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Discussion Starter · #1 ·
Hey all,

I got my OBD2 cabe from http://www.obd-2.com the other day and twice now I think it may have caused a starting issue with the car. Allow me to explain.

I hook the cable up to the car and check if there are any fault codes stored in the system (none are found) and remove the cable, then close the flap. Now I cannot start the car.

It will crank fine, but rather than raise to the 1,100 or so then equalise at the approx 650 that it idles at, it will raise to about 700 or so, then stall. It sounds like there is no fuel getting to the engine. To fix this I remove the neg battery lead for 30 seconds or so then put it back on and all is well, the car starts like nothing has gone wrong.

I thought that this was an issolated incident, but we went out for tea tonight and upon getting back in the car some 2 hours later, it would not start, with the same problem as the OBD2 issue. So I remove and reconnect the battery and sure enough the car starts.

So when I get home I check the codes via my OBD2 cable and there are none stored, but now once again I cannot start the car. I am going to leave it in this 'state' overnight to see if it is something that time can fix, but I am leaning toward the OBD2 cable has done something 'funky' to the electronics???? surely this cannot be the case?

This is the 4th time it has happened in the space of a week, two from OBD2 cable installation and twice just randomly.

Its not a battery issue as I have had a new BMW battery just installed and it certainly has enough charge.

It has me most perplexed as to what the problem could be. Has anyone experienced anything like this?

Any thoughts / suggestions?

Cheers,
Aaron
 

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This is a really weird error... I have been using the exact same type of OBD-II cable on several cars for a few years with no problems.

Just a thought: Have you checked that the lid on the round service connector in the engine room is on?

David
 

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Discussion Starter · #3 ·
Yep.... its tightly on.
 

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You reattach the OBDII socket cap under the dash?
I've never incountered this with my system.
I would contact them and ask for a replacement cable.
 

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Discussion Starter · #5 · (Edited)
It is re-attached yes .... If It happened only after using the cable then I would say for sure it is, but its the two times that it has not happened while using the cable that has me perplexed, and what removing and reconnecting the battery does to fix it.

What does removing and replacing the battery actually do? I know you lose your time/date, trip computer and seat memory. does an actual 'reset' of the ECU actually occur, or is that achieved another way.

My friend @ BMW is taking the car late this week anyway, to re-init the rain sensor so he will have a look at it then, but being such a sporatic and un-reproducable problem it is going to be hard to find, especially given that no fault codes are being stored.

-=Update=-

It happened again just before and this time I locked the car, then unlocked it and it started ok, so now im thinking perhaps an imobiliser / alarm issue? If that is true though I wonder why it starts then dies?
 

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It could be as simple as a battery problem.

If you go to the test-modes on the instrument cluster (same as is used for fuel-flow measurements) and then go to the test for battery voltage, and observe this voltage during starter operation you will know how deep the battery voltage drops. If this is below 8V or so, I think you might get problems with some of the electronics in the car.

If this is the case, the fix may be as simple as getting a new battery.

David
 

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Discussion Starter · #7 ·
Thought of that ... BMW installed a new battery, during cranking the battery drops to about 12.1.
 

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aaronmiles said:
Thought of that ... BMW installed a new battery, during cranking the battery drops to about 12.1.
Well, that rules the battery out as the source of the problem.

The only two things I can think of that has changed are the O2 sensors and the OBD-II scantool. But still, the whole thing could be coincidental.

Will be most interesting to see what the BMW service computer finds.

David
 

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Sorry I just used the link to the OBD-II and see its different from my system, which is OBDII.com(Ease system).
 

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Discussion Starter · #10 ·
Just an update on my problem.

Car went to BMW yesterday. They got the problem to occur only once and have been working on it ever since.

They tried to program the DME 4 times yesterday and it would fail 1/2 way through every time then threw an "Internal Error" code and was 'dead in the water', so the car was then VOR.

They let the car sit overnight and this morning it actually accepted the updated program.

The program that was in the car was out of date, and I was told there was a campaign on the MSS-52 software that I was running with all sorts of non-starting, idle problem, cutout at lights sort of issues which I hope fixes my problem.

If they had to replace the ECU, it would have to come from Germany and my friends 'buy price' was AUD$1700 so I would think RRP would easily be > AUD$2500

Will continue to update.
Cheers,
Aaron
 
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