w124 300 ce startup problem

[Ballajatt]

Hi
I recently bought Mercedes w124 300Ce 1990 , which was left parked in the garage for almost 4 years. I have changed all the spark-plugs, leads, distributor cap, ignition coil.But facing startup problem. I have checked the fuel pump which is working fine as you turn on the ignition ( you hear it working) and i get fuel in to the fuel injector. I tried easy start spray, the engine fires up and starts working until i spray and it cuts off as soon as i stop spraying?
Any help would be much appreciated as I love this car to bits and always wanted to buy one. But unfortunately this one came with bit of problem


I am also a new user to this forum and have very little knowledge about cars.

Thanks
Bal

 

[coupe deville]

Did you drain the 4 year old fuel

 

[walsi]

I will second that and add that i wonder how much water is now in the fuel as well after 4 years

Martin

 

[Ballajatt]

The guy who i bought a motor from said he had drained it. But i just poured one gallon of fuel two days ago, as this car came on the truck.

 

[Ballajatt]

should i drain all the fuel and replace the fuel filters and then pour a fresh petrol to see if that solves my problem.

Bal

 

[grober]

The fuel pump relay powers the fuel pump for a few seconds when you first switch on to pressurise the system. It continues to power the pump while the engine is being cranked --- but then requires a signal to prove the engine is running to continue to provide power to the pump- this is a safety feature to stop fuel being pumped to a stalled engine which might happen in a crash situation for example. You possibly have a faulty fuel pump relay or its not receiving the engine running signal. Lots of posts on here about FPR's and how to repair them.

 

[walsi]

The guy who i bought a motor from said he had drained it. But i just poured one gallon of fuel two days ago, as this car came on the truck.

If it was completely drained of fuel a gallon might not be enough to cover the fuel pickup and give a good supply, you might be pumping air and god knows what else up to the engine. If it was me i would drain the tank and fit a new filter and put at least 2 gallons in there just to be certain

Martin

 

[Ballajatt]

The fuel pump relay powers the fuel pump for a few seconds when you first switch on to pressurise the system. It continues to power the pump while the engine is being cranked --- but then requires a signal to prove the engine is running to continue to provide power to the pump- this is a safety feature to stop fuel being pumped to a stalled engine which might happen in a crash situation for example. You possibly have a faulty fuel pump relay or its not receiving the engine running signal. Lots of posts on here about FPR's and how to repair them.

Sorry if I am being dummy here, so if the fuel pumps power up for few second when I switch on the ignition does that mean fuel pump relay is fine?
Second, as you said it requires a signal to prove the engine is running to continue to power the fuel pump, how can I check or rectify that problem?
Every time I switch on the ignition, the fuel pump always powers up and I have also checked if the fuel is actually coming to the fuel distributor which it does. But the fuel does not go to the injectors. :S

 

[Ballajatt]

If it was completely drained of fuel a gallon might not be enough to cover the fuel pickup and give a good supply, you might be pumping air and god knows what else up to the engine. If it was me i would drain the tank and fit a new filter and put at least 2 gallons in there just to be certain

Martin

Hi Martin

I have topped up the fuel with extra 7 liters
Still no joy

 

[grober]

The fuel pump relay is actually several relays in one can. All you need to do is to jumper [ =bridge electrically] the pin sockets for pins 7 and 8 in the FPR base connector[ pin nos on marked on the base of the relay ] this will connect the constant 12v supply directly to the fuel pump and the fuel pump will then run CONSTANTLY!!!! - NO MATTER WHAT! --SO DON'T LEAVE IT LIKE THAT NORMALLY UNLESS THE ENGINE IS RUNNING. Try starting the car - If it runs you need to repair/replace the the FPR. As I said lots of posts about it on here if you do a search. http://www.mbclub.co.uk/forums/engine/130111-testing-fp-relay-question.html

ps the signal for engine running comes from the EZL ignition unit to the relay via pin 10 iirc

 

[Ballajatt]

The fuel pump relay is actually several relays in one can. All you need to do is to jumper [ =bridge electrically] the pin sockets for pins 7 and 8 in the FPR base connector[ pin nos on marked on the base of the relay ] this will connect the constant 12v supply directly to the fuel pump and the fuel pump will then run CONSTANTLY!!!! - NO MATTER WHAT! --SO DON'T LEAVE IT LIKE THAT NORMALLY UNLESS THE ENGINE IS RUNNING. Try starting the car - If it runs you need to repair/replace the the FPR. As I said lots of posts about it on here if you do a search. http://www.mbclub.co.uk/forums/engine/130111-testing-fp-relay-question.html

ps the signal for engine running comes from the EZL ignition unit to the relay via pin 10 iirc

Thanks Mate

This sounds bit too technical for me to handle my own, so I will get a mechanic in tomorrow to do exactly what you told me and try to pin point the problem.

