2nd turbo not 'coming on' - Help Appreciated!

Evening all,

Ever since I took my car into the garage to have an oil leak fixed it seems that something is wrong with my second turbo. The first works fine, the boost gauge goes up as I accelerate and then the pressure drops as it it goes through the first turbo. It then keeps building as I continue to accelerate but the second turbo doesn't kick in and the dial reaches 2.0, the red warning light comes on and I quickly take my foot off the gas and the gauge steadily goes down.

AFR gauge does go high when I am accelerating hard but goes back to normal thereafter. It is steady when im 'tootling' even when its at 80mph.

Car is at 1.3 bar at the moment but I am told by Guigsy that it has always run at this level so this can't be the problem. I do fancy turning this down more, as soon as I work out how to do it!

Now I know almost nothing about engines so I am at a loss. I've looked at the hoses and I can't find any problems. I did spot a clip too high on the cable to the dump valve and have now resolved that (pic 3 shows this clip before I fixed it) but it hasn'tresolved the problem.

Pics are below of parts of the engine.

Does anyone have any advice, suggestions they can give?

Ric

p.s. Yes I really do know very little.

Try the TTC conversion to see if it is the turbos, if it boost fine in TTC mode then at least you know its not the turbos.

So it would mean the fault could be a leak, pressure tank or the solenoids

My UK spec is in the garage at the moment as it lost second turbo. Turned out to be exhaust gas control valve, rod had broken possibly due to the valve seizing. Maybe worth checking

Try the TTC conversion to see if it is the turbos, if it boost fine in TTC mode then at least you know its not the turbos.

So it would mean the fault could be a leak, pressure tank or the solenoids

Hi.

I know TCC means true turbo conversion but how do I do this?

I note from the search that it can cause fuelling problems for autos (which mine is).

Have you heard a pop or bang at any point? 1.3 bar on stock turbos is really pushing the limits.

If its been running 1.3 bar for a while, it wouldn't surprise me if the turbo is dead.

Ignore me if you have hybrids.

Also, do you mean the boost gauge hit 2 bar? If so that's way too high and I would guess fins missing from the compressor wheel. As said, 1.3 is on the limits and depending on use, they could just pop.

what you have said does not make sence mate try and explane it a little better so maybe more will understand.

you say your afr goes high? do you mean you go lean as the higher the number the leaner you are 11.5 is about right for full boost 12's is lean 13's your gonna blow up

you say the boost drops then keeps bilding ? this is the second turbo coming on i would of thought

you say your getting 2 bar of boost ? if your getting that much boost from the first turbo allown i would be shocked that it is still in one peace and the shaft not snapped.

read this it might explain what your getting also read the link for the maxboost very good site for explaining the setup

http://www.mkiv.co.uk/vbb/showthread.php?35926-The-sequential-system

Have you heard a pop or bang at any point? 1.3 bar on stock turbos is really pushing the limits.

If its been running 1.3 bar for a while, it wouldn't surprise me if the turbo is dead.

 

Ignore me if you have hybrids.

If be surprised if it had popped. I've hardly driven since I bought it.

what you have said does not make sence mate try and explane it a little better so maybe more will understand.

Cheers for the response. I'll try explain myself better. Comments below.

you say your afr goes high? do you mean you go lean as the higher the number the leaner you are 11.5 is about right for full boost 12's is lean 13's your gonna blow up.

It must be lean then. Contrary to what I said in my first post, I have an AEM gauge (air/fuel ratio) rather than AFR gauge which idles at 14.7 and steadily increases as I accelerate. It is not jumping all over the place. The gauge indicates that 14.7 is dead in the middle of the gauge. As I accelerate it increases up toward 17 and then steadies back down again when I maintain a constant speed. Logically in my head this seems normal (something is going to increase as you press the gas) and furthermore it hasn't changed since I bought it from Guigsy and he said 14.6/14.7 was normal and he had always driven it like that.

you say the boost drops then keeps bilding ? this is the second turbo coming on i would of thought. you say your getting 2 bar of boost ? if your getting that much boost from the first turbo allown i would be shocked that it is still in one peace and the shaft not snapped

The boost pressure increases to about 0.8, the 1st turbo kicks in and I see the pressure drop a little. As I continue to accelerate the pressure continues to build and if I let it could go as high as 2 (although I've only let it do it once when trying to see I was being dumb and driving too slow to get the turbo to kick in). This is where I see the problem as being. Rather than the second turbo coming in (and you feeling the effect of the turbo) the turbo doesn't kick in and the pressure keeps building until I take my foot off the gas.

read this it might explain what your getting also read the link for the maxboost very good site for explaining the setup

http://www.mkiv.co.uk/vbb/showthread.php?35926-The-sequential-system

Cheers. I'll read that.

Don't know naff myself...... but r2ck_p has a jap TT with a problem with the 2nd turbo not working and the car backing off after 60. tried all pipes etc. ended up a faulty sensor on the wheel/brake affecting the traction control system. Worth a thought.

The AEM gauge is Air Fuel Ratio, i.e. an AFR gauge, so you were right in the first place

Higher numbers are bad when you are accelerating. 17 is really bad, it's 17 parts air to 1 part fuel, which is really lean. You want more like 11 to 12 when accelerating on boost.

