Juddering boost?

[Buster247]

I hate my car! It was running fine on the way back from national day, perfect under boost and nice and smooth all the way to the top. A couple of hours after i got home i took it out for a spin and the boost went round to about 1.4 bar (its only set to 0.8bar) and started backfiring. i've checked everything i can think of but can't find anything wrong!
It doesn't do it all the time mainly for the first 15minutes but then can decide to go silly anytime it likes.
Anyone got any ideas?
It only judders from 3800rpm onwards.
Cheers Chris

[Threedoorboy]

It would seem lie the boost is so high it is causing it to missfire. Strat with checking the amal valve

[Buster247]

How do i check the amal valve? OR should i just take it somewhere to have it checked and set up again?
Anyone recommend somewhere good in the Barnsley area?
I forgot to say when the boost isn't going crazy and it's holding at 0.8bar it still judders and seems to be holding back.
Chris

[markb]

You got a bleed valve? If so, I'd check no-ones been messing with it!
Presumably all hoses are connected and intact as well?

[JesseT]

I had the same type of problem and it was the MAP-sensor.

[markb]

Didn't think RSTs had a MAP sensor?

[Buster247]

I don't have a bleed valve and all the hoses seem to be there and in good condition. It ran so perfect i couldn't believe it, then it started playing up again!
Cold start valve not working this morning just wondered if this could affect it? even when its been running for an hour?
Chris

[markb]

hmmmm... could be a number of things i guess.. stickiing actuator/wastgate? amal valve could also affect it if you're running one... I reckon best bet is get it checked out/setup TBH, sorry - but i'm not much of an expert in this stuff!!

[Buster247]

Could it be the fuel? it was set up on optimax but i ran out and had to put normal unleaded in. Would this make such a big difference?
Markb_s1 you no way more than me!!
Chris

[PJay]

That is possible, my cos was setup to run unleaded and i put optimax in it and it started playing up/misfiring etc.

PJay

[markb]

I could understand the misfiring on normal unleaded (you should be on at least Super IMO) but I don't see how it could cause your peak boost to almost double though!!
still think the amal valve, a sticking actuator or wastegate are the best bet TBH. no idea how to test any of those thigns though... problem is, if it keeps doing this it'll be running well lean and you'll melt a piston or something really expensive like that!

[PJay]

i'm with you on this 1 mate, if it's running higher boost that it set up for you'll probably find thats detonation and not a misfire!!!!!!!

Get it checked out now, b4 it's too late!

Buster mate, put your location in your profile

PJay

[Scott_R]

Have you checked the hoses that goto the compressor housing from the Amal valve as if this has a hole in it or is broken will cause the boost to be unlimited, also when it does this you might be gettting the standard hoses collapsing, causeing it to judder hesitate.
It might now not start from cold because you have damaged one of your boost hoses from the extra pressure, if one of these have a hole in or is split, will cause all sorts of running problems. Have a VERY good look at ALL your hoses, as with S1's and S2's, they dont normally just start playing up, and in all the time i have been dealing with RST's i dont think i have ever come across a broken/faulty cold start valve.

[JesseT]

The MAP-sensor is in the spark-ecu and it is used to control ignition advance and Åmål-valve. The MAP has nothing to do with the fuelling itself in a RST.

[markb]

cool... thanks for theinfo JesseT

[Buster247]

O.k i checked the hoses from the amal valve and the one under the turbo was a little loose it's all tight now and holding 0.8 again but still misfiring or detenating. I've got some octane booster so i'll put that in and fill it with optimax and she how she goes.
Thanks for all your help i'll let you no how it goes.
Chris

[Buster247]

O.k bit of success, i filled it with optimax and it was still the same so i was pi$$ed off and decided to play with the timing and hey presto i got it running smoothly.
Now where would you recommend getting it set up? i'm in south yorkshire but will travel if you think it's wise.
Cheers
Chris

[markb]

No idea of people in your location matey.. sorry.

Karl @ Norris Motorsport has a really good reputation but is always well busy, so do Turbosystems, Power Engineering. I'd put a post up to see what people recommend to be honest.

HTH,

Mark,

[JesseT]

To where did you set the ignition timing and where was it?

[Buster247]

o.k i'll put up a post.
I don't no where i set the timing to, i just kept moving it slightly and got it to run smooth for now (i turned it clockwise).
Thanks for all your help
Chris