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Discussion Starter #1
Hello,

Problem starting a 1991 E34 M5. From the research I've done it seems the problem might be a bad ground from the engine to the chassis. I turn the key and the car won't start, but if I keep the key turned after about 10-20 seconds the car finally starts right away. It seems to get worse after a hot day. I'm not a mechanic so I'd like some opinions from the experts. Any other ideas of what the issue could be or am I on the right track? Also is replacing these wires relatively straight-forward? Thank you.
 

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Funny: I have the same problem! If the car has been shut down shortly after idling while (fuel/smoke-stop right after "no darling, I'm not spending the night here to find myself in 2,5 hours of traffic in the morning, so MOVE!!!") it won't turn over. When the key is inserted and the car started immediately it will also take 3 or 4 seconds before the starter engages, but if you turn on the ignition, wait 2 secs (seatbelt, put phone in cradle, etc) it will engage the starter immediately after twisting the key further....... I'm puzzled!!!!!

jamilor said:
Hello,


Problem starting a 1991 E34 M5. From the research I've done it seems the problem might be a bad ground from the engine to the chassis. I turn the key and the car won't start, but if I keep the key turned after about 10-20 seconds the car finally starts right away. It seems to get worse after a hot day. I'm not a mechanic so I'd like some opinions from the experts. Any other ideas of what the issue could be or am I on the right track? Also is replacing these wires relatively straight-forward? Thank you.
 

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If the engine turns when you try to start it but doesn't fire up, I would guess that the fuel pump in unable to deliver fuel at the right pressure to release the fule valve or the fuel release valve does not open. The fuel valve is located ath the very front of the fuel line, on top of the engine and if memory serves me right, there is a vacuum hose connected to it.
If that hose, or any other hose in the vacuum system is damaged, you may not get enough vacuum to open the valve. This may be caused by heat, tear and wear.
 

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My car had a leak in the fuel line. Symptoms were that the car would start up as normal immediately after being shut down but if a few hours past the engine would turn for a couple of seconds until the fuel pump was finally able to refill the now empty fuel line.
It's probably a good idea to have all your fuel lines checked out just in case considering the age of our cars.
 

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jamilor said:
Hello,

Problem starting a 1991 E34 M5. From the research I've done it seems the problem might be a bad ground from the engine to the chassis. I turn the key and the car won't start, but if I keep the key turned after about 10-20 seconds the car finally starts right away. It seems to get worse after a hot day. I'm not a mechanic so I'd like some opinions from the experts. Any other ideas of what the issue could be or am I on the right track? Also is replacing these wires relatively straight-forward? Thank you.
The problems with my BT started like that.Then it got worse and worse.My advice; check the cranksensor.
 

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Discussion Starter #9
Thanks for the replies,

Actually the symptoms are like this:

I turn the key and nothing happens. The engine doesn't even try to start. Then a few seconds later it fires up with no problem. Sometimes it takes if longer then a few seconds for anything to happen. Once I couldn't get it to start at all. I'll look into all the things you mentioned.
 

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I wonder if this is the problem I had? You would turn the key but the starter wouldn't run. If so, it turned out to be the relay that operates the starter solenoid - I think it was a yellow topped one under the cover where the ECU lives.
 

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Discussion Starter #11
Thanks for the replies gentlemen. I had Will Zaraska from http://www.willz.ca look at the car for me. It was the starter. Some of the bushings had come off. Could have been worse. Got another starter for $200 canadian :M5thumbs:
 
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