No fuel, no spark.

[JIMBOkye]

So I just finished a full rebuild of my m20 (1989 325is M20B25). Some of you may remember my previous thread about how my old rebuilt motor failed (Still no clue on that). Anyway, everything is all back together (new block from an 87 325is) and I am ready to start it! Except when I turn the key I get no spark/fuel... (Cranks fine)

I know this has been visited many times.. and I've read many threads at this point, but to no avail.

So here are the details:

The Main Relay is working fine. It is switching power as it should.

The fuel pump relay has power to the coil side as well as the input contact side. HOWEVER, ground is never made on the coil. This is done in the DME.

So the DME is never allowing fuel to ground.

So I figured okay, one of the interlocks for start is not being satisfied. I found a helpful list of interlocks and how to check them here (3rd post):

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

So I tested everything in this list and it all checks out EXCEPT DME pin 48 has continuity to ground. I have a new crank position sensor and it has continuity between 2 of the 3 wires internally. My old one was like that (but it has broken a wire so idk if I trust it) Should this be the case?

I've tested all grounds and powers on the plug, diagram found here:

http://www.e30zone.net/e30zonewiki/index.php/ECU_Pinouts

My DME is a 173. I also have a 152 (or 153 or whatever). There is no difference depending on which I plug in.

The DME appears to be working, if I have my DME plugged in the idle control valve actuates and buzzes away, if not this valve does nothing.

Any ideas or info on the CPS would be greatly appreciated. I'm running out of ideas.

[JIMBOkye]

More info: the stomp test shows the "No Codes" signal.

[5Toes]

you seem to be heading down the right path with your troubleshooting.

CPS certainly sounds like your issue. Buy a new one, I recommend OE BMW for crank/cam sensors, and have at it. The OE BMW parts are spendy but they have a 2 year warranty and are made to last a very long time. Even if your old one ends up being okay (it sounds fucked) a new one is going to make the car much more reliable, because all crank sensors fail eventually.

good luck!

[peterman]

Flip the connections for the CPS and the spark plug signal wire under the intake manifold.
If you have them backwards this is the exact problem you will have.

[Untouched]

Flip the connections for the CPS and the spark plug signal wire under the intake manifold.
If you have them backwards this is the exact problem you will have.

+1 for this. Ask me how I know...

[peterman]

Also, CPS should be have about 480 Ohms (or around there i think) of resistance when not near metal. You'll have to double check that cause I don't fully remember.

[Kershaw]

it's 540 ohms +/- 10%.

[JIMBOkye]

you seem to be heading down the right path with your troubleshooting.

CPS certainly sounds like your issue. Buy a new one, I recommend OE BMW for crank/cam sensors, and have at it. The OE BMW parts are spendy but they have a 2 year warranty and are made to last a very long time. Even if your old one ends up being okay (it sounds fucked) a new one is going to make the car much more reliable, because all crank sensors fail eventually.

good luck!

Thanks! The CPS is brand new, so that is why I'm confused. Before I drop another 75 dollars on another, I was hoping to confirm that there should be internal continuity between two of the pins. I am getting 544 Ohms at the DME plug and this drops when I take it away from any metal. My old one with the broken wire also has continuity across two of pins on the sensor (but I don't trust it is "good")

Flip the connections for the CPS and the spark plug signal wire under the intake manifold.
If you have them backwards this is the exact problem you will have.

I tried this. No change. Right now the CPS sensor plug is on the driver's side. I think that is how it is supposed to be... if I could get a confirmation on that, that'd be great too...

[peterman]

Do you know that fuel is not getting to the fuel rail? Or is that speculation? The supply line connects to the rail, the return connects to the FPR.
The CPS controls the injectors if I'm not mistaken. If they click when cranking then CPS is working fine. 544 is dead on, I would rule out the CPS being bad.
How do you know there is no spark?
In the run position you should see 12 volts from coil to body ground (like the shock tower) not across the coil.

Did you check all fuses?
Could your timing be off 180?
New cap and rotor?

[JIMBOkye]

Do you know that fuel is not getting to the fuel rail? Or is that speculation? The supply line connects to the rail, the return connects to the FPR.
The CPS controls the injectors if I'm not mistaken. If they click when cranking then CPS is working fine. 544 is dead on, I would rule out the CPS being bad.
How do you know there is no spark?
In the run position you should see 12 volts from coil to body ground (like the shock tower) not across the coil.

Did you check all fuses?
Could your timing be off 180?
New cap and rotor?

I can jump the fuel pump relay and turn the fuel pump on and off. You can hear it and I pulled the line on the FPR and it sprayed out of the regulator when jumped. The pump never turns on if the relay is in. I have the back seat out so it is very easy to hear it.

I tested spark by pulling a plug, grounding it and watching. Nothing. I have a timing gun too, and it wasn't getting anything when hooked up.

I agree the CPS is probably not the case...

I checked fuses and all appropriate relays. I have spare relays that I swapped around.

I have 12 VDC at the + on the coil to ground, not across the + and - of the coil...

The rotor and cap was replaced a few months before I tore rebuilt the engine so I don't think that is problem.

I'm not sure how the timing could be off 180... ? how does that happen? Timing on crank and cam were set at TDC when I rebuilt the motor.

[JIMBOkye]

It really bothers me I accidentally called this thread "No Fuel, Not Spark" and not "No Fuel, No Spark" ......

[Kershaw]

Then double click on the title and edit it. It's a bit tricky to do, you need to click near the words, but not actually on the words or it'll bring you into the thread.

[peterman]

If the coil contact on the cap is missing you will not be transferring any energy to the rotor. It's the little brass (?) pin on a spring in the center of the cap. You might want to check that it's still there. They have been known to jump out. You could also stick a plug in the coil wire and see if you get spark out of there. Then you would know that power is getting to the cap.
What about your c191 connector under the intake manifold? Could that be trashed? That would stop you from getting the injectors to click open.

[JIMBOkye]

Then double click on the title and edit it. It's a bit tricky to do, you need to click near the words, but not actually on the words or it'll bring you into the thread.

Didn't know you could do that... Thanks!

If the coil contact on the cap is missing you will not be transferring any energy to the rotor. It's the little brass (?) pin on a spring in the center of the cap. You might want to check that it's still there. They have been known to jump out. You could also stick a plug in the coil wire and see if you get spark out of there. Then you would know that power is getting to the cap.
What about your c191 connector under the intake manifold? Could that be trashed? That would stop you from getting the injectors to click open.

I will double check this brass piece tomorrow. Would the C191 being messed up cause the fuel to never turn on either? I think this connector is okay on my car.

[peterman]

The fuel will not be on in the run position if the engine is not running. At least this is the case for my car. I believe it has to do with safety - in case there is an accident that cuts the fuel lines and the engine stops but key still in run position. This is speculation, but it makes sense to me.
I only see fuel when cranking and not in the run position, until it's running obviously.
The C191 only controls the injectors (I think, but I'm pretty sure).