Aftermarket dump valves causing problems?

[Mastodon2]

Hey guys, I was on the phone to a Seat specialist garage in Newcastle this morning about my LCR 225 (03 reg) which is currently cutting out and going into limp mode at around 5700rpm in second and third gear (so far).

It looks like I'm going to have to get the fault codes read and go from there, I made a thread on here but did not get a reply, so perhaps it's not that common a fault. The bloke I was talking to seemed to know his stuff and suggested that it could be a problem with the turbo system, though according the boost gauge the turbo is working normally and it feels very strong until it cuts out! He asked at one point if the car had an aftermarket dump valve, remarking that they can cause some problems.

I don't know which dump valve is on my car, but it's silver and says FORGE on it, a 007 perhaps? I bought the car from a dealer who bought it in an auction, so I can't speak for what part this is, but could it cause any problems that anyone knows of? It's been fine for the last 3 months that I've owned it so I'm at a bit of a loss!

 

[DannyC87]

this:

or this:

???????????

 

[Mastodon2]

Looks like the top one!

I'm at a loss as to what problems could be caused by a DV - it seems to be functioning correctly, opening partly on part throttle, shutting on full throttle and then opening with a loud hiss on a closing throttle. Is there anyway a DV could cause an engine to cut out and go into limp mode?

I suppose I will find out what is wrong with my car when I get the codes read, but the idea that a DV could cause a fault of some kind has intrigued me, I've never heard about this before!

 

[DannyC87]

A loud hiss? The top valve is a recirculating valve which shouldn't make much noise unless you have an induction kit of sorts? Can you check the dumpvalve has the inlet connected to the charge pipe (comes out from turbo) and the outlet is connected to the turbo inlet pipe (TIP)??

 

[Stuart_cupra]

as above, shouldnt be a large hiss unless its venting to atmosphere like a BOV. Take a picture and whack it on here for us to look at mate.

 

[Mastodon2]

Can't rush out to my car the moment as I've got to go to work shortly, but I thought the point of a dump valve was to make a bit of a whoosh noise when closing the throttle?

I'm almost certain that the DV I have is the top one of the two that was posted above.

 

[DannyC87]

Can't rush out to my car the moment as I've got to go to work shortly, but I thought the point of a dump valve was to make a bit of a whoosh noise when closing the throttle?

I'm almost certain that the DV I have is the top one of the two that was posted above.

The top one is a Diverter Valve.. which is what is fitted to these 20vt engines as standard.. it recirculates the dumped air back into the intake rather than dumping it tot he atmosphere - near silent operation. A dump valve dumps air to atmosphere - however can cause problems with the ECU since it expects to see this air back in the intake..

 

[lcrsammy]

i have the top one (oo7p) and the only way i can hear it is with the windows closed and the stereo off! (its so quiet that you cant hear it over the wind noise of an open window)

maybey some split pipes? im no expert but am sure someone can point you in the right direction matey.

 

[sambryant]

my guess is a boost leak

 

[Mo Arif]

Sounds like a boost leak under the inlet

 

[Mastodon2]

Can a boost leak cause the engine to go into limp mode at high revs? I thought boost leaks just left your car way down on power, mine is cutting out then coming back on in limp mode at high speed and revs.

As I mentioned earlier, it will be going on a diagnostic some time this week so we'll see whats going on. The bloke mentioned possibly needing to do a smoke test to identify any leaking pipes and connections. He did describe the 1.8L T engine as having "pipes going everywhere", I have to agree!

Hopefully it will be a simple fault and an easy fix, fingers crossed. Cheers for all the help so far guys, really appreciate it!

 

[DannyC87]

Can a boost leak cause the engine to go into limp mode at high revs? I thought boost leaks just left your car way down on power, mine is cutting out then coming back on in limp mode at high speed and revs.

As I mentioned earlier, it will be going on a diagnostic some time this week so we'll see whats going on. The bloke mentioned possibly needing to do a smoke test to identify any leaking pipes and connections. He did describe the 1.8L T engine as having "pipes going everywhere", I have to agree!

Hopefully it will be a simple fault and an easy fix, fingers crossed. Cheers for all the help so far guys, really appreciate it!

yes, if the ECU detects a pressure drop between the turbo and intake it will go into limp mode. Bets that the fault code is 17705 anyone?

 

[Mastodon2]

yes, if the ECU detects a pressure drop between the turbo and intake it will go into limp mode. Bets that the fault code is 17705 anyone?

I hope you are right, it would be a royal pain in the arse if the codes get read and it's still a mystery!

I will take a photo of the DV in my car when I'm at work today and upload it when I get home. Is the silver Forge item a standard piece?

 

[Stuart_cupra]

no the forge one is an aftermarket item.

 

[Mastodon2]

Unfortunately I could not get a photo of my DV today, but I am starting to properly suspect a boost leak now!

I turned my car on this morning and looked at the boost gauge. Beyond 12 o clock on the boost gauge measures turbo pressure in psi, and to the left of 12 o clock measures vacuum in Hg. I'm almost certain that the car should (and did) read zero at idle, but on starting the car it immediately dropped all the way to the left, to about 30 in Hg of vacuum. That seems like a lot of vacuum for idle!

Maybe it's just me, but I'm sure I could hear a gentle hiss that was not there before, but it might just be me being paranoid. The car also seemed to feel a bit sluggish with boost taking longer to arrive and not coming on as strong. Perhaps it is the dump valve opening at incorrect times, all the hoses appear to be connected to it properly though.

Hopefully not a fault code reading and smoke test at the weekend should solve the problem.

 

[DannyC87]

Unfortunately I could not get a photo of my DV today, but I am starting to properly suspect a boost leak now!

I turned my car on this morning and looked at the boost gauge. Beyond 12 o clock on the boost gauge measures turbo pressure in psi, and to the left of 12 o clock measures vacuum in Hg. I'm almost certain that the car should (and did) read zero at idle, but on starting the car it immediately dropped all the way to the left, to about 30 in Hg of vacuum. That seems like a lot of vacuum for idle!

Maybe it's just me, but I'm sure I could hear a gentle hiss that was not there before, but it might just be me being paranoid. The car also seemed to feel a bit sluggish with boost taking longer to arrive and not coming on as strong. Perhaps it is the dump valve opening at incorrect times, all the hoses appear to be connected to it properly though.

Hopefully not a fault code reading and smoke test at the weekend should solve the problem.

around 27-30Hg vaccum at idle is normal.

I think a smoke test and code scan will get you alot closer to finding your problem

 

[LEE69]

around 27-30Hg vaccum at idle is normal.

I think a smoke test and code scan will get you alot closer to finding your problem

I only get that high on engine breaking.
-22 is my normal any less and it points to a leak.