engine cutting out when driving

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shotstew
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Joined: Tue Apr 05, 2016 5:33 pm

engine cutting out when driving

Post by shotstew »

Hi All. I have an 86 5 speed. I would be driving on the freeway when the engine would stall. Being a manual I would pop the clutch to get it going again. At first it was an occasional thing but over time it would happen more and more frequently. I don't think it's a fuel issue because it would start right up again. What's happening now is the idle seems to hunt between 800 and 1200 rpm on start up and my MPG gauge will peg itself to the far left for a second or two before calming down. Sounds like a short somewhere but I don't know. Here are the things either I or my mechanic have replaced.
Main Relay
Fuel Pump Relay
ICV
MAF

It's still doing it once the car is warmed up. Stupid question but could it be the cap, rotor, wires? They're pretty old but there's not a lot of mileage on them. Any thoughts will be greatly appreciated! :D
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RossDinan6
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Location: SW FL, USA

Re: engine cutting out when driving

Post by RossDinan6 »

Ignition switch, maybe? Loose connection someplace. How about your coil. Do you lose the tach? It is coil driven. Crank position sensor?

Don't see a way for the ICV to shut down the engine and I don't think the MAF will, but not positive (I no longer have one).

That's all I have off the top of my head.
Ross
'84 633 Dinan turbo
shotstew
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Re: engine cutting out when driving

Post by shotstew »

It interesting you mention the tach. I have seen that peg to the right for an instant too. It's obviously something electrical. Does anyone know of a good diagnostician in LA that doesn't charge too much money?
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sansouci
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Re: engine cutting out when driving

Post by sansouci »

You get what you pay for. An incorrect diagnosis means unnecessary parts and labor. Sounds like you need a real time oscilloscope to record voltages and signals.
Sansouci
84 E24 633Csi Auto, Bronzit/PearlBeige 6997510
93 E32 740il M60 Auto, Alpenweis/Ultramarine
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sideshowbob
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Re: engine cutting out when driving

Post by sideshowbob »

Hi shotstew...you have pm
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635sharknose
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Re: engine cutting out when driving

Post by 635sharknose »

Did all these issues start at the same time?
My first guess is that they are not related but that's just a guess.
I had a similar situation with a Peugeot once, the car stalled and was able to start again right after. Found out the fuse box was bad, it had a bad connection.
Paul
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sideshowbob
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Location: Hampshire UK

Re: engine cutting out when driving

Post by sideshowbob »

Having similar problems.....have been told that this is symptomatic of the crankshaft sensor starting to breakdown.
Mine is going into workshop tomorrow to be changed...fingers crossed.

Will post result after work done !
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Ralph in Socal
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Re: engine cutting out when driving

Post by Ralph in Socal »

To shotstew - your car should be running the 059 ecu. Those ecus are known to have solder joint issues that causes symptoms as you describe. Basically solder joints in the ecu are cracked and have minimal contact that allows for easy start but will loose connectivity during use from heat or physical jarring. The ecu is diy repairable and there are how to write ups on it. Sorry I don’t have links but I’ll try to research. I remember seeing it on mye28 before. Good luck

Ralph
There is a very fine line between "Hobby" and Mental Illness.

85 635csi Zinno Auto
84 528i Euro
83 635 Euro Arktik
81 528i Kastanien 5-speed
88 528e Bronzit (Granpa Car)
86 535i Auto (For Sale)
81 633 csi (retired)
bpoliakoff
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Re: engine cutting out when driving

Post by bpoliakoff »

Ralph is usually spot on, but I am wondering if there is a ground problem? Sounds like one of the two
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TimU
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Re: engine cutting out when driving

Post by TimU »

Ralph in Socal wrote: Mon Apr 12, 2021 3:12 am To shotstew - your car should be running the 059 ecu. Those ecus are known to have solder joint issues that causes symptoms as you describe. Basically solder joints in the ecu are cracked and have minimal contact that allows for easy start but will loose connectivity during use from heat or physical jarring. The ecu is diy repairable and there are how to write ups on it. Sorry I don’t have links but I’ll try to research. I remember seeing it on mye28 before. Good luck

Ralph
Is this the one you were referring to?
http://e28-535i.com/technical/e28-ECU_Repair.php
04/1986 635csi Euro spec
Australian Delivered, RHD
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