axx engine , sudden loss of power , no engine management light or fault codes

[steve71075]

hi all , new member and desperately in need of some help please 

had my 2005 mk5 gti engine code axx for around a year and its been running great until the last month or so when i would intermittently lose power once or twice a week almost as if i had turned the ignition off . throttle pedal becomes unresponsive for a few seconds and then it would pick up and drive as normal . at this time i was shown no engine management lights and it happened very rarely . car has not had a remap as far as i know and has covered approx 140k .

now a few weeks on its become near impossible to drive as the sudden loss of power happens all the time anywhere around 3-4k rev range , it is especially bad in 1st , 2nd and 3rd gear on hard acceleration and worse when the engine is up to running temps .
the engine management light did come on in the end .

i've been reading through the i must say very informative threads here for the last week or so and have found a few problems with the car which i have rectified .

diverter vavle was completely shot so have replaced it with the type d revised part

while i was under the car doing the diverter valve i noticed that the wiring to the post cat o2 sensor was damaged so have fitted a new one
 
checked the camshaft follower for the high pressure fuel pump and was incredibly surprised find there was not one fitted , no remains or anything so just been left out at some time  amazingly the camshaft looks pretty good all things considered but the plunger of the fuel pump has worn very very slightly to one side . obviously i'm going to have to replace this as well but can't see it being the fault at this moment at this time . if been running fine the whole year i've had it and having now fitted a follower i'd expect the pump to working better than without one fitted .

i've removed the throttle pedal and stripped it down to the circuit board and cleaned it out along with the pins that work along the back of the board with electrical cleaner . checked the pins through the plug with a multimeter for continuity and couldnt find anything obviously wrong .

i've replaced the camshaft sensor at the the belt end , bought a cheap obd2 scanner and after deleting all the many codes from me pulling sensors and checking connections and having to replace the battery i was left with p0010 camshaft position actuator a bank 1 circuit malfunction . turns out the sensor was fine but the plug was broken on the other sensor under the engine cover . i have removed the plug and hard soldered directly onto the pins of the sensor and do not have the p0010 code anymore .

i have been out and done 10 miles this evening and the power loss is constantly there , always somewhere between 3-4k under hard acceleration when boost is starting build nicely and the loss it that sudden i have nearly head butted the steering wheel more than once . if i tickle the power its not nearly as bad and in 4th , 5th and 6th it rarely happens . when the engine is cold it is also a lot better . the engine management light has not come back on since bypassing the broken plug to the camshaft sensor and i have no stored faults in the ecu at all .

i'm going to put a fuel filter on tomorrow , recheck all the boost pipes , have a look at the turbo wastegate , check plugs but after that i'm scratching for ideas . the lack of fault codes and engine management light are not helping as i'd expect to see something .

any other things i can check or take a look at before i get it booked in for some live readings ?

sorry a bit long winded but thought i'd give as much info as i could

thanks for taking the time to read and appreciate any help given

steve

[Shaw]

I can't believe it's been running for 12mo without a follower in the hpfp. Surely there's a groove in the cam and the plunger in the pump will be worn away?

[xjay1337]

 

12 months with no cam follower???

[doylebros]

This is worth a read taking into account your issue

http://www.mk5golfgti.co.uk/forum/index.php/topic,86890.0.html

[Tortaruga]

That's nuts. Could it be that the cam follower tappet has completely disintegrated over time and has been ingested into the engine?

[steve71075]

lol , i can see your as shocked as i was . i spent 15mins searching for the follower thinking i must have dropped it when pulling the pump out until i looked at the plunger .

yep at least 12 months and at least 6000 miles since i bought it and its run fine up till about a month a go with no follower at all . the camshaft still looks shiny and is smooth to the touch with no scoring or groove that i could feel or see . i will remove the pump and take another look but there was nothing that concerned me camshaft wise when i looked .

the pump plunger as i mentioned has worn slightly , more to one side so i will have to replace it anyway but i'm not so sure this is my problem causing the cutting out/loss of power .
if it was running fine with no follower , then started to have the loss of power fault and i fit a follower i'd expect the thickness of the follower would be far greater than the amount of wear to the plunger in the last maybe 200 miles that the car has done since its been playing up , so i would expect it to run as it was before if not better with the follower fitted .

steve

[steve71075]

i'm pretty sure that the whole follower could not disappear , not without causing a fair bit of damage to either the cam , fuel pump or follower housing as this had crossed my mind . i've also done two oil changes since i've owned the car , the last being only about 6 weeks ago when i had the sump off at the same time to have it welded back up after hitting something in the road and there were no signs of any metal particles in the sump or oil pick up . i think its either been forgot to be put back in or maybe it had worn and was just removed and sold on quickly .

thanks for the link , there were some signs of slight oil weap from the bottom hose on the drivers side of the intercooler but nothing more than i would normally expect to see . i'll be having all the boost pipes off tomorrow to inspect them properly though , for the price of a few seals its worth trying anyway .



thanks

steve

[th3_f15t]

I had a mk2 GTI that suffered the dreaded fuel evaporation problem, which would result in no power and the engine trying to stall while driving.

May I suggest changing your fuel filter and running some fuel system cleaner? My mk5 GTI got fitted the wrong fuel filter by a stupid garage and I suffered power losses occasionally.

Perhaps look at your intake system, including air box, pipes and intercooler? Long shot but maybe a lack of air getting in too?

[steve71075]

solved i think 

changed the fuel filter and thought id remove the in tank pump and fuel sender unit for a look and found this











steve

[steve71075]

£197 

[Spoonie]

I know one situation where the cam follower had completely broken down. Unfortunately there is only one way where the metal bits can go. Result, pretty much had to rebuild the whole engine.

[strongbow]

had same problem,would accelerate up to 60mph then no power for around 5 seconds.cam follower worn right through taking 3mm of hpfp and badly scoring cam. this cost me £1350 with cam chain and positioner. always give it a good hard drive before buying one of these. running great now and finally enjoying it.