Engine Shutdown at freeway speeds with no codes? Boost hose....

[CuStOm]

While driving home from a party on Saturday night my A4 shut down while on the freeway at 65mph! The interesting part is I did not get ANY codes out of the deal. Further inspection revealed that I did not get the hose clamp on the bottom of the diverter valve completely tight while I was lubricating the piston earlier in the day and it had popped off. Simply hooking the hose back up fixed everything and we were off and running. So two questions:

Why no codes?

Why in the hell did the ECU determine it was best to shut the car down rather than go into limp mode? This is VERY dangerous in my opinion.

[AudiA4_20T]

A. What code would it throw?
B. When the MAF is connected, blowing a boost hose off shuts down the car always

[eurogruppe]

the car wont show you anythign when its in limp mode unless its liek a blown coil pack or whatever, ive had the hose going from my tip to the dv folded not letting any circulation go through and it put me in limp mode as well. its a good idea to have a boost gauge to make sure your readings are ok because the computer wont show everythign the turbo is goign through

[CuStOm]

I have a boost gauge but if the car is not running, its as useless as the tits on a nun. :P

AudiA4_20T - If the MAF was not hooked up the car would have still ran? Am I understanding you correctly?

[old guy]

Why in the hell did the ECU determine it was best to shut the car down rather than go into limp mode? This is VERY dangerous in my opinion.

Your car didn't go into limp mode. Your car went into "how the hell do you expect me to run on a 100/1 A/F ratio" mode.

[CuStOm]

Maybe I am not completely fluent with the air path/hose routing or we have a communication problem. Or I am flat confused.

The DV is basically directly after the samco turbo outlet hose but its only a small branch hose and not the main flow path from the compressor to the front mount and then to the MAF. Thus the compressor is still able to function, just not very well. The engine is still able to breath and is getting air through the MAF from the turbo/airbox and now atmosphere due to the DV popping off. Granted the air volume and pressure has been reduced, but there is still plenty of air for combustion that is still able to be read from the MAF. Am I missing something?

I would have thought that the ECU would have used the MAP sensor and determined there is no boost even though there should be, throw the car in limp mode and tell you there is a problem with a MIL light. Not shut down. I am an engineer that writes code for similar systems, in my opinion this is a design miss. Unless of course I am not seeing something.

Granted the A/F will be wacked out initially, but the car can correct for that. Shutting down the engine at speed is dangerous. I had to pilot the car in off the freeway without power steering or brakes. I was fine with it, but many people would have freaked and made bad decisions.

[dougyfresh]

Your car was not rolling with the motor turned off and the car in gear, was it?

Does it run now?

[CuStOm]

Your car was not rolling with the motor turned off and the car in gear, was it?

Does it run now?

I clutched in immediately and coasted. The car runs just fine. Aside from the cat smelling a bit upon first start up due to the unburned fuel that went in there during the mishap all is well. I have logged a few pulls with the VAG-COM and everything works perfectly.

[dougyfresh]

Okay. Just wasn't sure.

The only time I've had a car shut off on me while driving was when my timing belt broke on my '91 VW GLI 2.0L 16V. That is why I asked.

[old guy]

Unless you have rearranged something the MAF is in front of the turbo just after the airbox. When you blew the hose off of the DV you began introducing un-metered air through the open hose which threw your A/F way out of whack.

[A4 TSCHUSS]

A. What code would it throw?
B. When the MAF is connected, blowing a boost hose off shuts down the car always

No it doesnt. I have blew mine off a few times and drove the car home. Tracee (Greg's wife) has done the same. I think he said she drover over an hour home one time after blowing an intercooler hose off.

[AudiA4_20T]

No it doesnt. I have blew mine off a few times and drove the car home. Tracee (Greg's wife) has done the same. I think he said she drover over an hour home one time after blowing an intercooler hose off.

um Tracee must have unplugged the MAF. You can have a large tear, but if you have the MAF hooked up your car WILL turn off. Seriously I've had it happen so many times on my B6

[CuStOm]

Unless you have rearranged something the MAF is in front of the turbo just after the airbox. When you blew the hose off of the DV you began introducing un-metered air through the open hose which threw your A/F way out of whack.

Crap, you're right. I should have walked my lazy ass out to the garage before I said that. I was thinking of the other car.

Ahhh...I see now. The A/F on the front 02 sensor did not match what the MAF saw so the ECU said "Oh Crap...shut her down Scotty!".

[A4 TSCHUSS]

um Tracee must have unplugged the MAF. You can have a large tear, but if you have the MAF hooked up your car WILL turn off. Seriously I've had it happen so many times on my B6

I guess you missed the part where I said I have blew off a hose a few times as well and drove the car home just fine without touching anything, just no boost. Sooooooooooooooo NO IT DOESNT!!!

I have been racing through a gear at 21psi and blew the hose off about gave myself a heart attach since it was so loud releasing the air when the hose blew off. Then I realized what happened and drove myself home like 3 or 4 times. I have blew it off directly at the turbo before and I have blew if off where it connects to the intercooler before.

[AudiA4_20T]

I guess you missed the part where I said I have blew off a hose a few times as well and drove the car home just fine, just no boost. Sooooooooooooooo NO IT DOESNT!!!

maybe the revo changes things. Hoenstly, on 3 stock cars and my car numerous times, my car has shut off.

[old guy]

Does the Revo BT tune utilize the MAF?

[A4 TSCHUSS]

Yes it does use the maf. Some people run without it though. But myself and Greg have always ran the maf (except when he had his original GT28rs like 4 years ago). And like I said both of the cars have driven fine after blowing off the hose.

[CuStOm]

No idea about the BT program but the REVO K04 file throught Eurocode obviously does.

[AudiA4_20T]

Yes it does use the maf. Some people run without it though. But myself and Greg have always ran the maf (except when he had his original GT28rs like 4 years ago). And like I said both of the cars have driven fine after blowing off the hose.

So, on Revo BT cars, you can blow off a hose and be fine. Otherwise, you are not and your car dies

[CuStOm]

So this damn hose blew off again last night. I am not sure what changed, all I did was re-lube the DV during a routine oil change. I've done that same sequence 10 times before. After the freeway fiasco I made sure that clamp was tight above the flare. Would there be something else that could be causing it to pop off? The car runs just fine....

[widgget]

mine just shuts down when i pop one of the turbo hoses, thought it was the fuel pump the first time. I've blown the hoses plenty of times and always had the same results. I''ve since put a bead of Gorilla glue on everyone of the hose connections except the one to the turbo outlet and the intake manifold, been solid since and haven't popped anything off.

[BEESIX]

lol quit re-using those same clamps, this happened to me multiple times so i took off the clamp it self and looked at it it wasnt a perfect circle, once you tighten it for the first feww times it takes shape around the clamping place, once you take it off and reclamp it, it looses its shape, it wont stay a perfect circle, i promise you if you just get another clamp to replace it, this will never happen again

[CuStOm]

Last night I swapped out to better stainless clamps instead of the shitty ones included with the silicone hoses. I race motorcycles and am intimately familiar with how to safety-wire a hose clamp so it does not come loose. I applied that method last night to all the clamps on the boost path. This should never happen again. It looks like a race car under there now. :D

My question was related more towards the DV possibly not lifting and causing an over pressure situation that would be responsible for popping the hose off.