2009 V8V Roadster Starts, but dies after a few seconds

[acole]

So I'm rebuilding a 2009 V8V Roadster that was in an accident. For some background, over the course of the rebuild I've changed the coolant, changed the engine oil, replaced the AC compressor (still not charged but sealed at vacuum), rebuilt the power steering pump and changed the power steering oil in the process. Finally, when it comes time to start up the car, the engine starts no problem but quickly dies. Here's a link to a video of what's happening: https://youtu.be/bixy-6Uho14

I'm not getting any useful errors from the Foxwell, all of the codes thrown do not have a description, and the live data from the OBD isn't saying anything telling. Here are the codes that it's throwing:

P0601
C3020
C0141
P0001
P0106
P2042

I've replaced the battery in the key, there are no wire shorts from the accident that I can find, and I've gone through engine cranking without firing to build up oil pressure just in case that was the issue. I'm thinking the ECU is seeing something that it doesn't like, but I can't figure out what.

So long story short, does anyone have any leads on what to look into that may be causing this behavior?

[Matt_E_Mulsion]

Have you ever had it running or is this the first time you've tried to fire it up?

[acole]

Matt_E_Mulsion said:

Have you ever had it running or is this the first time you've tried to fire it up?

This is the first time I’m trying to fire it up. I bought it from Copart and in their notes they mentioned that the engine runs but will not stay running, so I’m assuming whatever caused it happened in the accident. I forgot to mention that I also replaced the airbag module and haven’t gotten a chance to get it to the dealer to program it, so it’s not communicating on the high speed canbus, but I’ve read that shouldn’t be an issue for running.

[The V12 Way]

this has to be fuel related i would have thought

[Matt_E_Mulsion]

It's not something as simple as an inertia/fuel cut off switch is it?

[ian448]

Try cleaning the throttle bodies , had the same issue on my 9 , gave em a good clean and problem sorted

[acole]

The V12 Way said:

this has to be fuel related i would have thought

I thought so as well and haven't completely written it off, but during key on I'm seeing a fuel rail pressure of 78 psi, and during startup it drops down to 58 psi which makes sense to me. No idea though what it would be if it stayed running.

Matt_E_Mulsion said:

It's not something as simple as an inertia/fuel cut off switch is it?

This was one of my initial thoughts as well, but I can't find any evidence that these cars have a dedicated inertial cutoff switch outside of the CEM. I've read you can cycle the crash status by locking/unlocking the car, and I've checked the crash status with the Foxwell, and it's indicating that the crash status is 'not active.'

ian448 said:

Try cleaning the throttle bodies , had the same issue on my 9 , gave em a good clean and problem sorted

I've actually pulled the throttle body and gave it cursory clean, as well as disassembled the gear train on it to make sure there was nothing there to mess with operation. I actually pulled the intake and videoed the operation of the TBs to make sure they were working well. I thought maybe they sounded a bit funny, but I think they're making normal operational noises that are usually not audible due to the engine operation. I'm not quite sure they're operating at 100% health, they looked a bit shaky to me, but it may just be I'm not used to seeing fly-by-wire TBs in action. If you're interested in seeing them work, here's the video: https://youtu.be/08vci1dXG-M

[chris9682]

Do think the car could have had a Ghost immobiliser fitted by the previous owner?
Regards
Chris

[acole]

chris9682 said:

Do think the car could have had a Ghost immobiliser fitted by the previous owner?
Regards
Chris

It really does seem like an immobiliser is shutting it down, but I just verified with the previous owner and he has said there isn't one installed and that the car started acting like this immediately after the accident.

[leman600]

P0601 being the first choice on your list may be the biggest clue.
Internal error for PCM can be the cause of other codes and could cause the engine to behave as you see.
The ECU is the only accident safety fuel shut off and this should reset upon 1 or perhaps a few more ignition cycles or battery disconnect as you have done.
If the codes are displayed in the order you have written them in this post then this could be where you should turn your attention.
I think this would need AMDS at some point though.
Good luck to you.

[acole]

leman600 said:

P0601 being the first choice on your list may be the biggest clue.
Internal error for PCM can be the cause of other codes and could cause the engine to behave as you see.
The ECU is the only accident safety fuel shut off and this should reset upon 1 or perhaps a few more ignition cycles or battery disconnect as you have done.
If the codes are displayed in the order you have written them in this post then this could be where you should turn your attention.
I think this would need AMDS at some point though.
Good luck to you.

So I've since realized those were codes specific to the Brake Control Module, and they've since cleared and are not coming back, Which makes me wary of the reading, if they do come back then I think you may be right in that there's an internal fault in the BCM module. I think either way, I may need ADMS to diagnose this issue. I don't think I'm getting enough information through the foxwell.

I have found the crash mode in the main ECU and it is not currently activated, so I don't think it's specifically related to the ECU thinking it's still in crash mode. But I do think whatever is causing the ECU to shut down the engine is directly related to the accident.

