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E30 M3 wont start, help needed!!

Printed From: Bavarian-Board.co.uk - BMW Owners Discussion Forum
Category: Technical & Model Specific Forums
Forum Name: BMW ///M Power
Forum Discription: Ask your BMW M Power Technical Questions here (M1, M2 hybrids, M3, M5 & M6)
URL: http://www.bavarian-board.co.uk/forum_posts.asp?TID=5959
Printed Date: 02-May-2024 at 20:38


Topic: E30 M3 wont start, help needed!!
Posted By: Sean Bicknell
Subject: E30 M3 wont start, help needed!!
Date Posted: 29-February-2004 at 23:23

Hi Peeps,

I am having a problem where the car turns over but wont start. But unfortunatly it is intermittent, however today it has stopped totally and wont start at all. I was told to try changing the fuel pump and motronic relays as they can be a bit dickie. So did this today, but to no avail.

I have also cheked fuel pump, reg, fuel at rail, spark is fine etc etc etc, all of the usual stuff. Took the three sensors from out of the bellhousing and cleaned those, replaced the earth lead on the alternator, but still no joy. The airflow meter is not stuck and moves freely.

If anyone has any ideas I would love to hear them.

Thanks,

Sean..


Replies:
Posted By: Eamo
Date Posted: 01-March-2004 at 09:42
Dont suppose you have access to a spare ECU??

You may know this already but be carefull with tyring to continously turn the car over as you will burn our the plugs fairly quickly.

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Posted By: DAWIEM3
Date Posted: 01-March-2004 at 14:35

 

Try the following,

 

Establish if it is fuel or spark that is missing.

 

Take the coil lead from the dissy cap and hold it with insulated gloves about 10mm away from one of the silver acorn nuts. have someone turn the ignition on and turn the engine over. If you have spark then you are missing fuel. Check the relays behind the water expansion bottle. The fuel relay is usally the one nearest the engine. Look for burned contacts. Replace relay and try again.

 

You mentioned that you took out the timing sensors located in the gearbox housing. These are quite delicate and moving them side to side can cause them to go faulty. Take a digital multimete and set it to ohms . You should obtain a reading around 950 ohms on each of the 3 sensors arcoss two of the contacts. Without all three sensors working the car will not start. the sensor connectors are located underneath the roundish plastic cover at the top back of the engine.

You can also check that you are getting spark to the plugs by doing the same check as with the plug lead except you need to earth the spark plug. if no spark yet you had it before when you checked the coil lead, then either your plugs, rotor, dissycap or plug leads are faulty. Its a process of elimination.

 

Hope the above helps.



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E30 M3 Road car ( Now in Hongkong )
E30 M3 Track Car
S14 2.0L 2002 in progress
E30 C2 2.7 Alpina
E36 M3 3.2 EVO

Posted By: Ratbark
Date Posted: 01-March-2004 at 20:47
Sean

I had exactly the same problem!

Turned out to be the ECU. Have you noticed that after taking the engine revs above 4000rpm, it starts to play up? Thats what happened with mine. Once you passed 4000rpm it would die.

Give the ECU a slap with the palm of your hand whilst cranking, and see if it starts. If it does, then you have a dry joint in the ecu which may be able to be repaired. If not, then you will need a replacement.

I ended up buying a second hand one, which cured the problem.

Hope this helps?

Regards

Mark.

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'89 E30 M3, '89 325i Touring(red), '89 325i Touring(silver), '99 Suzuki TL1000R, '65 VW Splitty SO42


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