pete98e39

what is the correct startup procedure for flooded engine?

14 posts in this topic

hi everyone, hope you are all well. made a fatal error with my 1998 e39 523i. started it up a couple of days ago in the freezing cold weather we had. she was running for 10 secs then i decided to stop the engine as i had forgotten something and had to go into the house. i came back to the car to start it again to go on my merry way only to find it would not start and there was a strong smell of petrol coming out of the exhaust. after cranking it for a further 20 secs or so the battery was beginning to show signs of distress. the battery is now on charge as i speak and the fault i think is a flooded engine which seems common with this model and others? the engine is the m52b25 six cylinder. the reason i am posting is there seems to be conflicting views as how to clear a flooded engine with this model. some say

 

1. floor the accelerator and crank engine for 10 secs or so till it fires, i read that this is a sort of 'flood mode' in most fuel injection models, but again some say that if the throttle position thingy is cable operated this may or wont work? (i'm not sure if it is cable operated)

 

2. pull the fuse (number 54) out of socket (fuel pump fuse) and crank engine till the pressure in cylinders drop due to 'bore wash? it may temporarily fire then die due to fuel starvation?

 

which is best to use as i dont want to unecessarily put more strain on the engine and battery in a vain effort to get the thing started again. you guys are the experts and have helped me a lot in the past, any replies will be greatly appreciated. many thanks in advance for any replies, take care and regards, peter.

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no carbs so it shouldn't become flooded unless it has a sticky injector, more likely to be fouled plugs.

 

pull the plugs out and clean them, or just fit new.

 

test the coolant sensor to see if its reading correctly, does your engine run map or maf?

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i'm not sure what you mean welshplug? map or maf? i'm not very well up on the terms, only dong minor jobs on the car, nothing major lol

 

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Crank it over on a good battery with the throttle wide open i.e. foot to the floor. It should splutter into life.

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thankyou very much duncan. i assume then that the car is of the standard 'foot to the floor' remedy as for most fuel injected cars and that it does not use the cable thing to the wotsit lol. ( i know i'm hopeless!) :lol:

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I don't think its fly by wire. But that's the standard remedy.

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well i'll give it a go at weekend, the battery will be top notch by then, many thanks for your help.:D

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Wife's volvo 850 used to do this all the time, If you moved it then stopped it wouldn't start.  Nothing worked.  It would sometimes eventually start, battery was good. Towstarted it, manual. I thought this problem only happened to volvo 2.0.  I was lead to believe it was something to do with the oil in the valve buckets?????  It will probably start if left overnight. 

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Mine has done this before, seems its quite a common thing if you start a very cold M54 for a few seconds and shut it off, possibly something to do with the way they dump fuel in to warm the cats up. I've read before that it could be down to the lower injector O-rings not sealing properly but can't find the thread any more, it may have been on the bmwland forum that went offline.

 

 

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Don't do that to an M50! They can be an absolute pig to get going again! But to echo what others have said, foot down and lots of cranking will get them going again.

Carl-e34 likes this

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They can flood if they misfire on starting and leave excess fuel about, which them makes it harder and harder to start.
I've always found removing the fuel pump fuse to stop adding any more petrol, cranking with WOT until it just about starts to catch and it clears itself out, and then fuse back in, prime the system by ignition on/.off a couple of times and it should be ready to go.

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I was always told that the proper way to do this is to remove the fuel pump relay (or fuse, but fuse makes it more awkward) and make up a jumper cable to "short" the relay closed.

 

With your jumper cable disconnected (so no fuel going to engine) crank and crank with a wide open throttle until the engine splutters and tries to fire. While still cranking, on each splutter connect your jumper cable momentarily to put a small amount of fuel into the engine - keep doing this until the car is actually running, at which point keep the jumper connected and allow the car to run at idle for about 10 minutes.


Then reconnect the fuel relay and restart the car and allow to run for 5 or so minutes this time, to make sure everything is ok.

 

My experience of doing this on my M50 was that I would need the assistance of another car jumped on to my battery as otherwise I'd kill a fully charged battery before the car had recovered. I used to use my other half's crappy little Pug 106, running on idle, and connected to my car's battery (or more accurately to the jump points under the bonnet) to avoid battery murder.

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The lifters pump up under the high oil pressure, after you turn it off, the pressure holds them open, then they keep the valves from closing properly - You'll usually notice the engine sounds like it doesn't have the normal compression, or is very uneven compression. I know an AA Roadside Assistance guy, and gets it a LOT with BMWs, especiallu the M54's, but lots of cars do it.

 

Pretty much every Fuel Injected car has a feature where it doesn't inject (much) fuel with your foot hard down while cranking - becasue that's what people had to do on carbs cars.

 

On the odd occasion where I've done it to our E39, I hold the throttle hard down, and crank until it will run - maybe 8 seconds. If it's longer, I'll pause cranking, but leave my foot hard down and crank again.

 

If it missfires after starting, hold the revs up a bit - say 1500 for 30 seconds or so, then switch off and restart and you should be back to normal.

 

I had a Subaru that did it too, except it started fine, but would pump up the lifters, stall at the end of my road, and require about 30 seconds of cranking with almost no compression before it would catch and run!

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