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

[Sea Aych]

Checked so many searches and tried everything. Here's the situation on my M50nv

Fuel OK - smell in bay, fuel pump running, traced the lines, all OK
Grounds - OK. Engine mount arm on driver's side and strut tower on pass side
Harness adapter is from nando - trust it's all good. Grounded the Oil level sensor too
Starter is wired correctly - t30h and t50 are connected to the right wires
DME is known working from a running e34
CPS Reads 0.506-0.510 on the 2k range - so 506 ohms which is good
Coils all read fine from 1.3 to 1.8 ohms in that range


Cranks fine, get fuel, but no starting.

Could i have fried the DME by accident?
How do i check impulse getting to the coils?
Should i remove the fuel pump relay, crank it and run a multimeter to one of the coil leads?

Also worth noting, when I crank it, the lights on the dash DIM, not turn off.
Also my windows dont work. i checked the t30h and t50 connections on the starter and theyre correct.
I read that a possiblity was that if the t30h connection is cracked it could cause problems, but it looks okay...

Thanks for the help!

[e30austin]

Two things. If you run an e36 harness, you must ground the DME or it will not ground out and the car will not start. Also, just because your starter connections look good, doesn't mean they are. You could have pulled the threads out of the solenoid when tightening it down, and not have a good connection. Test that for power.

[Sea Aych]

Two things. If you run an e36 harness, you must ground the DME or it will not ground out and the car will not start. Also, just because your starter connections look good, doesn't mean they are. You could have pulled the threads out of the solenoid when tightening it down, and not have a good connection. Test that for power.

Thanks man - Do i need that 318 dme bracket thing to properly ground it? Or how should i go about that?

And testing the solenoid is just a matter of slapping a multimeter on there with the key in the ON position?

[Sh3rpak!ng]

check to see if you're getting spark

[justin_l_]

If you run an e36 harness, you must ground the DME or it will not ground out and the car will not start.

This is not true, you can even check the wiring diagram if you disagree. The ecu does not have to be grounded to start and run.

[Sea Aych]

Update:
1. Starter`s not the issue i don`t think - swapped a new one in and had the same window problem, but then it didn`t even crank.
Put the original one back in and back at square one.
2. have good voltage etc. at both K5 and K7 relays
3. Noticed a 100ohm resistance from pins 85 on both unloader relays to pin11 on the diagnostic port

I noticed that my voltage to the coil is 10.8, and voltage at the battery terminals is 12.7, which seems to be a little low, even though the engine cranks strong.

Would a 1V missing at the coil cause it to not send a spark at all AND cuase windows/hvac issues?

check to see if you're getting spark

Got nothing when i pulled the coil and plug, grounded them and cranked :(

[Sea Aych]

Update 2:
Now i have no fuel getting injected, and no spark. Windows still don't work unless i bridge pin 87 and 85 on the k7 or k5 relays

edit: have to jump pin 87 and 30 to get the fuel pump to run - then it's loud and i can hear it no problem

[e30austin]

This is not true, you can even check the wiring diagram if you disagree. The ecu does not have to be grounded to start and run.

On the E36 harness, it absolutely does. Please explain why any swap car I've done with an E36 harness will die and not start once the DME is not grounded to the chassis...

[peterz]

Try swapping a new crank pos sensor? Definitely have the cam and crank sensors correct way around?

On the E36 harness, it absolutely does. Please explain why any swap car I've done with an E36 harness will die and not start once the DME is not grounded to the chassis...

I know this doesn't help, but my dme doesn't need to be ground on my e36 harness. Works without ground. It is mounted now, however.

[328ijunkie]

Ecu is not supposed to 'need' to be grounded in any form or fashion although it is in stock form in an E36. Typically when the ecu itself needs to be grounded, it has an internal short causing it to find a ground through the case, or your engine harness ground is crap. Ive seen bad OBD2 DMEs do this same kinda thing. Wont work unless grounded. This is not the way its supposed to be however.

[GDA]

On the E36 harness, it absolutely does. Please explain why any swap car I've done with an E36 harness will die and not start once the DME is not grounded to the chassis...

FWIW we have run my Euro S50 for close to an hour total time over the past two weeks with the DME and Vanos controller laying ungrounded and on a towel on the front windshield while checking for leaks, proper run up to temp and operation of elec fan etc.

[Sea Aych]

Alright - Grabbed a new CPS, it's en route.
In the meantime, tomorrow i'll switch the cam and crank sensor connectors to see if that fixes anything
Also, i'll check my DME grounds through the harness, and on the x6000 connector side. is that the brown wire that goes to the strut tower?

Any advice on the windows? Swapped around the unloader relays in the fusebox and it doesn't fix it. Grounding the black/green wire from the starter post to the bottom peg doesn't change it, and neither does grounding it. weird...

Thanks for the help so far, all!

[justin_l_]

Ecu is not supposed to 'need' to be grounded in any form or fashion although it is in stock form in an E36. Typically when the ecu itself needs to be grounded, it has an internal short causing it to find a ground through the case, or your engine harness ground is crap. Ive seen bad OBD2 DMEs do this same kinda thing. Wont work unless grounded. This is not the way its supposed to be however.

+1
If you check the wiring diagrams nowhere does it show that it has to be grounded. I currently have an obd2 s52 in my garage with the ecu resting in the glove box that fires rite up. All my swaps have been started before the ecu was mounted and they ran fine.

[328ijunkie]

Hows your C101 wiring?

[nando]

I did the adapter for it

I'd wonder about your windows not working (that would be the unloader relay not working correctly, which could be tied to the starter). does the fuel pump run when you crank it?