Hi guys. Just having the old no start issue. Currently going through the steps. I read somewhere however that the check engine light can reveal if the DME is good or bad, can anyone say?
To try clarify the thread I was reading was ambiguous to say if it's on its bad, or if it's not on its bad. This is the light on the bottom row on the left not the amber centre one. Is this a solid way to tell or not?
For reference, mine is not on. Tia, Joe.
The car in question is a 1988 325i.
DME - quick diagnostic ??
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Cloggy Saint
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E30's don't have a check engine light 
E30 zone - promoting adult illiteracy since 2004
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Brianmoooore
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OP hasn't said where he is. UK E30s don't have a check engine light, but they do in some parts of the world.
HIGHLY unlikely DME is at fault, wherever in the world you are.
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Joe_30
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Hahah. I didn't expect this to be such a stupid question. It was on r3vlimited.com to be fair. And it would be a correct guess to say I'm in the UK and have a UK spec car.
Well I have spark, & power to pretty much everything apart from anything that goes to the fuel pump. Jumpered the relays, & checked for power at the fuel pump relay. Nope. Scratching my head, I'm sure it narrows it down to only afew bits now though atleast!?
I wasn't going to post about a no start issue cause it's been revised many times over, but thanks for you replies anyway
. Joe
Well I have spark, & power to pretty much everything apart from anything that goes to the fuel pump. Jumpered the relays, & checked for power at the fuel pump relay. Nope. Scratching my head, I'm sure it narrows it down to only afew bits now though atleast!?
I wasn't going to post about a no start issue cause it's been revised many times over, but thanks for you replies anyway
. Joe-
Brianmoooore
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If you've jumped the pump relay, and still aren't getting fuel pressure, then it's likely that the pump has jammed, which wouldn't be unusual, or fuse 11 has blown, which would be as a result of a jamming pump.
Another possibility is an immobiliser that you aren't aware of, cutting power to the pump.
Pull the two pin plug off of the fuel pump (access hatch under rear seat), and connect a 12 volt lamp to the plug. Should light when you crank the engine with the key.
Another possibility is an immobiliser that you aren't aware of, cutting power to the pump.
Pull the two pin plug off of the fuel pump (access hatch under rear seat), and connect a 12 volt lamp to the plug. Should light when you crank the engine with the key.
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Joe_30
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I should have added more diagnostics, my bad. But I've connected fuel pump to external power & it works just fine. Fuse 11 is good too, icv buzzes without main relay being jumped and unsure if I should have, but test bulbed fuel relay pins 30 - 87, the fuse and where it connects upto the pump. Nothing.
Immobiliser could be thing though! (Your correct in assuming I didn't know my car had an immobiliser also) A couple months ago the car deadlocked itself, had to take the windscreen out to get into it. Hadn't started it since, just been working on it. Not an expert, but no sign of an aftermarket alarm to my knowledge but I do have a 13button OBC, of which the screen is dead. Just read a thread about bridging the wires. Am I correct in thinking this is from the black box that's sits above the ABS unit above the drivers foot well where the 'thiccer' green & green & red wires go in & if I bridge these does it affect anything but the immobiliser?
There's a pretty good chance it could be that. I hope. Thanks for you help so far Brian.
Immobiliser could be thing though! (Your correct in assuming I didn't know my car had an immobiliser also) A couple months ago the car deadlocked itself, had to take the windscreen out to get into it. Hadn't started it since, just been working on it. Not an expert, but no sign of an aftermarket alarm to my knowledge but I do have a 13button OBC, of which the screen is dead. Just read a thread about bridging the wires. Am I correct in thinking this is from the black box that's sits above the ABS unit above the drivers foot well where the 'thiccer' green & green & red wires go in & if I bridge these does it affect anything but the immobiliser?
There's a pretty good chance it could be that. I hope. Thanks for you help so far Brian.
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Brianmoooore
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The green and green/red at the black box are the immobiliser wires, and the copper tracks inside the box are a bit under size and prone to failure, but this immobilises the ignition only, not the fuel pump, so if you are getting sparks, this is not the problem.
If you want to disconnect this immobiliser, then do it behind the glove box, where the green and green/red are plugged into a two pin socket with two plain green wires going to it. If your OBC is OE, there will be a matching plug, fitted with a short loop of green wire, tied up to the loom nearby, that you just plug in instead of the green and green/red.
The wire to the fuel pump leaves the fuel pump relay as a green/purple wire, goes to the 20 in C101 engine loom plug by the fusebox on pin 13, changes to purple/red for a few inches to fuse 11 , then changes back to green/purple, goes down through the duct beneath the fusebox into the cabin, goes down the front left corner, right along the LH sill to the rear seat pan, then across the seat pan to a multi pin plug and socket that should be cable tied to the vent pipe steel tube where it crosses the pan on the RH side. From here the wire goes down through a grommet in the seat pan, and across the short distance to the fuel pump. There's also the brown earth wire for the fuel pump, which shares the last part of the route, from the rear main earthing point on the LH side of the rear seat.
Most number of immobilisers I've disconnected from one E30 = 3. None of them were working.
If you want to disconnect this immobiliser, then do it behind the glove box, where the green and green/red are plugged into a two pin socket with two plain green wires going to it. If your OBC is OE, there will be a matching plug, fitted with a short loop of green wire, tied up to the loom nearby, that you just plug in instead of the green and green/red.
The wire to the fuel pump leaves the fuel pump relay as a green/purple wire, goes to the 20 in C101 engine loom plug by the fusebox on pin 13, changes to purple/red for a few inches to fuse 11 , then changes back to green/purple, goes down through the duct beneath the fusebox into the cabin, goes down the front left corner, right along the LH sill to the rear seat pan, then across the seat pan to a multi pin plug and socket that should be cable tied to the vent pipe steel tube where it crosses the pan on the RH side. From here the wire goes down through a grommet in the seat pan, and across the short distance to the fuel pump. There's also the brown earth wire for the fuel pump, which shares the last part of the route, from the rear main earthing point on the LH side of the rear seat.
Most number of immobilisers I've disconnected from one E30 = 3. None of them were working.
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omera60
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If I may chime in, also if the DME relay is bad there would be no power to the fuel pump relay. I learned this while trying to measure fuel output from the pump and had the DME relay off, got no fuel, after installing it started to pump.
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Brianmoooore
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The fuel pump relay is controlled by the DME (ECU), so if the DME relay is absent, the DME won't be powered up, so can't switch on the pump relay.
Doesn't affect linking 30 to 87 to bypass the pump relay and power the pump up though. That will still work even if the DME is removed entirely.