Starter or ground strap?

[GrauM3]

im having a very specific problem with my e92 M3.

The car starts perfectly fine on mornings where the temperature is above 45°F, after sitting all night. On cold mornings is where i seem to have the issues.

The car does not even attempt to start if it is too cold in the morning. But once it starts it has no problem starting for the rest of the day no matter how cold it is. Im leaning towards the solenoid in the starter going bad but someone had suggested the ground strap as a potential culprit as the metal can expand and contract in different temperatures, possibly moving the connection. I just had the strap mentioned to me and have not had a chance to look at the condition of the strap just yet.

Just trying to see if anyone else has had a similar problems and could offer any solutions.

Thanks!

[pbonsalb]

One is really easy to test.

[TX]

Since you mentioned temperature, I would check the battery. If it's a cold morning and your battery is on the edge it might throw in the towel.

[DanMpower]

Originally Posted by GrauM3

im having a very specific problem with my e92 M3.

The car starts perfectly fine on mornings where the temperature is above 45°F, after sitting all night. On cold mornings is where i seem to have the issues.

The car does not even attempt to start if it is too cold in the morning. But once it starts it has no problem starting for the rest of the day no matter how cold it is. Im leaning towards the solenoid in the starter going bad but someone had suggested the ground strap as a potential culprit as the metal can expand and contract in different temperatures, possibly moving the connection. I just had the strap mentioned to me and have not had a chance to look at the condition of the strap just yet.

Just trying to see if anyone else has had a similar problems and could offer any solutions.

Thanks!

Put a trickle charger on the battery on those cold days, go out and try to start it in the cold morning. If it fires up perfectly, it's your battery.

[pbonsalb]

Use a jumper cable only as a 2nd ground and see if that helps the cold start.

[Idfkman]

Originally Posted by GrauM3

im having a very specific problem with my e92 M3.

The car starts perfectly fine on mornings where the temperature is above 45°F, after sitting all night. On cold mornings is where i seem to have the issues.

The car does not even attempt to start if it is too cold in the morning. But once it starts it has no problem starting for the rest of the day no matter how cold it is. Im leaning towards the solenoid in the starter going bad but someone had suggested the ground strap as a potential culprit as the metal can expand and contract in different temperatures, possibly moving the connection. I just had the strap mentioned to me and have not had a chance to look at the condition of the strap just yet.

Just trying to see if anyone else has had a similar problems and could offer any solutions.

Thanks!

Ever find a solution to this? Having a similar issue.

Here’s an example:
https://share.icloud.com/photos/07ac0ndVDOFNLgevicnt1z7wA#Laurel

[Scrippy]

Originally Posted by pbonsalb

One is really easy to test.

Which one is that? Weird that you say that and offer him zero insight.

[JPSurratt2005]

I've replaced my ground strap and still had the cold weather issue, and a few warm days as well.

[Redd]

Can anyone tell me the length of the ground strap, connector to connector?

[Idfkman]

Originally Posted by Redd

Can anyone tell me the length of the ground strap, connector to connector?

Here are the part numbers for the ground cables

At starter - 12427840580

At exhaust - 12427840591

Full kit - 12427840580KT

[Redd]

Originally Posted by Idfkman

Here are the part numbers for the ground cables

At starter - 12427840580

At exhaust - 12427840591

Full kit - 12427840580KT

Yeah no one keeps stock of these here. So I was looking for generic, that's why need the length.

[pjk380]

I picked up the ground strap, the one at the exhaust and have not installed it just yet. It measures 11 5/8" from center of the bolt hole to bolt hole.

[Redd]

Originally Posted by pjk380

I picked up the ground strap, the one at the exhaust and have not installed it just yet. It measures 11 5/8" from center of the bolt hole to bolt hole.

Thanks!

[pbonsalb]

Originally Posted by Scrippy

Which one is that? Weird that you say that and offer him zero insight.

But I have offered the insight (see post #5). Test the engine ground. All you need is a set of jumper cables. Use one or both sides as ground cables. Block to chassis. Then try starting.

Easy to rule the ground in or out. Then move to battery/alternator since they are next easiest to test. Then to starter.

You can just make a replacement ground if you have the supplies. If not, measure and find an off the shelf part with the correct bolt hole size or terminals with enough meat to drill out larger. Or buy BMW's perfect fit ground.

There are also grounds at the tail pipes that are often rotten out that are probably there for a reason on these cars. There may be grounds at the hood hinges -- I cannot recall since I moved on to another car last year and am in the process of forgetting E90M3 tech and learning another car tech. I am just a DIYer and am best at remembering the cars I have.

[AirborneFF]

I was having the same symptoms. Long crank, battery was reading 12.7 v. The battery and alternator are both less than 3 years old. I had a track day recently where my TCS was very intrusive. When I got back to the paddock the yellow brake light, brake symbol and exclamation point were all on. I got under the car to take a look at the ground strap under the engine. It was completely green. It was NOT degrading in any way with slight twisting and inspection. It was very loose. I tightened it up with a 13mm wrench. The long crank was gone!. TCS acted normal. No more issues.

Fix: Try the extra ground test. If it starts fine or better check the ground strap.

[Honda]

Originally Posted by AirborneFF

I was having the same symptoms. Long crank, battery was reading 12.7 v. The battery and alternator are both less than 3 years old. I had a track day recently where my TCS was very intrusive. When I got back to the paddock the yellow brake light, brake symbol and exclamation point were all on. I got under the car to take a look at the ground strap under the engine. It was completely green. It was NOT degrading in any way with slight twisting and inspection. It was very loose. I tightened it up with a 13mm wrench. The long crank was gone!. TCS acted normal. No more issues.

Fix: Try the extra ground test. If it starts fine or better check the ground strap.

What is the extra ground test?