when you say nothing happens,meaning it doesn't crank at all?or does it crank but does not fire?Originally Posted by BMW 5 SERIES
My problem is that my 525 E34 wont start immediately after a 10-15 min or more run.
When I start the car for example in the morning everything is fine. No hesitations at the start up and no problems during the drive. If for example stop the car for one minute and then try to start the engine again nothing happens. But if I wait for about 10-15 min everything is back to normal. Any ideas what the problem might be?
It is really annoying to have the engine running if I want to make small stops.
Thanks
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when you say nothing happens,meaning it doesn't crank at all?or does it crank but does not fire?Originally Posted by BMW 5 SERIES
No crank at all !!Originally Posted by moots
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It is likely to be a fuel pressure problem- if pressure is not sufficient it won't crank (the ecu waits until the pump brings it up to 43.5 PSI).Originally Posted by BMW 5 SERIES
I believe there are several causes if it is this;
When was the last time you changed your fuel filter? It needs changing regularly on old cars, if you tend to leave your car empty it is really dangerous cos the air in the tank condenses every night and causes rust and clogs your filter. You should never leave it empty, and change your filter every 80,000km without fail. ON my car I do it every 40,000km since its old. When I get a look in the tank I'll decide if I go back to the standard replacement schedule. nick
- FPR
- Non-return valve
- Pump
- Physical damage to the fuel line or tank-mounted pickup
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Thank you for your reply. I must mention that the problem occurs more often at summer time where the temperature is high.
About the fuel filter the last time I change it was less than 2000 km ago and I never leave the fuel level to go under 30lt.
Nick
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It could also be a duff starter motor (sticky solenoid) or a combination of a duff ignition switch and old battery.
Although it might seem weird that a duff ignition switch could cause problems with hot cranking, I've had this problem on two different E34s (one a manual 525, the other an auto 540). On the 525 I assumed it was the starter motor but the starter turned out to be OK. Since (on the 540) replacing the ignition switch and battery, it cranks when hot every time.
For the both the 525 and the 540, things were worse in summer when the temperatures were higher. Cold starts were no problem, but if the engine had been running fro between 15 minutes and an hour (depending on whether summer or winter) then the car just became a huge paperweight.
Does the ECU have a sensor to measure the fuel pressure? Perhaps wrongly, I thought that there is no fuel pressure sensor connected to the ECU - if that is the case, how would the ECU be able to measure the fuel pressure in order inhibit cranking in the event of low fuel pressure?
The battery is new. I change it 2 weeks ago. So I will check the starter motor and then the ignition key to see what happens
Thanks for the input
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As a long shot, next time it acts up, try pushing the shifter farther up into park or pull it back into neutral. Could be a problem with the prndl switch. The ignition switch has a heavy load on it when the key is in run, they can overheat and cause a no start from excessive voltage drop.