E32 cranks but does not start after sitting for 3 days. New Battery.

[The Texas Sun]

Hello,

After sitting for 3 days, it started just fine, but after driving for 1 mile it started sputtering and died. This same thing happened a few months ago, but the car stopped sputtering and worked just fine.

I have been throwing parts at it.

-new battery


-new spark plugs (old ones had some oil on the threads, b/c leaking valve cover gasket, I think)


-rebuilt fuel injectors
There was fuel pressure when I removed the fuel rail
I can hear the fuel pump humming when the key is in position

I cannot find any threads on here that are this exact problem, and I do not understand the Bentley Manual (or the online manual.) Can yall tell me why this car wont start?


Thank you,
1991 735il, M30

[shogun]

check the crankshaft position sensor, the engine still might start sometimes, if the signal of the CPS is weak but usually engine will die then. Using digital multimeter, check resistance between terminals 1 and 2 in crankshaft position/rpm sensor connector.
Crankshaft Position/rpm Sensor Specifications
• Coil resistance (approx.) @ 20°C . . . . . . 540 ± 10% Ω
• Air gap (sensor distance from toothed wheel) . . . . . . . 1.0 ± 0.3 mm (0.04 ± 0.01 in.)

https://wiki.bentleypublishers.com/d...=1306522675840

[The Texas Sun]

Thank you for your reply, shogun. I checked that connector. It reads 519 ohms, and it is 23 degrees Celsius outside. Does this mean I have a bad CPS?

[jclausen]

Didn't the e32 have a large fuse strip either on the fire wall or under the rear set it was a metal 40 amp fuse that was bolted down

[shogun]

E32 has 2 fusible links, both near the battery under rear seat passenger side, 1 for the fuse box under driver side rear seat, the other one in the wire to the engine bay to feed B+ and e-box. Details with pics on my website
http://twrite.org/shogunnew/data/electrical.html
Fusible Link A is 50 Amps. Goes to X6400, that is the power post inside the E box. It feeds only DME loads.
Fusible B is 80 Amps. It feeds all the Rear Power Box loads

519 ohms is basically o.k., as the shop manual says 540 +/- 10%, but... measuring the ohm with a DMM is just a simple test, it is generally recommended to test a CPS sensor using an oscilloscope, this is not a common tool for many car owners or DIYers. Still, you can troubleshoot the sensor using a digital multimeter (DMM).

Fuel pump relay http://www.bimmerboard.com/forums/posts/366521/
main relay http://www.bimmerboard.com/forums/posts/1259287/

and yes, jclausen is probably showing you the right direction, maybe the fusible link has a haircrack, you mentioned: it started just fine, but after driving for 1 mile it started sputtering and died. This same thing happened a few months ago, but the car stopped sputtering and worked just fine.

check the one in pic 1 and 2 http://www.bimmerboard.com/forums/posts/377728/
it is in shrink wrap, here I posted typical haircracks http://www.bimmerboard.com/forums/posts/377948

[The Texas Sun]

- Both fusible links by rear passenger battery are fine.
- I have swapped my orange fuel pump relay with the other orange relay in fuse box under hood (driver side). The passenger side orange relay near the computer is fine too.

I think the electrical is sound. Seems like it is a combustion problem. It sounds strong when I crank it but it just wont catch. When I turn the key for a couple seconds, sometimes it makes a sneeze noise, I think it maybe the fuel system.
I know as soon as this car starts, it will stay running.

Can you guys please offer more suggestions?
Thanks,

[shogun]

Then you have to check fuel pump pressure and volume, I have posted that procedure here for the M60, basically same http://www.bimmernut.com/forum/showt...ight=fuel+pump
The M30 fuel pump is originally Bosch
operating pressure is 3 bar
conveying capcity at 12 V 1.9 liter/minute
conveying capacity against counterpressure 875 ccm/30 seconds
Power consumption is 5A

read also this about engine grounds http://www.bimmerboard.com/forums/posts/1268030/

What about the distributor and rotor? Did you check that already> Often the center pin in the distributor disappears. https://www.bimmerforums.com/forum/s...r-cap-just-now