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Discussion Starter · #1 ·
Ok,

still have the same old problem with my car. boost dropping from 15psi to 10psi back to 15psi and it keeps doing it only in gears 4 and 5 at WOT. It is intermittant but it happens more often than not. Since i've been trying to fix it i've replaced a coilpack, MAF and the temp sender. Next thing im going to try (as recommended by weeloon who has been a massive help!) is the MAP sensor. Does anyone have any additional input?

Another thing i wondered about was my mapping by jabba.

I'm spiking at 16-17psi and holding 15psi and it tails off to 10psi getting closer to the redline. Does this sound right?

If no where local can fix it then i guess i'll make a trip to Jabba (or JBS maybe) if they can update my mapping a bit for not too much.
 

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10 psi at redline chief? not far from it.... what is it holding at peak power (usually 6k ish on the sport)? I would definately consider your MAP sensor but i dont think they are cheap to replace, and it does seem VERY strange that it happens in the top gears. I would have thought a faulty MAP would do this anywhere..... so perhaps you only notice in these gears because you spend more time driving the car in them. Perhaps have a play about in 3rd a few times to see if it occurs... It would make sense, that the thing is reading the load incorrectly and affecting boost. What you need is a good ol' faxhioned AGU with no MAP and really on the MAF to do all the work for you , far less complex (and primitive [;)])...

JBS will not be able to adjust your mapping for you, and i would expect them to drop a big fat REVO sales pitch in. I would speak to jabba and tell them of your concerns, telling them you have tried pretty much everything and are fast running out of options? I think Bedrock Veedubs are Jabba's Scottish agents so perhaps they are more convenient for you?
 

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PS, you can easliy aquire more power from a more agresiv map. It will still be very drivable, a lot of the SPS3 lads get 20+ psi spike and about 14/15 psi at 6k with 12 ish at redline. Thats the 235-245 teritory with your other mods mate.
 

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Discussion Starter · #5 ·
I knew JBS won't be able to change my map hehe, was just interested in there RR diagnostics as it seems its solved alot of peoples problems. I think what i'm gonna do is replace the map sensor and if it does no good i'll take the trip down to jabba (1000 mile round trip LOL unless bedrock can do it). Its just so strange its only happening in 4th and 5th?!? I know it would be more evident anyway as its when im holding boost for longest but the car pulls so hard in 3rd. Maybe try a different N75.

Quote: posted by Tim Sims on 12/02/2005 10:23:06

PS, you can easliy aquire more power from a more agresiv map. It will still be very drivable, a lot of the SPS3 lads get 20+ psi spike and about 14/15 psi at 6k with 12 ish at redline. Thats the 235-245 teritory with your other mods mate.

Thats the sort of mapping i'd like [^]
 

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Discussion Starter · #6 ·
Tim just checked the car on a run tonight, seemed to be happening in 3rd aswell and at 6k in all gears it was only holding 10psi [:S]
 

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Chief,

I had the same problem. Seemed like the car was retarding the power but couldn't work it out. Anyway I changed the N75 and it was sorted. I was also getting a fault code on VAG COM which has never come back (Touch wood[B)]). It was one of those intermittent problems that never happen when you want it to. All the places I went thought I was imagining it
 

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Discussion Starter · #8 ·
Jim,

Is your car engine code AUM? Which N75 did you replace it with? Was it visible like my problem on the boost gauge? I'm not throwing any codes in vag-com so it'd be great if this was the cause of the problem.
 

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deffo sounds like n75 valve , just had mine replaced had the same symptoms as yours. mine didnt throw up any fault codes either !!!!
 

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Can you do some boost logs with VAGCOM rather than giving the gauge readings. To see requested boost and actual boost would help alot. We can then see if your not meeting requested boost or if the ECU is backing off for some reason.

I can vouch for JBS's diagnostics on the RR they did a great job on mine.

What DV are you running and have you checked it?

As for Revo I'm not running on max settings and I'm peaking around 20psi with no spike and a very smooth curve. Actual boost is held very close to requested boost throughout the complete rev range.
 

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NOt sure chief, but I seem to remember Mike saying he mapped mine to have a slightly lower boost in the higher gears (4+5)compared to 2nd and 3rd. Because under heavy oad, 2nd and third gears will nt be held for long wheras you can load the engine for much longer in 4th and 5th.

Have you called Mike to discuss you problem? He'll be able to check to see how he mapped your car.

Also how long ago did you change the MAF? May need a clean, did mine today (1st time in 10k miles) and its far more sprightly.

Do yu have the 4 bar FPR? I wonder if its runnning short on fuel, slightly blocked filter or something.

PS I did n't think the AGU motor had a MAP sensor, which is why it is so relatively crude to map?

PPS my jabba k03s map peaks at 1.5bar, (not sure in old money what that is) It was peaking at 1.6bar soon after done, as the new turbo freed up, so they tweaked it down a bit.
 

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Quote: posted by simch on 15/02/2005 13:31:47PS I did n't think the AGU motor had a MAP sensor, which is why it is so relatively crude to map?

The AGU doesn't have a MAP sensor but I'm pretty sure that thechief has an AUM.
 

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Quote: posted by simch on 15/02/2005 13:31:47PPS my jabba k03s map peaks at 1.5bar, (not sure in old money what that is) It was peaking at 1.6bar soon after done, as the new turbo freed up, so they tweaked it down a bit.

1.5bar is 21-22psi
 

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Discussion Starter · #14 ·
Simch,

i have AUM. No 4 bar.Mike couldn't help but he suggested MAF or MAP.I replaced the MAF on friday.

Eddy,

I have a Bailey DV which is in good order. I'll do a log tonight so hopefully it wil play up!

Huddo,

Which engine code are you? Which version of N75 did you get it replaced with? What was the current going rate for the valve?

Looks like i'll try N75 , then MAP. If that doesn't work i'll combine a trip to JBS for the RR diagnostics and an LSD lol!

Thanks for all the help guys.
 

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AUM eh? Well I've got no sympathy then, I mean if you go for all these posh new cars with NEW FANGLED technology, you gotta expect problems![;)]

Off to stick some coal in my AGU![:(]

Cripes [:O]22psi!!! That's more than I got in me tyres!
 

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engine code APY or AYP ! car had a faulty "C" fitted an "F" ?56ish main stealer fixed the fault let us know how you get on.
 

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Chief,

PM'd you mate. The one I had in the car causing problems was the 'J' version. I swapped it for the original 'f' and it cured my problems[:)]. Good luck mate.

Jim
 

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Discussion Starter · #20 ·
Jim,

I presume you'd put in the J or was it factory fit? Did it never work right since when you put it in?

Think i might try out F valve.

P.S. didn't get your PM Jim my inbox was full, doh!
 
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