problem when fully boosting

[M87NER]

Hey peeps,

Was driving the other day and when my car tried to fully boost my car would judder/popping noise from exhaust (very quick popping) and would go into limp mode this would happen in 3,4 and 5th gears and also sometimes cut out if i stopped, so i disconnected me maf sensor and it drove fine, boosted properly ect... so bought a new maf today....fitted it and everything is back to normal except i still get a slight popping from exhaust when fully on boost in 3rd 4th and 5th....

What could this be?

no faults by the way..

Cheers

Rich

 

[cus]

sounds like over fueling. haveyou checked your coils? mine went today and it juddered when hitting boost... possibly the same?

 

[Damoegan]

I agree with cus, prob a coil pack on its way out mate.

 

[DaNnY_LaD]

Yeah Coilpack for me..

 

[p34ch3y]

a faulty n75 valve could also do this

 

[M87NER]

HAvent checked the coils yet, i have been messing around with me n75 valve past couple of days so i'll give that a check,

strange how it doesnt do it when i unplug the maf sensor....runs beautifull.

 

[ian_cupra]

could be spark plugs too mate

 

[M87NER]

say if it is the coilpack/spark plugs would this not still do the same with the maf connected or not connected?

 

[ian_cupra]

could be the extra load the engine is under, as map might be slightly stronger with maf connected, not sure though

 

[M87NER]

i see, well its done the same again last night and went into limp mode.... will have check sparks and coils now then looks like

 

[loveturbopower]

mine done the same the other day, pulled over checked the coils, and happened to be a coil, luckily for me i had a spare in the boot, plugged and popped it in, drove spot on

 

[christian rea]

i had a bit of boost losss the other week but only when it got to 5k ,could this be my coils or maff sensor ? how do you tinker with the n75 valve

 

[cus]

make sure the n75 valve is clamped in place nice and tight. usually if you have a problem with the n75 valve you go into limp mode.. comes up as overboost in vag-com.

possibly maf, as you are more likely to notice boost loss much further down in the rev range if it was a coilpack imo

 

[M87NER]

had a look at the n75 it all looks nice and tight, going have to check all my hoses check see if they are tight as i was driving down the M1 last week and blew the charge pipe hose of that connects to me dump valve, lol,

Its constantly in limp mode now aswell! .....and me scan gauge says there is no faults and waiting for me vagcom lead to be delivered- any time now so i can scan with that, doing me head in only boosting 8psi,

brand new maf sensor fitted aswell...made no difference really, might disconnect me battery for half hour see if that gives me boost back then hopefully i will no if there is a ecu fault,

 

[cus]

the battery will give the boost back, but depends what the fault is and it is more then likely gonna go back into limp mode.

mine went into limp mode ages ago went booting it because of a loose pipe causing a boost leak.

if your charge pipe hose popped off, then double check all your others

 

[p34ch3y]

the battery????????????????

 

[footlong]

split hose/boost leak. back fire is unburned fuel cos of a lack of air going into charge mixture.
I know this cos mine was same until yesterday. i thought MAF or coil, but if a coil goes down, it'd run like **** all the time. it's no coincidence that it loses boost at peak pressure. the extra load will expose you split pipe or por fitment whichever it is. On the plus side, if an hose has poped off, it's free to fix


Take your time and cover all hoses AND your cooler for leaks.

Good luck pal.

 

[M87NER]

i think i will try the battery method tomorrow if my cable hasnt arrived, and also check under the car at the intercooler pipes cause ya never know as the garage didnt tighten up the pipes and doing 80 in the fast lane and when i put my foot down 'pop' and car was trying to cut out....lol not the best

 

[M87NER]

split hose/boost leak. back fire is unburned fuel cos of a lack of air going into charge mixture.
I know this cos mine was same until yesterday. i thought MAF or coil, but if a coil goes down, it'd run like **** all the time. it's no coincidence that it loses boost at peak pressure. the extra load will expose you split pipe or por fitment whichever it is. On the plus side, if an hose has poped off, it's free to fix


Take your time and cover all hoses AND your cooler for leaks.

Good luck pal.

Topman.. probs just strip it all and redo everything myself...

Cheers

 

[footlong]

I've got fingers for thumbs and vice versa combined with a basic knowledge of mechanics. i sorted mine. My method to a problem is start by the cheapest and easiest problems to rectify and take my time.