No start after track day.

[markseven]

Bumping this back up.

Tank has been replaced with a standard 14.5 gallon tank, decided not to fuck with the factory setup.

Yesterday buttoned everything up, on ignition pump turned on and started.

Car ran for approximately 10min and just died. Wouldn't start back up until I swapped back to old ECU and then had to swap in another fuel relay. Let it idle for about 10min again but it didn't shutdown.

This evening, inspected everything under the car, lowered it go to start the car and bam fucking thing does NOT want to start.

On ignition I heard the pump go on briefly and then cut out immediately.

Back track a bit, yesterday to check the symptoms I pulled the power to the fuel pump and the car gradually died. So this leads me to believe that it is not the actual source of the problem. Seems like some sort of electrical cut out almost as if EWS is enabled but it has a chip that cancels that out. I have been driving with that chip since October 09...

I'm kind of at a loss here :( I feel like I just replaced everything for no reason.

Still getting that check engine code and on ignition the voltmeter is showing 11v. Battery is nearly drained but I'm using a booster attached to the battery to try and start it up.

Any advice on another approach?

IMO moving to a 325 tank would not have solved the startvation issue - I was getting starvation with my M20 powered 325.

[dude8383]

IMO moving to a 325 tank would not have solved the startvation issue - I was getting starvation with my M20 powered 325.

Yeh, thats why I purchased the stock tank. If I experience starvation again at the next track event I already know whom to contact about a solution :)

Right now the lack of start seems to be some sort of electrical cut out.

[dude8383]

Okay, did some more tests.

According to my "trusty" Chilton manual there are several tests that can be done to see if everything is functioning as it should.

1. If a fuel supply problem is suspected, remove the pump relay and check for 12 v at terminal 30 of the relay socket. With ignition switch ON, there should be 12v at terminal 86 from the main DME relay.

Is the main DME relay the relay right next to the fuel relay? Typing this made me realize that I was checking for 12v at the fuel relay socket.

2. Jump terminals 30 and 87 with a fused jumper on the relay socket. There should be power to the pump's fuse and to the pump. Measure the voltage at the battery, then measure the voltage at the fuel pump. If the fuel pump voltage is 0.3v less than the battery voltage, check the fuel pump wiring for damage or a poor connection and repair as necessary.

For this one I am NOT getting 12v at the fuse # 11. There is also no power at the pump.

3.Use a fused jumper wire to supply 12v to terminal 86 and ground terminal 85 on the relay itself. Do not reverse polarity or the relay will be destroyed. The relay should close and there should be continuity between terminals 30 and 87

The stuff in bold is what I'm puzzled about. Can someone break this down into stupid, haha bear with me, my electrical skills are sub par but I am working on it!!

4. If the pump runs when the terminals are jumped and the relay is good, but the pump stops when the ignition switch is in RUN position, the control unit may not be receiving a signal from the crankshaft pulse sensor.

I can't even get to this step because all of the others have seemingly failed...

What do you guys recommend I do next?

Does this sound like an ECU issue? EWS?

[dude8383]

Okay, more diagnosis.

First things first...I found out whats wrong, it's me. haha

I was testing the wrong relay!!

So here's what we've determined:

Shorting the pin 30 and 87 forces the fuel pump to switch on however car still does NOT start. There is power at fuse 11 when these two are being shorted.

However when I swap in a tested working relay it doesn't click to close and there is NO power at fuse 11 when ignition is turned ON.

Could this be a fried chip?

[Danny]

Idk if its been asked but how is your cps?

[dude8383]

Idk if its been asked but how is your cps?

I'll take a look today! Good suggestion, I suppose I should check the camshaft and crank sensors.

[7pilot]

Another possible culprit could be the ignition switch.

m

[dude8383]

Another possible culprit could be the ignition switch.

m

How do I test the ignition switch? Could you tell me where its located as well? I've never had to diagnose so many problems with my car :(

[dude8383]

No spark and no fuel. There's power at the ECU though, 12v...

WTF is going?!

[Danny]

Cps dude. Check the Ohms.

[z31maniac]

I'm with Danny, check the resistance on the Crank sensor. As I believe the car will still run with a dead cam sensor, not 100% on that though.

[BMW_TUNER]

What is your current ground setup? All of these issues soundlike groundign issues that have gotten consistantly worse? How many grounds are you running? Are your running an engine ground? Where are your grounding the harness?

[dude8383]

Danny, Buddy, checked the resistance on the crank sensor...appears to be dead?

http://www.youtube.com/watch?v=CMJFrHqCo7U

I'm having a hard time believing that it could be a grounding issue, the symptoms don't add up. Engine ground is factory placement from right engine arm to right frame rail.

Factory grounding points everywhere.

The engine harness is being ground to chassis as well, its right where the battery compartment area, just behind the right strut tower.

[Danny]

Swap out the cps with a good one. That's where my money is.

[dude8383]

Swap out the cps with a good one. That's where my money is.

Haha, well time to make some phone calls then. Any other possibilities?