'88 325i No Fuel Pump, No Coil Spark

[icibuy]

Just rebuilt the engine and can't get a spark at the coil nor get the fuel pump to operate.

I have verified that the coil ohms out per the specs and I hot wired the pump at the relay and it pumps...cleared out all the air in the lines.

I have read some other posts that make it sound like I need to troubleshoot the DME Motronic. If that's the case, I haven't found any place that explains the troubleshooting procedures. Anyone have any advice on the direction I should take on this?

Bob

[coolbear1]

Sounds to me like your main relay is not closing. The main relay will not allow spark, fuel pump, or injectors, (or actually the other relays that control them) to actuate until it gets a signal from the DME that that is satisfied buy it recieving the correct signals from several places. (Ignition switch, crank position sensor, or pulse sensor( it needs to varify that the engine is turning before it allows fuel into the cylinders via the injectors, and also to continue the fuel pump to run after the initial prime of the system. My e30 had a BMW securithy system also that was part of its on board computer (the one inthe dash). it would allow the engine to spin

__________________
74 911 targa blk on blk, Carrera fend., tires & whls. gone, missed
85 325e bought new, totaled after 20 years & 465K miles, trouble free service.
01 Ford Ranger 4dr stpsd 4wd. I drive,here
88 325i convert. only 98k miles,gone, sold
93 325i.here, 98 Z-3 roadster. gone, 08 128 cabro gone

[icibuy]

I went the next step and began troubleshooting the Motronic 1.1 connection cable. Right off the bat the Main Relay Control has the 12v between pin 36 and ground but there is NO notable clicking at the relay. I removed the relay and tested by running 12 volts to actuate and verified continuity between 30 and 87 on the relay. I'm not sure if that is a suitable test but at least wanted to put that out there.

The list of items that aren't working:
1. 3 and ground - Fuel Pump
2. 48 and 47 is open - Reference Sensor
3. 45 and ground - coolant sensor
4. 8 and 31 is greater than 1 ohm - Cylinder identification
5. 40 and ground, 41 and ground no voltage - AC signal

The other 11 check out good.

I'm just wondering if there is a common theme here that I'm missing. After all I removed the engine and replaced it so there are a ton of variables.

Any help would be much appreciated.

Bob

[markdas]

Would have suggested the main relay also.....

Crank position sensor

Spark pulse sensor

These next few ideas are not meant to insult your ability, but could be possible

Distributor cap, rotor arm and leads all good

King wire on coil good

Low tension wires on coil all okay

Timing of the engine is correct at TDC static

Also the immobilisor on our car used to demand a key in position 1, disconnect the battery for 20 mins and then try again?

Are the fuel pumps getting 12volts?

[coolbear1]

I no longer have the refrence material for an e30. I let it go with my last car. But diagnostic practice is common to everything.
Start at the begining.
Do you have power to the main relay?Test it at the teminals that actuate it.

Test the socket with the relay removed.
1. with the ignition on.
2. while turning over the engine.
If relay closed at 1.
And open at 2.
DME is not happy.

[icibuy]

Wow, wiring--what can I say. I started from the top by checking all the component to verify that they are working as planned. Then went back to the DME and discovered that pins that weren't working before are now working. It appears that reseating all the connectors from the last test may have solved the problem. The Fuel Pump relay was inop and so I took it apart and discovered that the only moving part in it was misaligned and not allowing it to function properly. By tweaking it a bit the relay now works (i'll probably have problems down the road--for now though it's all good). Anyway, the engine now runs, although rough.

I was checking the inductive wire off of spark plug #6 and it supposed to read <1 ohm. at the DME but I'm getting an open. Does anyone know if I make the same check at pins 1 and 2 of the inductive cable itself it should also read <1 ohm. I couldn't find anywhere that indicated that in the manuals. I actually tried all 3 pins and still have nothing but really wanted to make sure before I buy a new set of plug wires.

Thanks for everyone's help.