Alternator not working? [Resolved]

[DXX]

Me neither really....just Trying to eliminate things...

If you think it’s the fuel it maybe easier just to change the fuel in the filter first.

 

[Cjscos]

Yeah . I have one and will do that at the same time. I did put some diesel addative in the tank when I filled up but I doubt that would make a difference. Hoping to borrow a vag code reader lead tonight which I hope will she more light on the problem.

 

[Loz]

Did you test if the lift pump was working? (Blue/yellow wire under the passenger seat)

 

[Cjscos]

I did try to find the wire, but it got too dark last night. I will check again today. I cannot hear it working but some say it only works when turning over and running. There is quite a lot of wiring under the seat. Think it's for two towbar and leisure batteries etc.

 

[Cjscos]

Lift pump only seems to work when cranking the engine. Could not find the wire. disconnected the flow and return and it is pumping diesel through. Changed the filter and no water in the diesel.

 

[Cjscos]

I noticed this today on the carista and my friends vag com came up with it too. This was just with the ignition on. Everything else looked fine on the vag com.

What do you think?

 

[Cjscos]

Fuel pump in tank is working. Drained the fuel. Still no luck. No fault codes. Egr valve vacuum flap is working. Will take egr off to give it a clean then it if does not work I will give it a good beating it with a branch

 

[DXX]

I don’t think any potential EGR problems including fouling would cause the symptoms you first reported in this discussion.

 

[Cjscos]

Would vvt turbo cause it if the vanes were sticking?

 

[DXX]

Would vvt turbo cause it if the vanes were sticking?

Would vvt turbo cause it if the vanes were sticking?

Hard to determine based on a discussion, I think you may need to get some professional diagnostics carried out.
If you want to eliminate that you maybe able to reach to the lever to operate the vanes, not sure on how accessible it is.
Or operate the actuator via the hose.
You might need a phone camera on a stick / mirror / endoscope etc to see it.
If this problem didn’t exist before you carried out the alternator repairs there is a very high chance that it was something disturbed or damaged during the initial repair that it causing the current problem.
Carefully re-trace your previous work is my advice.

 

[Cjscos]

Thank you. I think its time for the garage. Shame as I like to do most things myself but sometimes it time to let it go especially when it is electrical.
I will update the results

 

[Cjscos]

Started a lot better today with new premium diesel in.

Now I have disconnected every sensor to try and emlimate them and it it only runs and Revs perfectly when I disconnect the turbo wastegate valve connection. When I do this the glowpug light comes on but it idles and Revs perfectly and putting the aircon heated screens etc in does not affect it. I am getting 14.7v so the alternator is working.
When warm and the plug is connected to the wastewater valve the rod moves and it won't run correctly.

I am getting somewhere now..

 

[Cjscos]

Disconnected the turbo pressure boost control valve and vacuum pipe with the little filter on it and it will rev and run fine. Connect either back up and it will stall. So it's turbo related but no smoke or anything.

 

[DXX]

Waste gate open?

 

[Cjscos]

Yes. It is opening it on start up when cold and hot all the time. When I disconnected the n75 moo valve it will start perfectly and rev. Its opening the wastegate for the overboost. I hope it is just this or the boost pressure sensor....

 

[Cjscos]

Changed n75 valve form the caddy and its the same part number but still won't Start when connected
What controls the n75 valve
Is it the map sensor?

 

[DXX]

Changed n75 valve form the caddy and its the same part number but still won't Start when connected
What controls the n75 valve
Is it the map sensor?

The N75 is controlled by the ECU.
As I said before I assume you didn’t have an issue prior to repairing the alternator issue. Have you checked for wiring harness damage?
There is a boost pressure sensor that will be providing input to the ECU, no idea where it is on a single turbo engine (CAAC). I suspect it is on the front of the engine near the alternator - possible damage???

 

[Cjscos]

Thanks I will check later tonight
I have checked all connections and for damage throughly and all seems well. At least I can crawl it off the drive now. Its impossible to get a tow truck or tow it off the drive unless it's running.

 

[DXX]

@Cjscos here’s what I was mentioning earlier. The Charge Air Pressure Sender is quite close to the alternator perhaps there is some damage / disturbance from the previous repair?

what T6, what engine, what year?

wasn't sure if there was a valve runner on the inlet . . . . looks like there might be.

.

View attachment 49481 View attachment 49482

.

 

[Lightrofit]

If you take a step back and check the basics.

The N75 shares its power with the N345 Exhaust gas recirculation cooler changeover valve, Fuse SB10 (small fuse box next to coolant), 15a, Yellow/Black wire, check you're getting power at the sensor end.

The N75 also has a junction point inside the eboxx, white plug T10e, pin 6 Grey/Brown wire. This leads to the ECU plug T60, pin 20.

Check the ECU T60 plug for corrosion and white T10e plug for tampering.