Hi all, I picked it up this morning and the guy said he was told by a mechanic that it needed a new alternator. Ok no problem. Later a friend looked at it and did a few things and said it might be the coil. So Im asking you guys for input on which way to go first.
it does turn over, no clicking..just will not start.
The guy I got it from said it started 2 days ago and now it won't. I have all of the service records from 1984 to just 40 miles ago when the oil was changed.


Thanks

528e or 533i?
stick or auto?

You're going have to test stuff to narrow it down. Are you getting fuel? In the correct pressure? Are you getting spark? AFM plugged in ssecurely?

With any e28, first thing to do is check, clean (better yet replace), and retension the fuses. Clean up your engine grounds also. Battery terminals clean and tight, cables not internally corroded?

Automatic. I planned on giving it a good cleaning and replacing fuses just to do it. It's getting fuel ok. The coil is getting a spark in but not out giving me the idea it's the coil and my friend (mechanic for 30+ years believes that is a major possibility. AFM is fine. I don't think it's the alternator like the guy said. Haven't had time to mess with it much today, but i'll be playing around testing stuff as I can.

thanks

528e or 533i?
stick or auto?

You're going have to test stuff to narrow it down. Are you getting fuel? In the correct pressure? Are you getting spark? AFM plugged in ssecurely?

With any e28, first thing to do is check, clean (better yet replace), and retension the fuses. Clean up your engine grounds also. Battery terminals clean and tight, cables not internally corroded?

Alternator will have nothing to do with no start issue.

Thanks, thats what we thought.

Alternator will have nothing to do with no start issue.

Creepy..Im being watched in my area. Ok, now maybe sensors are the issue. It started 2 days ago and now it won't when I looked at it before I got it. So getting closer...

Any other possibility? Im making a list and going to check it off one at a time.

It could be several things. Check all of the relays, espcially the main relay and the fuel pump relay. Also a bad flywheel reference sensor (there are two but it only takes one to be bad) will cause a crank-but-no-start condition. Also, a fualty ecu, ususally due to a bad solder trace on the board, will cause this condition.

Thanks, those are on my list of things that my friend gave me. I'll be getting into it tomorrow and maybe I'll get lucky and solve this issue.

Well, it's running. Went to haul it to another site and it started right up. Got it to the new location and it started again. Maybe a short somewhere? Bad sensor?
The gas smelled odd and hasn't been sitting that long from the time the guy stopped driving it and when I bought it.
Maybe I'll know more tomorrow.

I guess it's the ignition coil. I checked everything I could think of and no problems found. At first it would die when you went a few yards and pressed the gas a bit harder. Toyed with it again, hooked the original antenna up, connecting all lose wires that were not connected to the new one and it stayed running. After driving it back and forth on the road a bit, it shut off and wouldn't start. The coil was very hot at that point. After the coil cooled down it started right up and drove like it should.

Sound like the problem to you guy?

Found the problem. A loose sensor wire. All is good now.

thanks for the help.

Glad you found the problem!

Ive had the same issue for 6 months, and no dice for me, good yours worked out better. (thanks god i have a work vehicle.)

Yeah I got lucky I guess. But good luck comes and goes. Last night the fuel pump went out.

Found the problem. A loose sensor wire. All is good now.

thanks for the help.
just out of curiousity which sensor wire was loose?

just out of curiousity which sensor wire was loose?


It was a small blue wire connected to the side of the battery. Not sure which sensor it was, but it it fixed the issue.

A small blue wire connected to the side of the battery? I certainly can't figure that out, particularly if you call it a sensor wire (maybe it's the coil ground?).

However, the most common "weird no start, or in-use dying" issues with these cars are the crankshaft sensors, and their crumbling plastic connectors.

Also, if it's been raining, the dme can get wet through leaks in the windshield. As long as the problem stays gone, don't worry; if it returns, look at these items.

535isCO, suggest you try these, and advise whether you have spark and fuel when the problem occurs.

I have an m30 that will turn over and even with starting fluid not start. I am assuming everyone is right and it is the flywheel position or crank sensor. Is there a way to by pass or test this before I shell out the money and wait for parts only to have them be wrong?

I have an m30 that will turn over and even with starting fluid not start. I am assuming everyone is right and it is the flywheel position or crank sensor. Is there a way to by pass or test this before I shell out the money and wait for parts only to have them be wrong?

You can ohm out the sensors if you have the bentley. I'll scan a page for you if you don't.

You can ohm out the sensors if you have the bentley. I'll scan a page for you if you don't.

