1.8T AGU no boost, lost all power

[sonyboy]

hi, i have 1.8T agu engine, chipped to 195bhp, and it lost all its boost.
checked no boost leaks, no vac leaks, try to put new n75j and DV 710N but nothing, changed g62 coolant sensor and spark plugs, changed line from inlet manifold to PCV valve, all vac lines changed an tied with metal ties, maf reading normal around 2,9g/s idle, around 142g/s at max, no ecu errors over vagcom, lambda is +15% at group 06 MULT field(second field) seems normal, changed vac line from brake system to inlet manifold, cleaned IAT and MAF, even try to disconnect all sensors, and even disconnect from battery. checked PCV system, PCV valve is fine blocking in one direction. fuel consumptoin is fine with or without boost.

I have no boost at all, i cannot hear it any revs in any gear. Sometimes i have all its power and running for few days, and suddenly its just loss at its power and sometimes when i start car in the morning i have half of my power. same problem is when temp. is 25C or -5C.
So when car sometimes running great, turbo is sucking air you can hear it, its very strong suck of air, and pull is amazing.

help please

[will gti]

i dont really no much but sounds like u have done a fair bit like ........maybe a turbo problem??? 

[Hulmie]

Faulty MAF

[sonyboy]

i can say when it is running its running amazing, i have no bad sounds and oil consumption so its not turbo, sometimes its running normal and there is strong sound of sucking air from turbo when spools, it is hard that turbo is sometimes working sometimes not. so its spools little bit at 1k you can barely hear it and than disapears.

i tried to disconnect maf but nothing, even cleaned it. i ordered new maf, should get it soon. 

[topher]

+15% is a little too lean for my liking. There are various reasons why that may or may not be related to your boost issue though. MAF is a good start because they can be a b!tch to diagnose when the issue is intermittent especially on AGUs. You seem quite capable with vcds so try logging block 118 which will give you requested vs actual boost but probably more importantly n75 duty cycle. You could also check that your actuator is moving freely without any "sticky" spots.

[sonyboy]

my engine is AGU, there is no groups past 35 as i notice, agu cannot measure boost. i will check wastegate thx.

[topher]

haha, yeah im tripping.. my bad. I forgot yours was agu in the space of one sentence (i blame lack of sleep). you should still be able to log duty cycle (block 25?) and engine load req/act. Output tests are also useful, n75 should produce a healthy click.

[sonyboy]

i connect my pc to my car over vcds and i got three messages, #1 Mixture adaptation( adaptation limit (add) exceeded, #2 n75 - output open, #3 intake manifold pressure - control limit not reached.

so i went and look at n75 and it was one of the two wires was broken at back of connector, so it was really hard to put wire back because only 4mm of wire was out of connector. i use a sort of wire clamp and solve it, when i cleared error message over vcds it didnt came back.

so ran car everything was like before, outside temp was -2 to -5, everything was fine.

even problem was solved, but i'm afraid that this not going to last long, problem is somewhere else because last time everything was fine no any errors no nothing and turbo did not want to spool. probably this was my mistake where i broke this wire trying to solve problem whn i was try to change n75 valve.

even from this view, let say small amount of power is needed from 1K to 3K, because before car ran amazing even from 1,5K you could spin the wheel in 2nd gear, now i need 3K at any gear except 1rs to make it spin wheels, it is small amout of boost al low revs only noticable for owner who drives car for a long time.


thanks, this was best forum ever i've visited, your answers where fastest and pleasant from any forum that i posted my problem.
i will let you know if any thing changes, or any error message apears, or my boost vanishes.
big thx

[topher]

Keep an eye on the fuel trims over the next few days. Avoid clearing the fault codes as that will reset the trims to 0. You should be able to get a new plug/repair wires for the n75 from a vw dealer

[sonyboy]

i've already check group 6, second field lambda ADD is zero, means that idle is fine, third field lambda MULT is pulsing from +5% to +20%, this means that during drive car runs lean, so ecu is able to adapt to -+25%, in this case it is from +5 to +20% adapting. i'll try to solve it.