5-Series (E12,E28, E34, E39, E60)Chat relating to the BMW 5-Series of all generations. Specific models include: BMW 518, BMW 520, BMW 520i, BMW 530i, BMW 528i, BMW 530i, BMW 518i, BMW 524d, BMW 525i, BMW 525e, BMW 528e, BMW 540i, BMW 535i, BMW 520d, BMW 525td, BMW 525d, BMW 530d, BMW 525i/xi, BMW 530i/xi. (BMW 5-Series Forum)
So my '91 535i was running strong as always. i take it to get new tires. I stand in the bay and watch them put on the fresh staggered rubber so I can vouch they did nothing other than the tires. They crank it up, pull it out, its running fine, i get in and it just sputters to a stop. After that it refuses to crank unless it has starter fluid. Starter motor is turning engine over, there is plenty of power from battery, but just no start. I was supposed to be at my grandmothers funeral in an hour, but no such luck. So I start with the obvious.
-Checked all Fuses-OK
-Checked Ignition coil(new MSD coil) plenty of spark.
-Checked Fuel pump-OK
-Checked Fuel Pump Relay. No ground, but when I jump ground to a nearby suspension bolt, fuel pump fires right up, so PUMP is OK.
-Relay told pump to turn on, so RELAY is OK
-Checked CrankShaft Position Sensor-not sure how to test, but also less than 6 months old and appears fine.
-Checked all connections and wires in both electronics boxes under hood,
-Checked all connections and wires under rear seat and in trunk.
So this is where I stand. Samantha(car) isn't running and I have no idea where to go. Does the DME provide ground for the relay? If so, what would cause it not to? I was debating on replacing the chip with a confortini or dinan chip, might this actually fix the problem, or would I still need to replace the DME as well? Any ideas or anyone seen this problem before?
OK, so i've narrowed it down to either the CPS or the DME. The CPS is new as of 6 months ago, so i'm leaning towards a DME. I just picked one up cheap, so I am gonna give that a try, but if not, then I will move on to the DME, lets say that doesnt work though, what would my next step be? All Relays check out with voltmeter.
OK, so I i must be missing something. here is everything that is new:
-Crankshaft position sensor-NEW
-Fuel Pump Relay- NEW
-Battery-NEW(and expensive optima battery)
-Fuel Pump turns on when jumped from relay terminals 30 and 87 but still no start.
-Fuel Pump does not turn on without jumper.
-No Spark from coil.
So to me it seems like maybe the DME isnt powering up? Maybe a bad ground somewhere? Gonna check the grounds in the morning, its dark and raining out there now.
yeah thats what I'm starting to think. Just the way it failed is making me think that. I went to get new tires. while I was heading there, it stumbled twice, but small, just a single missed fire on each occasion, but still idled smooth and ran strong. I pulled up at the tire place, and went inside. They came out a few minutes later and it didnt want to start on the first try, which is wierd, then it started right up but idled a bit low. They pulled it in, turned it off, and lifted it. they lifted it a bit off balance though. all pressure was on the back, the front was about 2 inches off the lift, but it was just one of those low lifts that brings the car up just high enough to do the wheels, so I didnt say much. Car wasnt teetering or anything. They put on new rubber. lower it, and it cranks right up. They back it out about 6 feet just past the bay doors and leave it idling, I get in and get ready to backup and it just sputters out. I try to crank again and no start. no spark, no fuel.
Does this sound like typical failure for a ground lead? think maybe they knocked something loose when they had it on the lift? Maybe the pressure from lifting it off balance and shifting all the weight to small area maybe damaged a line?
ok, so after cleaning and re-gapping the spark plugs just for something to do while i was thinking, I attempt to fire it up and get spark....sort of. what I actually got was high resistance at the ignition coil causing arcing through the output tower.
But hell, at this point, I'll take it, its spark, and I figure the MSD blaster 2 is probably putting out too much for the stock wires anyway. I am gonna go get a new coil in a few hours when the shop opens. so now I gotta figure out why the fuel pump isnt turning on.
Would a cylinder 6 identity sensor stop the pump from turning on?
OK, im beginning to feel like I'm chasing my tail on this one. Basically, I've narrowed down that I now have spark, but my plug wires are kinda old and have alot more resistence than they should, but the system does have spark.
However, the DME(ECU) is not providing a ground to terminal 85 of my fuel pump relay to close the circuit and turn the pump on. I have no idea why. I thought it was the DME so i replaced it, but that didnt work. I replaced the relay, but that didnt work. I tested the wires with the multimeter and they are all fine.
Normally, the ignition sequence starts with checking the Crankshaft position sensor. if its working it turns on fuel and spark. it isnt turning on fuel pump, but it is turning on spark and it passed a resistance test with 545ohms, so I beleive its good. so what else would prevent the DME from turning on the pumps? does anyone know where all the DME ground are?
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