Fuel Sender Unit

[wannaeatyourbrains]

Still having issues with the VZ running rough. Only 4 or 5 cylinders now. I have put in new coil packs, plugs, injectors, fuel filter.

There are no error codes.

Could someone enlighten me, are the fuel sender units interchangeable between all VZs?

I got one out of a 2004. Mine is 2006. I just noticed the fuel filter from the new one has a smaller diameter.

I have no way of checking fuel pressure, other than to say that when the engine is running, if I depress the Schrader valve, plenty of fuel sprays out. (Only for the brave hearted.)

Could fuel pressure still be the issue? Is it the wrong sender unit?

I actually suspect the ECU, cause the engine got wet, and it was shortly thereafter all problems started. I think the fuel injectors are not firing.

Would I get error codes for a malfunctioning ECU? Would it stop generating error codes for other problems?

Thanks in advance.

 

[Fu Manchu]

Firstly. It's not about brave hearted. It's just fricken mental to depress the Schrader valve with the car running. Do you want fire? Because thats how you get fire.

That valve is meant for a pressure gauge to fit to it so the pressure can be read.
Low pressure and you will still have fire enhancing liquid, that goes bang, spray out.

The ECM is sealed. The plugs are sealed. Co-incidence.

The tests needed to diagnose your issue can only be done with a Tech2 diagnostic tool. Different circuits can be isolated and operated to check the systems.

MY06 have slight differences in many components as they transitioned to the new VE platform. Fuel pumps are different, some have three ports on the top, others have a oneway/non return setup. MY06 MY07 will have nonreturn.
Get the correct part for the model/year.

Fuel senders should be matched to the body type.

You need to check for vacuum leaks.
Use new gaskets when refitting the intake manifold. Check the vacuum hoses for cracking or brittleness, especially where they connect to the intake manifold. replace with new ones. Available on eBay.
Clean the manifold with carby cleaner. Clean the throttle body with throttle body cleaner.

Go back and redo the spark plugs. Take extra care to see they are torqued correctly and more importantly gapped correctly.
Then refit the coils carefully.
Take care unplugging the connectors.

On the intake manifold, some had the brass vacuum ports. They will seal fine. Others have a screw in/threaded plastic port. Replace with a brass port from auto parts store. (There is a thread about this and a video on youtube). Others have a plastic push/pull out tube that has an o-ring on it. That perishes. Vacuum leak. Replace with a threaded brass port. Clean out the intake manifold again incase any swarth is in there from threading in the new ports.

You could have a faulty coil. (even if new) A Tech2 device will test it.

 

[wannaeatyourbrains]

Thanks my man.

Fuel senders are identical to look at. Only difference is the diameter of the fuel filter nozzles, oddly enough. I even tried swapping over to a brand new fuel pump I have just now, but still no joy.

Sadly, all that other **** is rock solid. Pulled it apart and reassembled it several times already. It's all good advice. Actually put in another throttle body too.

Even more sadly, that exhausts my DIY options. Poor old car will have to take a trip to the city on a tilt tray to be properly diagnosed.

What a pain in the bum.

Appreciate your help.

PS: I tested for fault codes with the Torque app. It's not good enough?

 

[Fu Manchu]

It’s one thing to use an app to get fault codes. Some can get more detail too, like live data.

What the Tech2 can do is isolate sensors and run diagnostic tests on them.
Eg. operate the throttle butterfly without the car running, isolate actuators in a HVAC system, test out independent injectors, dig into BCM or ECM functions and that’s just a basic description.

So an app or OBD connected device is like looking in a shop window.
Tech2 is when you get the key to the door.

 

[wannaeatyourbrains]

I want to buy one, because a trip into the city on a tilt tray is a $100 every time. And it is better than chucking parts at the car on the basis of conjecture.

Besides, I like this hobby, messing with Commodores. I am keen to resurrect some more.

Although I am a bit off it at the moment, because this dilemma has proved unsolvable. The spanner has been thrown. No beer has been chugged.

Anyway, when I look on AliExpress, there are different kinds of Tech 2 devices. Amazon won't ship to Saudi Arabia. Which is the right one to buy?

Also, my mate with a garage here, his is not hand-held like the ones I see online. His data comes up on a PC. Surely that must be nicer than a handheld unit?

Oh, and if you don't mind, I am keen to try my hand at repairing the electronics, too. I saw some interesting videos with guys repairing the ECUs. Fixing the wires, which I damn well bet is what is wrong with mine.