If you are seeing 0.8bar of boost on the first turbo, that's rather high. If you're seeing 2bar of boost on both turbos, that's suicidally high and I can only hope you haven't suffered any damage to engine or turbos. Combine that with 17:1 AFRs and I'd imagine the engine is detonating its nuts off. You are lucky that you have VVti, the knock sensors are excellent and the ECU closes the drive-by-wire throttle to limit boost and try and save the engine.

Do you mean you see 0.8bar *before* putting your foot down, as you might be reading absolute pressure instead of atmospheric pressure, in which case you're only seeing 1bar of actual boost as the first 1.0bar is atmospheric pressure. I hope this is the case otherwise things might be rather mangled inside the engine.

will best place to start is , replace ALL vac hoses, (no matter what the look like ).

it alao sounds like problem 1 on the link, have you tried taking you foot off the throttle and slamming it back down this normally get the egbv to open correctly as any vac leak would now have more preasure to work with, normally and 2nd turbo issues are related to the vsv at the top back of the engine (its one of the smaller vsv's)

all that being said 17:1 afrs like ian said is big big trouble on boost at 2 bar, hell 17;1 afr is bad even for idle

this is you gauge right http://www.autoanything.com/gauges/65A4449A0A0.aspx

I'd say before you go messing with any hoses or anything we need to know exactly how it's behaving right now - no good chasing solutions if we don't know the symptoms

Can you take a piccy of your boost gauge with the engine idling and stick it up here? Even better, a vid of the boost gauge as you go through say 2nd gear?

It's a UK spec isn't it?

I had similar on my 97 TT Auto, turned out to be that one of the vac connectors was snapped on my IACV VSV.

Not sure on AFR's though as I didn't have a gauge. might be worth a look.

Evening all. Thank you for the continued help.

The gauge is the one in Mellonman's link.

Boost and AFR are 'fine' when the car is idleing. Please see the below pic taken this evening. When idling, it stays around 14.8 and boost as in the picture. The gauges were like this when I bought the car from Guigsy and he assured me that the figures were normal. I assume he's right since he knows his stuff.

The AEM goes up to about 17 when I am accelerating to try get the second turbo to kick in. I assumed the higher the number (i.e. 17 is higher than 14) it meant more fuel (or air) was being used due to the acceleration. I assumed it was fuel since more power should mean more fuel being used (in my head atleast). The AFR does decrease back toward the idle number when I take my foot off the gas. I assumed this was all normal to be honest!

To clarify my earlier posts.... when I accelerate the first turbo kicks in with boost at approximatley around 0.2 and will then drop to 0.4 as it kicks in. This 'seems' normal to me (correct me if im wrong). What my concern is that if I continue to accelerate with a view to trying to get the 2nd turbo to kick in, the pressure gauge simply consistantly climbs up toward 2.0 as I continue to accelerate. It will reach 2.0 if I let it and then the red light gones on and a little alarm. I have only let it get that high once after the problem had kicked in. Despite the pressure gauge constantly increasing, the second turbo does not kick in.

I'm noting people's comments about the engine being about to explode but I have to say it doesn't seem like that. The engine is perhaps slightly louder (albeit its probably paranoia setting in) but there isn't black smoke, or dodgy smells etc. She seems fine. My layman thought is that something is stuck or split but then what do I know!

Are you in Australia? Lol

Are you in Australia? Lol

I have no idea what you are on about I'm afraid!

I have no idea what you are on about I'm afraid!

Think he's referring to the upside down photo lol

Think he's referring to the upside down photo lol

Its not upside down on my computer?!

Haha oops

Your local to me and Iky, we could take a look and help diagnose. My worked out my turbo was duff...

Okay

The small numbers under the 0 ie -0.2,-0.4 ect are vacuum

All above the 0 the larger 0.5 are actual boost

Just to clear up the 1st turbo gets 0.2 boost which would be way down should be about 0.6-7

If you are accelerating and making boost you need to see a lower number ie 11.3 if your foot is to the floor and when you lift off completly should go 17 or greater.

The way you say that it goes back to 14.7 while your accelerating means your not putting your foot down and the engine is trying to economical at stoick (using o2 sensor feed back)

Is this car bpu?

Also did you read the link about the sequencial system?

Okay

The small numbers under the 0 ie -0.2,-0.4 ect are vacuum

All above the 0 the larger 0.5 are actual boost

 

Just to clear up the 1st turbo gets 0.2 boost which would be way down should be about 0.6-7

If you are accelerating and making boost you need to see a lower number ie 11.3 if your foot is to the floor and when you lift off completly should go 17 or greater.

 

The way you say that it goes back to 14.7 while your accelerating means your not putting your foot down and the engine is trying to economical at stoick (using o2 sensor feed back)

 

Is this car bpu?

 

Also did you read the link about the sequencial system?

He said it was running 1.3 bar so assume it is bpu

Boost and AFR are 'fine' when the car is idleing. Please see the below pic taken this evening. When idling, it stays around 14.8 and boost as in the picture. The gauges were like this when I bought the car from Guigsy and he assured me that the figures were normal. I assume he's right since he knows his stuff.

