Catastrophic engine failure

[220bhp]

.The MAP sensor is a new bosch 3bar,., and was supplied buy MRC, but it is interesting what you say,what make was the faulty map sensor.

[s2_bo]

Really sorry to hear this Lou, what a nightmare! I hope you manage to rebuild it with a new engine and can still use the other parts.

Will keep checking this thread.

Good luck with everything.

[Jamo]

We feel for your loss, I hope you come back stronger than ever with a car, have you tried VRS and Spink for an engine?

[macspring]

220,

Can't be of any help, but you have my sympathy, I know what it feels like when an engine lets go.

Hopefully you can source a complete ABY for a rebuild, as mentioned keep the faith, it will get better.

[spink]

.The MAP sensor is a new bosch 3bar,., and was supplied buy MRC, but it is interesting what you say,what make was the faulty map sensor.

it was the original bosch 2.5 as fitted to all aby/aan ecus from factory

[prj]

Motronic has sanity checks for the MAP sensor.
The way they fail is they show a constant value all the time, in that case it will throw a code.
If you have that code in your ECU, it will not boost over 0.4 bar. MAP sensors failing is not a commonly occuring event, and I do not think a MAP sensor failure can account for engine damage.

If there is a MAP sensor code in the ECU and the ECU still boosts over 0.4 bar it means the wastegate has been tampered with. This is also the reason Audi uses a spring which allows for 0.4 bar boost without electronic control - to prevent bad things from happening if there is something wrong.
Out of everything that can fail - a MAP sensor is almost instantly diagnosed by the ECU and boost is turned off. Much worse is if the ECU can't hear knock for some reason.

[spink]

ok but car was totally standard,had covered about 100.000 miles and had an almost full history.after i put another engine in i was seeing 2.5 bar on the dash,seemed quicker than a standard car(ecu had never been opened before) but was not nice to drive.after much searching it was the last thing on the list to try,we all know ecus rarely fail but swapped the map sensor and it ran 110 percent after that so i presume the previous owner had been unlucky or had driven it like that for a while and it eventually let go.only code that i remember i was getting was 'max overboost reached',nothing saying faulty ecu etc

[prj]

The 2.5 stuck on the dash means that the sensor is stuck at 5 volts, which is exactly how they fail.
If the car was still boosting like that, then it must have been tampered with.
The stock ECU cuts fuel before any damage can occur to the engine... It won't go over 1.2 bar boost.

[spink]

no it wasnt stuck at 2.5,it was climbing up to that,and very quick aswell

[prj]

no it wasnt stuck at 2.5,it was climbing up to that,and very quick aswell

That would mean it would be boosting 1.5 bar or the voltage output from the MAP sensor is wrong.
It can't boost that much on stock ECU though - the stock ECU cuts fuel very quickly.
Also, as I said, if you have a MAP code in diagnostics, it is set to spring pressure...

Either way - I can say with 99% certainty that the cause of your engine failure was not the MAP sensor. If the MAP sensor shows more boost than there really is, motronic will actually lower boost to meet target. It will also cut boost at 1.4 bar and 1.15 bar at redline.

[220bhp]

When I first got this car with its original engine it would not perform at all, it was always in limp mode, or there abouts,it never matched the pace of my s6 avant,a much heaver car,this turned out to be a front knock sensor.

[220bhp]

I have been trying to reflect on what happened with the help of my friend Glen Morangie , and on reflection I remember several miles before this happened something appeared to fall of the car,and I sore it. bounsing around in my rear view mirror,
cant say what it was, or if I had just run over something in the road. there was no indication of any problems, no warning lights extera,and the car was OK.I stopped of to .see someone for an hour or so ,then continued, the engine exsploded about 6 or seven miles down the road.
This may of been coinsidental, but if not what small object could fall of and cause this.

[DJones]

I have been trying to reflect on what happened with the help of my friend Glen Morangie , and on reflection I remember several miles before this happened something appeared to fall of the car,and I sore it. bounsing around in my rear view mirror,
cant say what it was, or if I had just run over something in the road. there was no indication of any problems, no warning lights extera,and the car was OK.I stopped of to .see someone for an hour or so ,then continued, the engine exsploded about 6 or seven miles down the road.
This may of been coinsidental, but if not what small object could fall of and cause this.

What sort of size object did you see in the mirror?

For the damage you have described it would need to be something that allowed the sump to empty.

As mad as it sounds i knew someone who's oil filter fell off...

[quattro]

Have a look around the bay, if not go have a look for it if its possible (not on the fast lane of the m6).

Best thing to do is to strip it and look at the 'evidence' then make an educated guess, for this to happen it cant be many things, oil starvation, broken valve,baring failure or a massive knock which was not detected by ecu.

[220bhp]

Having had issues in the past,I keep a keen eye on the dials and there was no indication of any problems, until the engine went, then all the warning lights came on,
first water then oil.
As far as the object is concerned it was small and bounsedi thought it was may be an exhaust hanger.