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E28 535i and 525e Motronic non-start trouble shooting guide

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DME relay

Ive tried this guide on my 518i. my fuel pump is working but my relay is making a strange buzzing sound. Like it's constantly opening and closing fast. I replaced the relay £70 but it's still the same. And the pump don't prime it just crackles like its shorting out. The car hadn't been started for a year and I booster packed it. When I removed booster she cut out. And the problems then began. Hope someone can help I'm at my wits end. Not sure where the main relay is either.

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may I bring up a old topic please:

 

my m535 decided not to start one day NO SPARK

 

12v at coil (fitted new one just incase as looked old )

main relay clicking and putting out two lives to pins 87

fuel pump is priming plus I can smell the fuel after cranking

 

at ecu plug I have live at pin 35 but I do not have a pin 18 in the ecu plug for a live??

 

reference sensor showing within tolerance, the engine speed sensor  is not showing within tollerence? im presuming plugs right the sensor I cant see (lower one) goes to grey plug

switching plugs still no attempt to start

 

earths are showing at the ecu at the pins mentioned earlier

 

 

what is this obc relay I have read about that can be bypassed to check?

Edited by apples24

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its a while since i wrote it - though manual says that should be pin 87 from the dme relay?

 

the 520/525e haynes manual is useful

 

I can't guarantee there isn't variations its just what i found.

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yes i found your write up very usefull for that im thankfull, on the main relay i have the two outputs from pins 87, one only seems to go to my ecu pin 18 on the plug is empty, must just be a variation

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cant get crank sensors out!!!

bolts out, can put mole grips on them and rotate them but can i pull the buggers out the hole can i fuck!!

 

only possible thing i can think of is to get some heat on the alloy housing?

 

they rotate but wont budge outwards, cars jacked up so got room underneith, cant believe its stuck like that! they look like the original from new sensors

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They should just pull out with little resistance but if they have been in a while the rubber o ring half way down the sensor could be causing the resistance.

 

As you have the new ones I would try a screw driver between the bell housing and the sensor and try to leaver it upwards slightly to get it moving. I would resist any heat.

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yes i tried that it snapped the sensor lol

 

i cat twist but no pull, thrown a load wd40 of them now and left them till tomorrow, i really dont want to be trying to drill them out!

 

id say they have been in there an extremely long time, original bmw ones still got all clips etc going up and metal cover fitted. cars only done 99000 miles from new never really went anywhere

Edited by apples24

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Just a thought, once you have removed the bolts, remove the gearbox to engine cover ( inspection plate) you then should be able drive them out from inside the bell housing by drifting them outwards.

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Do manual transmition have these sensors?  If yours is auto then there is definentley a large inspection plate that needs to be removed which is a cover between the gearbox and engine so you can access the  torque converter bolts which normally gets covered in lots of crud and can be difficult to see at first if you don't know that it's there.

 

part number on real oem is 11141286367 and it looks like it's on there wether it's manual or auto.

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ive attatched a picyure yu can see my two sensors, to the left i have circled some bolts which looks like to me can only be anything close to a inspection plate? someone else told me it is not right?

14705706_10157729648815106_8324615803501789140_n.jpg

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8 hours ago, apples24 said:

ive attatched a picyure yu can see my two sensors, to the left i have circled some bolts which looks like to me can only be anything close to a inspection plate? someone else told me it is not right?

Hi apples, this is the engine to gear box  inspection  plate so you can acces either the manual gear box clutch assembly or the auto tourqe converter. Your picture shows two of the 5 or six bolts that need to be removed to access the bottom of the bell housing of the Gearbox. You will need to unbolt the body strengthen bar and move the steering  linkage bar a little to remove this inspection cover, not a massive job, just a bit fiddly.

some bolts will go through into the bel housing to secure it and others that are fairly long will go up into the block, it's really quite easy and am hoping this will give you extra access from extracting them from behind.

goog lick

gary.

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so i have got to drop the anti roll bar, i was wondering if could just slide it past or not, its raining hard at the moment and car is jacked up on my driveway so will just have to stay like that for a bit

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Yes, that bar in the middle ( Bentley manual calls this a crossmember ) of your picture needs to come off I'm afraid, two bolts either side hold it on. The plate will not wiggle out with this in the way. 

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