87 325e stroker (w/ i top, etc), no spark

[DetailAddict]

So right now, I get no power to 87 and 30 at the fuel pump relay and fuse 11 is good. I checked with a known good e30 next to me so I know my checking methods are good.

I've tried 3 wiring harnesses already and no good. I don't mind buying a NEW harness if I know for sure it is the harness since it's not cheap.

New on the following: plugs, coil, cap, rotor, plug wire, and cps.
Swapped with known good: wiring harness, dme, icv, and tps

Did the following...

http://spece30.com/forum/41-electrical-gauges-and-sensors/53136-no-start-no-spark-totally-stumped#53139

For the engine to run the following conditions must be met:
· Power on DME pins:
· 27 Start Input
· 18 Un-switched Power input
· 37 Power Input from Main Relay
· Ground on DME pins 2, 14, 19, 24
· Timing data from the CPS on DME pins 47 & 48 from a rotating engine
To have spark power must be present at the coil positive and ground pulses from the DME's pin 1 must reach the coil negative. Power to the coil is controlled by the ignition switch via C101. When checking for spark, use the output lead from the coil to eliminate the distributor, rotor and plug wires.
To have injector firing power must be present at each injector and ground pulses from the DME's pin 16 (Bank1) and pin 17 (Bank2) must reach the respective injector bank. Note that the injectors are wired as two banks of three. With cylinder 1, 3, 5 being bank 1 and 2, 4, 6 being bank 2. Power to the injectors is controlled by the main relay.
The fuel pump relay must have power on pin 86 (relay coil) from the main relay output (pin 87) and power on pin 30. The DME will ground pin 85 to turn on the relay and power the pump(s) via pin 87. Of the above, only the fuel pump power is fused. So if the there's power at pin 87, but not at the pump, check fuse 11.
The main relay and DME pin 18 receive power from the smaller of the two wires that connect to the battery's positive terminal. That wire incorporates an in-line fuse. When the DME is presented with a start signal, it grounds the main relay pin 85 and furnishes power to the fuel pump relay, injectors, and DME.
Troubleshooting:

Disconnect the battery and the DME cable. Then:
1) Disconnect the coil negative and check continuity from that connector to DME pin 1. Also verify that from DME pin 1 to ground is an open circuit.
2) Check the resistance across DME 47 & 48, which should be 500-560 ohms. If the CPS is dismounted, the resistance can be seen to change from about 500 to 540-540 when a ferrous object is brought to the face of the sensor. Neither pin should be grounded.
3) Check for continuity from DME 36 to main relay 85 and from DME 3 to fuel pump relay 85.
Reconnect the coil, remount the CPS (air gap should be 0.040"), plug the relays back in, reconnect the DME, and connect the battery.

Then do the following checks:
1) With the key off, verify that power is present at DME pin 18 and main relay 86 & 30.
2) With the key on, verify that power is present at DME pin 27 and pin 18. Power to pin 18 is from the main relay and there should be power to the injectors and fuel pump relay.
3) With the key on, verify that no voltage is present at the DME grounds (2, 14, 19, 24).
4) Verify that power is present at the coil positive and at fuel pump relay pin 30. Those get switched power from the ignition switch via C101.
The engine will start and run (if poorly) with only those connections to the DME in place. The other signals from Cylinder ID, AFM, temp sensor, etc., are necessary for proper operation. But they won't prevent the engine from firing.

IMPORTANT:
A power check means seeing a voltage within about a tenth of a volt of what you measure across the batter terminals, which should be at least 12.6v on a charged battery.
A continuity check means seeing less that 1 ohm of resistance.
An open circuit means seeing a resistance of at least 100k ohms.
A good quality auto-ranging Digital Multi-meter will make these tests much easier.

[Cabriolet]

Leo, what did you do about the difference in starters? i have an extra 88+ one for you to borrow.

[DetailAddict]

i am still using the 87 325e starter. It was running fine before and it seems to be still spinning the motor. Just no start.

Leo

Leo, what did you do about the difference in starters? i have an extra 88+ one for you to borrow.

[DetailAddict]

btw, does anyone know how to trace that line from 30 on the fuel pump relay (where is "the other end"?)?

[Chriskbmx]

I would check and make sure you didn't get the crank sensor, and the reference sensor on the harness backwards.

[TG Goose]

would still be able to jump the fuel pump relay with the CPS and ref sensor reversed

[Jahman093]

what year harness are you using?

[DetailAddict]

i checked by measuring the resistance from the DME harness side to make sure I have that correct.

I would check and make sure you didn't get the crank sensor, and the reference sensor on the harness backwards.

[DetailAddict]

late model. Pin 20 on the C101 has been removed. I know late model has that line coming out hot from the main relay (85), where the C101 on the body side has it to the ground.

BTW, the car was running and driving, hell, even tracked for a while. Until one day it just went dead in the water on the freeway. Just shutoff without and signs or indication of something going wrong right before that.

Leo

what year harness are you using?

[DetailAddict]

looking at the wiring diagram (p. 1362-2), 30 at the fuel pump relay should go directly to the battery junction block. I am going to check for that later today. I only know of one line from the wiring harness that goes to that. So I should be able to check for continuity easily. Unless it goes through the fuse box first then to the battery junction block. In that case, the wiring diagram is not showing it.

[DetailAddict]

okay, got the fuel pump relay issue figured out.... Passed every test in the original post.

Still no spark...

Here is another question... If I bump start the car, even if it doesn't run, should the car lock up? or just roll to a stop? I would think it just roll to a stop. If it locks up, what could it be? starter does not disengage?

Leo

[TurboJake]

How's your timing belt?
Suddenly die with no signs, symptom of timing belt snap.
No spark, can be symptom of timing belt (On the M20, no cam rotation thus no spark).

Look at that timing belt, asap.

[DetailAddict]

all belts are good. the stroker was done pretty recently (meaning all belts are new) and i think i've only put down less than 1k miles on it.

Leo

How's your timing belt?
Suddenly die with no signs, symptom of timing belt snap.
No spark, can be symptom of timing belt (On the M20, no cam rotation thus no spark).

Look at that timing belt, asap.

[DetailAddict]

ttt... :(

[DetailAddict]

so for some reason i can't find the CEL bulb under the dash anywhere so I rigged one directly off of DME pin 15 to junction with a T10 bulb. Was able to do the stomp test and got 1444, no fault code. Also checked for spark directly out of the coil, nothing. Anything else I can check?

Leo