Starting Issue, I'm stumped.

[rudygetz]

Hopefully there are some E30 experts in here. I'll give you a sequence of events but some may have nothing to do with the current issue.

1987 E30 Vert, always pretty reliable with no real issues, owned it for 4 years now.

• Took the car to have a spot welded on the exhaust, it wasn't an extensive job, it was literally just a simple weld on the exhaust I had cut weeks prior that were held together with clamps but the time came to need welding.
• Drove to car home, parked it, few hours later went to drive it and it wouldn't start, meaning it would crank and crank but not start. (This is constant for the rest of the story). I "messed" with some stuff that I thought was the fix and it magically started.
• Drove it to a BMW shop to have the A/C worked on, they fixed it, but when I went to pick it up it wouldn't start. I left it there as they wanted to take a look but they said it magically started again so I had to pick it up since they couldn't source the problem if it didn't act up again.
• Drove it away from the BMW shop and it shut off about 6 blocks away from the shop. Sat on the side of the road for about 30 minutes, with some of the guys from the shop that came to look at it and they concluded it was some spark issue. Friend came by to "tow" me to the shop but when he showed up (probably 45 minutes after I initially broke down) the car started again so I drove it back to the BMW shop so they can source the problem.
• They couldn't get to it the same day so it sat overnight. The next day it started again and did not act up again for days. After about 3-4 days of it not acting up again I went to pick it up and drove it home. It made it home.
• Next day it wouldn't start again and so I started to check the possibilites.
• Checked all the relays, checked all the fuses, jumped relay for fuel pump, checked grounds, swapped Crank Position Sensors to a brand new one.
• All while the same issues coming and going.
• One issue I noticed continued to happen over and over again and didn't seem to be a coinsidence. Each and every time I put the key in the second position and all the dash lights came on (ie battery, oil, cel, etc) when the CEL light showed it would start. Each and every time I put the key in the second position and the CEL didn't show to car wouldn't start.
• Today I managed to source a DME to swap in. The "new" DME went in and the car started right up (showing the CEL when key was in the second position). I swapped back in the older DME and it fired right up. Swapped back in the newer DME and it started back up. I let it idle with the new DME and I noticed the housing around A/C and Circulation buttons weren't all the way pushed in, so I pushed them and the housing in the sit flush the car shut off. Now it's doing the same thing. No CEL light on key 2nd position and the car won't start.

I'm completed stumped.

[twright]

The first thing you need to do is narrow down the possible reasons that it doesn't start. If it were my car, I would determine if the reason for the "no-start" is because you don't have spark or you don't have fuel.

The next time it doesn't start, pull one of the plugs and, with the wire connected, ground the plug and see if there is a spark. ( You will probably have to have someone else turn the key so you can look for spark)

This test will tell you if you need to start looking for electrical issues.

To determine if you have a fuel problem, pull the fuel line off of the rail and put it into a bucket. If fuel doesn't come out during cranking, something is wrong with the pump, filter or one of the lines.

Report back here when you get some info from above. You will get plenty of help.

[ADEN]

You have narrowed it down to the center of your dash. The ecu wiring harness pass behind the dash try opening your glove compartment and wiggle the ecu connector with the harness when key in ignition 2nd position until the check light illuminates.

[ButtJuice]

If I were to take a shot in the dark, fuel pressure regulator.