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Discussion Starter · #1 ·
Hi - an update on the fuel cut problems (I've started afresh so as not to make the other thread too big).

I deliberately 'kinked' the pipe containing the plastic restrictor and put a cable tie round it, essentially closing off the vent path through the solenoid. See pic


The result is NO FUEL CUT! However I noted that it wasn't nearly as powerful and the exhaust note was subdued (although the turbo SSSshhhhhhhhhh on full boost seemed more pronounced). As I'm still waiting for the boost guage I borrowed one again today just to see what would happen - previously when it was fuel-cutting it surged to 1.3bar and after a second or two it dropped to 1.0bar. With the kinked pipe it is now going directly up to 1.0bar and sitting there (ie. no surge). From HH6's explanation the surge is due to the plastic restrictor in the path to the boost control solenoid. Now I've closed the path entirely I expected this to happen.

Questions;
I assume if I fit the bypass valve I'll get SOME surge back?
Do I want this pressure surge? What purpose is the surge there for?
Why does it seem slower if the constant post-surge pressure before and after I kinked the pipe is the same at 1.0bar?
I assume that the ECU shuts the solenoid to reduce boost, so does the plastic restrictor on the way to the solenoid cause the fuel cut?

I think until I refit the bypass valve I'll leave it this way - seems slower, but obviously much safer.
 
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Discussion Starter · #2 ·
DOH I spoke too soon........

I borrowed an ITG filter from my mates at Camskill and fitted it tonight. Much noisier on partial throttle, no more noise on full throttle. Seems slightly more responsive but I got fuel cut once on my test run just now!! (although the air is a lot cooler and it's kinda misty/foggy now). Do you think this is directly due to the filter, atmospherics, or both?

Is this the part where you tell me What did you expect? and Fit the standard airbox back you nonce! ???
 
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Discussion Starter · #3 ·
Dave,
What did you expect..... Put the standard airbox back you nonce http://www.lancerregister.com/graphics/tonguewink1.gif border|EQU| 0 align|EQU| absmiddle >[img]http://www.lancerregister.com/graphics/tonguewink1.gif border|EQU| 0 align|EQU| absmiddle >[img]http://www.lancerregister.com/graphics/tonguewink1.gif border|EQU| 0 align|EQU| absmiddle >

Seriously though, it would appear that you are very close to the point of fuel cutting with your existing setup. If you have kinked the pipe and are still getting 1.0 bar without the boost spikes then by fitting a freer flowing air filter, you will be gettting more air through the intake and therefore hitting the fuel cut level again.

Until you sort out the fuel cut problem, it really is, as you say, best to put the original airbox back in and leave it at that.

Andy
 
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Discussion Starter · #4 ·
Thanks for the reply Andy.

I'm beginning to wonder if the dealer-diagnosed fault with the wastegate actuator is faulty at all, especially after I kinked the pipe today. Would you have expected an improvement (fuel cut wise) after kinking the pipe even with a faulty actuator?

If I wanted to keep this setup, what would I be looking at now? I'm dreading the way forward being something like a replacement ECU as that's cash I don't have. I'll see if I can give them the ITG filter back and re-fit the standard air box.

I really need to have a good old fasioned chat with someone about this at a meet or something.
 
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Discussion Starter · #5 ·
Dave,
If it was a faulty actuator then you shouldn't have seen any improvement in the fuel cuts as the actuator is what determines your boost level. If the actuator was faulty and stuck closed therefore causing overboost then you wouldn't have noticed any improvement in the fuel cuts. What might have happened however is that by kinking the pipe, you are feeding more pressure to the actuator and so it may well be opening up under the higher pressure that you are feeding it.
One other thing is that I know that with my setup, if I don't bleed off any air, I only get about 0.7 bar boost pressure which seems considerably lower than yours. Are you sure that no-one has done any other mods to the boost system e.g. the length of the actuator rod or something else?

Andy

Edited to say that I might well be up at Sellafield tomorrow if you're around that area and want to discuss it but I won't be able to confirm that until after about 11'o'clock today. Alternatively, if you want to come down to Knutsford for the meet up on May 5th then we can chat about it then.
 
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Discussion Starter · #6 ·
Interesting thread(s)

I am taking my car in today to have varification that the actuater is fooked (they wont order the part just on advice of some northern nuclear dude!). my car overboosts under load real early in the rev range then surges a bit and then runs out of puff at the top end. doesn't sound like your problem. sounds to me a simple fact of mods|EQU|raised boost. is this not a common problem? seems to be a lot of talk for a relatively simlple although expensive fix? or am i talking ######?

ps they have checked and ccc carry the actuater ex-stock so one of us is being lied to?
 
