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Could the 3" exhaust cause the problem , due to back pressure or the lack of it... causing the turbo to act like a scavenge pump and possible exasperated by the cams? removing the dump valve should confirm this as with it missing the turbo should almost be stalled...
I think TBH, the problem could be somewhere else When i had Ross' old car, that was running 7A exhaust cam, samcos, S3 DV,cone filter @ 1.5bar no probs.
When Ross had his engine rebuilt and fitted his big turbo and manifold etc he began to get the same problem. I can see how this could be with the excess boost pressure been dumped at high boost but @1.2 bar?? I'd maybe change/swap the MAF for a try.
I run stock cams but will be changing to 7A when the engine gets a rebuild, and 1.5bar. It started to happen after i replaced the original hoses with samco ones???
If you catch the trottel you can keep it going but it really wants to drop off and die.
I did find a kink in the fuel line And i sorted that but have not driven the car since
Hmmm I've had this problem ever since I got my 3B back in 1999, the car is was stock when I got it, and is still pretty much stock ( Samco hoses, magnecor HT leads and forge DV - only fitted last year ).
The problem went away last for a little while after I had, the samco's, forge DV, WGFV, PCV , flame trap and MAF replaced.
I have the next 4 weeks off work so assuming the chemo doesn't knock me flat I can pop over if you want another 3B with the same problem to look at for comparison.
I had the same problem but I was using a Bailey sport piston type dump valve, now changed to a recirc type but the return point is lower in my MAF to turbo hose than standard but I also adjusted the throttle damper (to slow throttle return) and throttle closed position/angle to allow slightly more air passed so its not as reliant on the idle control valve to catch the engine.
Not teaching you to suck eggs i see the vac hoses have been replaced including samcos but is there a boost leak, may be on the breather side of things as this will make things way to rich and the ecu can't copy at first when dropping to idle??!
Could the tunner/mapper increase the injector on position from the standard 1800 rpm to say 2400 to give it more chance of sorting it self as you say with the light fly wheel it will return to idle very quickly?
Jay
Reset all the throttle position and tried it at different openings.
No leaks whatsoever. Please don't worry about me sucking eggs as I am open to all ideas. The PCV system has been replaced.
Would be a possiblity to tweak the on position, we had discussed tweaking the map to reduce the fuelling being put in at the decel point but it would have an adverse affect on the accel also as the ecu uses the same area of the map at certain points.
It had a Carbon CDI filter thingy but we changed that to an RS2 airbox, which made it a little bit better but didn't cure it.
One thing I was going to try was to remove the DV totally and blank the hoses to see if it still happened, it wouldn't be permanent as it would cause issues elsewhere.
I had the same problem but I was using a Bailey sport piston type dump valve, now changed to a recirc type but the return point is lower in my MAF to turbo hose than standard but I also adjusted the throttle damper (to slow throttle return) and throttle closed position/angle to allow slightly more air passed so its not as reliant on the idle control valve to catch the engine.
Not teaching you to suck eggs i see the vac hoses have been replaced including samcos but is there a boost leak, may be on the breather side of things as this will make things way to rich and the ecu can't copy at first when dropping to idle??!
Could the tunner/mapper increase the injector on position from the standard 1800 rpm to say 2400 to give it more chance of sorting it self as you say with the light fly wheel it will return to idle very quickly?
I don't mind having to find any problems on my car, i've usually got time
Always looking for willing victi... er I mean volunteers
Originally posted by Chris M
TBH, i wouldn't have thought the DV would make too much of a difference Its not really running that much diffferent to mine. How much boost is it running and what DV?
I'm also running a cone filter, been looking at modding my existing 3B airbox tho.
Cheers
1.2Bar boost, normally I wouldn't put more than 1Bar through the K24 but with the exhaust system it just loved what we through at it.
The DV removal would be to see if the air rushing back theory could be proved, it was using a Forge 007 recirc but that has been removed at the moment as it was sticking, it has a brand new OE S3 item on.
I don't mind having to find any problems on my car, i've usually got time
TBH, i wouldn't have thought the DV would make too much of a difference Its not really running that much diffferent to mine. How much boost is it running and what DV?
I'm also running a cone filter, been looking at modding my existing 3B airbox tho.
Well as you know, i'm interested in the clutch/flywheel combo (if you can get me a price ) so would be more than happy to try them in my car, and its RS2 spec too. I will be running the MAF on the pressure side too, so we will see if that does or doesn't make any difference
Cheers,
Yes I know
When we have this 3B in I am going to rig up the MAF temporarily on the pressure side to see what happens.
It had a Carbon CDI filter thingy but we changed that to an RS2 airbox, which made it a little bit better but didn't cure it.
One thing I was going to try was to remove the DV totally and blank the hoses to see if it still happened, it wouldn't be permanent as it would cause issues elsewhere.
I have the same issue corey,
Is the car running a cone filter?
When this happens to me the fuel light can come on some times.....
I have also cleaned all sensors tested and check them and replaced the plugs and checked the DV.
My car is remaped but this problem came out of the blue and has nothing to do with my map.
Well as you know, i'm interested in the clutch/flywheel combo (if you can get me a price ) so would be more than happy to try them in my car, and its RS2 spec too. I will be running the MAF on the pressure side too, so we will see if that does or doesn't make any difference
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, due to back pressure or the lack of it... causing the turbo to act like a scavenge pump and possible exasperated by the cams? removing the dump valve should confirm this as with it missing the turbo should almost be stalled...
When i had Ross' old car, that was running 7A exhaust cam, samcos, S3 DV,cone filter @ 1.5bar no probs.
And i sorted that but have not driven the car since
i see the vac hoses have been replaced including samcos but is there a boost leak, may be on the breather side of things as this will make things way to rich and the ecu can't copy at first when dropping to idle??!
) so would be more than happy to try them in my car, and its RS2 spec too. I will be running the MAF on the pressure side too, so we will see if that does or doesn't make any difference 
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