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E28 (1982 - 1988)

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Old 03-04-2018, 06:33 PM
Sluf2 Sluf2 is offline
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Location: Oregon
Join Date: Mar 2018
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Mein Auto: BMW 533i
Mysterious engine start problem

Hi fellow E28 lovers, I have had 3, my current BMW 5331 that I have had for 20+ years. I did a full Euro conversion and installed a glass roof. It's not my daily driver now but it gets used regular use. I have done all work to the car myself. About 2 years ago I got in, turned the key to start and nothing happened. Dah lights were working, AAA delivered it to a BMW independent BMW shop. They did a few things and it started. The next time it would not start was about 6 months later, this time I got a jump start and replaced the battery. The car performed flawlessly for about 6 months and then it would not turn over, everything else electrical worked. By that time I had a start box and it sprang to life. I don' work on the car any more but took it to a 30 year BMW only technician. He checked and cleaned all connections and I drove it for a while until it did it again. Back to the technician. This time we just threw parts at it, replaced ignition switch, some re and went over the entire electrical system. I used the jump box when ever it would not turn over. The only things left are the starter and alternator, I have purchased Bosch Remanufactured units. The last time it did it I connected the jump box as usual, I was shocked, it would not turn over. I called AAA and wile waiting for them I remembered there was a factory ground lug on the left fender well so I connected the negative lead of the start box to the ground lug and the positive lead from the jump box to the car's battery and presto it started. We are going to replace battery cables and install a new Interstate battery. I have read on several BMW boards about cars doing the same thing but there have not been follow ups on what they did to fix the problem. I would like to hear from anyone familiar with the problem and what the cure was.
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Old 03-05-2018, 12:05 AM
Solo1 Solo1 is offline
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Location: Winter Park, FL.
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Mein Auto: 1987 535i; 1998 528i; +
check the electrical signal from 2 reference sensors and flywheel. These dogged me over several years until properly diagnosed.

The man in the boat!
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Old 03-05-2018, 10:50 AM
Sluf2 Sluf2 is offline
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Location: Oregon
Join Date: Mar 2018
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Mein Auto: BMW 533i
Mysterious Engine Start

Thanks for your reply. I have a box of parts, my technician put replaced items in baggies, I have a boat load. I checked the box and the removed sensors were there. We have done everything except change out the battery and engine grounds, I did install a BMW transport harness which can disconnect the negative terminal of the battery so the cars do not go dead on the trip from Germany. The switch has been bullet proof since installed. Ground cables are NLA fo0r the E28 but I researched it and a ground cable for an 850 will work, it will be installed direct to the battery bypassing the kill switch.
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Old 03-06-2018, 11:38 AM
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catso catso is offline
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Mein Auto: 2000 323i, 1988 528e
Corroded electric terminals are a never ending problem with older cars, especially in places you can't see like under the wire or connector's insulation. Keep inspecting and correcting whatever suspect connections and terminals you find and you will probably eventually solve the problem.
Don't be gormless; get some gorm!
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Old 03-06-2018, 02:02 PM
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hornhospital hornhospital is offline
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Mein Auto: E24x2,E36x3,E30x2, F150
I think you've already found the problem, you just haven't addressed it yet. It's the engine ground. I had almost identical problems with my 633CSi (same basic chassis/electrical as the E28), and adding a ground cable from the negative battery post to the lower bolt on the starter cured it instantly. It was easier doing that than replacing the OEM engine ground cable (which is still in place).
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1993 325is M3 clone"Ashlyn"; 1993 325is "Elvira"; 1985 635CSi "Katja"; 1984 633CSi "Sylvia"; 1987 325is "Odette";1995 318is"Bebe "; 1985 325e "Hazel Ann"

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