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Discussion Starter · #7 ·
Robert,
The design of the actuator and it's location means that it can very easily get covered in water and rusts. This means that it doesn't open, overboosts and fuel cuts. What then happens is that the boost pressure is lost from the intake and so everything goes back to normal after the fuel cut and the boost build up again.

It is a common problem to have the actuator fail (I've had mine go before) due to rusting and then sticking.

From what it looks like in Daves case, I too would say that it's mods|EQU|more air|EQU|overboost and the easiest way is to fit some form of boost controller to turn the boost down. This is why there was a bleed valve on the line to his solenoid when he bought the car, I believe.

Andy
 
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Discussion Starter · #8 ·
so what u r saying is that i have posted something technical that sounds correct..wow wonders will never cease. I will see if i can get my picture in practical mechanic:D
 
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Discussion Starter · #9 ·
(Quoted): One other thing is that I know that with my setup, if I don't bleed off any air, I only get about 0.7 bar boost pressure which seems considerably lower than yours. Are you sure that no-one has done any other mods to the boost system e.g. the length of the actuator rod or something else?

It's definately running 1.0bar with the vent pipe to the solenoid blocked. Blowdog and amp; Quentin assure me that nothing other than the exhaust has been done. I intend to re-fit the standard air box at lunchtime (WHAT a **** it was to get the bolts our of the air metering unit!!)

I'm trying to learn a lot more about these engines, I'm finding it hard to get used to the fact that it's possible to over modify them (results are fuel cuts) where as on the FTO you couldn't do enough!!!!

(Quoted): I might well be up at Sellafield tomorrow

Offlist...
 
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Discussion Starter · #10 ·
It really is simple!
If only you'd listened to me from the beginning and not Dragon! That is what the valve was doing.
 
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Discussion Starter · #11 ·
Have to agree with you Cem,
Put the bleed valve back in and screw it down to reduce the max boost. All seems fairly simple really.

Andy
 
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Discussion Starter · #12 ·
Cem, initially I was uncertain where the valve went due to the mis-information I was given. I took my time over it and now I know exactly where it goes (with help from the likes of yourself, Colin and amp; Andy) and I intend to re-fit it asap. The 'test' I did yesterday (kinking the pipe) was a simple and quick way to confirm to myself where the valve would go.

The problem initially was just so much conflicting information but thanks to everyone on here I realised yesterday (when I kinked the pipe) that Dragon Autosport were indeed talking cobblers. Not that I dis-believed anyone, rather I needed to understand myself it before I did anything to the car. I'm sure you're the same.

..... and WHAT a car this is :) :) :) I polished it yesterday and did the obligatory slow cruise :)
 
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Discussion Starter · #13 ·
Got the bleed valve fitted today:


The valve is shut tight and as a result the engine is way down on power and takes a while for it to spool up now but a good price to pay for no more fuel cuts. When I get the boost guage I'll wind it up to around 1.2bar (what kind of increments should I make? Half turn? Full turn?)
 
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Discussion Starter · #14 ·
Dave,

In theory, you shouldn't really experience any powerloss at all. You can make huge differences simply by turning the tap 5 degrees either way, it is that sensitive.
There IS a lot of trial and error required, youre best bet is to find a long open stretch of road and cane up it, pull over, decrease restriction, cane up the road again et ad infinitum until you get to the point where it's litterally JUST cutting off that excess overboost.

In reality, I would say buy a boost controller. Not only will you maximise available performance, bur you'll also be doing your engine a favour.

Cheers,

Cem
 
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Discussion Starter · #15 ·
Cheers Cem.
What boost controllers do people recommend? (and can anyone point me to a website where they're explained in full please?)
 
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Discussion Starter · #16 ·
Okay, something is wrong. This morning on the way to work I got another fuel-cut. The car feels quite slow under full throttle with the bleed valve shut and it's only running a max of 1.0bar....!

:(
 
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Discussion Starter · #18 ·
Dave I'd go for thr Apexi AVC-R
Then you could always add the AFC (fuel controller) at a later date, with a FSE.

Hope you get the problem sorted soon.

Jeremy
 
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Discussion Starter · #19 ·
had my car looked at yesterday, the actuater is being replaced. the mechanic also noted that the arm was not central in the guide hole so could also be binding up alittle? dont know if that is true or not.

Andy,

if only 1 bar is showing. surely fuel cut should not happen until 1.3. does this not suggest that a) the guage is faulty ? B) maybe ecu seeing boost pressure wrongly?

I dont know, i don't make the rules?
 
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Discussion Starter · #20 ·
Andy - But the wastegate must be opening for the boost to be this low...? Even if it's only opening a crack, 1.0bar can't be over-boost now...?

Jeremy - cheers, I'll have a look.

I obviously need to lie down and take some pills at this point.
 
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