Booost problem on way home from work.

[Luke_buk]

Hi

i was coming home from work as you do most days.
but today as i put my foot down to shake the cobwebs from my head my car only boosted to about 4-5 psi.

it usualy boosts about 9-10 psi

my car is standard setup leon cupra 180 bhp with a k&n induction kit

anyway i pulled up turned of the ignition. then restarted. when i drove off i went into second and put my foot down and the boost was back to normal. what the hell could this be

help!!!

 

[lee_woollett]

could possibly be a collapsed TIP? Or somehow went into limp mode which was reset by turning off the ignition

 

[LEE69]

Yeah 5 psi is limp mode, for what reason, who knows

 

[OFI]

Should you get a dash indication of limp mode?

Occasionally mine appears to be in a limp mode as it just doesn't appear to boost at all but turn it off and on again and it clears. It appears to be at random from a cold engine..

 

[Ruddmeister]

I'll have £5 it's the MAF

Should you get a dash indication of limp mode?

Not always

 

[ScoobyJawa]

No you don't get dash indication always.

Get it on VAGCOM to see the problem, proabably an air leak.....

 

[Luke_buk]

could possibly be a collapsed TIP? Or somehow went into limp mode which was reset by turning off the ignition

please excuse my ignorance but what is a TIP?
sorry but i am new to these engines and so i am learning all the time

 

[lee_woollett]

Turbo Intake Pipe, the pipe running from the air filter box to the turbo. Standard ones are black with a ribbed outer surface to prevent collapse under boost, as the turbo spools up, the air is being sucked in and this causes the pipe to collapse on itself. Over time, the heat will cause it to happen. Also, re-mapped cars will probably cause this due to higher pressures. Change it for a silicone TIP (THS, Forge, etc, etc) which are re-inforced to stop them collapsing.

 

[philjc99]

Aright mate, i've got the diesel 110 bhp tdi engine and mine did something similar when i was driving back the day i got it. i put my foot down, and then there was a shudder where the turbo kicks in, and i had no power. it seemed like i was driving a shitty 1 litre car again. And like you when i turned the ignition off and back on, the boost was back and working fine. I took it back to garage and they said i'd blown a pressure valve in my intercooler. They replaced it and its been fine since. Don't know if the engine's work the same but hope this might help.

 

[OFI]

No you don't get dash indication always.

Get it on VAGCOM to see the problem, proabably an air leak.....

Yea sorry, right after I posted I remembered it being a common problem and started reading through all the threads on the issue!

I found the answer anyway

It's the MAF
No, the DV
No, a split hose.
No, the N75.
No, the 249.



I'll check those hoses first as I did have a 17705 (IIRC) code a while ago which points in that direction. It's so infrequent and simple to temporarily fix it's easy to be lazy..

 

[Muttley]

philjc99 wrote

Aright mate, i've got the diesel 110 bhp tdi engine and mine did something similar when i was driving back the day i got it. i put my foot down, and then there was a shudder where the turbo kicks in, and i had no power. it seemed like i was driving a shitty 1 litre car again. And like you when i turned the ignition off and back on, the boost was back and working fine. I took it back to garage and they said i'd blown a pressure valve in my intercooler.

There isn't a valve or a sensor in the intercooler, but there is a sensor in the pipe connecting the intercooler with the inlet manifold, on the left-hand side of the engine bay: the Manifold Absolute Pressure (MAP) sensor. There is a temperature sensor in the same unit. The fault would show up straight away on the diagnostic computer and the fix is easy, the sensor is in plain view. Hope they didn't charge an arm and a leg for labour.

They replaced it and its been fine since. Don't know if the engine's work the same but hope this might help.

On the petrol engine the charge pressure sensor is mounted on the intercooler itself. Garage diagnostics or VAG-com would show up a failure.

 

[ScoobyJawa]

Yea sorry, right after I posted I remembered it being a common problem and started reading through all the threads on the issue!

