2004 VZ Alloytec Running Rough

[ToastMalone]

Hey having some issues with my 2004 vz, high output LY7
So the car starts fine and seems fine until the car warms up then i get the 'Service Vehicle Soon' and it starts missfiring and running really rough and can even occasionally stall, Just done new plugs, injectors, fuel pump/filter, air filter, oil change/filter, evap purge valve, new ECT, cleaned throttle body/MAF, new pre cat oxy sensors, checked PCV but its good

Smells a little fuely but not extreme

Pre start it says System Ok!

To my knowledge the 'Service Vehicle Soon' warning should throw a error code but have not had any error codes coming up

Don't have the right attachment for my fuel pressure tester to try fuel pressure


Sorry for the random comments everywhere was trying to think of things that may help and adding them along the way lol can anyone think of any other easy tests?

 

[Fu Manchu]

I’d look at injectors.

Check the resistance on them and then heat them up with a hair drier or a heat gun and then test the resistance.

Do a smoke test on the intake side to find leaks. Do it cold. Then heat the engine up and check it hot. There are videos showing how to make one. It will absolutely show any vacuum leaks and where.

Then there is the possibility of mechanical causes. It might not be much, but removing the valve covers and visually inspecting the valves. Turn the motor over by hand and watch what they are doing.

Get the cam sensors out, give them a clean and re-install. Again, might not help but it might as well.

Get the cam actuators out. Clean them out with some throttle body cleaner. Test them (there’s videos showing how) for good operation.
That can be done out of the car. Re-install.

Then go around the various earth points and with the negative terminal disconnected and isolated away from the battery post, undo and clean the surfaces with some CO Contact cleaner or @lout suggests some stuff called De-Oxit which many swear by. Use a brass brush. Retorque them all, snug them up.

That sort of thing covers off on more basic maintenance that has a chance of resolving it… maybe. If not, you know you’ve done what you can and there maybe more sinister causes.

 

[ToastMalone]

I did the injectors the day prior to the main post trying to resolve the issue, felt smoother when it was cold but same issue once it warmed up and revs dropped back to their natural habitat

As for the smoke test i don't own one of those devices sadly, I will have to do some research and try find a cheaper alternative

About to go outside and clean me up some earths / cam sensors / actuators and anything else i can get to

Valve covers sound like a job for if the above fails lol

Appreciate the feedback

 

[Fu Manchu]

 

[Fu Manchu]

I made a smoke tester and it worked really well.

 

[ToastMalone]

Thanks for the video my dude, had so much going on so haven't had much time to play around with it,
How did u make the smoke tester if you don't mind me asking lol

Cleaned up the cam sensors/actuators but haven't tested the units uninstalled yet,
Also cleaned up some earth points

Noticed on the scan tool live data:
FuelSys1 and FuelSys2 keep fluctuating between OL-DRIVE and CL, which i believe is open/closed loop? by rights shouldn't it stay open once the car is warm?

Could that indicate a issue with the fuel pump / grounds or would that be injectors? or?

Really need to check the fuel pressure

 

[Fu Manchu]

I’m sick and miserable so I’ll go out to the garage and do a thread on y ghetto smoke tester later.

 

[ToastMalone]

Haven't touched the car in forever so its been a while - just wanted to update the post with the solution in the off chance it helps anyone in the future.
Took the car to a mechanic yesterday and he told me the alternator is buggered and causing low voltage - shutting the fuel pump and possibly other things off. Never even thought of this being an issue as the battery always stayed charged. Hes sourcing and replacing the alternator as we speak, will update the post if need be but praying that fixes all the issues

 

[krusing]

A scan tool would have logged a DTC for Low Voltage,
or, it would of shown up on live scan data.

 

[ToastMalone]

A scan tool would have logged a DTC for Low Voltage,
or, it would of shown up on live scan data.

Thats what i assumed also, the auto elec should have picked up that in seconds but after multiple visits he was also confused what the issue was, few different mechanics used scan tools on it and were also confused what the issue was. Even had one mechanic tell me it was the timing chains

Edit: The mechanic that has it now had to take it for a pretty good drive to get the error codes to show up - at first he was telling me to come pick the car up there is nothing wrong with it. I insisted he takes it on a proper drive because there is actually issues lol. He took it for a proper drive and then told me the codes are displaying now and its the alternator causing the issues :shrug: (the alternator is on the way out and is shutting down the fuel pump)