help - newbie with no boost !!

[nick]

hello all,

i've being running my bog standard 855R for about 6 weeks and everything seems OK. over the past couple of weeks it seems like its getting slower and slower and using a lot more fuel (even for an 855R !!). took it for a blast today and the boost gauge is barely in the white zone - more worryingly i got out accelerated by a turbo diesel saab 93:redface:

i've read through just about all the info i can find on the forum about this issue and have visually checked as many of the vac hoses as i can see apart from the lower intercooler hose (which looks a bit old from the top) and the vac hose that goes to the turbo (how do you get to the end of that as it disappears underneath a plate by the wastegate actuator ?)

its recently had the PCV done with new hoses but looking at the state of the other hoses, they look old(1996 'N' reg) - would it be worth replacing all the intercooler/vac hoses as a matter of course anyway ?

could it be the wastegate actuator or spark plugs (they are due for replacement very soon (150K miles) as the hot idle is a bit lumpy.

any help or hints would be greatly appreciated. ideally don't want to take it to the garage but will let CP Motors have it unless i can find someone local who can help me out and diagnose the problem ?.

is it OK to run the car as it is ?. i don't want to screw things up even more than they are.

thanks,

nick

[t5 stealth]

welcome mate,
1st thing to check is the vaccuum pipes,as uv done,
check the larger pipes on the intercooler to turbo as if the leak or split then u get no boost....
follow all the smaller vaccum pipes & check where they all go,ie boost controler etc,
if its just had the pcv done then id check the vaccum pipe below the fuel rail,goes under or through the inlet manifold as that would of been disconnected,
on the left of the fuel rail,below is the end of the pipe,make sure it isnt pulled to tight & chafed or worn through causing a leak etc.
have u tried reving it up with the bonnet up (obviously not driving lol) to listen for a boost leak,if its a pipe of u should hear it.

[Tomcat]

There's quite a lot that could have gone wrong, start by checking the rubber boost pipes these can split as they get older. If you look at the one that comes off the throttle body there is a second smaller pipe that comes off it, these can split where they join. Secondly check the rubber elbows in the vac pipes, these split over time (One is located just under the fuel rail (to the left as you look from the front).

Your other option is to get someone to check the codes for you, if it's a fueling fault then the car will have picked up on it and logged the fault in the ecu. If there is a serious fault then the car will automaticaly limit the boost to protect the engine, has the engine management light on the dash come on?(orange light with a green Lambda symbol), this is the cars way of telling you it has detected a fault.

Sadly there are a great many things that can effect boost on these cars so it's a process of elimination, start with the easy free stuff first before you starting throwing money at it.

[nick]

thanks for that.

no warning lights at all (so far.....)

the inlet manifold pipe looks all secure and isn't pulled tight.

the pipes to the boost controller all 'look' OK and feel secure.

on tickover there is an air rushing sound, not loud but you can definately hear it. it sounds like its coming from the intercooler pipe area on the turbo but i don't know enough about these engines to say whether thats just a normal sound. there is a build-up of gunk around the jubilee clips that clamps the short flexible bit of pipe to the rigid intercooler pipe / turbo outlet but can't tell if its just a build up of muck over the years or a leak.

can i get to the vac hose that attaches to the turbo without removing stuff first ?.

the car doesn't run badly at all (when not trying to boost) - can anyone confirm whether its ok to run it as it is as i need it for work next week ?.

[Tomcat]

Not really, I replaced mine today and you need to remove the plastic intake pipe and probably the air box to get enough room to get at it. If you can hear something then rev the engine while your under the bonnet and the leak should be fairly easy to locate. When my boost pipe split coming off the throttle body it wasn't obvious, however, like you I could hear it when the car was running. The pipe won't be loose or hanging off, there will be a small split in the pipe perhaps, have a damn good look, with a tourch if you need it and feel around, it won't take much of a split to loose you your boost.

[t5 stealth]

as tomcat says,
check around the pipe work closely,
if it aint putting a light up on the dash & it seems to run ok then shld b ok to drive,just dont rag it or make it try to boost hard until u find the problem,
u shldnt hear air leakijng from it while its running,
unless u got a cone filter on it as they tend to be a bit noisey compared to standard air filter.
try to pin point the air leak you can hear....id say thats ur problem

[nick]

hello all,

just a quick update on my (lack of) boost issue.

double checked as many of the vac hoses as i can get to and can't hear any whoosing BUT found one of the PTC hoses was loose and, more importantly, the small pipe going into the PTC valve was totally blocked (i had to drill it out !!) - bit miffed cos the garage said they'd cleaned it out when they did the PCV - hey look, no smoking dipstick whatd'ya know....:D

none of this has helped with the boost problem. she's running just fine but feels like about 50-75BHP down on previous (subjective i know) and the gauge is still only getting to about 12.30ish o'clock whereas it was about 3/4 way into the white zone before all this started.

the only thing i can now hear is a VERY small whoosing sound around the vac tree / throttle body. i didn't take those pipes off but had a good look at them and nothing is apparent as far as leaks go. does the vac tree emit an air rushing sound as normal ?

could it be a boost control valve issue ?

i checked the actuator arm on the wastegate and it moves OK

the other thing i found was a load of oily crap around where the intercooler outlet from the turbo is. its all over that area - any thoughts ?

do you think a complete set of new vac hoses is in order or is my turbo knackered ?

sorry for the long post and all the questions....

nick

[Ed.]

