Bentley Publishers - Technical Discussions : 735i not starting ...

Charlie

Posts: 4,669
Registered: 12/09/03

Re: 735i not starting
Posted: Aug 17, 2004 8:57 AM

in response to: BeemerWguy

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Coil primary res. 1 (–) and 15

0.50 ohms

Coil secondary res. 15

and 4 (center tower) 6000 ohms

hookipa

Posts: 3
Registered: 02/08/07

Re: 735i not starting
Posted: Mar 1, 2007 9:24 AM

in response to: Charlie

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It cranks and cranks,,,I would like to go to the fuel relay first...where is it located?

Thanks Kyle

kwirth@relogistechs.com

mpo702

Posts: 3
Registered: 04/20/07

Re: 735i not starting
Posted: Apr 20, 2007 12:56 PM

in response to: pmm

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I am also having the same no spark problem, I have a 1986 735i and it was fine until one day I hit a good bump in the road and then it stalled, I was able to start it and get home. The next day there was no spark; I went to the pic a parts and changed all the relays in the engine compartment with no luck until I changed the one on the firewall on the passenger’s side, it ran for about a week then had the same problem. Here is the kicker, I own two of the same exact model cars, so I figured I would switch the relays from one to the other, no luck, but the other car runs great after the switch, I even switched out the ECU with a certified good one, still nothing (note: the ECU worked in the running car). I was told it could be a bad earthen ground connection, but I have cleaned and tightened every connection I could find, I did see a posting about a relay around the bell housing I may have missed, but I must be blind since I do not see one… Can someone help me on this? Finding a book for this is a pain in the butt, I have a CD set from BMW but it offers no help.
If someone has the book for a 1986 735i in PDF, or a electrical diagram in pdf, I would really appreciate it if you could email it to me at mpo702@yahoo.com.
Thanks,
Mike

Message was edited by: mpo702

smoot735i

Posts: 1
Registered: 04/25/07

Re: 735i not starting
Posted: Apr 25, 2007 11:10 AM

in response to: mpo702

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my situation is the same as everyone elses', no spark but coil is good, ect. the problem is the relay located under the panel that covers the driver compartment wires under the steering wheel. the relay or relays are contained in a plastic box screwed to this cover, 2 wire connectors plug into this device. the problem is the relay under the plastic cover is the one that sends power to the dme relay when the key is in the start mode. have spark now and going to get there.!!!

mpo702

Posts: 3
Registered: 04/20/07

Re: 735i not starting
Posted: Apr 25, 2007 6:11 PM

in response to: smoot735i

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Smoot,
You mean that black box, if so, dang thats the only thing I have not changed. So, if I get another box I should be good to go... I'll give that a shot. Thanks.

dlduke

Posts: 1
Registered: 08/24/09

Re: 735i not starting
Posted: Aug 24, 2009 9:07 PM

in response to: mpo702

Reply

I checked out the black box and re-soldered all suspect connections. There were two relays mounted on a circuit board: one small, one medium; Plugged it back in; nothing; took tiny pieces of plastic packaging and held the relays in "on" mode; A horn went off near the fire wall. I guess it is part of a burglar alarm. Could this actually be something that would keep the car from starting? I still don't have a spark good enough to start the car.*****Went to pull a part this afternoon and bought another "black box" off of an '86. Noticed that this car had three computers. one behind the left kick panel, one behind the right kick panel, and one above the glove box. Does the '85 also have three? I didn't think so, but I guess I'll find out tomorrow when I work on my car again. I'm guessing the one above the glove box is the engine computer. Tomorrow I will check out the switch that keeps the starter from turning over when the transmission is not in park or neutral. May have to bypass that one if it is bad. Not that my starter doesn't turn over; just that someone suggested that a bad ground from it may cause a no-spark situation.******Installed a used engine computer, a computer inside of the right kick plate, a couple of relays and another "black box". Still nothing. Not even getting any fire now. Guess a new speed sensor is in the plan soon. Forgot to mention that since I have fooled with the black box, I am getting a "check" light.

Message was edited by: dlduke
update

Message was edited by: dlduke