boost decreasing

[Ade]

Today I swapped to a Rica mapped ECU on my 855 T5.
All was well at first, lots more boost, power and plenty whooshy noises!

After some enthusiastic driving though the boost gauge didn't go as far, and performance seemed to drop off.
(Still making all the boosty noises though!)

Any ideas why? Is this the ECU reducing boost due to excess heat or something similar?

[Dangerous Dave]

Could be a number of things.

Easy thing to try first is to check all the piping, see if the extra boost has broken something. Another thing to try is pressure testing the intake system. I did this with a bit of hosepipe gaffa taped onto the turbo intake (to just test the pressure side) and I found that the injector seals leaked badly, and a check valve was leaking too.

Also try putting the old ecu back in to see if the boost holds and doesn't drop off. That could point to a problem with the remap.

[The Flying Moose]

I would give it a little while to "adapt" as it were, the ecu's adapt to the hardware and setup of the car. As the ecu was running with larger injectors and a bigger turbo it will need to adjust to the smaller ones.

The more likely cause as bomb192 says is a damaged boost or vacuum hose, just a case of checking the hoses etc.With the remap you are almost doubling the boost from 8psi to 14psi.

[Dangerous Dave]

It will certainly find the weak points in the system

[Ade]

Hmmm, ok. So I'll see how it is tomorrow then.

Got it booked into a garage on Monday anyway to get a few odds and ends sorted, so I can get them to have a hunt for boost leaks etc if nothing has changed by then.

[Ade]

Still the same, actually a bit worse!
Couldn't see anything wrong with any elbows or hoses. :(

Replaced the rather shoddy looking actuator pipe, but that turned out to be a waste of time as it made no difference :(
Puzzled......

[BruceT]

Could be a weak actuator, might it needs tightening?

You may need to get it smoke tested to look for leaks

[lance]

Im having a similar issue went out last night and boosting near the end of the gauge lovely, drove through town then back on the open road and only just getting a little way into the white going to have a look if I can see anything, I guess if it isnt an air leak could be a faulty BCS?

[BruceT]

Faulty BCS (Boost Control Solenoid) or TCV (Turbo Control Valve) depending on what you want to call it is another good shout

[nobananas]

I remember when I first fitted my Rica to my T5, just before we went on holiday. I'd been enjoying the extra go on the motorway when it blew a boost pipe at full boost, frightened the cr@p out of me I can tell you !

[The Flying Moose]

I remember when I first fitted my Rica to my T5, just before we went on holiday. I'd been enjoying the extra go on the motorway when it blew a boost pipe at full boost, frightened the cr@p out of me I can tell you !

The first time I blew a boost pipe I was overtaking a Skoda Favorite on the A17... extremely embarrassing when I grind to a halt and hit the hazards in the opposite carriageway.

[LiamT4]

The first time I blew a boost pipe I was overtaking a Skoda Favorite on the A17... extremely embarrassing when I grind to a halt and hit the hazards in the opposite carriageway.

Its very embarrassing when theres an astra vxr behind you ;)

[nobananas]

The first time I blew a boost pipe I was overtaking a Skoda Favorite on the A17... extremely embarrassing when I grind to a halt and hit the hazards in the opposite carriageway.

What was most frightening for me was that I had only rebuilt the engine 3 months previously and the missus kept saying 'don't put the ecu in if we are going on holiday tomorrow in case you break something'. When the pipe blew there was a load bang then a grating noise, when I tried accelerating again the grating noise kept happening (which was the slit in the pipe flapping !), of course the missus was giving me 'the look' as we coasted across three lanes and onto the hard shoulder !

[Dangerous Dave]

What was most frightening for me was that I had only rebuilt the engine 3 months previously and the missus kept saying 'don't put the ecu in if we are going on holiday tomorrow in case you break something'. When the pipe blew there was a load bang then a grating noise, when I tried accelerating again the grating noise kept happening (which was the slit in the pipe flapping !), of course the missus was giving me 'the look' as we coasted across three lanes and onto the hard shoulder !
LOL, I keep the spare ecu in the boot just in case, but I still get "the look" you speak of.

[lance]

Mines decided to be intermiten and I cant see anything obvious so im going in for a smoke test but it could well be a faulty bcs