inconsistant boost

[Adam Davis]

Hi guys, ive tried finding the answer to this specific problem but i cant find it. Sometimes when i hit full boost, it will peak at 0.9 of a bar, creep up to 1.1 with rpm and then tail off like normal. Other times it
willl peak straight to 1.1-1.2 and then tail off. Whats your opinions on this?? Would you put it down to tired n75 or maf?? I was going to change both. Its stage 1 revo
Thanks

 

[badger5]

its low for revo, unless the revo settings are low..
what are the settings?

 

[Adam Davis]

Thanks for the reply. I dont know what the settings are. I forgot to mention its an agu. I thought 1.1-1.2 is normal for this engine??

 

[STEALTHQUATTRO]

hi guys really sorry for hijacking your threds, am bit new on here and dint have a clue how to start my own!

 

[Adam Davis]

Bump

 

[<tuffty/>]

Scan for fault codes and do some airflow logs in VCDS

<tuffty/>

 

[STEALTHQUATTRO]

Don't worry mate! I did the same last week

 

[Adam Davis]

Right no fault codes. I cant data log on vas at work so used live readigs. I got 145 g/s on maf, 77% duty on n75 which shows my tubby aint working flat out so hopefully OK. I couldnt find a boost leak, bearing in mind i havnt used a boost leak tester, just visual inspection of all pipes/vac lines, also boost gauge sits at 0.7 of a bar on idle. What other blocks will be useful to log? can you log requested/actual boost? i used 006 for fuel trims but i dont think it is correct, as im not sure it can be logged on agu?! but i am uncertain what parameters the ecu uses to adjust fuelling, is it just narrowband lambda?
When driving recently it boosts to about 0.8 of a bar at 2500 rpm, then creeps to 1 at 3k. WOT at 3k it just goes straight to a bar, no spiking which i come to expect on a k03.
Thats all the information ive gathered so far. and help would be great.
thanks

 

[Adam Davis]

Bump.

 

[Adam Davis]

Right since the colder weather has kicked in it now doesnt even boost to a bar. 0.8 then creeps to 0.9 feels slow as **** lol.the n75 duty seems real low. Would the low n75 readings be becuse the maf is nackered?? or would it be low maf readings because the n75 is gone? If u get my drift lol.

 

[Adam Davis]

Just pulled actuator pipe off, 1.2 bar :s knackered turbo??!!

 

[badger5]

what a max of 1.2bar?
@ >5krpm, pseudo in the ball park of normal, but i would expect a big spike on initial spool

 

[Adam Davis]

Peaked at about 1.3, but my car has never spiked thats what i find weird. Now it shoots to 0.8 and creeps up to 1bar . Can the boost settings be altered on the revo map for an agu?? Whats the max boost i can run on the map as i might plumb in a mbc. Is the map just over conservative?? Cuz my maf readings are low also.
Thanks for your input bill

 

[Adam Davis]

Ive made a boost leak tester and am going to try that tomorrow also.

 

[badger5]

Peaked at about 1.3, but my car has never spiked thats what i find weird. Now it shoots to 0.8 and creeps up to 1bar . Can the boost settings be altered on the revo map for an agu?? Whats the max boost i can run on the map as i might plumb in a mbc. Is the map just over conservative?? Cuz my maf readings are low also.
Thanks for your input bill

revo not adjustable on agu.
low maf readings may be a cause not a symptum as me3.8 ecu is very dependant on airflow measurements

 

[Adam Davis]

Well......my boost leak tester worked a treat!! I thought i didnt have any but i found a split pipe and all my injector seals are leaking. Waiting for o rings arriving tomorrow and bought new seats that sit in the inlet manifold. At 1.1 bar now and thats just from the split pipe.

 

[cabrio boy]

Adam how did you make you boost leek tester I've the same problem with mine ?....