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Old 07-17-2015, 11:07 PM   #1
ilokano
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Unhappy DME relay plug (socket) with a burned wire

Hello everyone, I'm new to this forum and hope you could help me with my problem. I just bought a 98 318ti 5 speed but got a problem while driving home, before buying the car I test drove it maybe for about 30 min or more and everything works fine no cell lights and any unusual thing showing up so I took the car. While driving the car about 10 or 15 miles going home I noticed the temp gauges going up to the red line so I pulled over to the service road and not even to a stop the engine died but did not noticed any smoke coming out or water spilled on the engine and not even a smoke comming out on the tail pipe as per my son following me so in short I pulled my car with a dolly until I got home. I tried to start the car but will not run it just turns the engine. The first thing I checked is the fuel pump and is not receiving no power but jumping the fuel pump socket 30 and 87 I hear fuel pump runs so it's not the pump the next thing I did is check the DME relay and check for current on the socket and it shows that it has a current coming out on 30, 87 and 86 by the way it has 5 wires coming out

1) 30 - (red with yellow stripe)
2) 87 - (plain red)
3) 87a - (plain brown-thin wire at middle plug)
4) 85 - (brown with white stripe-thin wire)
5) 86 - (red with white stripe-thin wire)

after playing around with the relays I notice that the 87- brown wire is burnt or something like being shorted so I trace the wire and it was spliced to a couple of brown wire. I'll check tomorrow if the DME has a sign of shortage. Any idea what maybe the fault? Any help will be greatly appreciated
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Last edited by ilokano; 07-18-2015 at 07:22 AM.
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Old 07-18-2015, 08:42 PM   #2
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I melted a ground wire just like that while troubleshooting a SAP relay in a E36 6 cylinder. Once the smoke cleared and I assessed the damage, I went ahead and replaced the engine harness. There were just too many other wires fused to the melted brown insulation and I didn't want to take any chances.
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Old 07-18-2015, 11:33 PM   #3
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Are brown wires ground? I followed the burnt wire and it was spliced to a bundle of brown wire (5 wires) Now it puzzles me why that brown wire is connected to the relay pin 87 which is bridge to pin 87a. What I know about relay is when pin 85 and pin 86 are activated, pin 30 which has a constant 12V will send current to pin 87 and pin 87a then theres no way that it will not be shorted unless the DME sends signal to the relay to stop activating and instead send that ground pin 87a (brown wire) to 87 (red wire). just wondering if the red wire goes to the fuel pump relay. I'll try to replace that burnt wire but will install a 25A fuse so not to damage any more wires.
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Old 07-19-2015, 12:04 AM   #4
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Yes, brown wires inside of the steering column are ground wires. I assume there are several routed from under there.
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Old 07-19-2015, 01:43 AM   #5
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open my DME today but did not show or smell like is burn. Any more ideas?
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Old 07-19-2015, 09:22 AM   #6
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Quote:
Originally Posted by Shellback View Post
I melted a ground wire just like that while troubleshooting a SAP relay in a E36 6 cylinder....
Looking at sheet 1210.20-08 of the BMW NA 1998 318ti ETM, could that be the secondary air pump relay?



If it is, I wonder how the thin, brown ground wire got cooked. Ohhhh. When you jumpered 87 to 30 (the 4 RT wire to the 4 RT/GE wire), was the relay plugged in? That would have applied unfused 12V, via the relay, to the ground wire. You probably would not expect a ground wire in the circuit – I think it keeps a switched-off air pump from windmilling.

Last edited by John Firestone; 07-19-2015 at 10:03 AM.
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Old 07-19-2015, 09:48 PM   #7
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just wondering, does my car has an air pump? can't work on my car till friday. I will still be looking at the schematics. Will try to change the wire that's been burnt and put a fuse on it to be safe then put all things back and try what it does.Ill keep you posted and thanks for the help

Last edited by ilokano; 07-23-2015 at 10:00 PM.
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Old 07-19-2015, 10:16 PM   #8
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reason mine fried: I accidently swapped relays.
I removed the SAP relay and installed a Fuel pump relay. Never again!
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Old 07-19-2015, 10:25 PM   #9
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Quote:
Originally Posted by ilokano View Post
just wondering, does my car has an air pump?...
I believe it does, if it is an U.S. model built in 1997 or later.

Quote:
Originally Posted by Shellback View Post
reason mine fried: I accidently swapped relays.
I removed the SAP relay and installed a Fuel pump relay. Never again!
That little brown wire is hazardous.
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Old 07-20-2015, 01:33 AM   #10
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I just bought a DME with the same part number in case the DME went bad. Do I still need to let it be program or paired?
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Old 07-20-2015, 06:34 AM   #11
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Yes, if don't have the capability to do it, go the dealer but it will cost you. Some people do is to buy the DME/EWS and Key Chip Kit. This is the cheapest way.
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Old 07-20-2015, 06:40 AM   #12
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Here is the wiring diagram just in case you don't have yet. You need to be certain before buying the DME/EWS. Check the CPS (crank position sensor), if this this is bad, it will stop power into the fuel system. I think it should be read at least 500 ohms. Good luck. Checks all
the relays, there's a relay inside the DME compartment too which energize the fuel pump relay, etc.
http://wedophones.com/Manuals/BMW/19...g%20Manual.pdf
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Old 07-20-2015, 06:46 AM   #13
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Quote:
Originally Posted by ilokano View Post
what kind of relay should it go to that secondary pump relay? I've mixed those relays and don't know which is which
Check this site and compare if it matches your car.
http://blog.bavauto.com/6476/bmw-e36...-325i-328i-m3/
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Old 07-20-2015, 06:50 AM   #14
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But if you need the DME/EWS Kit, just PM me.

http://www.318ti.org/forum/showthread.php?t=40970
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Old 07-23-2015, 09:50 PM   #15
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Fixed the burnt wire on the secondary air pump relay and did some troubleshooting, check for voltages on the relay socket terminal (without relay)


DME RELAY

PIN ------------------------ switch off (v) --------------switch on (v)
30 ----------------------------- 12 ----------------------- 12
86 ----------------------------- 12 ----------------------- 12
85 ----------------------------- 0 ----------------------- 0
87 ----------------------------- 0 ----------------------- 2.5

FUEL RELAY

PIN
30 ---------------------------- 12 ----------------------- 12
86 ---------------------------- 0 ----------------------- 2.5
85 ---------------------------- 0 ----------------------- 0
87 ---------------------------- 0 ----------------------- 0

SEC. AIR. PUMP RELAY

PIN
30 ---------------------------- 12 ------------------------ 12
86 ---------------------------- 0 ------------------------ 0
85 ---------------------------- 0 ------------------------ 2.5
87 ---------------------------- 0 ------------------------ 0
87a --------------------------- 0 ------------------------ 0

Also checked the secondary air pump by jumping terminal 30 and 87 and the air pump motor runs. I also checked the plug wires if there's a spark and it shows sparks on all of the four plugs. Tried to start it but it just keeps on cranking. next I'll be checking the pressure. Any advice if I need to change my crankshaft sensor or is there any way I could test it?

Last edited by ilokano; 07-25-2015 at 07:21 AM.
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