Run out of options on this no start situation (solved)

[GDA]

mis-spoke, sorry - the power to the harness is still attached at the distribution block on the passenger side. harness has power


As well, i'm getting a power to fuse 11, but the pump won't prime, and doesn't sounds like it's on during cranking..
I think the residual fuel in the lines is from me testing the pump by jumping the relay.

I also tested almost 12 volts at quite a few DME pins at the x6000 connector

Have you tested power at the DME with ignition turned so main relay is engaged?


Still trying to verify proper harness power....

Oh, is battery fully charged from all this cranking?

[Sea Aych]

Have you tested power at the DME with ignition turned so main relay is engaged?


Still trying to verify proper harness power....

Oh, is battery fully charged from all this cranking?

Yeah i've kept it charged.
Which pins should be checking at the dme? I can't find any sort of conclusive pinout to work with. Which is why i'm seriously lost as to how the starter just doesn't even do anything anymore. And i hadnt changed anything

[Sea Aych]

Did some continuity testing on the harness adapter i bought, and compared to as many other pinouts i could find, and these two things stood out.
FYI my car is a 1989 325i

My C101 pin 7 goes to pin 15 on the X20
My C101 pin 15 goes to pin 21 on the X20

Are those backwards? It seems that it could also solve the issue with my windows not working since pin 15 on the X20 should come from the starter Blk/Grn wire and go to the K5 and K7 unloader relays.

[mpowerful]

Yeah 7----> 21

[Sea Aych]

Yeah 7----> 21

well, f*ck.
Anyone know how to get pins out of the c101 side without breaking the locking tabs that hold them in?

[mpowerful]

Pin removal tool.something like whats in the link or find something similar thats hallow and fits around the pin and between the plastic. http://images.tech2.guru/afl/terminal.jpg

[Sea Aych]

Alright, pins in the adapter have been swapped so now they're correct:
C101<-->X20
7 <---->21
15<--->15

Solved my window issues!
But now i get no check engine light when I put the key in the ON position, but the oil, battery and other lights come on. Is the only possibility that I fried my DME somehow, or how is it now not getting any power?

EDIT: here is my pinout
1--25
2--
3--
4--12
5--23
6--22
7--21
8--24
9--20
10--
11--19
12--8
13--13
14--14
15--15
16--
17--
18--18
19--
20--

EDIT 2:
I have no power to the body side C101 pin 7

[Sea Aych]

Yet another update. I'm starting to get really really frustrated with this damn car. I'm losing my mind

I've got no power to pin 7 on the C101 when the key is ON.
As such, the main relay won't click, the DME won't turn on, and the car won't crank.

I found that if i bridge the two wires (Grn and Grn/Red on the obc relay box side, Grn and Grn on the side that has continuity with pin 7 and 6) going to the OBC relay box, the main relay does click on.
However, my OBC doesn't Display CODE, so maybe its the relay box that just ate it?
OR is it safe just to bridge those two pins, bypass the OBC relay box (since afaik it's only useful for the code function), and let that be it?

Isn't one of the ignition 12v leads supposed to go straight to Pin 7 unfused?

[Sea Aych]

Holy moly guys it STARTED!!!!!

Fixed a splice under the dash, no dice.
Then I bridged the Grn/Red and Grn wires going to the OBC Relay box and it fired right up!

I think it's then either the relay box or the OBC thinking it has a code even though it's not displaying it!

[GDA]

Good to see... persistence pays off. Now we need to see more pics of the car!

My only idea is to swap in another OBC from another friend/parts car to isolate the issue

[cris.pepa]

Make sure that you engine to chassis ground has a good connection!!!!!!! I had the same problem with my M20. I had no power to windows either, I removed the ground strap and cleaned it with a wire wheel and car fired right up. Even the smallest amount of corrosion can result in a no-start condition. Lemme know what happens.

[Sea Aych]

Make sure that you engine to chassis ground has a good connection!!!!!!! I had the same problem with my M20. I had no power to windows either, I removed the ground strap and cleaned it with a wire wheel and car fired right up. Even the smallest amount of corrosion can result in a no-start condition. Lemme know what happens.

Solved it a few posts above, but thanks for the help!



In other news i have another questions:
It starts up strong now, but the idle is all screwed up. I replaced the cracked vacuum boot and hose from it to the ICV, but still no dice.

On start, it revs up to 2900 then falls back down to around 600, then about a second later climbs back up fairly quickly to 2500-2900ish then repeats...
Any ideas?

where are the rest of the vacuum lines on the m50nv?

[e30austin]

I've seen a bad TPS do something similar. M50 only really has a couple vacuum lines. Make sure the intake gaskets are good, as well as the hoses that go to the ICV.

[Sea Aych]

I've seen a bad TPS do something similar. M50 only really has a couple vacuum lines. Make sure the intake gaskets are good, as well as the hoses that go to the ICV.

would intake manifold gaskets (to the head) cause it? Or should i check the TB gasket? (i don't think the tb was ever removed, so i'm not convinced it'd be that)

[e30austin]

I seriously doubt the TB gasket would do it, but it's definitely possible.