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dazh90 posted a topic in E28 1982-1988Hey all, So my eta 525e AUTO still refuses to start (from my previous threads). Changed almost all the ignition components, distributor cap, ECU, relays, sensors, etc etc. I still do not have any spark to the plugs hence a healthy turn over but no idle. So, i finally had a look into the bell housing where both the Speed sensor, and the Reference sensor are positioned. Because this was new to me when i first had the problem, i'm going to give as much detail as possible with the hope someone may stumble upon this thread in the future. The Speed and Reference sensors push into the bell housing of the gearbox between the torque converter and the flywheel/ring gear. They are both side by side on the nearside of the car, behind the airbox. They are both connected to the engine harness and these connectors can be accessed by removing the airbox and can be seen attached to the block side by side. Grey connector plugs into the sensor pushed into hole B and the black connector connectors to sensor pushed into hole D. Both sensors are the same part number (12141710668) and are interchangeable but you can not get the connectors confused as they must go to the correct sensor relative to the hole identified by B and D. This is what i can see when i look into the reference sensor hole and a i believe my trigger pin has snapped because everything else has been changed and i get quite funky results when the engine is turned over and a AC Volts are measured across the sensor. See Duncan's amazing guide on how to check this if you do not know already below. MASSIVE thanks to Duncan for this, has helped me and tonnes of other people. So the sensor that i discovered was faulty was the reference sensor, which goes into the hole closest to the road. The lowest hole. This sensor was absolutely shot, it had no resistance so was not detecting anything. I changed it for a working new one which i can confirm works as it was tested in a university lab using an oscilloscope. Correct resistance and AC sine wave replicated by a spinning neodymium magnet. This has not solved my issue so this is what i see when i look into the hole. I need help and peoples experienced opinion on this as its the first time i'm investigating it: Now analysing this photo, reveals to me.... this does not look right. Although it does not look aggressively snapped, it does not look long enough!? The only angle i could take the photo forces it to be taken bias to the front of the engine so you can even see the ring gear. If you look at it from the angle the sensor would read, you can barely see the pin! I've drawn out roughly what you would see if you looked at it head on.. So, does everyone agree that this does not look right? Has my pin snapped or is this normal? As the flywheel rotates, it will not swipe across the sensors face/tip. Also, an interesting observation i made of the old, faulty sensor backs up the theory that the pin has snapped. The old sensor has swollen out creating a dome to its face (interesting?...). There are also scrape marks on its face and a dent to suggest its been grinding against something. Wondering if anyone know about this, if they have changed a flywheel on these cars. As the engine rotates and you pass the trigger pin on the flywheel, you periodically come across large tabs of the flywheel that pass by the sensor which are NOT trigger pins. They are just large areas of the flywheel that match the length of the trigger pin. These have long scratches on them like the rust of the wheel has been removed. Long lines of exposed fresh metal as if the sensors swollen tip has made them. So, that is where i am at currently. What do people think? Is this enough to pull the transmission out and replace the flywheel? Has the trigger pin snapped off? Is this normal what i am showing and if so, where would my next area of investigation be? Is changing both sensors enough to move on and look elsewhere? ALL help and opinions are immensely appreciated, i really am stuck. I also hope some of this information will inspire someone else with the same problem and help them repair their own fault!! Kindest regards, Darren - From Brighton, UK
Hi all, I have a 1987 525e (Motronic) which after spending two weeks in America, i come back to my car and she refuse to fire. I've done what i can and im out of ideas so really hoping someone can help! Also, worth mentioning that on the day that i got back and i realised the car refused to fire up i went to the petrol station and got £12 worth of fuel and some carb cleaner to assist a start. SHE STARTED UP! left running fine for 10 minutes but when ignition was switched off she refused to start immediately after (STRANGE, what is going on!?) . Problem/Symptoms; - No spark to any of the plugs apart from a single spark when coil is engaged at Pos3 - I believe im getting fuel as plugs are wet The facts; (strange results shown in RED) - Engine turns over by the key, top of engine moves (in time) with bottom - Brand new distributor cap and rotor arm - Brand new ignition coil - Swapped out CPS with one i had from 520i e28 (same hardwired one facing front harmonic balancer) - Swapped out main fuel relay with one from 520i - Swapped out MAF from 520i (i know it's trivial but, meh) - Checked for 12v heading towards the coil between 15+ and 0. (12v upon pos3, 10v when cranking) - Although coil is new, Resistance across posts all check out fine - Spark plugs are 2 months old - Continuity between both ends of main HT lead (coil tower to distributor) - Battery charged fully externally inside the house - DME socket where relay fits; - Tab30 suppose to have 12v, shows 0v - Tab85 suppose to have 0v, shows 0v - Tab 86 suppose to have 12v, shows 0v - Tab 87 and 87 suppose to both show 12v, shows 12v - Tab 87 and 87 suppose to both show 0v, shows 12v with ignition off - Checked for click from DME relay, it clicks just fine and i get the engine hum Questions that i am asking myself; - If my 520i M20 uses Jetronic fuel injection, and my 525e M20 uses motronic, why do they both have the same hard wired (no clip, needed cutting and soldering) crankshaft position sensors? - Why do i only get one spark when ignition is turned on, but none whilst cranking? - Does p.d towards the coil normalling drop from 12v to 10v when cranking? - Why did she start ONCE but refused to start immediately after? - Is my ECU fried? and if so.... why? only sat for 2 weeks... Any help is very much appreciated!! Regards, Darren (From Brighton)