introduction

Post your E12 technical questions and comments here. Please, no off-topic posts.

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don
Posts: 22
Joined: Tue Apr 21, 2009 1:22 pm
Location: Richmond Va

introduction

Post by don »

I would like to introduce myself and my car.My most recent is a 1980 (Build date 4/80) Euro 635 csi.It is an e12 chassis with Jet-tronic (L-jet) fuel mamagement.She has a few electrical gremlins and an ignition issue that is driving me mad.The car will not re-start when hot.I have replaced the fuel pressure regulator,ignition coil and checked wiring.A combination relay is on order.I am in the process of cleaning grounds and further diagnosis.Thanks,Don Elliott
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Mike W.
Posts: 2889
Joined: Wed Aug 30, 2006 12:12 am
Location: Sonoma County

Post by Mike W. »

Welcom aboard!

First things first, check for fuel and check for spark. You mentioned spark, but also replaced the FPR. If it is spark, my best guess would be the ignition control unit.
Mike W.



02 525ita. Wife's, aka grocery getter
02 530i. New to the fleet, 3 pedals.
03 QX4, AKA the Datsun. Finally got the 4WD vacationmoble to stop smoking.
07 Xterra. Still on the DL, a purchase from hell.
T.Hanson
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Joined: Wed Jul 26, 2006 7:39 am

Post by T.Hanson »

Check the electronic control unit: Aluminum box mounted inside fender opposite air cleaner. Swap out one that you know is good, as used are hard to find and new are about $400.

Hot start or die when warmed up drove me crazy changing things you have. The ECU is some kind of computer spark control that can go bad without going completely dead.

Not that it's the problem, more for info: go over all the brown (ground) wire connections under the hood and dash, and the braided straps, negative battery cable and one off the back bolt of the valve cover, passenger side, all clean and tight.

Nuts how just doing that revives lots of quirky stuff.
don
Posts: 22
Joined: Tue Apr 21, 2009 1:22 pm
Location: Richmond Va

Thank you

Post by don »

for the responses.Here is a list of the symptoms and my findings:
1) No spark until the car cools
2) Occasionaly the tachometer jumps erratically..very rarely
3) It appears the coil gets no 12v power when hot.I have not been able to test the ballast resistors.They are on long term back-order from BMW.
4) fuel delivery and pressure seem fine
5) The battery cables ,both pos and neg are in terrible condition.Parts are on order.
6) I hope it's not the ignition controller.$1200 from BMW,rebuilt,indefinate back order.
8) I'll be checking the ECU next week.
After shut down I only have about 30 minutes to run test so it is a slow processThanks,don
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Mike W.
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Location: Sonoma County

Post by Mike W. »

You've got to know where to buy things. Check the link.
http://www.autohausaz.com/search/produc ... l%20Module

ECU on L-jet cars has nothing to do with spark, so don't bother if you know you don't have spark. If you suspect the ballast resistor, bypass it for testing, just jumper a wire from one side to the other. That's what the car does for starting anyway, and it won't hurt the coil if you just do it for a minute or two for testing.

Unless you have to have new, post for a used one, lots of us have spares and or sometimes access at junkyards. $1200 for a new one, wow :shock:

Ignition switch is another possibility, though unlikely the problem.
Mike W.



02 525ita. Wife's, aka grocery getter
02 530i. New to the fleet, 3 pedals.
03 QX4, AKA the Datsun. Finally got the 4WD vacationmoble to stop smoking.
07 Xterra. Still on the DL, a purchase from hell.
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1st 5er
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Joined: Sat Jan 10, 2009 10:43 pm
Location: Cypress, Texas
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Post by 1st 5er »

Hey Don,
Missed welcoming you, sorry. WELCOME!

Did you get your no hot start sorted?
Sherman

TexFest LSB&F V

95 525iT (Her DD)
92 ///M5 (????)
91 ///M5 (T donor)
88 ///M5 (Das Beast)
86 535i (Snob)
79 528i (1st 5er)
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Lenny D.
Posts: 287
Joined: Wed Jan 07, 2009 3:05 am
Location: New Orleans (Metry!), LA
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My $0.02...

Post by Lenny D. »

I had a random no-restart condition that turned out to be the impulse sender in the distributor.

Just for clarification - the ECU (electronic control unit) is the 'brain' of the L-jet system. That box lives in your glove box. They rarely fail. The ICU (ignition control unit) controls spark. That box lives in the engine compartment, right side fender well near the front, the one you've already had a heart attack over :!: Listen closely, we'll tell you where to shop. :wink:
HTH

'80 528i
under the radar
Posts: 106
Joined: Fri Jan 09, 2009 12:39 am
Location: half moon bay CA

Post by under the radar »

hey Don, welcome to my nightmare!
the early nineties called. they want their awesome back

OO==00==OO
GripGreg
Posts: 1797
Joined: Tue Jan 06, 2009 1:50 pm
Location: Long Beach, Cal.

Post by GripGreg »

Welcome Don. Great website for e12's. The guys want to help in a big way. Do dealers still exist?? Also, there's Bavauto.com. & a coupla others that escape my brain for now. Dealers,,,don't they have the plague? Greg
don
Posts: 22
Joined: Tue Apr 21, 2009 1:22 pm
Location: Richmond Va

Thank You

Post by don »

The car is coming along nicely,rust abatemnet and exterior work is complete.I've reskinned the front seats and redyed the rest of the interior to match.It's currently awaiting a 5 speed conversion.
The no-start when hot issue has not been solved.I installed a used but reliable ignition controller but it appears my issue is the pulse module in the distributor.I have not been able to run an accurate test.Process of elimation points that way,though.
I was fortunate to find a used Euro distributor from a low mileage M90 that I'll rob parts from over the week-end.
Thank y'all for the warm welcome and assistance.I look forward to returning the favors
Don
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Lenny D.
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Location: New Orleans (Metry!), LA
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Re: Thank You

Post by Lenny D. »

don wrote: The no-start when hot issue has not been solved.I installed a used but reliable ignition controller but it appears my issue is the pulse module in the distributor.I have not been able to run an accurate test.
Don
To my knowledge there is no accuarate test for this other than replacing it to see if that solves the complaint. You mentioned an alternate distributor, try swapping the whole unit (if possible) to see if that resolves the issue.
HTH

'80 528i
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