1990 BMW 525i cold starts

Tiny
525IGIVEUP
  • MEMBER
  • 1990 BMW 525I
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 19,800 MILES
Bought this car 5 years ago with 87k and I love it. I pound out a lot of miles for a living and it has been extremely tight until last winter. It does not want to start under 25-30 degrees and I hesitate to pump the foot feed on a fuel injected engine for fear of flooding it out.
BMW mech. Says there is no "cold weather start" sensor on this model - so that's apparently out even if I coud find it. Suggestions/identification of related parts appreciated.
Yesterday (10 degrees actual temp) I finally got it running by holding the foot feed halfway down and using jumper cables. It ran rough and I assumed that I had gotten a plug wet with too much fuel. I let it run for 20 minutes and shut it off for an hour. Once it starts it'll restart the rest of the day. It restarted just like clockwork but still ran rough - and I am showing a "low coolant temp" light that has never appeared in the last 110k. Coolant temp light on initial start not the restart.
HELP NEEDED - and don't worry about hurting my feelings. I never claimed to be a mechanic, but R&Ring parts doesn't scare me - as long as I know I have the right part in the first place; guessing with these things gets expensive in a hurry
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Wednesday, January 6th, 2010 AT 5:16 AM

8 Replies

Tiny
SERVICE WRITER
  • EXPERT
IS this a case of it cranking at a normal speed and not starting?

OR is it turning over (cranking) slowly?
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Thursday, January 7th, 2010 AT 5:19 AM
Tiny
525IGIVEUP
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Normal speed
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Thursday, January 7th, 2010 AT 1:15 PM
Tiny
SERVICE WRITER
  • EXPERT
Okay so a jumper cable will make no difference unless you run it down.

We need to find if this is a loss of spark or fuel first to get a direction to go in.

When it is cold, spray some ether or carb cleaner into the throttlebody and then crank it. Does it start?

If it does fire we are on track for a lack of fuel path.
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Thursday, January 7th, 2010 AT 7:25 PM
Tiny
525IGIVEUP
  • MEMBER
It's been in the single digits here for about a week and I have not messed with it since I last jumped it. The temps will be up next week and I will be more inclined to "play" mechanic. I am leaning toward a spark/fuel problem also and have the ether on hand to see what happens.
I let it run the other day for about 20 minutes because once it starts it will light the rest of the day. I changed out the plugs last year due to this same situation and it lit right up. I put in the high dollar multi-electrode plugs but that doesn't mean they're still all good. It ran really rough, but it ran the other day. I stopped there before I really screwed it up. I will pick up some new plugs in the event I have fouled out one or more by putting too much fuel in to try to start it.
I am by no means a mechanic but I have pulled and rebuilt motors before - but that was forty years ago. I am totally at a loss with the new fuel injection configurations (mechanical, electronic, combos). I may have a bad injector but I don't know how to test them or if I even can on my own. My economic situation has changed also with the "new" economy and that puts the BMW dealer out of the equation.
I will get back with you next week and probably make more sense by then. For now I really appreciate the moral support and having someone with some sense to point me in the right direction. We bought this car in '05 with 87k on it. I have put 110k on it with no problems, I do my own oil changes. Beyond that I have neglected what would be considered preventive maintenance because it has always ran strong and been really dependable. But it's been rode hard and put away wet once too often and it's time to pay the piper. I was planning to put some money into it this spring (run the valves, etc.) With a BMW mechanic on his own time when I lined one up with the friend I bought this from. I obviously didn't make it to spring. So let me get into some weather that isn't so brutal - no garage, and I will have more info/questions. Thanks again right now for just "being there".
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Saturday, January 9th, 2010 AT 2:10 PM
Tiny
SERVICE WRITER
  • EXPERT
I would definitely get caught up on the maintenance first. Cap, rotor, wires, fuel filter for sure.

I would stay away from the multi-electroded plugs. Bosch split fires have created there share of problems.
I would go toward either NGK or Autolite myself.

Wouldn't be surprised if that alone got you back running.
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Saturday, January 9th, 2010 AT 3:27 PM
Tiny
525IGIVEUP
  • MEMBER
Thanks for the heads up on the multi-electrode plugs - I'll snatch them out of my scooters also now. I will get the suggested maint. Issues taken care of. How much of a pain is it to adjust the valves also - I understand BMW is famous for special tools. I've got one ticking and don't need it coming through the valve cover. Did that once on a 327/365hp with solids and it cracked a finned set of aluminum Corvette valve covers. And we all know what those are worth these days. That motor was in my first car '62 Impala SS that I gave $125.00 for in 1967 'cause the motor was locked up - would only turn a little either way. Turned out that one of the oil plugs across the back of the block had worked it's way out and was in one of the holes in the flywheel. The cars I should have kept Adjusting those valves with oil shooting out over the fenders was a pain in the @$$ though. They either didn't have the little covers for the rockers at the time - or I didn't know about them. My money is on the latter scenario.
Thanks gentlemen, I appreciate it.
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Sunday, January 10th, 2010 AT 11:19 AM
Tiny
SERVICE WRITER
  • EXPERT
I haven't dealt wioth the valves persopnally, but I did alert the BMW specialist here to your post.
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Monday, January 11th, 2010 AT 7:39 AM
Tiny
DR. HAGERTY
  • MEMBER
That model(and others with the M-20 motor) have a problem with the wiring connector under the throttle body, down low up next to the block. It is round and black, about an inch and a half in diameter. Take it loose and inspect the connections and see if that does anything, I will be here if you need me. And Service Writer has given you the exact advice I would have, to the letter. This is just a model sensitive issue.
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Monday, January 11th, 2010 AT 8:34 AM

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