Ps- someone also mentioned that if I am getting fuel supply in to the fuel distributor but it is not going to the injectors, it is probably the plunger inside the fuel distributor that is stuck. :S

 

[grober]

Thanks Mate

This sounds bit too technical for me to handle my own, so I will get a mechanic in tomorrow to do exactly what you told me and try to pin point the problem.

Ps- someone also mentioned that if I am getting fuel supply in to the fuel distributor but it is not going to the injectors, it is probably the plunger inside the fuel distributor that is stuck. :S

Yes that's a distinct possibility if the car has been parked up. The plunger in the fuel distributor is pressurised by the fuel pressure and its movement controlled by the air sensor plate in the air intake moving up and down as air is sucked into the engine.

 

[Ballajatt]

Thanks everyone for your help/input I shall be tackling few of the solutions tomorrow with my mechanic. I will keep you posting with the results and any hurdles that I cannot understand.


ps- Hopefully after all the problems are solved I shall also post some pictures of my baby
Thanks again

 

[boomtings]

As Grober has stated, the fuel pump is triggered by up to four separate signals ( 4 if fitted with ASR).

1. the relays are triggered for a second on ignition position 2.
2. on engine crank.
3. on rpm signal between 400-cutoff rpm.
4. by some ASR signal. ( cuts fuel to control traction?)

when my fuel pump relay was stuck , my car would start and die within seconds. (3rd condition was not working).

to bypass the relay short pins 1 and 2. (never tried this as)

I have 2 fuel relays in the garage , you can borrow one to test if you cover the postage, pm me if interested.

 

[Ballajatt]

As Grober has stated, the fuel pump is triggered by up to four separate signals ( 4 if fitted with ASR).

1. the relays are triggered for a second on ignition position 2.
2. on engine crank.
3. on rpm signal between 400-cutoff rpm.
4. by some ASR signal. ( cuts fuel to control traction?)

when my fuel pump relay was stuck , my car would start and die within seconds. (3rd condition was not working).

to bypass the relay short pins 1 and 2. (never tried this as)

I have 2 fuel relays in the garage , you can borrow one to test if you cover the postage, pm me if interested.

Thanks for your help mate, I will look in to all these things tomorrow with my mechanic and if I am in need of that part I will let you know and pay for the postage.

cheers mate.

 

[Ballajatt]

Hi guys,
The car is still facing the same issue. So far I have changed all the ignition coil pack (sparkplugs, distributor cap, leads, and ignition coil). I have also changed fuel filter and oil filter.
I have carried out all the checks, checking fuel pump relays etc. Everything seems to be working fine, as my mechanic tested it. After all those we have found that one of the fuel pumps (primary fuel pump) is not working. Secondary fuel pump works fine as we could hear it and done test on the electric circuit as well. Both pumps receive electric volts but the primary one just clicks and doesn’t run/rotate. Hence no fuel pressure.
So we suspect it’s the faulty primary fuel pump.


Any advice guys
thanks in advance and you lots been very helpful thanks again
Bal

 

[Ballajatt]

Hi guys

After couple of hours of testing we manage to narrow the problem to fuel pump. This model has two fuel pumps, one primary and other one secondary. The primary pump is not working and hence I am not getting very little pressure to the fuel distributor. All the electric circuits and relays are working fine as we have done the entire test with your help and used same parts in my friends Mercedes to double check them.
Bal

 

[Ballajatt]

Hi guys just to let you after install new fuel pump, car fired up first time.
Thanks again for your help.

Now all the other works begins, installing new leather seats, new head lights, sound, repairing all the alloys and dropping 40 mm

bal

 

[BoyracerAU]

And don't forget the pix!