Only 0.5 bar boost...

[sharkrider]

As title, I was driving to work today ( cold, snow) and after I went around a roundabout the boost then limited itself to 0.4 bar..... Car still ran well ( apart from a traffic cue earlier , when I let it pull me alone in 2nd on tickover... This is usually smooth, and was a little jerky, didn't think twice about it!) no warning lights. After about 10 miles, car fine just low boost... I stopped at traffic lights and turned the engine off, started it again at green, and drove off, normal boost resumed!!

Any ideas?! Thanks in advance

[KenONeill]

"a traffic cue" - You had a snooker ball in the tailpipe, and the restart expelled it?

 

More seriously, I really would need fault codes to do anything more than make daft jokes.

[sharkrider]

Lol... Cheers, thinking the ECU list a sensor feed or something like that ...

[Azzy12]

Try unplugging the MAF and see how it runs. If runs at normal boost, would seem the MAF needs replacing.

[sharkrider]

well I got home from work fine, had a nice drive, full boost flying through the cold air..... all seems well again...

 

I won't let it pass without figuring it out though, i will do a scan tomorow...

[sharkrider]

update, scanned the car , no fault codes stored, it did however pick up MIL light de-activated, I assume thats because my de-cat was "mapped" disabling whatever systems are going to throw up a warning light due to missing cat! lol..

[Obrut]

Have a look at faulty N75 valve/controller for the 1.8t engine range. I'm about to start trouble shooting mine as i think i have the same problem but i dont have a boost gauge so cant be sure. I'll start with MAF disconnect as thats free, then n75 replacement and boost pipes and turbo intake pipe. I havent had those replaced since ownership and the car has just hit 105k. I've had this problem for years but it comes and goes so i've never really bothered with it until I had a twitchy bum moment trying to over take and i had a passenger.... floored it and it felt like i was down about 50hp..

 

Be interesting to know if you get this resolved! Good luck!

Edited 13 November, 2016 by Obrut

[sharkrider]

Have a look at faulty N75 valve/controller for the 1.8t engine range. I'm about to start trouble shooting mine as i think i have the same problem but i dont have a boost gauge so cant be sure. I'll start with MAF disconnect as thats free, then n75 replacement and boost pipes and turbo intake pipe. I havent had those replaced since ownership and the car has just hit 105k. I've had this problem for years but it comes and goes so i've never really bothered with it until I had a twitchy bum moment trying to over take and i had a passenger.... floored it and it felt like i was down about 50hp..

 

Be interesting to know if you get this resolved! Good luck!

it hasn't misbehaved since, so I've left well alone! lol... I believe it was N75, and I have a spare somewhere, but not messing with it while it works agin! was quite driveable so no worries with etc.... gonna find the spare N75 and put it in the glovebox

[Obrut]

Slight post highjack here but what size jubilee clips do i need for the n75 pipe and boost hose? I am about to purchase some new silcone pipes that dont come with the required clips. I dont want to reuse the old ones and one is missing anyway (cable tied!  :thumbdown: ) .I suspect this may be part of the reason for my intermittent boost loss. Cheers in advance!

[sharkrider]

not sure of the exact size, but very small! lol...

 

my car has behaved since this one off, I have just left it alone, when I eventually find my spare N75 its going in the boot with the spare coil pack! lol..

[Obrut]

well i found that my Forge recirc has been fitted with cable ties all round and no clip for the small vaccum pipe.... bought some jubilee clips from a local car motor factor cost all of £5.60. If this isn't a direct cause of my boost issue it was probably going to be at some point Drive to work and home was good no noticeable power drop but that's the joys of having an intermittent fault.

[sharkrider]

well i found that my Forge recirc has been fitted with cable ties all round and no clip for the small vaccum pipe.... bought some jubilee clips from a local car motor factor cost all of £5.60. If this isn't a direct cause of my boost issue it was probably going to be at some point Drive to work and home was good no noticeable power drop but that's the joys of having an intermittent fault.

Have you tried servicing the forge r/v ...I have a forge 007p, my car had boost issues when I bought it, I had a diagnostics done, and all standard stuff was fine, so they said, had to be one of the aftermarket things.... I bought a service kit from awesome, and it had an extra o-ring seal too, changed all the seals, new lubricant on, and hey presto, boost issues fixed...

 

its a very cheap and easy thing to do to rule that out if you have issues...

[Obrut]

I actually ordered one off Ebay just before I read your post as I found out the recirc needs servicing every 12k. Mine hasn't been touched for at least 50k and came installed on the car when I bought it. I noticed scoring to the piston and thankfully the service kit came with a new redesigned piston, gaskets and lube. Just installed it an hour ago so its too early to say if its fixed my issue yet but the power curve felt more linear (perhaps old piston was leaking and sticking). It was also quieter when throttling off too (again possible sign old one was leaking).

 

FYI I got my Forge service kit through AwesomeGTI's online Ebay shop its cheaper than through Forge direct!! You can service the valve without removing it from the car (Forge 007p) , just unscrew the top. I'll be removing it next weekend when I go to install the new boost pipe and n75 pipe I also bought, i'll give it a full inspection. I wish I had taken pictures of the servicing kit and install, it might prove useful to someone. It was really very easy even for a total novice like me. I may upload the damaged piston I removed so people with Forge valves can see what happens if you don't service it. Oh I got a bit carried away and bought a boost gauge + pod too but that will have to wait for now

 

I take it your issue hasn't resurfaced?

Edited 26 November, 2016 by Obrut

[sharkrider]

I actually ordered one off Ebay just before I read your post as I found out the recirc needs servicing every 12k. Mine hasn't been touched for at least 50k and came installed on the car when I bought it. I noticed scoring to the piston and thankfully the service kit came with a new redesigned piston, gaskets and lube. Just installed it an hour ago so its too early to say if its fixed my issue yet but the power curve felt more linear (perhaps old piston was leaking and sticking). It was also quieter when throttling off too (again possible sign old one was leaking).

 

FYI I got my Forge service kit through AwesomeGTI's online Ebay shop its cheaper than through Forge direct!! You can service the valve without removing it from the car (Forge 007p) , just unscrew the top. I'll be removing it next weekend when I go to install the new boost pipe and n75 pipe I also bought, i'll give it a full inspection. I wish I had taken pictures of the servicing kit and install, it might prove useful to someone. It was really very easy even for a total novice like me. I may upload the damaged piston I removed so people with Forge valves can see what happens if you don't service it. Oh I got a bit carried away and bought a boost gauge + pod too but that will have to wait for now

 

I take it your issue hasn't resurfaced?

feel free to use this thread to keep us updated on how you go, I was all set to change all the "obvious" things, hence having a spare N75, but I was lucky that the 007p was the issue, and that was the first thing I went to!

 

my issue hasn't returned, I have also started a new job which is a 75 mile commute for the WEEK, before I was doing 250 miles a week.... it will give the old boy a bit of a rest.....

 

He is still running perfectly at the moment, so i am going to leave well alone until the spring/summer, when i will have saved up some money, and start treating him to new stuff! As I go on, I will be replacing anything that looks "old" as all these little bits don't cost that much.....