Stalling after supercharger fitment..

[mrzigazaga]

Hi Peeps..I have still to go to the tuners but wondered if anyone would have any ideas as to why after having the blower fitted the car it keeps stalling when returning to idle..Could it be a vacuum leak?...Fuelling or any other issue...Cheers..Ziga

[Danny Hoffman]

Air leak seems a good possibility. Does it stall consistently or intermittently? Does it stall when cold and hot?


If you google stalling and supercharger you might find some other suggestions re other makes, there are certainly plenty of hits.

[mrzigazaga]

Thanks Danny..I did google it and quite a few did mention air leaks..It mainly does it when its hot..Unfortunately i have a blocked earhole at the moment and its my good ear so i cant hear shyte..I have checked all the pipework and capped off pipes but have found nothing..Probably need to spray some WD all over my recently cleaned engine..Cheers..Ziga

[adam quantrill]

Mine stalls when cold until it's warmed up a little bit.

It might not be so unusual because the supercharger puts more drag on the engine so I think you'll just have to set the idle revs a bit higher than normal.

As yours stalls when hot, have you had the idle mixture measured and if so what is it?

[mrzigazaga]

Hi Adam..My idle is set to 1100rpm but i have yet to take it to the rolling road for a tune so that could have something to do with it..The amethyst ignition is set to 12 degrees of static timing..Although it was creeping up to 13 when i monitored it the other day..I cant see where it is advancing when i rev it though??..It might have something to do with the ignition curve/map...cheers..Ziga

[Mr Tank]

Hi Mark

Mine stalls when its cold, it needs to warm up a bit and then it's great!

Drives like a dream they tell me!

Hopefully I will soon find out for myself!

Keep at it mate you will find what the problem is eventually!

Andy

[Transmitter Man]

Has the new rad arrived yet?

If not, when?

Phil
420 SEAC

[mrzigazaga]

Cheers Andy...I think i need a by-pass valve..Been reading that when you de-accelerate suddenly it closes the throttle plate and the intake pressure from the blower that has built up has nowhere to go and acts like a compression surge..The by-pass valve relieves this pressure and apparently it also helps keep the charged air cooler as you accelerate again..Kind of makes sense..Cheers..Ziga

Bit like this


Hi Phil...Not received the rad yet..It should be here tomorrow...cheers...Ziga

Edited by mrzigazaga on Wednesday 26th June 09:14

[adam quantrill]

Zig - on that diagram where is the throttle body - by the air filter?

[mrzigazaga]

adam quantrill said:

Zig - on that diagram where is the throttle body - by the air filter?

Sorry mate..Just ammended it..Yes the throttle body is positioned where it is in the installation for the sierra...Some cars have the throttle body on the exhaust of the blower...Could this be an option rather than a by-pass valve?..Incidentally is a dump valve the same as a by-pass valve?...Cheers...Ziga

[mrzigazaga]

Just spoke to power engineering and they said that they didnt use any blow off valves..The idle fuel mixture was set to .1 and the static timing was set to 10 degrees...Mine is 12 degrees...Not sure what the mixture is..Maybe this is the cause....Cheers..Ziga

[chedder]

Hi Zig, glad to see you are getting there with the SC conversion and nice to see you are having the same problems I did!
If your SC is fitted to suck through rather than a blow through the throttle body then no dump valve is needed. Your issues with a stalling engine brobably do stem from a lack of a bypass valve, I ended up using a BMW stepper motor (air idle valve) controlled from
the Emerald ECU to give a stable idle.
One other method you could look into is to use a manual turbo boost adjuster to bypass the SC and throttle body this would allow you to fine tune your air idle speed.

Chedder

http://www.ebay.co.uk/itm/New-Adjustable-Boost-Con...

Edited by chedder on Wednesday 26th June 11:04

[Danny Hoffman]

mrzigazaga said:

Just spoke to power engineering and they said that they didnt use any blow off valves..The idle fuel mixture was set to .1 and the static timing was set to 10 degrees...Mine is 12 degrees...Not sure what the mixture is..Maybe this is the cause....Cheers..Ziga

A couple of degrees change in the ignition timing would have a significant impact on the idling speed I would have thought.

[mrzigazaga]

chedder said:

nice to see you are having the same problems I did!

Hi Tony..That actually sounds promising..I did have a read of one of your early post..(2007)..I think as regards to a by-pass valve..It does make more sense..Cheers for that...Ziga

Hi Danny..I have lowered the static advance to 10 degrees and taken 2 degrees off each level of RPM which is in 500 rpm increments..It does feel slightly better but still stalls if i rev hard..Maybe the by-pass valve is a good investment..Cheers...Ziga

[Oz2]

Hi zig
No probs with stalling hot or cold and just lowered my idle to about 950rpm.
It was up around 1100rpm, I don't like the idle reves high.
Well done with your mods mate Delilah is coming along nicely.

[mk2 24v]

The CO is set to .1? Sounds a bit low to me, and would mean the engine is running too lean (and hot)
The MFI stuff is usually set to 2-2% CO at idle if thats any help Zig

[Mr Tank]

Hi Mark

Sounds like you need to take the car to the experts to have it set up, then you may find alot of your problems will go away, even the hot running could be down to the incorrect set up of you systems, as you said the garage was a bit of a back street place who did the work etc.

Andy

[mrzigazaga]

mk2 24v said:

The CO is set to .1? Sounds a bit low to me, and would mean the engine is running too lean (and hot)
The MFI stuff is usually set to 2-2% CO at idle if thats any help Zig

Hi Mate..Thats what power engineering recommended..They said it needs to run lean at idle..

Mr Tank said:

Hi Mark

Sounds like you need to take the car to the experts to have it set up, then you may find alot of your problems will go away, even the hot running could be down to the incorrect set up of you systems, as you said the garage was a bit of a back street place who did the work etc.

Andy

Thats the plan mate..The rad should be with me friday morning so at least i will be able to sort out the cooling issues...At the moment the engine wont run properly or rev at all???...Just checking all the plugs and leads...Ziga

[Jack Valiant]

Mark as you have been adjusting the maps put them back to the pre problem levels I cannot see why over night the leads would be a problem??

[mrzigazaga]

Jack Valiant said:

Mark as you have been adjusting the maps put them back to the pre problem levels I cannot see why over night the leads would be a problem??

I have mate..Delilah dont like 10 degrees of static timing..Hopefully once the rad is here i can get it sorted and get it to power for the dyno tune..I think i might just get myself a by-pass valve..I know they didnt fit them when they did the conversion but it makes more sense to me..The idle is between 1100-1180rpm and as it fluctuates so does the timing..This is probably not helping as it must make it hotter..Do you think you will have time saturday to fit the fan as i dont really want to take to you know who...Cheers...Ziga