Hard to diagnose running problems - need to fix before Legends of the East!

[E9Wayne]

Hello Coupers, and Don/Chris, Sven, etc. it's been a long time since my last post because, honestly, my E9 has been running perfectly for so long now. But ever since her return from a movie opportunity over 2.5 months that I'll post up about early next year before its debut, she's been running terrible. It occurs when she's warm or cold and the ignition or fuel seems to cut out abruptly and sometimes restores itself -- but usually not and I have to restart. Specifically, she will stutter or stumble briefly with the tach cutting to zero and then return to normal about 5 or so seconds later; other times she cuts out entirely under steady throttle and I have to restart her at speed which might take 2 or 3 attempts...I originally had it towed in to the shop about 3 weeks ago as the intermittent cutting out was so bad I was fearful of making it to the shop.

My local shop replaced what they suspected was as a faulty crankshaft position sensor and fuel temperature sensor to start and it appeared to solve the issue. But they claim it came back getting the car ready to return to me and so they next looked at the ignition switch (per the advice of Chris at Don's shop). The switch was not in great shape and they eventually tried to replace it with a new unit I had Chris send to the shop, but that unit didn't work with my setup and so the mechic cleaned out and rebuilt my current switch...they claimed the car was running well after that, but I don't think their test drive was long enough.

I just returned from picking my car up and the first 20 minutes or so on the ride home she seemed like her old self. Then, the sputtered very briefly and returned to normal rpm. The next time it was a longer period of the power cutting out, the tach went to zero and she returned to cruising on her own, if I recall. I should have turned around and headed back to the mechanic at that point because, after that, she died more frequently and only a restart with 2 or 3 cranks would get her going.

After two experiences like this, it seems to arise after the car has been driven for 15 to 20 minutes, although my mechanic saids it started and then stalled when cold at last once. And it seems to get worse the longer I drive her which perhaps means a heating issue at a faulty relay?

Other background - my car got a new Megasquirt ECU in May along with fortified connectors, plug wires and spark plugs. Prior to that, a new distributor cap and rotor was installed. Prior to the movie scenes, she was really driving perfectly.

I'm going to try and drive her back to the shop today (and data log along the way for Chris/Don) as it's a work holiday for me and my local mechanic will do some more checks on the ignition and fuel delivery. I'l need to check with Don and Chris also to see what they think for next steps. I'm hoping it's a simple relay problem and I'll bring spare fuel pump and ECU relays with me when I go back to the shop.

I'm getting a little nervous now since Legends of the East is coming up soon and there's no way I can take my car in her current condition.

Thanks for any help on this very strange problem!

Wayne

 

[Stevehose]

How old is your ignition coil? I'd replace it. Are all connections at the coil clean and tight? I'm not sure with Megasquirt if you're still using a ballast resistor?

 

[E9Wayne]

Thanks Steve, it's original to the engine (2011) and I will check that out!

 

[E9Wayne]

My coil seems to be an E32/E34 part # and is numbered 2051.0171.100 BMW nr 1 720 166 2. Is this the best one to use or is another type recommended?

 

[Stevehose]

My coil seems to be an E32/E34 part # and is numbered 2051.0171.100 BMW nr 1 720 166 2. Is this the best one to use or is another type recommended?

that's an @sfdon question

 

[E9Wayne]

well guys, thanks to Steve's suggestion, we might have identified the problem. I checked my coil and the connections seemed secure. After removing it, though, I noticed two small hairline cracks (attached) in the bottom that run up each side almost symetrically. Chris' theory is that my coil might be arching from these cracks against the radiator support that's located close by. How did this happen? I think the movie studio had my car in accessory mode for prolonged periods waiting for shots and maybe the coil cracked from the pressure created by that situation and not delivering spark to the motor as it is supposed to do. This is my car's first and last movie, by the way. They say they take such great care but this situation and the rock quarry dust I had to remove from some many places is not worth what they pay you.

I'm going to install a new coil next per Chris/Don's suggestion and it likely won't be this same unit as you can only get them used now...

