Turbo cut

[HYDROSCOBY]

Hi all, today I was pushing the car and I was in 4th boosting and the turbo seemed to cut out for half a second, it Didn't drop any turbo pressure but cut out and kicked back in again a couple of times. The same in 5th as well. Could it be the turbo or fuel cut out. I don't have a fuel pressure gauge fitted but I might just to see (recommendations) any ideas anyone. It has a td05 turbo and 255 fuel pump

[scooby doo]

Sounds like boost cut, what boost are you mapped for ?

[HYDROSCOBY]

1.5 bar boost gauge didn't change when it happened.

[scooby doo]

Possibly blew the spark out he plug ? Are they gapped right

[HYDROSCOBY]

Unsure but I can pull them out Sunday and check. What gap should they be? All runs fine other than that and no pops unless I put anti lag on anyway lol

[scooby doo]

Are you using grade 7 plugs and .6-7 gap.

[HYDROSCOBY]

Yeah 7s mate. I would of though that if the plugs wasnt gapped right I would of noticed by now, but I will check Sunday. Thanks

[HYDROSCOBY]

Put in just before the ring trip so not old either

[scooby doo]

True. Are you on the factory ecu ? As I remember seeing 1.5bar is the limit? Not sure could be talking crap

[HYDROSCOBY]

Yes it's a stock ecu. My gut is saying turbo waste gate

[Scott.T]

Sounds like a spot of overboost in the higher gears.
Mapping is often done with 3rd gear pulls, especially if done on a dyno.
When on the road you can generate boost spike or longer sustained higher boost in 4th/5th that can cause fuel cut or boost oscillation, dependant on where the boost/fuel cut threshold is set.

Could be worth looking at the tune to see what it's actually mapped to achieve vs what it's achieving and where the limits are set.

[HYDROSCOBY]

Originally Posted by Scott.T

Sounds like a spot of overboost in the higher gears.
Mapping is often done with 3rd gear pulls, especially if done on a dyno.
When on the road you can generate boost spike or longer sustained higher boost in 4th/5th that can cause fuel cut or boost oscillation, dependant on where the boost/fuel cut threshold is set.

Could be worth looking at the tune to see what it's actually mapped to achieve vs what it's achieving and where the limits are set.

Thanks for the right up a advice mate. You could be right. It was road mapped by fb tuning a 5 months ago and done it once on the drive home, but it has done it since then until the other day. He had mentioned the the actuator needs adjusting but it already had been. He advised a new turbo housing and is on my near future plans. I will pull the plugs tomorrow and check the gapping. Hopefully all should be good soon

[Scott.T]

Originally Posted by HYDROSCOBY

Thanks for the right up a advice mate. You could be right. It was road mapped by fb tuning a 5 months ago and done it once on the drive home, but it has done it since then until the other day. He had mentioned the the actuator needs adjusting but it already had been. He advised a new turbo housing and is on my near future plans. I will pull the plugs tomorrow and check the gapping. Hopefully all should be good soon

Could add a turn or two on the actuator (making it longer) May just be enough to calm it down but shouldn't effect target boost.

[HYDROSCOBY]

I might of found the issue. A injector wire looks really dodgy and that might be why I am getting fuel cut.

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[HYDROSCOBY]

As above I think this is fuel cut more than anything else. I haven't checked the plugs yet but I got a feeler gauge now and I will pull them next weekend and rewire that injector.
I want to get a fuel/lambda fuel gauge to keep a eye on this in the future. Does anyone run a fuel gauge or lambda gauge for fuel and air mix?

[HYDROSCOBY]

I think these look OK and done about 3k miles on them. Gap was 0.67mm I have put new plugs in anyway

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[HYDROSCOBY]

Hi all, update on this. It must of been fuel cut. As I re wired a bodged job of wiring to a injector and now seems fine but not fully tested it yet.

Does anyone run a wideband AFR gauge if? I am thinking a AEM gauge or stack brands

[viper1982]

I use a Wideband prosport with a very good result and the response time is very good. So far I have not had problems. Prosport EVO with Bosch LSU 4.9 oxygen sensor

[Scott.T]

I use an innovate hardwired with gauge in the car and also have used an innovate with tailpipe probe and pc/laptop when road mapping.

[HYDROSCOBY]

Thanks viper1982 and Scott. The car still isn't right
What Is the best thing to do? Put it on a dyno to find out what is going wrong. Even if I get a afr gauge it won't tell me if its a air issue or fuel, but when I do finally find out it will of course let me know something isnt right.