Hi Nick,

Glad to hear you got the smoking dipstick issue sorted. The bcs could be at fault, its not a uncommon thing to happen with a 14 year old car. I changed the boost hoses to silicone ones and also the bcs hoses on my car and this solved a boost problem i had a while ago. The symptoms with mine were the car would momentarily boost into the white and back off and hold at around 12:30 position. The original hoses do tend to perish with age so i would definitely recommend changing those.

Ed

[JelT5]

I'll second what Ed says, use silicone hoses; I did when I did my reverse intercooler pipework- they're definitely worth the investment.

[nick]

attached is a picture of the intercooler pipe joint that comes straight off the turbo compressor side.

looks a bit manky with oily/dirt build up around that area - do you think this could be the cause of my lack of boost. there is no whistling sound around this area (to my untrained ear) but doesn't look right to me.

the car isn't using any appreciable amount of oil and no blue smoke from the exhaust. there doesn't seem to be any oil leaks in that area from the top of the engine either that could cause the build-up.

ideas anyone ?

thanks,

nick

[woody]

Hello there Nick. Tomcat mentioned limp mode, well mine went into limp mode several times before the MAF sensor packed up completely. Whilst in Limp Mode, she lost half her boost and drank buckets of fuel! May be worth a look, as all your hoses seem ok. Hope you find it soon Nik.

PS Nick. Once my MAF was replaced, she seemed faster than ever! Just makes me wonder if it was in the early stages of failure, a long time before it actually quit!

[nick]

thanks for the reply. i reset the mpg meter on the way to work today and whilst they aren't the most accurate of things, it averaged 24 mpg so that doesn't seem too bad (i'm not booting it cos of any potential issues)

please excuse my ignorance but how would i know if its in limp mode ? (apart from the things mentioned by woody)

so you think that pipework looks OK ?.

it does seem to have been a gradual decline in power over the past 2 weeks and not a sudden drop-off

[woody]

please excuse my ignorance but how would i know if its in limp mode ? (apart from the things mentioned by woody)

For me it was very noticeable, usually my boost reading was off the gauge (Chipped) then every now and again it would only just clear half way. Funnily enough, the symptoms went away for 5 months, so I naturally put it down to a bad batch of Tesco's 99RON. Then out of the blue, complete failure! As has been mentioned already, you probably wouldn't go far wrong with connecting a fault code reader to it Nik and see what's been logged, if anything at all.

[p fandango]

the computer may log a fault without putting the CEL light on so may be worth getting the codes read anyway

you say about a whistling from the vac tree area, the tree itself is held on by 1 nut & has got an O ring underneath. Might be an idea to get a new seal put on just incase, & obviously check the pipes to the vac tree are good & secure & you haven't blown a blanking cover off from the unused ports on the tree

[nick]

thanks all for the advice.

i've decided that it's going back into the garage (again) later this week to get sorted once and for all (until the next time lol !!) - i haven't time to play with it this weekend unfortunately as i'm gigging.

gonna get all the vac hoses replaced and intercooler pipework checked as a matter of course, full service, codes read/cleared and get that damm boost back in the zone !!!. i've spent too long faffing about on half power and need to give it some well earned throttle !!

if you see a silver focus on the M1 on saturday around leicester with a driver looking a bit bored - that'll be me...:ashamed:

[woody]

Nick, any news buddy?

[nick]

eh up woody,

just got back from dropping the old girl into the garage.

i'm having a stage 0 tune to get her back to spec and all the work done to get her boosting properly. having spoken to the garage and following the advice of fellow members on here, i think it may well be the MAF on its way out. they will check the codes as a matter of course and they are changing the vac hoses and any others that look a bit tired.

fingers crossed she will be back to normal soon. i intend running her totally standard for a while and then we'll see about some tasteful 'improvements' later !

nick

[Tomcat]

Keep us posted.....

[nick]

looks like a dodgy MAF - swapped for a known working version and 3/4 boost on the gauge straight away :). gonna fit a genuine bosch MAF and replace all hoses so that should be that....

does a stock engine & ECU boost beyond 3/4 on the gauge normally ?

[cameron]

Yep spot on that matey 3/4 standard and off the end chipped like mine :D

[walter leever]

Nick,3/4 is perfect on a stock engine and ecu :biggrin:

gr,walter

Looks like it's sorted.

[nick]

cheers - 3/4 is enough for now (certainly better than nowt !!)

please excuse the dumb question but do i always have to run it on 98 RON petrol or is normal unleaded fine for a stock engine/ECU ?

[walter leever]

Well you can run it with the 95ron but,possible more nocks(engine)and offcourse a bit less power.
So the best thing is to use 98ron even with a stock engine/ecu,and certainly when it's flashed.

Gr,walter

[woody]

Good news Nick. Glad it's sorted. Bloody MAF's eh!

[nick]

yeah, MAF's, CAT's, etc etc the list goes on (and on, and on)...lol

picking the old dear up tomorrow night and will be giving her a damm good thrashing on the way home :eye-poppi (just re-read that and it sounds a bit finbar saunders but hey...)

thanks to all on the forum - much appreciated

[nick]

the old bus is back up to speed - oh yeah. had a load of other work done at the same time and i'm well happy (so far, fingers crossed etc etc)

the mpg has improved dramatically too which is a bonus

[walter leever]

Great news,mate.:biggrin:

Now go out and enjoy the old bus.:haha:

walter

[cameron]

Glad you got it sorted mate :D