That's normal so far. The gauge is a bit odd with the numbers as it doesn't indicate it's a vacuum under the 0. In the picture, you're running 0.6bar less than atmospheric. Here's a quick explanation if you want to know what that means - the engine is a big air pump. The pistons going up and down suck air into the engine so it can be mixed with fuel and turned into fun. When a piston goes down the cylinder, it creates a vacuum and air rushes in to fill it. When your throttle is closed, it restricts the power of the engine by restricting the amount of air that can get in, so much like sucking a McDonalds straw in a thickshake causes the straw to collapse because of the vacuum you cause, the intake is depressurised by the piston sucking against the closed throttle plate That's what the gauge is showing, the pressure inside the intake is just under half of that of the general outdoors.

Turbochargers make an engine seem bigger than it is by forcing more air than atmospheric into the cylinders - that's what boost is. 1 Bar is atmospheric pressure, so adding 1 bar of boost to that means your engine is seeing twice as much air as a non-turbo engine would.

The AEM goes up to about 17 when I am accelerating to try get the second turbo to kick in. I assumed the higher the number (i.e. 17 is higher than 14) it meant more fuel (or air) was being used due to the acceleration. I assumed it was fuel since more power should mean more fuel being used (in my head atleast). The AFR does decrease back toward the idle number when I take my foot off the gas. I assumed this was all normal to be honest!

That's an understandable conclusion to draw, but it's the wrong way around. The gauge is measuring Air to Fuel Ratio, and the fuel bit is always taken as 1, so an AFR of 14 really means an A:Fr of 14:1, 14 parts air to 1 part fuel. 14 to 15 is normal for idle and cruise, it's efficient and clean burning, but it's crap for power and turbo engines also need extra fuel to cool things down in the cylinders, so when you boot it you need to see around 11.5:1 on your gauge, certainly not 17!

I'm simplifying things a bit so not to bury you under if's and but's, for example you can see 19+ when you lift off, which is normal as you aren't putting any fuel in and the engine isn't under load, and also the stock ECU runs the first turbo at 13:1 under full boost until about 3500rpm because you can and it's more economical etc., but the basic upshot here is 17:1 AFRs = bad

To clarify my earlier posts.... when I accelerate the first turbo kicks in with boost at approximatley around 0.2 and will then drop to 0.4 as it kicks in.

0.2 is far too low, barely noticeable boost, but then you say it "drops" to a higher number so now I think you're still on the small numbers below the big 0? Which means you're drawing more vacuum, not even on boost? It's all very counterintuitive at the moment Also, the turbo produces the boost, it doesn't kick in at a certain value on the gauge, it kicks in and then *causes* a certain value on the gauge. This might sound pedantic but from what I've read of your posts so far you're using the gauge to judge when the turbo should come online so your cause and effect is the wrong way around The gauge tells you exactly what the turbos are up to, and if it's reading below the big 0 then your turbo isn't kicking in at all!

This 'seems' normal to me (correct me if im wrong). What my concern is that if I continue to accelerate with a view to trying to get the 2nd turbo to kick in, the pressure gauge simply consistantly climbs up toward 2.0 as I continue to accelerate. It will reach 2.0 if I let it and then the red light gones on and a little alarm. I have only let it get that high once after the problem had kicked in. Despite the pressure gauge constantly increasing, the second turbo does not kick in.

If you can reach 2bar on that gauge and not feel like you're going into warp, something's behaving VERY strangely. 2 bar of boost is almost double what most BPU cars run at, almost impossible for stock turbos to even achieve under any circumstances, and they wouldn't do it more than a couple of times before exploding. It'd run very lean and be a disaster if you really hit 2bar, but I don't think you are as you certainly wouldn't be saying the second turbo isn't kicking in, you'd be saying it goes effing mental and then misfires/loses power

Can you trace where the turbo boost gauge is plumbed in, and check the hoses going to its sensor? Also, can you try and get a video of this behaviour, it'd really help

I'm noting people's comments about the engine being about to explode but I have to say it doesn't seem like that. The engine is perhaps slightly louder (albeit its probably paranoia setting in) but there isn't black smoke, or dodgy smells etc. She seems fine. My layman thought is that something is stuck or split but then what do I know!

As I said above, at the moment I don't think you're hitting much actual boost at all because of the odd behaviour, but detonation damage is a nasty bugger as it'll seem to be fine as the piston top is eroded away, then suddenly lose compression on a cylinder and eat it's own piston rings. No real in between stage.

At the moment I think the boost gauge is reading incorrectly and you've got some sort of boost leak. I hope it's that and the turbos aren't being overspeeded etc. as it's easiest and cheapest to fix

Edit - having said that, you still shouldn't be seeing 17:1 AFRs. Hmm. Need that video of the gauges

maybe the best way to show us would be doing a video, so we can see all the guages and the dash clocks would be helpful too.

as ian has said im starting to think that you are not making any boost at all , this could explain the lean afr and the dip to more boost being a dip to more vacuum .