[Scott.T]

A dyno probably won't help.
Have you taken the intercooler off and checked for splits.
I have witnessed a very bad misfire on a WR1 That ended up being the flange coming apart on the underside of the intercooler.
Obviously this only happened when trying to push some air/boost through it.

[Scott.T]

I could bring my laptop to Brands and read out your map to see how close it's running to the boost cut limit.

Do you know what boost its achieving in 4th/5th compared to 3rd. It sounds like it's over achieving in the higher gears.

Did you try adjusting the actuator ?

[HYDROSCOBY]

Originally Posted by Scott.T

A dyno probably won't help.
Have you taken the intercooler off and checked for splits.
I have witnessed a very bad misfire on a WR1 That ended up being the flange coming apart on the underside of the intercooler.
Obviously this only happened when trying to push some air/boost through it.

No I haven't checked that to be honest, but I will go and have a look at break and see if I can see any air leaks.

The car a constant speed seems a bit like it wants to ride away, hard to explain really. I wouldn't say lumpy but maybe abit learchy and not smoth.

[HYDROSCOBY]

Originally Posted by Scott.T

I could bring my laptop to Brands and read out your map to see how close it's running to the boost cut limit.

Do you know what boost its achieving in 4th/5th compared to 3rd. It sounds like it's over achieving in the higher gears.

Did you try adjusting the actuator ?

That would be very kind of you thanks.

Of the top of my head I would say 1.3 bar in 3rd and 1.5 in 4th and 5th.

Not yet no as I wanted to do one thing at a time to find out the fix. But I will try and see if it can take a few more turns.

[Scott.T]

Gauge may be over reading at 1.5.
I'd expect a standard turbo to be mapped to around 1.4/1.45.
3rd should be close to 4th/5th and is controlled by max and min boost control solenoid %.

But saying that, if you are feeling surging it sounds like a fuelling/air leak.

Common places to get a large enough leak post MAF are the turbo inlet hose split/mounting and under the intercooler. Either the hose connections or split intercooler flanges.

[Scott.T]

Also try blanking off the dump valve with a dummy plate fitted under dv. In case that's blowing back in (assuming you running a recirc)

[HYDROSCOBY]

It's a td05 turbo so not standard turbo. I also have blocked d/valve plate and blocked pipe. When I get a chance I will have a look at the areas us said to see if there are any leaks. Standard ecu, mapper said my gauge doesn't read right, so a mate has given me a spare to plug in and see what that says. Mapped to 1.5 but on the way home put it into high boost setti g and it was reading 1.3 in 3rd and 1.4 in 4th

[scooby doo]

I dont think you can run 1.5 on the stock ecu your boost readings are about right mine was mapped to 1.45bar and made 1.3 in 3rd then 1.45 in 4th and 5th

[HYDROSCOBY]

Originally Posted by scooby doo

I dont think you can run 1.5 on the stock ecu your boost readings are about right mine was mapped to 1.45bar and made 1.3 in 3rd then 1.45 in 4th and 5th

Yeah that's annoying lol. Got so much I want to do with the car and the list just gets longer and never gets any shorter. Never mind fixing issues along the way

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[scooby doo]

Originally Posted by HYDROSCOBY

Yeah that's annoying lol. Got so much I want to do with the car and the list just gets longer and never gets any shorter. Never mind fixing issues along the way

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joys of owning these cars and start modifying them. life would of been easier if stayed oem ,,,

[HYDROSCOBY]

I would say I will get there in the end but you never do lol

[scooby doo]

Nope always something thats needs doing

[Scott.T]

Are you running Carberry ?

[HYDROSCOBY]

Originally Posted by Scott.T

Are you running Carberry ?

Stock I believe mate, is carberry aftermarket I guess

[Scott.T]

Originally Posted by scooby doo

I dont think you can run 1.5 on the stock ecu your boost readings are about right mine was mapped to 1.45bar and made 1.3 in 3rd then 1.45 in 4th and 5th

There is a 300g/s limit on the MAF for the 16 bit ECU, but this is not a physical limit of the MAF/MAF tube, but the resolution of how it's coded i.e it won't accept a value entered greater than 300 for MAF scaling i.e a 4.69V MAF reading = 292g/s on a stock ROM..

There is a work around to re-scale the MAF and associated tables that use a load scale. You can 1/2 your MAF g/s scale parameters then 1/2 all maps that use a load scale (the load is derived/calculate by using the MAF reading). This in theory allows you to run upto 600g/s on a stock MAF sensor if the MAF tube was of a size that could flow it.

