it out
 
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benlauren

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They measure 1 k ohm when good and open circuit when bad.

Is there fuel coming up, with the circuit your guy should be able to work it out

apparently there is no fuel coming up. I don't know if he has checked the sensor, he says he has but would the faulty crankshaft sensor cause both leads to the fuel injector read 12.5 volts? He says one of them should be negative. If the leads to the fuel pump read positive on both of them does that mean:
1- the fuel injector could also have been damaged?
2- does it mean that the compartment may be still be wet/damp thus causing the current to go through the earth wire?
if 2 is a possibility could it all be sorted by just drying out that area?

The compartment to the right of the engine looking at it from the front there are dead leaves and is slightly damp. There is sign that that area may have been flooded.

BTW the car is 1996 model
 
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television

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If these engines do not receive a pulse from the CPS, then the fuel pump cannot run.

No problem in that both injector wires at a plus voltage as the grounding is done via the ECU when it receives a pulse also

Does your man have the pin outs on the ECU, its motronic on your car
 
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benlauren

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If these engines do not receive a pulse from the CPS, then the fuel pump cannot run.

No problem in that both injector wires at a plus voltage as the grounding is done via the ECU when it receives a pulse also

Does your man have the pin outs on the ECU, its motronic on your car
No idea what that is but he wanted to call another guy to come and find the fault and possible repair. That would cost me hundreds before telling me if the ecu needs to be replaced. Unfortunately I cannot afford that at the moment so I am going to tow the car back and see if I can either sit down and pray and see if it sorts itself out or just scrap it. :cry:
BTW Do you mean that both wire should read positive anyway?
 
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television

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No idea what that is but he wanted to call another guy to come and find the fault and possible repair. That would cost me hundreds before telling me if the ecu needs to be replaced. Unfortunately I cannot afford that at the moment so I am going to tow the car back and see if I can either sit down and pray and see if it sorts itself out or just scrap it. :cry:
BTW Do you mean that both wire should read positive anyway?

In the not working mode, both wires will read positive, one is grounded by the ECU when the pulse tells it to
 

turbopete

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not necessarily. the ecu will need pulses, probably from the crank position sensor, in order to make the pump run and the injectors operate.
 

bigasotonuk

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Hi,
You mention that you don,t think it is the immobiliser, on what are you basing this? As the immobiliser on these early 202's worked by cutting the fuel supply off (mine does), have you got red & green LED's in the rear view mirror and in the door or boot lid? Are these flashing?
MB fitted immobiliser/alarm systems of this era of Merc were prone to problems.
 
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benlauren

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Hi,
You mention that you don,t think it is the immobiliser, on what are you basing this? As the immobiliser on these early 202's worked by cutting the fuel supply off (mine does), have you got red & green LED's in the rear view mirror and in the door or boot lid? Are these flashing?
MB fitted immobiliser/alarm systems of this era of Merc were prone to problems.

Yeah the immobiliser works as both the green and red lights flash and when reset they go off. I go through the reseting procedure and that works,i.e. the flashing lights stop and the engine should then start but doesn't.
 
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benlauren

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not necessarily. the ecu will need pulses, probably from the crank position sensor, in order to make the pump run and the injectors operate.

So the cps is faulty? where is it and how can I get it out? Is it easy to replace?
 

television

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From above,,if you have a multi meter you can measure it and it should be 1k ohms
 

bigasotonuk

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Are the red & green lights flashing together and/or alternatly when you operate the alarm fob? Correct operation of these led's when you lock the car the red one flashs at the mirror and the door and serves as a visual deterent as it continues to flash every 15 seconds or so.
Upon opening the green led flashes at the door and the mirror this indicates that the car is now open alarm/immobiliser is disarmed, if the car is not started or the ignition key is not put in the ignition and turned to pos 1, after 30 seconds or so the indicators will flash 3 times and will beep to tell you the immobilser is armed, to now disarm this you will need to lock and unlock the car.
If any of these led's don,t work or the red & green led's flash alternatly and/or together the immobilser will not be releasing the car.
 


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