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*RESOLVED* Fault Code(s) 0.4 Bar Max Boost = Constant Limp Mode!

herb2578

now a cupra owner
Jul 14, 2007
145
0
west mids
after





I figured that much mate, but readings etc, maths I'm not good at


like i said a stab in the dark my mate recently did a xe to let conversion in his astra and couldnt get it to boost properly!!!
it turned out he had fitted his maf the wrong way round it took him ages to figure out what he had done wrong (and he is a mechanic!)
sorry mate just a thought.
 

Pyro

Guest
All you need to do is plug it in and build the pressure up while someone listens for air escaping and you watch the pressure gauge once you hear the air you keep it pumping till you find the leak ;)
 

Pyro

Guest
like i said a stab in the dark my mate recently did a xe to let conversion in his astra and couldnt get it to boost properly!!!
it turned out he had fitted his maf the wrong way round it took him ages to figure out what he had done wrong (and he is a mechanic!)
sorry mate just a thought.

Lol was a good thought tho mate ;)
 

Mo Arif

V.A.G Planet
May 5, 2010
2,510
0
Birmingham
like i said a stab in the dark my mate recently did a xe to let conversion in his astra and couldnt get it to boost properly!!!
it turned out he had fitted his maf the wrong way round it took him ages to figure out what he had done wrong (and he is a mechanic!)
sorry mate just a thought.

Thanks for the heads up mate, I'm pretty sure I've fitted the MAF the correct way around, I can take some pictures to confirm



All you need to do is plug it in and build the pressure up while someone listens for air escaping and you watch the pressure gauge once you hear the air you keep it pumping till you find the leak ;)

I know where one leak is mate, there is another way to do it, it might sound silly but works well, get some 4mm silicon tubing, the one you use for the DV etc, at least half a meter, put one end in you ear! and the other in suspected leaking area's it amplifies the leak noise! and works like one of those doctors heartbeat monitoring things, it's pretty effective and I have found one more leak under the inlet manifold but my boggle is that one two or three small leaks should not restrict the car from boosting above 0.4 bar, if anyone can confirm this.


Well i've thrown a small fortune at this car / engine now, I really don't know what to do check next, I'm going to order a new MAF next and 'attempt' fitting the catch can etc.
 

Pyro

Guest
I can whstbyou mean bybthis test mate but some leaks won't show on tick you need to be under load but I dont think the leaks causing it :( have you checked the map sensor? Is the tip still on?
 

Mo Arif

V.A.G Planet
May 5, 2010
2,510
0
Birmingham
Could a FPR cause this?

I feel like taking a building jack hammer to the car now

Jap cars are so easy to work with
 

Pyro

Guest
And read this ;) citrusy of Dave (DPJ)


Log 003, 118, 115,020, 031, and 032

Do no more than 2 at a time to get any reasonable samples.
003 and 020, then 115 and 031, then 118 and 032.
This gives you, airflow, actual timing, timing pull, requested boost, actual boost, target air fuel, actual airfuel, n75 duty, inlet temp, actual boost, and then finally fuel trims.
 

Mo Arif

V.A.G Planet
May 5, 2010
2,510
0
Birmingham
I pm'd the chap from the thread i posted above he said:


"Mo,

I did figure out my boost problem however, it was not in Limp Mode just losing boost pressure. It turned out to be a rip in the new Diverter Valve I replaced. I also went through alot of time and trial to try to find this out and it sucked. I would try to get someone with a smoke machine to pressure test the system and look for any hoses you may have missed for leaks. (It pumps smoke into the system through the MAF under pressure and makes it easier to detect any type of leak in your boost system). Have you checked the wastgate on the turbo to make sure it is functioning correctly.

It sounds like you have been going through everything. One time my 1.8 was running poorly and took forever to find a leak until I smoke checked it and it turned out to be a small hole in one of the hoses connected to the throttle body."




How do I check if the actuator is operating correctly? and which tuning specialist has a smoke boost leak testing machine ?
 

Pyro

Guest
Bill has a pressure tester but may be able to adapt it other than that phone about mate sumone will have one ;)
 
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