Difficulty starting uphill 300GE
This one's got me a bit flummoxed, I recall reading about someone having trouble starting uphill but can't find it now (maybe was on P3?!).
Opinions and educated guesses welcome.
Problem: while parked on a steep hill with the vehicle's front pointing skywards the car is very difficult to start, requiring about 3 tries, every time cranking for a good while each time, until it fires.
Pointing downwards on the same hill, it starts fine.
What's been done:
-Fuel pumps/accumulator/filter all been changed at least once within the last 20k miles/2years.
-Idle adjusted last week to factory-spec CO figure (was running too lean, 0% before) to cure a stalling problem while running, doesn't stall any more.
-Cold start injector tested by removing plug when cold, engine does not start at all, when plugged in it starts.
Also it takes a bit of cranking to start from cold, then runs rough for 2-5 seconds then runs great, whereas it starts straight away when warm or hot.
I'm looking to get a fuel pressure tester for the next step in the diagnosis as advised by our ever helpful tech rep, and as I said, any ideas welcome.
~120k on the clock, plugs, distributor cap and leads etc all new, even the ignition coil was changed! oh and the fuel tank was full of shell's finest :evil:
might be as simple as a porous fuel pipe somewhere in the system causing a loss of system pressure.the fuel pumps have to build the pressure again before the fuel distributor can function properly...try switching on the ignition and waiting for 30 seconds before attempting a start.this will allow the pumps to build up the pressure.....of course if there is air in the system it has bleed through the injectors before the correct fuel mix lets the engine run properly.....
this exactly matches my starting problem, on mine it will always start on the first key turn, only taking about 5+ seconds of cranking. after turning off the engine for a good 1.5-2 hours, the problem comes back. but starts very well if the engine has only been off for less than 45 minutes or so.
tested the pressure on the fuel distributor yesterday, turned out it definitely was losing pressure. this despite a new accumulator. both fuel pumps were also changed last year, along with all six injectors. it is my mechanic's opinion that the pressure valve in the fuel pumps has gone bad, within one year.
not enough fuel makes sense for the rough few seconds
i'd be very happy to hear other opinions on this matter
How is the condition of the filter inside the fuel tank, these things can foul up. More of a problem with a diesel, but worth checking on a petrol.
I used to listen to the fuel pump when I had a 280E which had a similar system to the 300E. The pressure needs to build up against the accumulator after a period of rest, thus the initial running then slowing down as the pressure reaches the required level. That was my standard M.O.
There was a non return valve on the 280E on the fuel distributor which used to prevent fuel flowing back into the tank when the engine was switched off, this helped maintain the pressure. I replaced mine (£10) and it made a big difference, the pressure would hold for 6-8 hours or so.
Ah shochu it was you, thanks for the input. My advice to people with G300/GEs if they want to keep them a while is to buy the fuel pumps in bulk! I purposely put BOSCH in there in the hope they would last longer, maybe I should try the "alternative" next time and see how long that lasts.
Roly: non-return valve is exactly the kind of thing that sounds like causing the problem, but I'm not sure if there is one in the 300's fuel distributor, and I'm reluctant to experiment what with the thing only being available as one piece ~£600.
Have a look where the fuel pipe enters the distributor from the pump, that is where it was on the 280E. Only a small thing, you could easily miss it.
good topic mostafa,i have a similar problem....only when first intial start up .
i did have a very slight petrol wetness by the rear tank fuel line. my mechanic replaced it with a braided one :D fantastic!!!
now its booked in for a complete fuel line replacement, the lot :wink:
plus i will change the acumulator and fuel filter to put my mind at ease before my voyage :wink:
will post detailed pics once its done.
Thanks Roly hope to have a look next time I have the air filter housing off.
Huss so it is more common than I thought, I might just change the pump and see if that cures it.
I'd recommend the fuel line replacement (just like brake lines) soon as they start leaking, not something you want to mess about with. Look forward to the pics..as always :)
let us know the outcome if you decide to have the fuel pumps changed.
i also have BOSCH pumps, not sure if there are other alternatives available in the market
Sorry I was mistaken, one of the pumps fitted appears to be a Pierburg unit. I know at least 1 or 2 other makers produce this type of pump. Checked at the local motor factors and they wanted £120 for their own brand. Will check with MB too though they are normally more...it's just that last time I think I got it off eurocarparts.com for around £70.
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Hi I've suspected a loss of pressure there, so when it's cold I prime the fuel pumps by turning the ignition to "on" but not starting, 3 times, every time waiting until the fuel pump turns off itself, then try to start but with no difference.
Is it just me or do other people (who listen to their fuel pumps prime) hear the pump build up pressure and slow down before it gradually stops? I distinctly remember the sound, but can't remember if it was this car or the G500 or the 190E :/
In the current state the fuel pump primes at a regular frequency i.e. the sound doesn't change as if it is facing increased pressure.
My suspicion: a leaky injector perhaps? That behaves at all other times.