It's cranking and won't start

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rs6
Posts: 44
Joined: Tue Jan 28, 2020 7:55 pm
Location: Ljubljana, Slovenia

It's cranking and won't start

Post by rs6 »

Hello guys,

I'm loosing my ming in here for the past 2 months.
On Monday I managed to get cranking on my 1983 635csi. I did auto to manual gearbox swap.
Now after I turn the key I'm only getting cranking.
Any idea what to do next? Some peoples gave up already.

The symptoms are:
- I don't get spark
- Not sure if I get fuel but I hear fuel pump on the start - new fuel pump installed and hoses
- It looks like wires from fuse box to coil pack are dead
- It's cranking with or without bypass because gearbox swap (2 brown wires bypass)
- Replaced fuses and relays for new one

- I got single mass flywheel for motronic
- Pulse sensors (both) are old, getting them new on Friday but fired up 1,5 years ago before we started restoration . Also tried to change positions.
- Distributor cap is new
- Ignition wiring to distributor cap is new
- Starter is refurbished

Now what I'm thinking it must be something electrical but don't know where to start looking as we went through everything.
Also web can be wrong about bypass wires for gearbox swap to manual.
I did a lot of research on that but have no clue...
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hornhospital
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Joined: Sun Jul 11, 2010 6:46 pm
Location: Silverhill, AL
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Re: It's cranking and won't start

Post by hornhospital »

I'll guess there's at least a 70% chance that it's the crank sensors. Just because they worked 1.5 years ago doesn't mean they still work. I hope the new ones cure your anxiety. [-o<
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
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