Sometimes no crank no fire

[Car Addict]

Good afternoon gentlemen,

This is gonna be a long one so grab some popcorn. :popcorn:

As some of you know others may not I have been a LONG time member on here and have owned 3 classic bmws and currently own 1 which I have had for a little over 11 years now. Enough about me onto why I request your knowledge.

About 4 years ago my 1991 318is started developing an odd issue where every once in a while the car would crank over then stop, crank then stop, and finally usually the third time it would crank and fire and run fine. This happened for just about 5 months until it finally decided to not crank anymore. When this happened I figured that the battery just died and i needed a new one. so off i went to get a new battery and all was well, or so i thought. I drove it for another month then stored it for the winter by taking the new battery out of it and leaving it on a battery tender all winter.

Come spring time popped the battery in and VROOM started like a champ.."Great all my problems are behind me".

Fast forward 2 months and the same issue starts arising vehicle wont start first time and eventually wont crank at all. However this time I check the battery and have full voltage and amperage is fine so i figure it must be the starter. Order a "new", rebuilt, starter and while removing the old one discover that the brass bushing at the end of the starter wheel that guides the wheel onto the flywheel is completely missing on the old one. So i figured that was another issue and put the new starter in and off i go.

A month later check my volt meter while driving discover i am only getting at most 13.1V from the alternator so i replace that with the assumption it is bad. keep driving and all seems good voltage while driving is between 13.5V and 14.2V.

Near the end of that season about a year ago now it develops a new symptom every once in a while the car when you sit in to start it you will turn the Key and NOTHING, not even a click from the starter.

Now for the odd part, I go to check the voltage at the battery and it shows 12.6V. when the key is turned to accesories or on everything in the car works fine. Figure it must be a dead cell in the battery so i get it jumped by a friend and it fires up fine and drives fine. Bring the car to my house pull the battery, test it with a load tester test just as good as a brand new battery.

SAID FUCK it put it away for the winter and took it out in the spring again this year and had NO ISSUES, until this week.

Get in the car after work turn the key and nothing. Accesories still work fine but nothing when trying to crank.

However, just now when a friend jumped it for me I tried to drive off and the Car began to BUCK LIKE A BASTARD, with the ABS light flashing came to a stop and all was fine, started driving again and BUCKED again, let it run for 25 minutes with me holding it at 2000 RPM to get the battery charged by the new alternator, shut it off and again NOTHING no crank.

Please someone help I am very quickly running out of ideas on where to go next to diagnose this vehicle

Thanks In Advance

-Car addict

[uturn]

Ignition switch? I lug my engine sometimes when I forget to take it out of gear and let off on the clutch when I park. I think the engine cutting off is the cause of your bucking so it's possibly a symptom of your other issue.

[ahlem]

I'd clean the grounds and connections between the alternator and starter just because it's cheap insurance.
Do you have the little plug connected in the wiring loom by the battery tray area on the firewall perhaps?
Check the relays to see if something is amiss there that is interrupting your electrical supply to your critical components. Check the area around the starter solenoid to be sure none of the wires is close to a ground and may be arcing out.
You may have a fuel supply related issue.

[Car Addict]

^Thanks for the response
the little connector in the wire loom is disconnected.
will check relays once i am able to actually look at the car again should be this coming week.
The starter solenoid idea makes the most sense to me the only weird part of that is the engine starting and stopping while moving. Weirder things have happened so I will check that also.

As far as a Fuel supply issue i have good pressure at at the fuel rail so unless my injectors are totally fucked. I find that hard to believe since before this week it would run fine.

any other ideas please let me know

[dnguyen1963]

smoke test, baby...if your car is bucking like a wild mustang.

[Car Addict]

I really need to get better at answering my posts when I finally figure out what went wrong. Anyways

Positive battery cable.

More precisely the positive battery cable connector where it attaches to the battery mine had somehow developed a small crack which got larger and larger, eventually this caused the battery to have such a problem flowing the required power into the cable it jumped and grounded itself out, causing the issue of it not working until i clamped jumper cables to either the other end of the Positive cable in the engine bay or the actual wire in the trunk.

long story short if you are having the same issue thoroughly inspect your battery cables.