E30 S50 no start - no spark/no fuel

[Poeman446]

I had the same problem for a while, and I used an E36 power block. I realized that the wire to power my ECU fuel and other relays was not connected. Check to see if you have power at the relays.

[e30austin]

Had a friend come over and help diagnose this. Here's what we found:

-all C101 wiring is correct and getting power
-all grounds/hot leads in correct places and doing what they are supposed to
-relays not grounding out (ie, the load is not unloading, and ground wires at the relays are getting power)
-DME not getting power at pin 15 of DME connector

Which leads me to the ground at the front of the cylinder head (the main DME ground), that comes out of the fuel injector harness. I remembered there was a resistor, so I removed the cover off, and sure as shit, that was completely disintegrated. Sourcing a new resistor and perhaps will have this fixed tomorrow...if that is, in fact, the issue. If not, I am replacing this engine harness.

FWIW, I called the dealer. The resistor is a EU only part, costs $25 retail (no discount), and takes 3-10 business weeks to get here from the dealer...or can be found on ebay for 1/3 the price and here in 3 days. LOL

[Poeman446]

Nice work. Hopefully that fixes it!

[Ekisto]

Had a friend come over and help diagnose this. Here's what we found:

-all C101 wiring is correct and getting power
-all grounds/hot leads in correct places and doing what they are supposed to
-relays not grounding out (ie, the load is not unloading, and ground wires at the relays are getting power)
-DME not getting power at pin 15 of DME connector

Which leads me to the ground at the front of the cylinder head (the main DME ground), that comes out of the fuel injector harness. I remembered there was a resistor, so I removed the cover off, and sure as shit, that was completely disintegrated. Sourcing a new resistor and perhaps will have this fixed tomorrow...if that is, in fact, the issue. If not, I am replacing this engine harness.

FWIW, I called the dealer. The resistor is a EU only part, costs $25 retail (no discount), and takes 3-10 business weeks to get here from the dealer...or can be found on ebay for 1/3 the price and here in 3 days. LOL

Tell us if it works! Can you give me the part number?

[e30austin]

Well, that's a no go. Fuck....

[Ekisto]

Well, that's a no go. Fuck....

10000 kilometers of distance and we have exact the same problem!

[e30austin]

Bumping this up again one last time before I give up...

I've changed the engine harness with one off another known good '93 325is manual car. I built an adapter for it. It's all still doing exactly the same thing it was before I changed the engine harness.

[dewme5]

Have you tried a different computer?

Sent from my HTC6435LVW using Tapatalk

[Roysneon]

Still should make the IAC buzz if it was a bad DME. I had a bad DME when I first swapped my car and I'm pretty sure it still worked.

[e30austin]

It's not the DME. The only thing I can think of is some sort of a grounding issue. Literally don't know what else it could be.

[e30rapidic]

is the ecu itself grounded? Also the ground strap from the oil pan to chassis in place?

[Wanganstyle]

from our race car a 24V swap E30 (obd1 413 dme) only needs a few things to fire:

crank position sensor
coolant temp sensor - the one in cylinder head that goes to DME not the cluster one; DME could care less about what the driver sees.

Things that can be left unplugged:

AFM - car doesnt need it to drive around in limp mode
Camshaft sensor - not needed to drive around in limp mode
TPS
IAC - BMW DME is smart enough to idle without the IAC if there are no vacuum leaks;
Vanos
Speed sensor
Intake Air Temp sensor

Things you absolutely need:

A functioning starter - external push button start is made by longacre and really useful for race cars or testing swaps. (ours is race car with swap so naturally used it)
a functioning Fuel pump - fuel pump is easily jumped with a 12V power source directly; if the car is a early car with external fuel pump its super super easy to jump power it.


If you suspect that the car is producing spark but not squirting fuel you can start the car and idle it on starting fluid or brake cleaner to test this theory.

-relays not grounding out (ie, the load is not unloading, and ground wires at the relays are getting power)
-DME not getting power at pin 15 of DME connector

Does the engine crank?

Engine Harness takes the the power to the DME;
Engine harness and DME directly ground to the engine.

Why do you have power on the ground side of the bundle at the relays?

12+ voltage @ the brown ground wires @ relays would be the #1 problem; fix this and your car will likely run

[wakdog]

Im having a similar issue that has come up on my S50 swap after I replaced my fuel pressure regulator.

Car was running perfectly for 3 months prior to changing the FPR (apart from it pushing fuel into the intake through the vac line when idling for long enough)

Put it all back together and now I get no fuel pump prime (fuel pump runs when I jump the relay), no spark and I have a Code 26 on my scanner for 'Control Unit Supply B+'.

Things I have so far tested that have not helped:

Replaced DME+FP relays from my other car
Checked fusible link
New crank pos sensor
Checked continuity on power to DME (pin 26/54) + these wires have 12v at source when ign is on.
Car runs a Silver 413 with EWS delete chip, also tried a red 413

Im basically at the point where I think its time to give up on this harness (it came with the motor and had all the Auto wires cut which I cleaned up and removed the auto harness connector a few months ago).

[e30austin]

It was the fucking OBC relay in my case. Even though the car was a 318i with no OBC lockout...

[Matt-B]

They still come wired, mine is, just no obc