W126 380 SEC - Starting Problem

[silvio13]

When starting her up, either on a warm day or cold day she will be cranking for at least 15 seconds and then kick into life. Thereafter she will turn over instantly or be moody again and take a long crank! Had a full 'A' Service plus new dizzy cap, leads, sparks, air filter etc. The miss fire has stopped but shes still struggling to start which is annoying and the neighbours are getting sick of it as i leave for work at 5:00am Battery is brand new too. When driving never cuts out and drives like it should.

The ignition coil wasnt changed, could this be causing the problem?

 

[television]

No not the coil,, it must be a cold start device,,I will post back

 

[silvio13]

Could it be the battery crank voltage! Spoke to friend of mine whos an ex mercedes technician, he says if the fuel pump is engaging and it turns over normally it could be that the battery isnt always giving enough volts to the pump and the ignition coil on crank so basically fuel stravation on startup! I could check with a volt meter but im unaware of what values i should be looking for.

Plus the car was left standing for at least 6 months, could the injectors be blocked. Is Redex additive for fuel injectors worth trying as its a cheap option.....

 

[television]

Using any injector cleaner must help,, the very fact that it does start and runs OK when it does could well be sticky injectors. I do not think fuel pump as this runs on your car and stops when charged.

With the injectors, if they do stick, and this also goes for the cold starting device, then it would take some cranking to build up the pressure to free what ever is sticking,,cheap to buy and use many makes of injector cleaner out there.

Give it a go

 

[silvio13]

cheers malcolm,

Its going back to my Indie on monday as i paid him to fix the problem in the 1st place and obviosly he hasnt fixed it! Ive filled her up and added Redex injector cleaner lets see what happens. Ill try and find out what the exact problem is from the indie as he refrained from telling me when i picked up the car :S

 

[television]

This could only be the cold start device,,this is an injector that is used when cold, this can be taken out and the spray pattern checked where it must spray at an angle of 45º

 

[silvio13]

Does is do what is says.......... i stated the car this morning and it was -6 here and it started first time with no crank at all. I only have problems after where the car has been started driven and then standstill ......... i have problems cranking it over! such a headache. Also just had a call from my ex MB techie, he said dont use fuel system cleaner if it hasnt been used on every other service as it will cause more problems ----- oops bit late now! :S

 

[silvio13]

What does the cold start device look like malcolm. I know of a place in surrey that do ultrasonic cleaning, might send it to them for a good old cleaning. Im sure these devices cost the earth brand new! Might get the injectors done too while im at it.

 

[television]

Its 381 in the link, this is only an injector that sprays in more fuel for a cold start.

To test, hold the valve in a suitable container and remove the fuel pump relay and bridge pins 30 to 87, this will run the fuel pump all of the time.

The fuel coming out of the valve should have a spray angle of 45º and should be an even spray all around

 

[silvio13]

Hi malcolm, no link :S

 

[television]

Hi malcolm, no link :S

Sorry getting old

http://www.detali.ru/cat/oem_mb2.as...&L=765.706&CT=M&cat=288&SID=07&SGR=070&SGN=02

 

[silvio13]

by pins you mean fuses? .... :s sorry im very slow @ these things

 

[television]

by pins you mean fuses? .... :s sorry im very slow @ these things

When you pull the relay out,,use a piece of wire to short out pins 7 & 8 this will run the fuel pump all the time in order to test the cold start valve, so when you have the valve out,have someone turn on the ignition, then the fuel will spray out and the angle can be checked

 

[silvio13]

Success,

The cold start valve is blocked. Havent managed to find anyone that can clean it manually or ultrasonically. Mercedes pricing is £274! However, if you log onto www.mercedes-benz-parts.co.uk its @ £159 inc Vat plus another 10% discount!!! They are a genuine mercedes franchise and the parts are ordered directly from Germany.Good website to put in your favourites.

 

[television]

Success,

The cold start valve is blocked. Havent managed to find anyone that can clean it manually or ultrasonically. Mercedes pricing is £274! However, if you log onto www.mercedes-benz-parts.co.uk its @ £159 inc Vat plus another 10% discount!!! They are a genuine mercedes franchise and the parts are ordered directly from Germany.Good website to put in your favourites.

There must be firms that can clean it

 

[television]

Do not go buying things yet. When you are testing the cold start injector you must manually press down the air flow plate, ignition on

 

[silvio13]

Hi M,

Havent bought anything yet, no money :S. Its going back to the Indie for another check on thursday. Before i give it to him and he gives me more lies lol! is this something i can do myself. Im not a mechanic but ill have a go at anything. What does the air flow plate look like?

 

[roofless]

Does is do what is says.......... i stated the car this morning and it was -6 here and it started first time with no crank at all. I only have problems after where the car has been started driven and then standstill ......... i have problems cranking it over! such a headache. Also just had a call from my ex MB techie, he said dont use fuel system cleaner if it hasnt been used on every other service as it will cause more problems ----- oops bit late now! :S

if it starts first thing when cold it's probably not the cold start..when you say you have problem cranking it over after it's been run is the engine finding it hard to turn over or is it turning over ok but not firing up ?

 

[silvio13]

erm, well the only way i can explain it is that when i turn the key it tries to fire, kind of like when the batteries about to go and it just doesnt start. then it will shake and spring into life. I guess its not firing up. My indie is 150% sure its the cold start valve. i will get him to pay for the damn thing if it isnt but ill wait a while and see what else the forum offers.

 

[roofless]

erm, well the only way i can explain it is that when i turn the key it tries to fire, kind of like when the batteries about to go and it just doesnt start. then it will shake and spring into life. I guess its not firing up. My indie is 150% sure its the cold start valve. i will get him to pay for the damn thing if it isnt but ill wait a while and see what else the forum offers.

it's just when you said it started first time when it was -6. it souds like it might be the timing a tad to far advanced or lean mixture both easy for your indie to check