What kind of soldering iron do you recommend for that? Cause there is a bewildering array to choose from. And is any additional software required other than Tech 2?

I don't mind chucking a bit of money at my hobby, but I am not going to do anything on a commercial scale.

If I can get the right tools, I will enjoy learning to use them. Maybe someone can put it in a nutshell for me, direct me to the right stuff straight up.

Actually, I feel inspired enough to go and rip everything off and check one more time it is all assembled correctly. Although I am sure it is. I see nothing but oil on cylinder one after it has been running. There's nothing happening in there. And it isn't just running rough. That piston is just bashing up and down with no combustion - and you know me, I invite combustion - and I am pretty sure one on the other bank as well. I don't think there is any fuel going in there. I am, on the bass of inspection, sure that everything is AOK except that ECU.

Like I say, although it was a blocked fuel pressure regulator that initiated the overhaul of the fuel system, the other drama that happened simultaneously was I found condensation in the throttle body. Maybe the car wash guys got overzealous, I am thinking, and were spraying from underneath up in the engine bay.

I neglected to do what is necessary here, and personally oversee things.

Anyway, much appreciate you hearing me out and helping.

 

[Fu Manchu]

Buy on eBay. If you can, set to Aussie eBay to find a Tech2 with genuine GM Australian Holden software.
There are also genuine VZ factory manuals available as PDF's. Once you have that and the Tech2, you can do a fair bit and once you learn your way around, the sky is the limit.

Now when it comes to ECM repairs. That **** is so fricken difficult, you are best to turn to the Aussie ECM repair services. Melbourne and Sydney have businesses specialising in this. You aren't going to repair these at home with a soldering iron. Some BCM features, yes, but not ECM. That takes highly specialised equipment.

 

[wannaeatyourbrains]

There may have been a breakthrough.

I reassembled the coils, plugs and fuel system one more time. That **** was tight as before, now it is triple checked.

I pulled the tank out one more time while I was at it. Second time today. Friday and Saturday are the weekend here, interestingly enough, not Saturday and Sunday.

I found that the new fuel sender is a little different to the original. The original one is the one at the top. It has the valve that became stuck, and that caused me so many difficulties in the first place. Foremost in the pic.

The new one, from the older model Commodore, bottom pic, does not have it. Now you think I would have noticed that before...

Are these two units interchangeable?

Or is this the cause of my woes? I hope so.

I am going to scavenge an identical one to the original in the morning, and try that.

 

[Fu Manchu]

Bet it works

 

[wannaeatyourbrains]

This is very promising. You inspired me to do that, mate.
View attachment 207498

Here is the line-up in Mecca. Commodes bring style to the car park.

 

[wannaeatyourbrains]

I can show readers how to disassemble the fuel sender unit, although I am not having any joy getting the car going yet. I could not find the right fuel sender, but I got a new valve. I will modify the sender I got.

First, you gotta remove the float, cause you are only gonna break the ceramic chip for the fuel gauge if you don't. Gently pull it out of those clips - pushing the clips with your thumb more than you pull the wire, actually, while gripping it like I am there - and it will come.

Then you gotta remove the return line. Either pry the clip off, and slide something down between it and the valve, if you got a valve. Just twist and wiggle the valve out of the hole where I got the driver.

If you got the straight return line, grab it with some pliers and twist then wiggle.

After that, it is a piece of piss to get the swirl tank off. Just pry the clips off at the side and wiggle it down. Mind you don't grab the ceramic chip for the fuel gauge by accident. Those things are delicate as. Very brittle.

Then you can pull out the fuel pump. Just depress the clips with your fingers and pull it down.

Here's the clips. They are attached to the filter.

There is another filter in the valve too. You can pry the valve out and clean it.

I tested it was working with a bicycle pump after cleaning, cause it had been lying out in the desert in a wreck god knows how long. It was OK.

Wife's away, so I am working in the lounge, ha ha. You won't get the original pipes off or on again, so you gotta get new fuel line. Make sure it is flexible enough to do the spring thing. I had three pumps. I went with a new one I bought. Had to do a bit of wiring.

And that was it. Put it all back together, and back in the tank. Car still won't go. I am wondering if the new pump pumps hard enough. I will pull it all back out and try one of the other two - an original one - next weekend.

Still pretty sure the ECU is the drama. Injectors are not firing. The fuel line won't self bleed any more.

Either that or the new pump doesn't give me enough fuel pressure.