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BMW E30 3 Series 1984-1991 (318i/s, 325/e/i/is/ix, M3, conv) 1986 325e no start


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Last Post: Apr 22, 2014 12:45 PM Last Post By: aviator69
M3bob

Posts: 23
Registered: 05/08/06
1986 325e no start
Posted: Jul 1, 2006 6:11 PM
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Well my cars hot sun "no start" problem finally has evolved to a no start at all problem. Car cranks good but has no ignition (fire to the plugs). Ignition "on" gives power to the main relay and at the pos (15) post of the coil. The neg side of this brand new coil has continuity to pin 1 on the DME (computer). The ignition switch tests ok on all it's output terminals. The only thing wrong that I can find is Bentley's test at the 35 pin DME connector for power on pins 18 and 35 is not there. Ignition switch on and test for battery voltage at pins 18 and 35 is no voltage. Does anyone understand where the current comes from on this test? I have cleaned and tightened all ground points although they appear clean, dry and not corroded at all. Along the way I have put new relays, new coil, a known good computer and new position sensor on the car to no avail. Obviously no power to the computer kills the ignition so now I am tring to run down how the power gets from the ignition switch to the computer. Help!!
Thanks.
M3bob

Posts: 23
Registered: 05/08/06
Re: 1986 325e no start
Posted: Jul 1, 2006 10:04 PM   in response to: M3bob in response to: M3bob
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More info since I am working on the problem as I go --
The wires on the computer connector runing from pins 18 and 35 are red and blue striped and run back to a the single center pin on the main relay. That pin is numbered as one of two 87 type on the relay. Does this seem right? Do the 87 pins pick up voltage when the key is on? I have tried 3 different relays, all used - no help. The red wire feeding the 30 pin of the main relay is hot all the time. Thanks.
M3bob

Posts: 23
Registered: 05/08/06
Re: 1986 325e no start
Posted: Jul 1, 2006 10:10 PM   in response to: M3bob in response to: M3bob
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Where do the other 87 pin wires go?
M3bob

Posts: 23
Registered: 05/08/06
Re: 1986 325e no start
Posted: Jul 2, 2006 5:34 PM   in response to: M3bob in response to: M3bob
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Ok more info - I bench tested my relays, they are all good. So back at the cars main relay plug I test the 86 terminal for power with the switch on. None - in fact 86 seems to go to ground. Ignition switch outputs are good so I look for connections between the relay and the ignition switch. On the firewall is a round mounted screw together connector. Take it apart and pull back the top rubber boot. Inside I find the small brown wire that looks like the 86 terminal wire. The bottom part of the connector has the female so I test for power with key on - Yes, 12.3 volts. Top part goes to ground for this small brown wire. Does this sound like a short in the brown wire somewhere between the relay plug and this connector? Thanks.
magcuda

Posts: 771
Registered: 12/09/03
Re: 1986 325e no start
Posted: Jul 3, 2006 9:44 AM   in response to: M3bob in response to: M3bob
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you need to check the speed and reference sensors on the fly wheel. they wake up the DME, then the DME grounds the main relay to supply power to the DME and fuel pump relay.
M3bob

Posts: 23
Registered: 05/08/06
Re: 1986 325e no start
Posted: Jul 3, 2006 5:26 PM   in response to: magcuda in response to: magcuda
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I really thank you for your help and response. I made an error in that I was looking at the main relay plug backwards. The 85 terminal is the brown wire and goes to ground as it should. The 86 terminal should provide the positive to kick the relay on. It (86) has a green wire. I have checked the position reference sensor at pins 25 and 26 of the DME connector and get 905 ohms. Also checked it at the sensor connector and got 904 ohms so these seem good. The bentley manual says only the reference sensor is used at start time not the speed sensor. It also gives a test that says turn the ignition to "on" and check pins 18 and 35 for battery voltage. This tells me that power should be coming to the DME with the ignition in the on position. That can only happen if the main relay kicks on because the center 87 pin is where the 18 and 35 wire comes from. Ok so I jump power from pin 30 to 87 and force power to the DME. Still does not start! Any help is really appreciated. Thanks
eman

