Eta-to-M50: Build thread

[dude8383]

Crank Position Sensor? Have you checked the resistance on it?

[Jand3rson]

Crank Position Sensor? Have you checked the resistance on it?

I haven't, I don't have a multimeter, I'll have to wait until later to check that stuff, Andrew does, but he works until this afternoon.

[trackjunkie21]

CPS and cam position sensor interchanged?

[Jand3rson]

CPS and cam position sensor interchanged?

No, I have checked that several times now.

[shiboujin]

No you aren't getting fuel. Do the injectors squirt with the pump jumped? If you aren't getting spark, then the fuel injectors aren't firing more than likely. Your method of testing for spark is a little iffy but I'm going to say your ECU isn't getting a signal for something.

Humor me and swap those coolant temp sensors. You never know...

Next step would be checking for proper resistance from your CPS. The car will start without a CAS but def won't start without the CPS. Your engine grounding is fine, otherwise the car wouldn't crank over that strongly. Do you have another ECU you can try out? You'll need to really start breaking out that multimeter.

[Jand3rson]

Gotcha, we'll bust the multimeter out and start checking everywhere we can as soon as I get access to one.

Nothing else I can really check until then.

[samiam3356]

immpossible to have the crank and cam swithced. One is male and the other is female. You could have them plugged into one another but not wrong on the harness side.

good luck man...This is the frustrating part but also very rewarding when you figure it out. BTW did you use new sensors?

[nando]

AFAIK the FP and O2 relays are different from say, a foglight relay. It's been a while since I looked at them closely.

Normally the FP turns on when the ECU sees an RPM signal from the crank sensor. If you hear the FP when you've jumped it, it means that the FP is working and there is power. It doesn't tell you if the ECU is seeing timing signal, but it could mean the relay is bad. What you could do next is check for spark. It can be a little difficult to hear the FP turning on while you're cranking it - but if there is spark, the ECU is definitely getting an RPM signal.

Since you can't just put a timing light on the spark plug wires, what I normally do is carefully ground a spark plug on the block somewhere and watch for it to fire. just make sure your heart isn't part of the circuit..

[shiboujin]

immpossible to have the crank and cam swithced. One is male and the other is female. You could have them plugged into one another but not wrong on the harness side.

good luck man...This is the frustrating part but also very rewarding when you figure it out. BTW did you use new sensors?

I'm pretty sure on a non vanos they are the same. I'm trying to find evidence but I'm actually busy today.

AFAIK the FP and O2 relays are different from say, a foglight relay. It's been a while since I looked at them closely.

Normally the FP turns on when the ECU sees an RPM signal from the crank sensor. If you hear the FP when you've jumped it, it means that the FP is working and there is power. It doesn't tell you if the ECU is seeing timing signal, but it could mean the relay is bad. What you could do next is check for spark. It can be a little difficult to hear the FP turning on while you're cranking it - but if there is spark, the ECU is definitely getting an RPM signal.

Since you can't just put a timing light on the spark plug wires, what I normally do is carefully ground a spark plug on the block somewhere and watch for it to fire. just make sure your heart isn't part of the circuit..

They do make magnetic pickups for spark. But they do make testers and such anyway. I think at this point it's safe to say that the ecu isn't sending out signals for anything. Meaning the problem is ECU or prior on the electrical food chain.

[Wh33lhop]

AFAIK the FP and O2 relays are different from say, a foglight relay. It's been a while since I looked at them closely.

I don't see how the FP relay would differ from the other simple normally-on relays.

Normally the FP turns on when the ECU sees an RPM signal from the crank sensor. If you hear the FP when you've jumped it, it means that the FP is working and there is power. It doesn't tell you if the ECU is seeing timing signal, but it could mean the relay is bad. What you could do next is check for spark. It can be a little difficult to hear the FP turning on while you're cranking it - but if there is spark, the ECU is definitely getting an RPM signal.

Since you can't just put a timing light on the spark plug wires, what I normally do is carefully ground a spark plug on the block somewhere and watch for it to fire. just make sure your heart isn't part of the circuit..

He is not getting spark dude, catch up! :p

But I think Yoshi is right, it does not seem like the DME is actually trying to start the car.

[nando]

I don't see how the FP relay would differ from the other simple normally-on relays.

look at them sometime - there are a few different relays that are triggered differently and that react differently. Some are normally closed and open when tripped, others are opposite. There are of course a lot of generic Bosch style relays but they are most definitely not all the same. They can even differ slightly between generations of BMW.

[Farbin Kaiber]

As long as the unloader circuit is not suspect, I'm going to assume an issue in/at either harness ore the DME itself. More likely the former than the later, but it could be.

[Van Westervelt]

Did you jump the FP at the tank or in the fusebox? If you only jumped it at the fuse box using its own signal, then its a bad relay.

[Wh33lhop]

look at them sometime - there are a few different relays that are triggered differently and that react differently. Some are normally closed and open when tripped, others are opposite. There are of course a lot of generic Bosch style relays but they are most definitely not all the same. They can even differ slightly between generations of BMW.

Basic relays like the FP, fan and headlights are typically normally open. Unless there is wildly different current handling (fan/lights/FP are all on the same order of magnitude), triggering voltage (no) or pin configuration there is not a whole lot left to differ, functionally at least.

[Jand3rson]

Redhoodridah ok'd me and said that he was having the same issue, and his ECU wasn't getting any power. At this point, that seems like the most likely culprit.