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Still digging on this one whilst I await to get the car into a specialist.
I was checking the manual to see if there is a proper procedure on charging the batteries and I noticed that all the items I have codes for seem to correspond to fuse number 7 in the engine bay fuse box.
will investigate tomorrow and see if that fuse is indeed blown causing the circuit low codes for the above items.
If that does turn out to be the case either me or the specialist will need to determine what's causing the fuse to blow.
As suspected 10 amp fuse no 7 in the engine bay fuse box was blown.
Replacing this cleared the codes until the fuse blew again. Just as a test only I fitted a 20 amp fuse and let it idle. Codes cleared and didn't come back until I raised engine rpm to 2k which then blew the 20 amp fuse.
Would I be correct in deducing that something on this circuit the fuse protects is potentially having issues and drawing too much current blowing the fuse?
There is so much going on that is wrong. It makes it hard to visualise what has failed.
Why is the filter element destroyed?
Why us there soot around the turbo area ?
Why is the engine louder on that side?
Why does it smell of exhaust in that area.
One answers and only an educated guess is it could be some form of turbo or gasket or manifold failure allowing hot gasses to damage sensors or wiring . Hence fuse blowing.
Why only above 2k rpm ??
What is attempting to be activated in that area above 2k? Turbo actuator valve/solenoid perhaps??
Does the valve timing solenoid operate at 2k?
what the cause is, is going to require proper diagnostics.
Hopefully once the car us picked up you will have an answer.
Firstly, well done for pinning down your problem to that fuse.
Next, and sorry to be brusque, but fuse values are not chosen for fun. Doubling the current flowing through cables that are the cheapest/thinnest that VW could get away with, is asking for trouble. Even doing so for a few seconds is not a good idea. Modern wiring is termed “thin wall” for a reason: the insulation is of minimal thickness, so is readily melted by excess heat.
Also, consider the poor little output transistor in the ECU which is now switching twice as much current as it was designed for. Frying the ECU in this way is not a smart move. Even stressing it as you have done is weakening it for the future.
Anyway, lecture over, now I'll be more helpful: I’ve looked at IETIS and these are the actuators that are powered through Fuse 7:
Engine mount valve (X00806 81-way connector Pin 22)
Boost control valve (X01176 40-way connector Pin 116)
All of them are powered from F7 via Red/Slate wires on one pin, and the other can be grounded by the ECU to switch the appropriate device on.
If it was me I would disconnect both ECU plugs, and then measure resistance between F7 and the appropriate pin as listed above. i.e. the resistance through the wiring and the actuator. I would expect somewhere of the order of 10 - 20 Ohms in each case.
At the same time I would measure the resistance between each of the pins listed and ground, to see whether an actuator has gone short circuit.
If more than one wire measures short to ground, then obviously it’s a loom chafing or exposed to heat problem. Edited to add: This is unlikely to be the case because of the failure mode.
HTH
Hi Dark Green,
Completely take on board what you are saying. Fitting the 20 amp fuse was not the best idea in hindsight!
I won't be trying that again.
As I say I am just working on the logistics of having the car recovered to the specialist next week where hopefully I will get the answers and post them back here.
I enjoy working on my own cars and coming from Range Rovers I am more than used to doing so!
I like to try and diagnose faults myself If I can even if it isn't me that eventually ends up fixing them. I'm happy at this point that there is either some kind of electrical issue blowing fuse 7 or perhaps a solenoid behind this fuse that is having problems and thus blowing the fuse. Will be interesting to find out.
As for the potential exhaust leak it sounds much worse when the secondary air injection pump is running. Would I be correct in thinking there will be a connection to the exhaust system or manifold somewhere?
Completely take on board what you are saying. Fitting the 20 amp fuse was not the best idea in hindsight!
I won't be trying that again.
As I say I am just working on the logistics of having the car recovered to the specialist next week where hopefully I will get the answers and post them back here.
I enjoy working on my own cars and coming from Range Rovers I am more than used to doing so!
I like to try and diagnose faults myself If I can even if it isn't me that eventually ends up fixing them. I'm happy at this point that there is either some kind of electrical issue blowing fuse 7 or perhaps a solenoid behind this fuse that is having problems and thus blowing the fuse. Will be interesting to find out.
As for the potential exhaust leak it sounds much worse when the secondary air injection pump is running. Would I be correct in thinking there will be a connection to the exhaust system or manifold somewhere?
The air from the sai blowers goes along a casting in the head comes back out the head sandwiched between the manifold gasget and a groove/ slot cut into the face of the manifold and then back into the head via a slot just after the exhaust valves and hence into the actual manifold.
A loose manifold or blown manifold gasget would indeed make the sound of sai much louder and would probably create heat out side the manifold.
They say the turbo boost control solenoid requires replacement as they have determined it is the cause of fuse #7 blowing.
They reckon the exhaust leak is coming from a core plug in the head?
The front end of the car is coming off to access everything and a new drive belt is being fitted as the existing is cracked up and overdue for replacement.
Im not sure how they ate going to change the turbo actuator without taking the engine out. I hope they can. Im really interested to see the outcome.
As to core plug in the head. The only 2 plugs that are related to exhaust are the 2 screw in metal plugs in the SAI system at the top of the head.
Im not totally unsure the engine might have to come out.
However its best for all us Continental owners to find ways of doing repairs without removing the engine.
I look forward to your updates.
Frank.
03-26-2021, 02:25 PM
