w124 e300-24 starts and cuts out --HELP

[boomtings]

Hi Guys ,

Im stuck in south london car was driving fine, parked up for a few hours and now it starts and then cuts out after a few seconds.

I know there are lots of post similar but I cant seem to find one thats solved.

AA bloke reckons that when turning the starter motor fuel is there. but when the key is put to normal position its possibly not powering the fuelpump. could be ignition barrel or relay ?

anyone have any ideas?

OVP appears to be original and fuse is ok.

Where is the fuel pump relay? and what is that green relay for?

Thanks and like princess liea im counting on you guys for some insight.
Im no waiting for a tow home.
brokendowntings!

 

[BlackC55]

Give the fuel pump relay a tap and the OVP too.

Do you know where the FP relay is?

Just read you don't

It is in the right fuse box under the bonnet. You have to unscrew the lid.

 

[boomtings]

Thanks.

This tow truck is taking ages .

Played with relays . No effect.

Car seems to run fine when crankin the engine ,let go of the key and it dies shortly after.
Almost as if the starter motor circuit is operating the fuel pump and then its cutting.

 

[boomtings]

After searching for my fuel pump relay for a day , Ive found that its this big thing here and it controls multiple things.

ordered a cheapo multimeter from ebay and will have to check the pump etc.

 

[boomtings]

Fuel Pump Primes does this mean its working?

As I can hear my fuel pump prime can i assume its working ?

 

[boomtings]

Solved (ish).

For anyone else out there that is suffering from problems related to the MAS fuel pump relay:

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?)


therefore my car was most likely not running because of condition 3. i.e the car primed and cranked then cut out.

For anyone else stuck and has a car with the MAS relay (£303 p/n 012 545 42 38) you can short pins 1 and 2 for bypassing the fuel pump.

Ive ordered a second hand MAS relay from Ebay, however got so ****** with the old one that i tried to open it to repair. I could not open it and smacked it very hard and threw it around, the casings worst for it but it started to work again (i think).

There was another small lucas srb525 relay (red/black grey /black and large orange cable) next to the MAS i also played with this one and am not so sure what its for, i suspect it could have been fitted as part of the alarm/ immob fuel cut off and may also have been preventing me from starting. I hate it when i fix more then one thing and then not sure what the caused the initial problem. When the car was running i pushed the contact on this relay down and it cut the engine? ( this could this have been stuck prior)

Anyway for anyone having suspected fuel starvation problems or hesitation,cutting out when driving at low revs bear in mind the fuel pump relay as well as ht/dist etc.

Also apparently there are only two MAS relays left in the world according to the sales guy who is younger then my car, i asked if there is a new p/n to replace it however he said no. I find this hard to believe as a there are a lot of cars out there with the 24v 3liter m104.

regards

p.s is it safe to drive now that it appears to be working again.