You get a more negative reading when on full throttle? 
Surely you'd be getting a +ve reading (ie 20psi)?
Surely you'd be getting a +ve reading (ie 20psi)?
m.r.davies said:
....yes from cold start & poss worse after CC re-map. 1st/2nd gear culprits driving dead slow. it just pulls by itself!
gazjones
Guest
no aqfter lifiting off the throttle depending how much boost has been made ie more boost gives more vac when lifting off!Pabs said:You get a more negative reading when on full throttle?
Surely you'd be getting a +ve reading (ie 20psi)?
gazjones said:
ah gotcha. I don't get that - i always hit the same vac reading of -20, (+/- 2) no matter on the conditions.
bit of an update here.....
If I let off the boost quickly - ie foot on gas - lift foot off pedal quickly - then i get this issue where boost drops to vac -10, then slows right down and gets to -20 about 1/2second to 1 second later.
if I let off the gas slower, (sometimes i get a chatter when doing this) the boost drops smoothly and straight to -20 without hesitation.
I'm thinking it must be one of my n27 or n249 valves... or perhaps a split pipe somewhere?
If this helps anyone to help me - let me know
If I let off the boost quickly - ie foot on gas - lift foot off pedal quickly - then i get this issue where boost drops to vac -10, then slows right down and gets to -20 about 1/2second to 1 second later.
if I let off the gas slower, (sometimes i get a chatter when doing this) the boost drops smoothly and straight to -20 without hesitation.
I'm thinking it must be one of my n27 or n249 valves... or perhaps a split pipe somewhere?
If this helps anyone to help me - let me know
well iv done the n249 bypass and i would advise against it going on my experiences, i got what seemed like turbo stalling and also it didnt seem like it was really dumping, couldnt hear it like I could before etc
what exactly did u do? Same as what m0rk said?
My first thing to do is to check all hoses and the DV out - something just aint right on my car. I just seem to have soo many different boost issues since getting the car.
Fluctuating/bouncing, "dv chatter/oscillation" (we think) and now this.
I'll also have a play with electrical connection to n75, make sure all is clean etc. Somethings wrong, just gotta find out what.
My first thing to do is to check all hoses and the DV out - something just aint right on my car. I just seem to have soo many different boost issues since getting the car.
Fluctuating/bouncing, "dv chatter/oscillation" (we think) and now this.
I'll also have a play with electrical connection to n75, make sure all is clean etc. Somethings wrong, just gotta find out what.
i would say n75 or DV
I put a t piece in the FPR pipe and ran a direct feed to the top of the DV, then blocked off the normal pie going into the top of the DV with a screw
I got normal VAC and normal boosting etc but car sometimes hesitated whilst changing gear, i couldnt hear the DV dump and was making fluttering compressor stall sounds
I put a t piece in the FPR pipe and ran a direct feed to the top of the DV, then blocked off the normal pie going into the top of the DV with a screw
I got normal VAC and normal boosting etc but car sometimes hesitated whilst changing gear, i couldnt hear the DV dump and was making fluttering compressor stall sounds
I had a split pipe between the n249 and DV - that gave me some similar symptoms (chatter particularly). I don't have a boost gauge, so I don't know about the vacuum readings.
I guess the low vacuum reading shows that you have a leak - air is getting in.
I guess the low vacuum reading shows that you have a leak - air is getting in.
Feel said:
I don't have low vac reading? It always gets to the same -20 reading, just hesitates to get down there when letting off the gas quickly - almost as though something is fighting the vacuum?
does it stop then jump all the way down, or does it drop then falls slowly but steadily the rest of the way?
Yeh, but it gets to the right vac reading FINE if i let my foot off slowly - needle drops fine and steadily to the -20 reading, at the same speed as i lift my foot off the pedal.
If I let foot off quickly, thats when it almost stops at -10vac, and then it drops at a slower rate to -20.
Its like a strong "dump" from the DV seems to cause the problem...
If I let foot off quickly, thats when it almost stops at -10vac, and then it drops at a slower rate to -20.
Its like a strong "dump" from the DV seems to cause the problem...
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if you take off your DV and plug the top thin pipe with your finger then psh the piston up does the piston stay there or return to its sprung position?
currently - i don't know until tomorrow when i pull the car apart.
I know how to service the DV - and i'll know if its knackered/leaking or not. It should stay in the up most position, ie the vac holding the piston up. It has done in the past.
I might need to try a new dv..... or stick the bosch one on for a test-drive..
I know how to service the DV - and i'll know if its knackered/leaking or not. It should stay in the up most position, ie the vac holding the piston up. It has done in the past.
I might need to try a new dv..... or stick the bosch one on for a test-drive..
gazjones
Guest
pabs i took a vid of my gauge to show you what mine is like to compaire to yours
http://s51.photobucket.com/albums/f...rent=video-0008.flv&refPage=&imgAnch=imgAnch1
http://s51.photobucket.com/albums/f...rent=video-0008.flv&refPage=&imgAnch=imgAnch1
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