Posts: 4
Registered: 06/22/06
Re: 1986 325e no start
Posted: Jul 3, 2006 11:16 PM   in response to: M3bob in response to: M3bob
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hey, i know the feeling, nothing for nothing but i had the same problem on a 94 318i, it turend out to be the the mirco switch on the door pillar for the drivers side , it was worn to the point where the door didn't make enough contact to indicate that the door was in fact close. i know the years and makes are different but it worked for me i pressed and held this micro switch turned the key and she started right up. give it a try you never know.
M3bob

Posts: 23
Registered: 05/08/06
Re: 1986 325e no start
Posted: Jul 4, 2006 4:32 PM   in response to: eman in response to: eman
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Thanks eman but not it. I have further tested and can now say that the power coming to the main relay on terminal 86 comes from the on board computer relay. I have power coming into the relay but not coming out. So it is boiling down to a bad obc relay or a bad on board computer. Will post when I get some parts to test with. Thanks
streatleathul

Posts: 2
Registered: 07/05/06
Re: 1986 325e no start
Posted: Jul 5, 2006 10:20 PM   in response to: M3bob in response to: M3bob
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Sorry, I know this not helping but I have same problem on a 7-90 325i,it is still intermediate,it does run for the most part.
Does your car have a noid signal to the injectors.{noid being a signal from the comp. to injectors}
Mine has no noid but has good spark and good signal from the crank sensor. The crank sensor on this one is on the front does it have another on the flywheel?
We may have the opposite problem?
You with no ignition and me with no noid???
Thanks for any help

Message was edited by: streatleathul

M3bob

Posts: 23
Registered: 05/08/06
Re: 1986 325e no start
Posted: Jul 6, 2006 10:47 PM   in response to: streatleathul in response to: streatleathul
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Thanks for the help all. It was the obc relay. For those who don't know the obc has a code feature which when set can cut the power to the main relay. It also can cut power if the circutry in the obc fails or the obc relay fails. One other point, the cars dme also will kill the ignition if the steering wheel is not installed. So if you have removed it to get to the ignition switch or some other testing don't expect the engine to start. Something I found on my car that is not in the bentley manual is that the negative (1) side of the coil goes to pin #1 of my 027 DME and is used as a low voltage gound by the DME to fire the coil. Also the DME's pin 18 and 35 receive power for the DME from the center 87 terminal of the main relay. So the power path is Ignition switch to obc relay to main relay which kicks battery voltage to the DME which fires the coil and fuel injectors based on timing from the position sensor and speed sensor. Thanks again.
streatleathul

Posts: 2
Registered: 07/05/06
Re: 1986 325e no start
Posted: Jul 7, 2006 10:34 PM   in response to: M3bob in response to: M3bob
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Hey thats great ,I replaced the main relay in mine today and its started every time so far!!!
karmaking

