Mechanics

ELECTRIC PROBLEM

1998 BMW 740 • 130,000 miles

I have a 98 BMW 740i, Recently my wife left her lights on and her card Died, I jump started her car using my BMW I hooked both batteries with my car running and told her to start her car, he car started but then mine started to smell like burnt cable, and after a few seconds I saw smoke coming from the engine I checked and I saw that the thermostat sensor had melted, after that the car stopped working and would start but die right away, I changed the thermostat, and the car started, so I thought the problem was solved, but after turning it off and trying to start it again, the car its still dying right after it starts, I don't know what it could be, any suggestions?
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Franxua1
August 18, 2012.



Check for blown fuses. Have the alternator and charging tested.

KHLow2008
Aug 18, 2012.
Ok I will try this tomorrow and I'll let you know thanks.

Tiny
Franxua1
Aug 18, 2012.
Any update on this?

KHLow2008
Aug 21, 2012.
Not yet, I have been really busy at work seems like I'll be off on Friday that's when I'll check the car and let you know. Thanks.

Tiny
Franxua1
Aug 21, 2012.
So I checked the car and the fuses are all ok. Also the alternator it's fine. Any other suggestions on what it could be one thing I noticed its that once the car starts if I step on the gas it will die instantly.(Once I start it it will stay running for a couple of seconds)

Tiny
Franxua1
Aug 24, 2012.
Get a scan to check for trouble codes.

Yu mentioned the thermostat sensor melting and that can mean a poor ground circuit between engine and body.

KHLow2008
Aug 24, 2012.
I did, before changing the thermostat there was like 7 different codes, but after changing it, all codes went away.

Tiny
Franxua1
Aug 24, 2012.
You should have a look at the engine computer. The smoking when jump starting might have caused damage to it.

KHLow2008
Aug 24, 2012.
Ok so I unplugged the sensor cable from the thermostat and started the car and it started and was actually running nicely, but after I plugged back the car shut off again, what could that mean!

Tiny
Franxua1
Aug 24, 2012.
You could have replaced the component with a faulty one or of the wrong specifications.

KHLow2008
Aug 25, 2012.
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