That would be sweet if you could, I have a bentley for my e34 m60 and e32 m70, m30, m40 but the e28 manual has not made its way to me yet. Both cars are newly acquired. Seem to be great deals so far. :eyecrazy

Coil is getting spark in, not out? What does that mean. Does it have power in, and does it get the ground, which is the signal to fire, from the dme? If there is no ground signal coming from the dme, the coil is fine, and the dme isn't trying to fire it!

Larse, do you have spark? If you have spark, it's not the sensors.

negative on spark. I am pulling the cap and rotor to check the button.

First things I'd check, then, are the flywheel sensor plugs. Likely, the plastic plugs at rear top of engine have crumbled, and a connector isn't making contact. Not that it hurts to check the rotor, but if the coil isn't receiving the fire signal ( a ground) from the dme, the problem is happening BEFORE the distributor. If you can, check whether the coil is receiving the timed ground signal while you're cranking. If it's not, you can ignore EVERYTHING else, and we'll trace why not...

First things I'd check, then, are the flywheel sensor plugs. Likely, the plastic plugs at rear top of engine have crumbled, and a connector isn't making contact. Not that it hurts to check the rotor, but if the coil isn't receiving the fire signal ( a ground) from the dme, the problem is happening BEFORE the distributor. If you can, check whether the coil is receiving the timed ground signal while you're cranking. If it's not, you can ignore EVERYTHING else, and we'll trace why not...

I ordered and replaced both sensors to the flywheel. I still seem to have no spark. I will have to wait until tonight to see if I can get someone to turn it over while I pull a plug and recheck for spark. It may be a multi part issue. The guy I bought it from told me it the car as it was, but after looking under the dash, I see alot (5) of jumpered wires. one of them is the OBC, which I have heard can be a problem but there is some other stuff that does not look right to me. Also they have the OBC and light check controls unplugged? If you turn the key to off the check bulb center stays lit. Needless to say I unplugged it again but why would they do that?

Probably they disconnected it because they couldn't get rid of the brake light circuit warning. Either way, that's not your no start problem. You need to see whether the coil is receiving the ground which tells it when to fire. If not, and the wire is intact, the dme is missing something it needs. Do you have fuel pressure and injector pulse?

Please note that if you accidentally swapped the two sensor plugs, the same symptom will prevail. But if the main relay is bad, you'll also get no spark (or fuel, or injector pulse).. Test first, then throw parts.

How handy! I'm having starting trouble with my 1983 533i 5 speed. It ran fine last wednesday, then I tried to start it yesterday morning- it cranked, then acted like it was starting, so I backed off the key, and it croaked. Hasn't started since. I started trouble shooting this evening. After cranking, I smell raw gas at the exhaust tips. The ECU was pulled and renovated by a firm in Florida about 4 weeks ago. I bought the car from a friend of mine, and he wanted the computer gone through before I got it because the car had died on the highway on him twice. Both times he had to let the car sit for about 15 minutes before it restarted. Then with a big puff of black smoke out the tail. The coil was replaced about three months ago with a new Spanish made Bosch unit. I measured the coil ohms- it is within spec across the poss & neg, but it measures 7030 ohms from the poss to the output. (The Bentley book shows 6000 ohms max.) I don't know whether this is a real issue or a red herring. The flywheel sensors measure within spec, but the reference one broke nicely at the connector. I pushed it back together and it seems to be holding. Since getting the car, I've felt it has taken longer than it should to crank over. (Average of 8+ seconds of cranking for a cold start). Oh, well. I'm learning...

Probably they disconnected it because they couldn't get rid of the brake light circuit warning. Either way, that's not your no start problem. You need to see whether the coil is receiving the ground which tells it when to fire. If not, and the wire is intact, the dme is missing something it needs. Do you have fuel pressure and injector pulse?

Please note that if you accidentally swapped the two sensor plugs, the same symptom will prevail. But if the main relay is bad, you'll also get no spark (or fuel, or injector pulse).. Test first, then throw parts.

How can I check that? I used a test light while it was being turned over and got nothing. When I turn my 535 over the light functions.

Forget the OBC, it's only the problem if a "CODE" has been set by the owner to prevent starting. It does happen.

Did you replace the sensors one at a time? They MUST be connected to the correct hole.

And check coil ground/fire signal, and for injector pulse; if you have neither, the dme isn't trying to start the car..

Forget the OBC, it's only the problem if a "CODE" has been set by the owner to prevent starting. It does happen.

Did you replace the sensors one at a time? They MUST be connected to the correct hole.

And check coil ground/fire signal, and for injector pulse; if you have neither, the dme isn't trying to start the car..

Is there anyway to bypass the DME To test fire the car or can I jumper the coil to start it?