I found the answer anyway

It's the MAF
No, the DV
No, a split hose.
No, the N75.
No, the 249.



I'll check those hoses first as I did have a 17705 (IIRC) code a while ago which points in that direction. It's so infrequent and simple to temporarily fix it's easy to be lazy..

Mine suffers the same and I've fitted a new MAF (so its not that!) put on a Forge 007 DV, done the N249 bypass and replaced quite a few hoses. Can be fine for weeks then goes into limp mode with the code about:

Fault: * VW 17705 (P1297) - Pressure Drop between Turbo and Throttle Valve (check D.V.!)

Restart car, reset code and it fine for ages!

 

[H_man]

As said before it is the maf, and the reson for this is that K&N are a oil based air filter. The oil from the air filter destrois mafs. As well as a new maf ,get a new air filter.

But to be on the safe side it might also be the N75 value,as I remember something to do with boost pressure!!!!!!

 

[lee_woollett]

the rumour about K&N filters destroying MAF sensors is crap, there is a link on here somewhere with videos showing a MAF completely coated in oil and it still works. I've used K&N filters on other cars with MAF's and never had any issues with them. I think it's more likely to be the MAF being a bit too delicate than the filter

 

[Ruddmeister]

Can I close this thread now we have established it's the MAF?

Who's paying me my £5?

 

[H_man]

the rumour about K&N filters destroying MAF sensors is crap, there is a link on here somewhere with videos showing a MAF completely coated in oil and it still works. I've used K&N filters on other cars with MAF's and never had any issues with them. I think it's more likely to be the MAF being a bit too delicate than the filter

Explain this the me than: some I know has a cupra R, and all was working fine, chaged to the K&N panal filter did what the instruction said, and in less that a day of booting the it around, the maf was f¤#"ed, One new maf , and one differant air filter ,and the car is still working fine.

Yip I have also use K&N on other cars and they work fab!!!!Maybe it is just a few maf that are effected by this I would not be able to tell you!!!!!

 

[philjc99]

philjc99 wrote

Aright mate, i've got the diesel 110 bhp tdi engine and mine did something similar when i was driving back the day i got it. i put my foot down, and then there was a shudder where the turbo kicks in, and i had no power. it seemed like i was driving a shitty 1 litre car again. And like you when i turned the ignition off and back on, the boost was back and working fine. I took it back to garage and they said i'd blown a pressure valve in my intercooler.

There isn't a valve or a sensor in the intercooler, but there is a sensor in the pipe connecting the intercooler with the inlet manifold, on the left-hand side of the engine bay: the Manifold Absolute Pressure (MAP) sensor. There is a temperature sensor in the same unit. The fault would show up straight away on the diagnostic computer and the fix is easy, the sensor is in plain view. Hope they didn't charge an arm and a leg for labour.

They replaced it and its been fine since. Don't know if the engine's work the same but hope this might help.

On the petrol engine the charge pressure sensor is mounted on the intercooler itself. Garage diagnostics or VAG-com would show up a failure.

Thats probably what it was then. Wasn't really listening to the mechanic when he told me on the phone. All i listened to was when i coukd pick it up. I managed to break it on the way home from the dealership the day i picked it up. Didn;t cost me a penny, the joys of having a waranty!

 

[ScoobyJawa]

Guys he HASN'T found the answer. He was saying he looked through the threads and 1 says MAF, next says N249, next says N75, next says DV next says hose - he's making a joke that it could be any one.

If you read my post I have the same problem as him, and only thing I haven't fiddled with is the N75, I have a NEW MAF ON MINE AND IT STILL DOES IT.

SO IT ISN'T THE MAF!!!!!!!!!!!!!!

 

[Luke_buk]

as said before it is the maf, and the reson for this is that k&n are a oil based air filter. The oil from the air filter destrois mafs. As well as a new maf ,get a new air filter.

But to be on the safe side it might also be the n75 value,as i remember something to do with boost pressure!!!!!!

its not the maf as it is a brand new bosche one that i fitted 4 days ago.