[N7GTX]

The engine is firing and running on the initial fuel pressure generated when the key goes to ignition on and the fuel pumps run.

If you turn the key to ignition on, no start, the pump will run for a couple of seconds to prime the fuel rail which you can hear as a buzz. Then the pump stops. Once the engine starts to turn the PCM receives various signals including the crankshaft sensor which is essential for the ignition system to start along with the cam sensor for accurate firing.

In view of the damage to the other front end ancilliary components such as compressor and power steering pump I would be very carefully checking the alternator. As the engine turns the alternator starts to spin up and sends a 'run' signal to the PCM. If there is a fault in this circuit you can get this start and die scenario as the PCM does not then send the signal to the pump to keep running.

In live data on the Foxwell can you see the engine rpm value? Is there a crank/sensor synchronisation value of yes/no? Check the value of the battery - must be min of 12.6v before starting - then the alternator in the data - 14.4v approx when running. If these are not shown a multimeter will do. If the Foxwell is limited in Aston mode, try OBD.

One often overlooked start/die cause is a blockage in the exhaust. The engine starts and the gas builds up. As it cannot escape the back pressure snuffs out the engine. Easy way to check is to remove a lambda (oxygen) sensor and try starting (it will make a loud noise but gives enough room for the gases to escape).

Edited by N7GTX on Saturday 25th September 23:44

Edited by N7GTX on Saturday 25th September 23:46

[acole]

N7GTX said:

In live data on the Foxwell can you see the engine rpm value? Is there a crank/sensor synchronisation value of yes/no? Check the value of the battery - must be min of 12.6v before starting - then the alternator in the data - 14.4v approx when running. If these are not shown a multimeter will do. If the Foxwell is limited in Aston mode, try OBD.

These were great tips, I was able to check off all of these values as healthy. I'm seeing an engine RPM, the crank/cam synchronization happens only when it's running. The batter is over 12.6V (hooked up to a CTEK) and the value jumps to over 14V when started. None of the CID (cam sensor) values are indicating a failure in the live data. I did notice one strange value, the IAT was about 11deg C higher than ambient, it was reading 35C air temp and my garage is about 19C. I'll plan on replacing it, but I don't suspect it as the culprit. I wasn't able to check the blocked exhaust yet.

The exhaust does smell very much like fuel, especially when you get underneath the car. So that may just be normal during startup, or it's due to the spark being cut. The engine will restart very easily, so it doesn't seem like it's getting flooded.

Also, after it stalls, it makes a very strange humming noise that almost sounds like an electric transformer, except that it pulses. The pulses get softer and softer until it finishes and then the AMS suddenly indicates it's in neutral. I'm not sure if that has something to do with the clutch or AMS pumps, or is not normal at all. I tried my best to video it, but I don't think the audio truly captures the humming sound well. https://youtu.be/8IH6ksoSgMY

Edited by acole on Sunday 26th September 04:50

[Matt_E_Mulsion]

I wouldn't get bogged down and side tracked by checking things like the exhaust.

If the car was running fine right up until the point of impact, it's something to do with the accident/damage. Especially as you stated that the previous owner had confirmed this.

[acole]

So I took it into a shop that has AMDS because I figured they may have better luck diagnosing the car with more information. They think that the car has jumped timing in the accident. I'm still a bit suspect because my Foxwell gave me a "yes" value for the cam and crank being in phase after 720, but it's possible they may have more info than I did. I will certainly check that again. They did tell me they checked all of the cam and crank shaft sensors and none of them indicated a fault. I got the car out of there after they wanted $1800 just to take the valve covers off to verify timing.

Would a leak down test be an effective way of verifying jumped timing? Or would a small jump be too small to measure?

[embdenb]

Jumped timing does not sound right. During the period of time the the engine runs, does the engine sound normal?

[acole]

embdenb said:

Jumped timing does not sound right. During the period of time the the engine runs, does the engine sound normal?

Yes, it sounds perfectly normal.

[N7GTX]

If your scanner says the crank/cam phasing is correct then its not the chain.

Can you remove the fuel pump relay and bridge it with a jumper wire? Ignition on and the pump will run permanently. Or disconnect the fuel pump harness plug and supply a 12v supply direct from the battery or another source to the pump. Try starting it and if it runs you've found the area to check more thoroughly.

If it does the same and cuts out I'd be checking the exhaust for blockage. I have found cats to have broken internally and the debris has blocked the outlet. That's why I suggested removing the lambda sensors upstream of the cats just to eliminate.

[KnowsAnAston]

Can you get a volt meter onto the fuel pump feed and see if it drops to 0 after engine start, or wire up a permanent 12V to the pump to see if it continues to run?

Could be something as simple as a damaged harness connector that has slipped a pin in the crash.

[leman600]

This sounds much more like computers and electricals than timing chain issues. I do think N7GTX makes some good points and if no more than to rule out an easy check his exhaust tip is worthy of performing. (That issue would confuse computer modules)
Are there any other minor seemingly irrelevant symptoms or even fault codes present.