I've done this on 18G, 20G and 2.5's running 20G, but can't recall why or how close we got to the 300g/s limit. But it was 10 years ago (which was a surprise when I just looked and the file dates).

[Scott.T]

Originally Posted by HYDROSCOBY

Stock I believe mate, is carberry aftermarket I guess

It's just that you said you had map switching. Is this via a boost controller or via button press combinations ?

[HYDROSCOBY]

I have a switch but unsure on if its throu boost controller. It was fitted by previous owner who also had anti lag and launch control by a button as well

[Scott.T]

Originally Posted by HYDROSCOBY

I have a switch but unsure on if its throu boost controller. It was fitted by previous owner who also had anti lag and launch control by a button as well

What's the difference in boost between on and off ?
Do you get the same issue in both settings

[scooby doo]

If you have switchable maps, launch control and anti lag you most likely on Carberry.
Who mapped the car?

[SeanMcKnetic]

I live 3 streets from you and have a 2005 WRX on a TD05. You're welcome to come and compare bits / borrow things that are quick to unbolt if they help diagnose the issue. Gotta be quick though as I am getting rid of the car asap.

[HYDROSCOBY]

Originally Posted by Scott.T

What's the difference in boost between on and off ?
Do you get the same issue in both settings

Had a few pulls today in low boost 0.8 and seemed OK to be honest but only a few pulls

[HYDROSCOBY]

Originally Posted by scooby doo

If you have switchable maps, launch control and anti lag you most likely on Carberry.
Who mapped the car?

Sounds good to me lol.

It was mapped by fb tuning on the road before the ring trip this year

[HYDROSCOBY]

Originally Posted by SeanMcKnetic

I live 3 streets from you and have a 2005 WRX on a TD05. You're welcome to come and compare bits / borrow things that are quick to unbolt if they help diagnose the issue. Gotta be quick though as I am getting rid of the car asap.

Oh really lol. Unsure on what the issue is at moment but thanks for the offer, appreciate it. I can always pop over to have a look and meet up.

[scooby doo]

Fb tuning does carberry mapping withthe added features, I plan to use them for my current set up.

[viper1982]

The electrode light between the original NGK spark plug that is 0.6 to 0.7 mm must be respected when placing them but equivalence in Iridium? Since I have observed that the Iridiums already bring another light between 1.1 mm electrodes

[Pottsy1973]

Originally Posted by viper1982

The electrode light between the original NGK spark plug that is 0.6 to 0.7 mm must be respected when placing them but equivalence in Iridium? Since I have observed that the Iridiums already bring another light between 1.1 mm electrodes

I replaced my plugs in June with PFR7B NGK but since then above 2500rpm to 6000rpm I seem to get a stuttering in power.... do you think this will be the plugs or likely to be something else that I may have dislodged in the process of changing the plugs???
Also are these the best plugs for the classic?


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[viper1982]

Originally Posted by Pottsy1973

I replaced my plugs in June with PFR7B NGK but since then above 2500rpm to 6000rpm I seem to get a stuttering in power.... do you think this will be the plugs or likely to be something else that I may have dislodged in the process of changing the plugs???
Also are these the best plugs for the classic?


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I am of the idea that the best spark plug is the original one recommended by the manufacturer as long as the engine is completely original. I put the NGK BKR7EIX which are a colder because of the modifications I have. In any case, it is not very clear to me if the 1.1 mm iridium GAP should be reduced when they are placed in a turbocharged engine since in the subaru turbocharged engine the GAP is 0.7 mm.

[asperformance]

PFR6B is the common replacement plug and using PFR7B is of no issue at all and something we have done on may cars for the past 20yrs or so...........

std boost gapping of around 0.7 / 0.75mm works fine and if more heavily modded we reduce to 0.65mm

if the plugs were new and undamaged / gapped correctly then highly unlikely this is any issue

[Pottsy1973]

I cleaned my maf sensor today and put in a new pipercross foam filter and the power is now clean and no more lumpy power after 2500 rpm .... yaaaay it wasn’t the spark plugs !!


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[viper1982]

Originally Posted by Pottsy1973

I cleaned my maf sensor today and put in a new pipercross foam filter and the power is now clean and no more lumpy power after 2500 rpm .... yaaaay it wasn’t the spark plugs !!


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Good, I'm glad you found the source of your problem.