My 93 318iS, after 10 years reliable service, broke down this week. The engine started misfiring. I pulled over and switched off for a few minutes. Started the car and all seemed normal. Ran for another 2 miles and this time it just stopped. It repeated this scenario 3 more times (cutting out immediately, with fewer and fewer miles)until it finaly refused to start. The next day it started fine and has been running in the garage for 2 hours trying to recreate the problem.
Two questions.
1) Any experience/advise on what might be causing the problem and best PD method ?
2) This is the first time I have had a problem with an ECU controlled car. I have always been able to resolve problems on older cars, but feel somewhat at arms length without access to the failure codes out of the ECU. I have been looking for ECU readout equipment online, but there doesn't seem much available for the home user. Is there anything out there that can utilize a laptop PC below £200:00 ?
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If there were diagnostic kit out there for that money I'd be banging on the door. Maverick technology do some good kit but expect to pay £2k +.
Start simple, we need to find out what has disappeared when it stops, fuel or spark or both. Providing the fault manifests itself when being tested this would set me down the route to resolving the problem.
Trouble is that there is a tie up with spark and fuel within the operation of the ECU ie if no ignition signal is seen then the system will deliver no fuel so it wont be an easy DIY fix.
However, a very common fault with these cars is corrosion of the ECU pins (located above your right knee), with the ignition off remove the connecting plug from the ecu and reconnect it, some times works wonders!
Andrew
Simplicate and add lightness!
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Take all your connectors off and put them back together;the other thought is whatever sort of coil you have-they tend to fail when they get hot.
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I had the same problem on my E30 318i. I eventually traced the problem to the Motronic DME relay. This relay is the white one on the bulkhead under a cover next to the diagnostic socket. It is used to connect the battery power to the engine management and fuel injection system when the ignition switch is turned on. On my car, the relay internal contacts had gone high resistance resulting in intermittent hard starts and cutting out. The relay next to it is orange coloured and is the fuel pump relay. My local BMW specialist recommends routinely changing both at 10 years. They cost less than £10 each from Euro Car Parts.
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Yes, I reckon it could well be the fuel pump relay. The cutting out after 'fewer and fewer miles' bit suggests it.
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Thank you for info. I have replaced the fuel pump and the pump relay. Will update with success(or not....)
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Failed again, shortly after washing the car. (Had washed it prior to the first failure). Managed to restart and get home. Did some PD under the bonnet, looking to see if anything had got wet. Noticed 1" - 2" of water sitting at the bottom of the ventilation air intake. Investigation showed that this had sploshed around and the area around the ECU was damp. After a while, found where the water should drain from, removed the rubber tube and found it blocked with leaves etc. Cleared and replaced. The water now drains and the car seems to be running OK.
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