Posts: 9
Registered: 04/28/07
Re: 1986 325e no start
Posted: Apr 28, 2007 12:39 AM   in response to: streatleathul in response to: streatleathul
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Hello,I read your posts.I just recently have purchased a 11/86 325 e.I have i think the same exact problems that you did with the no start situation.I have so far been reading from bently and your posts and looking,searching posts etc and yours has sounded like what i have for a problem.This is my first bmw and i love it.BUT I am not a wire fixer man YET>?!!I want to fix this car that the local @#$%head mechanic could not figure out from a lack of not trying i believe.This is my first post to a forum and i really want to get this bmw running again.Your posts are very informative and i belive self explanatory but i might need a little coaching if you would help me out I would be very grateful and i also look forward to being an active forum user etc..I am going to buy or borrow a correct ohm meter volt meter etc with the high impedence or what ever it is called tomorrow and i am going to give it a try.I have learned a lot so far and i have a beautiful rust free car that is just waiting for my tlc..OI hope that i can get her running probably ??? with your help or some others that are on this forum.I will get in to more detail tomorrow on what diagnostics i have done so far etc..I can tell u that the coil is okay and i have a spare brain but i am not sure where the obc relay is?Is it the rectangular silver box that is up under my left knee when sitting in car?I have a spare one of those also.But some one did a hack job of putting in a kenwood stereo alarm and a over anxious helper of mine went and tore it out w/out my consent so i have been trying to keep my patience and i am ready.I hope that i get a post from you or someone it will make my day as i am very involved mentally in fixing and learning,diagnosing this car wuth minimal exprience.I am a carpenter,fisherman,medial technician,with a pretty good iq so i think i can get thru this one.I will post some pics of the ol' beauty soon as i am becoming computer literate.I am from the old school of technology.I have a 84 cj 7 i restored and many other muscle cars over they years.My f/inlaw turned me on to the e 30's as of 2 months ago.He is in his 60's and has a nice 84 318 i that he loves and is proud of and he understands the cars pretty well but he is color blind and to be honest w/you he is the one that pulled out the kenwood alarm w/out my permission because"he didnt't like the looks of it."But i cant condemn him because he was trying to help but i must admit it has been a little traumatic for me as you very welll know i bet after reading what you went thru for diag, work on your car.The coil is okay,both sensors are new,new rotor,cap,plugs,wires.I had it running but he went for a test ride after the alarm deal and it has only gotten spark like twice since two moths ago.I am going to check for power in the main relay tomorrow and hopefully fig out how to check pins 18+35???But i must admit i am a little lost in that area but i am keeping a good positive attitude that with my new freinds opn bntlypblshrs website that we can together get this cream puff of a car some spark again.I will be very happy and i am sorry to pour out all of this stuff to the world tonite but i am a little lost in this deal and w/little hands on exp so far it is a little intimidating but luckily the old man in law has found a good donor car in the area.Also if any body is interested i am parting out my 1984 volvo 850 t wagon with brand new never used d+sltd rotors,ceramic pads,new starter,i also have 2 complete front light grille qassmblies and 4 front doors 6 rear doors 8 turbo rims and the list goes ona nd on and i have finnaly gven up on the volvo to switch to bmw as the e 30's seem much more user freindly to me.More like the old school abd very eadsy to get your hands into tight areas that the t 5 wagon.If anyone wants to call me tomorrow and check in on my nightmare please ffeel free to call and ask for john in maine coast usa 207-633-3619.Thanks for your time reading this essay!!Report etc.Bye for now and oi look foreward to making some new freinds and or aqtcs on here.Over and out.
John Karmaking coastal maine
karmaking

Posts: 9
Registered: 04/28/07
Re: 1986 325e no start
Posted: Sep 12, 2007 5:45 AM   in response to: karmaking in response to: karmaking
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Hello,
I am getting ready to try again to get spark to the old 86 325 e.But i forgot where the obc relay is.I am ordering a new main relay today and alsothe other auxillary panel relays.My father in law took the bentley manual so i need to purchase another one.Any help on where to start will be very helpful
bearing01

Posts: 228
Registered: 05/24/04
Re: 1986 325e no start
Posted: Sep 12, 2007 9:24 PM   in response to: karmaking in response to: karmaking
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It's under the drivers side dash
aviator69

Posts: 1
Registered: 04/22/14
Re: 1986 325e no start
Posted: Apr 22, 2014 12:45 PM   in response to: M3bob in response to: M3bob
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I'm looking at an 86 e30 that also has a similar starting issue... it cranks strongly but does not fire.
The vacuum lines are broken at the triple connection point behind the manifold which could be part of it but I also noticed in the cabin that the OBC display is dead and has a pin hole in it... if the OBC is non functional would that lead to a crank but no fire condition?

I picked up a replacement OBC but installing it to test before I actually own this car would be too much like work lol... IK buying a non functional car yada yada but the price is really right and everything else body wise is great...

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