Lscobra

Hi.
This is my first post here.

I am building a cobra with an LS3 in it.
It's a standard ls3 crate motor, e38 with vats removed, and psi conversion harness.

Car ran when first wires up and started first go. I then didn't run the motor for 12months and did only a few other thing on the car but nothing to do with the engine management.

Car won't start now. Everything seems fine but no fuel injectors and no spark.

I have checked:
1. Aerostart sprayed in TB
2. Checked 12v at ecu during cranking and confirmed voltage drop is to about 11.5v.
3. Removed and cleaned earths
4. Scanned codes and got p0315 (shouldn't stop it starting)
5. Scanner shows 175rpm when cranking so has crank signal.
6. Fuel pump runs when cranking and has pressure at the rails using regulator/filter at correct about 60psi pressure.
7. Checked connectors on sensors are secure.
8. Checked voltage at injectors and coils
9. Checked voltage at cam sensor key on is 5v, continuity exists with earth, signal wire has no voltage or earth. Cam sensor shows ohms across positive and earth pins.
10. Checked crank sensor. Key on, Have 5v on positive, continuity with earth. The signal wire to the ecu with no sensor connected is 5v. Is this normal?? Sensor has ohms across positive and earth pins.

I'm now lost as to what to check next.
Anyone know if it's normal for there to be 5volts on the crank signal wire without the sensor plugged in? I wasn't expecting this wire to have 5volts.

Appreciate any help you guys can give.

Cheers
Liam

LS1MCSS

iTrader: (18)

No fuel or spark sounds like a blown fuse. Coils and injectors are usually on the same fuse.

Lscobra

Has voltage at injectors and coils so fuses ok.

RonSSNova

iTrader: (3)

What scanner? Will it show crank pulses?

Something you did possibly in the wiring area has changed. Maybe replay the work you have done since in your mind and see what you come up with.

Ron

mrvedit

Found this similar thread about swapping an LS3 into a Mustang:

http://www.hptuners.com/forum/showth...-swap-no-spark

Make sure the ECM has +12V not only with ignition ON, but also in START position.

Someone confirm, but IIRC the E38 disables spark and injectors when VATS is enabled and sees the wrong key. This would be far from the 1st time someone thought the VATS was disabled when it really was not.

Lscobra

Thanks for the replies.

Power has been confirmed during cranking. I have push button start for the starter so the key stays at the on position.

I don't have a decent scanner, but it does show cranking at 175rpm.

The car has run before a couple of times but I only ran it for short periods of time maybe 30 sec - 1 min, because the cooling system wasn't hooked up.

Could VATS have come back on some how?

Lscobra

This was first start. Would it run like this if vats was on? Does vats eventually shut it down all together? I thought it allowed you to run for a few seconds before cutting out.

https://youtu.be/wDGTyJUR-70

mrvedit

The VATS on the 411 PCM runs for a few seconds before cutting out, but IIRC the E38 doesn't run at all.
Hopefully some of the experts/pros here will chime in soon.

Lscobra

Interesting.

Doesn't the VATS just shut off the fuel injectors? I have no spark also.
I ordered a HP Tuners VCM scanner today from summit, but i noticed after purchasing it that it said ship date 7/13/2015. So its going to take a month until i get it in Australia. Doh!

Im hoping someone can tell me if it is normal to have 5v on the signal wire for the crank sensor. I have 5v coming from the PCM on the signal wire, but the signal wire for the cam sensor has no voltage. This is the only questionable item i can find everything else checks out fine.

I have only scanned with VCDS which is Audi/VW specific with OBD scanning tacked on but not very well.
The full list of codes i have are:
P0315 - Crankshaft position system variation not learned
P0463 Fuel level sensor circuit signal too high
P0807 - Clutch position sensor short to ground
P2068 - Fuel level sensor B circuit high

I have no BCM so there is no fuel circuits plugged in other than fuel pump. Are they needed? It started before.

Hoping with VCM scanner i can look at each sensor a bit better.

RonSSNova

iTrader: (3)

There is a crank relearn process. But I don't know much about it

mrvedit

The experts here say it only calibrates the misfire detection.
It is certainly not related to starting problems.

EXPERTS: Is this a vats problem or what do you suggest?

Lscobra

Thanks MRV

PSI conversions who supplied the harness have suggested it sounds like the PCM. (They have great customer service)

I have had confirmation from summit that VCM Suite has been sent. I changed my order to the tuner so I can remove VATs myself if I need to.

Hopefully I can look at the sensors with VCM and find an abnormality.

Should have VCM in 7-10days I hope

Lscobra

Finally solved this problem.


Turns out the signal wire in the cam sensor connector had come out of the terminal. My questions above about the signal wire voltage were on the right track. When I found out it is normal to have 5v on the crank sensor signal I should have done more investigation on the cam signal wire. I was told on another forum the rpm comes from the cam sensor so didn't look at it since rpm was showing on the scanner.

mrvedit

Glad to hear you have solved your problem.
I don't have personal experience with the E38, but with the 0411 PCM even a completely disconnected cam sensor does not prevent the engine from starting. It may backfire and require a few tries, but it will start and then run perfectly.

joecar

Not to mention that the crank relearn can only be done if the engine is running.

joecar

+1 glad you found it.