 

[adawil2002]

I had that same issue in 2012, Wayne. If you are running a Pertronix, it is most likely the problem, especially is you are running the original distributor, the curve is all out of whack & not advancing properly. That's what my overall issue was.

 

[sfdon]

good catch Wayne!

 

[Arde]

Movie stardom has ruined many lives .
Is the theory that in accessory mode you have DC through the coil and never the chance to rest between sparks?
The ignition switch should not energize the coil in position 1 I think.

 

[E9Wayne]

Thanks Arde, I think it was position 2 just before cranking but above the first click. The other thing that happens, apparently, in this position is the fuel pump dumps fuel into the cylinders…

 

[sfdon]

Sent you info on coil purchase

 

[E9Wayne]

thanks, Don and thanks again to Chris P and Steve Armstrong for helping figure this out... I found a good condition same part # coil off a 61K mile 735i for $45 which I will try first. Fingers crossed..

 

[Stevehose]

If this solves your problem I would start looking for an NOS one and keep the used one in the spare wheel well as a backup. Along with a spare fuel pump

 

[E9Wayne]

Thanks, Steve, Don has recommended some good options including a Bosch Ignition Coil 00120 at $49 and Facet Ignition Coil also. I think I'll order the Bosch as NOS doesn't appear available anymore with the above part #. My list of "in the trunk for road trip" parts is growing for sure - alternator voltage regulators, spare relays, bulbs, etc. And it doesn't include a fuel pump yet so I need to ask Don what I should get as he would likely need to build it up first - I'm running a 12 year old 318Ti fuel pump at the moment...

 

[sfdon]

Brand new -58.00

BMW Ignition Coil - Bosch 12131742925

BMW Ignition Coil - Bosch 12131742925

www.fcpeuro.com

 

[E9Wayne]

ok, folks, alas the new/old coil did not improve things. Prior to this, a new crankshaft position sensor and reworked ignition key switch were done. Within 15 minutes of driving this morning and data logging to send to Don and Chris, my car died about six times. What's weird is that, on some occasions, the car will start back up after 5 to 10 seconds on its own but other times it doesn't and I have to crank her over once or twice to light up. Each time, when she quits, the tach drops to zero and sometimes the dash lights come on but other times they don't. If I can't fix this locally (problem is beyond my local decent mechanic), I'll have to fly Chris Pederson out for a house call. Either way, things are not looking good for Legends East in about three weeks. Oh well, I'd still go but take my 16V and live vicariously through my E9 commrades there - Chris Ohmes, Tom Baruch, Andrew Wilson, and Doug Dolan...

Happily, Don looking at my data log this weekend....

New theories welcome!

 

[Arde]

In my ignorance I wold think that the dash lights being off points to a coarse electrical problem. AFAIK dash lights do not go through the ignition switch or load shedding relay, so it must be the 12V or ground themselves that are intermittent. No fuse blown suggests it is not an intermittent short.
Data logging? Do E9s log data to a flash device?

 

[Ohmess]

Wayne - Let's return, shall we, to the 2017 Vintage. I recall driving in the pouring rain when Tom signaled me that he needed to pull over. His drivers' side wiper blade had departed his vehicle at speed and he was left without a wiper in the pouring rain. We pulled over, switched the passenger side wiper to the drivers' side, and safety wired it on so he could make it home.

Now, if I remember the sequence correctly, during the stop to repair Tom's car, you had a hard time restarting your car. I remember giving you a jump, which for some reason got you going again.

You then had trouble restarting later at the pump when we stopped for gas.

After we got home, Tom determined the problem was electrical, and, I think he did a wiring repair in your trunk. Not sure if this was fuel pump related; memory is a little hazy here. Anyway, I toss this out there following up on Arde's comment.

 

[Stevehose]

Yes and as Arde said, check the battery cables connections to the body and starter, and even the battery itself.

 

[adawil2002]

Re-look at the distributor, that was my problem when the car would shut off while driving. The trigger module would act as a capacitor & randomly shut down.