Major Contributor
540 starts, then dies
I have a rather odd problem with my '95 540/6. Sometimes when I start it, especially when cold, it will crank and start as usual, idle for maybe a second, then die. I start it again, and it runs great. It idles up like it's supposed to when cold, then slows down as it warms up. Overall it runs well. I recently did the upstream oxygen sensors, cleaned the TB and ICV. No codes or CEL. DME temp sensor maybe? Any ideas?
Major Contributor
My guess is a small airleak in the fuel line where the metal tube joins the rubber one, under the hood, over by the relays. New clamp or use heavy duty cable ties. I think you car is starting on what's left in the fuel rail. Then, because of a small leak (letting air in the line but not necessarily leaking), you have a bubble that stalls the car, then everything is fine once the pressure gets up again.
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Major Contributor
So are you talking left side near the fuse/ relay box? Does the 540 have a fuel pump check valve?
Major Contributor
No, but it can be retrofitted cheaply as many have done. You can put it alot of places, but I like after the filters, right after where the two join back to one. There's some extra hose there and some breathing room before it turns into the metal pipe.
o/______\o
(Oo=00=oO)
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Super Moderator
Yes it does have an integral check valve on top of the fuel pump, but if that
was the problem you would have longer cranking times when hot. And if you have the leak at the fuel line that is mentioned below then you would smell gas.. My guess would be the icv or the contacts on the main or fuel pump relay.. i would start by cleaning all the connections and treating with stabilant 22
Originally Posted by onewhippedpuppy
Major Contributor
Never had a gas smell, and I just cleaned the ICV. I'll check the relay contacts.
Super Moderator
Just cleaning the icv doesn't mean that its working correctly, I'd clean the contacts
on it as well... electrical connections on bmw's are very sensitive to small amounts of corrosion, not always visible. I get a fair amount of use out of my bottles of stabilant 22 on euro cars. Japanese cars never seem to have this problem.
Green Beret Special Ops
mine does the same type of rolling start, smooth then cuts back like the oil pressure bogs it down for a minute....obsure? Maybe this is a sympton of the oil drain back check valve? I havent noticed the oil pressure light staying on any more than usual though.
95 E34 530I V2.37
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Those who make peaceful revolution impossible will make violent revolution inevitable.
John F. Kennedy
Major Contributor
Oddly enough, this morning I turned the key to #2 and let it sit for 5 seconds or so, then started it. No problem! This might support the ICV contacts, if there's too much resistance and it's responding slowly. Where can I get stabilant 22, or are there suitable alternatives?
Super Moderator
deoxit d5 is what i use to clean the terminals on the dme, temp sensor , afm, maf
light bulbs etc basically every contact on the car with the exception of any of the connectors for the oxygen sensor. Bmw says no on the o2 sensor connectors. Then after cleaning them i treat them with stabilant 22 which is a connection enhancer and is recommended by bmw , vw, audi etc..
Stabilant is available from Volkswagen with a vw part number of
ZVW 186 001 STABILANT 22A or you can get it from a number of electronics shops if you check google or it has a napa part number of napa echlin CE-1, Borgwarner CL85 , Neihoff NL 5, partsplus CL85, Or from these guys who seem the most reasonably priced of the bunch.
I haven't bought from them so i can't say how they are, Gordon got me mine a couple of years ago..
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