hello mark just brought a c20let corsa.

it started hunting when you pull up and mark phoned the old owner and he says its the idle control valve, but its only raising the revs by a few hundred rpm and as it hunts the dump valve is fully opening and closing?

mark says he thinks the dump valve should not do that, should it?

we know its over fueling on boost but mark thinks the dump valve might be sucking in air when its driving? due to as soon as the revs raise even the slightist its fully open?

comments please mark just wants to get it sorted before taking it for a set up.

spec is
phase 3.5 chips
evo 4 td05 turbo (custom down pipe and side exit)
200sx tubular manifold
rebuilt engine with xe inlet cam
saab red injectors
60mm top hat and hard pipes
frontera 2.8 intercooler (which is being changed)
8v baffle plate
got a rolling road print out for 291bhp at 13psi

but we think this problem and the intercooler is restricting it?

thanks

 

p.s its a shitty skyline dump valve

mark thinks its meant to have a recirc valve, is that true or could we just blank off the dump valve?

 

I'd be pretty certain it is the iscv,quite common on vauxhalls.
Pop over to migweb as there's loads of good guides on how too clean/repair it.
It's a really good website,a bit like this place but perhaps even a bit more technically minded and you usually get an answer pretty quick or use the search function,saved me a ton of hassle on my vauxhalls over the years.
Bet that flies!!!!

 

many thanks mate will do

the guy said that it needs living up out of the car and a cleaner running thorugh it, but im guessing could you buy a new one?

yes it flies lol

its fully stripped out with just bucket seats and harnesses lol and its still got the 1.0 12v badges, and in a old ladys green

 

Ha ha sounds awesome!!!
Get some pics up too,I love those cars as well,problem was that a lot of people did them years ago and they got a bit popular like the saxo is now and people started looking at them as "just another corsa LET" but realistically it's 300bhp in a shopping car so it's going to be completely awesome in everyway anyway.
As they get broken up for parts their starting to get rarer so people are going back now and thinking "wow,when was the last time I saw one of those?" so IMO the only way for them is up in value.
Nova red top's and LETS are starting to get a bit of classic status now and starting to fetch good money for a clean one.

 

Ha ha sounds awesome!!!
Get some pics up too,I love those cars as well,problem was that a lot of people did them years ago and they got a bit popular like the saxo is now and people started looking at them as "just another corsa LET" but realistically it's 300bhp in a shopping car so it's going to be completely awesome in everyway anyway.
As they get broken up for parts their starting to get rarer so people are going back now and thinking "wow,when was the last time I saw one of those?" so IMO the only way for them is up in value.
Nova red top's and LETS are starting to get a bit of classic status now and starting to fetch good money for a clean one.

 

we paid Ł2600 for it and rust wise its mint, good body work with only 2 minor dents and spec as above, if we change the intercooler and sort the above it can run anything upto 350bhp and it weighs what 800kg stripped?

bargain lol

mark does not like the steering on it and says its too slow and needs some sort of quick rack or a "quicker rack"? so hes looking in to that, and the brakes could be better as they have v6 brakes but the pedal is a little spongy but hes leaving it with his brother to sort all this anyway.

then its decide weather to use
mtech
regal
courtney
thorney motorsport

so need to look around at tuners

 

regal or courtney are the firms I remember from back in the max power days

 

thats what i heard but alot of people are using this thorney motorsport now...

we need to sign up too these vauxhall forums and see

 

blank off dump valve first and check for air leaks/split breathers

they love an air leak or two

 

wicked cheers mate will do.

just looked at what plugs to use with the phase 3.5 chips and they are different to whats fitted so that wont help either

 

plug type wont matter too much to test a problem, just gap the plugs to something sensible and see if it helps tickover

Easy elimination

 

yeh i dont think its plugs, defo idle control? air leak?

mark thinks the dump valve has something to do with it, do they need a dump valve or recirc or can it just be blanked off

 

If the car has so many problems, why buy it???

 

because the running problem got worse it wasnt really doing it when we got it, just started on the way home.

but im thinking its a vac leak along with wrong plugs and idle control needs a clean out

 

blank dumpvalve off i had same problem on my astra c20let

 

wicked we are going to check a few things that i read on migweb

blank off dump valve and check for leaks

check afm is in correct position and not to close to turbo

new "cold plugs"

alternator voltage after hard rev

throttle stop screw isnt loose

breather system

coolant temp sensor

clean idle control

these are other peoples things that have cured their problems so mark will run through the car today.

cheers for you help guys other wise we will just drop it off at a tuner

 

It's usually something pretty simple on a vauxhall of that generation to be fair as they were really well made cars in the 80's/90's.
Nothing like the rust issues of fords of that age either so don't get too concerned about that and all those problems listed above wouldn't cost Ł150 to fix if you did the lot.
Could pm chip as well as he's done a lot with these,particularly the c20Let motor.
I think the Saab motor almost fits in directly if theres a LET in it already and they start at about Ł200 second hand so even if the worst happens it's not too expensive!!!
Migwebs a good site as well,glad your enjoying it.

 

Going through it, it seems it's not got the "cold" plugs to suit the phase 3.5 set up so when it's hot it cuts out ect and not helped but over fueling

We are Gunna just tidy it up and drop it off at regal?