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[LC0112G]

If that came off, two things would have happened - the huge influx of unmetered air would have caused your engine to run at full revs, and your braking ability reduced by at least 80%. So thank god you caught it.

No it wouldn't. The engine would stall at the first (and every) opportunity.

Agree about the brakes, they would be very wooden and ineffective, although the brake servo would hold vacuum for a while if it fell off mid drive.

[Lizzie Zoom]

As a business owner Serek has a responsibility to rectify any issues raised as a potential short coming of recent work.

I don't believe that he has been given this opportunity.

And there's the underlying niggle that if something that obvious wasn't tightened securely for whatever reason (not the actual point of debate here), then what else may have been overlooked?

Taking the car back in and rechecking everything done wouldn't have been an unreasonable course of action. Not that he was afforded that opportunity.

As I have said before, I understand where you are coming from DG

But, Serek, like the rest of us is allowed the odd slip up.  As James states, Serek is only human.  In fact when Serek has done work on my car in the past it has been excellent.  This time the rest of the work was also done to a very high standard, and, very importantly, at a overall price that puts the greedy sods down here in their place.  They want well over double Serek charges, and DO make the errors that even skilled mechanics, like Serek, can make. 

To put right what I have SIMPLY rectified, albeit with great observations along with advice from you DG and others, has meant not driving a round trip of 232 miles, and paying Dart Charges.  So I am a pragmatist who just puts this all down to experience. I did this when a brand new Cortina Estate I had almost lost it's prop shaft due to only two bolts holding it together, or another brand new Cortina Estate needing me to take the water inlet pipe off to take out a big lump of metal crud, left in there by Dagenham, which made the engine go into meltdown!  Other Carltons and a Senator were also left with potentially dangerous issues by main dealer garages at times, needing me to urgently return them.  They all got my sharp tongue, but all was sorted and the errors not repeated.

Again No one was luckily hurt, and I could put the issue right. I still believe Serek is a very honest, friendly, guy who knows his way around an Omega like many others in the trade do not.  Unlike those 'others' he does not, like they did when seeking a price for a cam belt change with me supplying the parts, suck in air and say "that is a lot of work....all that at the top of the engine must come off.......£480!!!  Again, things can be overlooked as Serek did on this one occasion, but it does not put me off from using his services because that suits my pocket and I know things usually will be done correctly.  For instance the cam belt has been fitted perfectly, with the engine running very well and MPG at an acceptable level; also the hand brake has been adjusted to a tightness not achieved by others, with the rear brakes feeling superb.  The steering is also now not "moaning" and feels like new after he changed the fluid.

I will be phoning Serek this week now I know what was wrong and how to fix it, with a small reprimand given!  But that will be the end of it.  Nothing has changed.

[Doctor Gollum]

You obviously don't.

It's not a question of reprimand, but rather verification that nothing else was overlooked. As the person responsible for that work, regardless of who carried it out, Serek has a responsibility to check and rectify where required.

A reputable garage would graciously accept any reasonable costs incurred as a result of that. But you are simply making any and every excuse not to afford him that opportunity.

Which begs the question as to why.

[Lizzie Zoom]

 

This is getting boring now.  Just read my last post.  End of.

[Doctor Gollum]

This is getting boring now.  Just read my last post.  End of.

I will reread yours if you actually read mine.

[dave the builder]

DG , play fair
make sure Lizzie is on-line before posting, so she can have the last word 

[Doctor Gollum]

DG , play fair
make sure Lizzie is on-line before posting, so she can have the last word 

[JamesV6CDX]

If that came off, two things would have happened - the huge influx of unmetered air would have caused your engine to run at full revs, and your braking ability reduced by at least 80%. So thank god you caught it.

No it wouldn't. The engine would stall at the first (and every) opportunity.

Agree about the brakes, they would be very wooden and ineffective, although the brake servo would hold vacuum for a while if it fell off mid drive.

I don't think you're wrong, but I do think it depends on how loose the pipe was. If it didn't totally detach, but let enough air in, the revs could rise.

But it's academic.... main thing it isn't been caught early, and everyone is ok

[LC0112G]

If that came off, two things would have happened - the huge influx of unmetered air would have caused your engine to run at full revs, and your braking ability reduced by at least 80%. So thank god you caught it.

No it wouldn't. The engine would stall at the first (and every) opportunity.

Agree about the brakes, they would be very wooden and ineffective, although the brake servo would hold vacuum for a while if it fell off mid drive.

I don't think you're wrong, but I do think it depends on how loose the pipe was. If it didn't totally detach, but let enough air in, the revs could rise.

But it's academic.... main thing it isn't been caught early, and everyone is ok

You just have to consider where is the extra fuel going to come from. The ECU doesn't know about the extra air, so won't inject extra fuel to burn the extra (leaking) air. This will result in a lean mixture. Fuel/Air won't burn if the mix is greater than about 20:1 - normal stoichimetric is about 14.7:1. So if the air leak makes up more than about 30% of the air going into the engine, there won't be enough fuel to sustain combustion, and the engine will stall. This is most likely to happen when the throttle is closed - so at idle, or during overrun/deceleration. To keep the engine running you are likely to have to apply some throttle whilst sitting at traffic lights.

At larger throttle openings the engine will run, but it'll run leaner than desired. The volume of air passing through the throttle bodies (and more importantly over the MAF sensor) will be (much) larger than that through the air leak, so the ECU will inject enough fuel to sustain combustion. It'll still be running leaner than ideal though coz there won't be enough fuel to burn all the air, and at high power settings this could be damaging to the pistons. Lean mixtures burn hotter.

Lambda sensors don't despond quickly enough to catch this sort of behaviour - they're basically used to adjust medium and long term fuel trims. They won't learn quickly enough to compensate for air leaks, and even if they did, they only have enough authority to change the injector duration by about +/- 15%.

So on MAF (Mass Air Flow) based systems, air leaks tend to cause lean running, and stalling at low throttle openings. On a MAP (Manifold Absolute Pressure) sensor setup things are different - and the engine would/could run away, but Omega B and most Vauxhalls are MAF setups.

[Lizzie Zoom]

As a final comment from me, I can confirm that I have discussed all matters with Serek, who couldn’t have been more apologetic.  He offered to check over all the work, but I said that wasn’t necessary as the problem had been overcome.  He also stated he would make amends when I next take the car to him, which I will do.
As far as I am concerned, case closed as all that I have stated before applies.

[YZ250]

…………..
the huge influx of unmetered air would have caused your engine to run at full revs, ……………….

This happens with two stroke bikes.    A split carburettor boot, a leaking crank seal, any air that gets in the cylinder and away they go at full throttle. Just hope that you are in gear when it happens so that you can jump on the rear brake or stick it against a tree to stall it, as you’ve got no chance using the kill switch and by the time you’ve pulled a lead off the engine would have eaten itself. 

Anyway, glad you’re sorted Lizzie.