boost problem ie its all gone

cyman · December 28, 2008, 04:03:55 PM

i am running an fd with a non sequential setup apexi powerfc etc all setup by reworx. its been running sweet for the last year just had an oil change a few weeks ago and every level etc checked over. however today i went on a 20 mile run to poole to spend xmas cash everything was fine running sweet didnt cane it give it some beens a couple of times overtaking but thats about it. but after i had been into one shop after looking round for about 20 mins i drove down the road for about 5 mins pulled away from a set of lights on a duel carriagway and noticed it wasnt pulling.

i checked boost gauge it read zero, pulled over checked small vaccum pipes all on,checked the main inlet flexis between turbos and throttle couldnt find anything. the car is running fine no smoke good idle no hunting so i set off home 20 miles, it ran fine except no turbo boost whatsoever. i listened and it still sounds like i can hear a turbo spinning up but no whooshes or air leaks when i put my foot down.both the apexi and the greddy boost controller dont register any boost at all just the negative figures they have when its not boosting.

its got me scratching my head :confused::confused::confused:

anyone got any thoughts or had similar happen to them.

cheers

si

rx7boy · December 28, 2008, 04:15:08 PM

MAP Sensor maybe ?? Using PFC u can check if it is working properly!!

cyman · December 28, 2008, 04:42:15 PM

i did think that the map sensor might be the prob is this likely to give zero boost though?? do you know how to check if it working properly on the pfc?

cyman · December 28, 2008, 06:21:58 PM

has no one else come across this before?? i have read as many threads as i can find and it seems people get lots of issues with partial/low boost from the rats nest running sequential but i cant find any that have gotten zero boost before let alone non sequential?

? :3Confused:3Confused:3Confused:3Confused:3Confused

Bobbit · December 28, 2008, 06:57:17 PM

It\'s strange that you have no boost at all, normally the boost drops to 7psi or so and this can be traced to a solenoid or split pipe. But i\'ve not heard of 0 boost, might be worth checking the y-pipe coupler just incase it\'s come loose or split.

ro284 · December 28, 2008, 09:19:21 PM

This does sound odd Si, i would have thought you would hear a huge wooshing noise at least if there was a hose popped off, you are not far from Tim at RX Motors, he would sort it very quick if you are not sure what to do next, let me know if you need his address,
Good luck Bob

cyman · December 28, 2008, 09:37:48 PM

Quote from: ro284;569155This does sound odd Si, i would have thought you would hear a huge wooshing noise at least if there was a hose popped off, you are not far from Tim at RX Motors, he would sort it very quick if you are not sure what to do next, let me know if you need his address,
Good luck Bob

yeah it is odd. sort of gets a bit confusing that its running smooth but no boost and that as its non seq aswell so most of the solenoids etc arent used which are normally the main culprit for this sort of thing. ive been to rxmotors a few times for spares i\'m only in weymouth so bout half an hour from them. was thinking of phoning them and reworx up to see if they had any ideas that i can check over before taking my car in to one of them. was sort of hopeing someone might of come across this before so i could take it into my mates workshop and sort it myself :confused:

Nik da Greek · December 29, 2008, 12:44:16 AM

The only time I had anything similar was when my primary turbo shat a blade. It was so mullered that as soon as it tried to spool up, the shaft play from the imbalance meant the impeller wheel just wedged itself solid into the housing, and with the primary wide open, obviously the secondary was never gonna get going either. Hence, no boost. That\'s on a normal sequential set up, but I guess the effect would be the same on non-seq because if the primary isn\'t spinning all the gas will just vent straight past it? :confused: I think....

cyman · December 29, 2008, 11:53:46 AM

well ive gone out and checked all the pipes again and cant find any splits. i have checked all the sensor readings on the pfc and none are faulty and the pim sensor (which after a bit of searching appears to be the map sensor) is working with voltage going up and down as i touch the throttle.

nik if the primary is jammed surely i would still get at least some boost but mine doesnt go above zero.

has anyone ever had a wastegate jam open?? would that give zero boost or just low boost??

Archbish · December 29, 2008, 11:58:08 AM

If you have the stock turbo\'s, then the wastegate sticking open shouldn\'t mean that you\'ve got no boost at all, just not a lot of boost.

I\'d spend the first 5 minutes going through the hoses from the turbo\'s to the intake manifold - it does sound more like a leak somewhere, even if you can\'t hear it...

Another classic is the intake hose to the turbo\'s. This can collapse under load when it gets warm, and reduce the boost significantly, but this would only occur once the turbo\'s and engine were warm, and not before.

Archbish · December 29, 2008, 11:59:58 AM

is your boost gauge plumbed in OK? *grin* if it\'s come off the manifold, it could be enough of a leak to stop the second turbo spooking, and you wouldn\'t see any movement on the needle. Does it move at all, or is it stationary ALL the time?

cyman · December 29, 2008, 12:15:32 PM

Quote from: Archbish;569325is your boost gauge plumbed in OK? *grin* if it\'s come off the manifold, it could be enough of a leak to stop the second turbo spooking, and you wouldn\'t see any movement on the needle. Does it move at all, or is it stationary ALL the time?

boost gauge is fine as i have a seperate greddy pro 2 and the apexi pfc. both read the same they go to negative boost rising and falling on normal running but neither go above zero. being non seq the thing i can\'t get my head around is why no boost at all. surely if one tub had gone pop the other would still spool at least at higher revs :2Confused:2Confused

Archbish · December 29, 2008, 12:23:36 PM

Definitely sounds like a boost leak then... You\'ll just need to double check all the points of failure (top of y-pipe, boost hoses, throttle body bolts, etc) to start with, and go from there...

cyman · December 29, 2008, 01:38:44 PM

got filters off took front 90 bend off can see the turbo spinning but only when you give it some beans at low revs it hardly moves at all stopping half the time. it has very little endplay as they were turbo technics units done 5k ago at a cost of 1850 quid by the previous owner. the actuator and waste gate are moving and free. can find no leaks anywhere. if the y pipe is the pipe on top of the turbos that would normaly have some valves on it mine is a metal one with a blanking plate fitted.

is there an internal way for the exhaust gases to bypass the turbos besides the wastegate??? has anyone had the wastegate actuator and control arm move but have it shared internally so its open???

i am even more stumped than i was.

cyman · December 29, 2008, 02:57:23 PM

update:

took off a few inlet pipes to check the turbos. the front one hardly moves stopping on tickover and only moving a little on low revs only spinning when you give it some revs. got a camera down the back turbo which is not spinning at all.

any ideas on this bearing in mind this is non seq with all the valves/bypass valves removed and blanked off. i am thinking maybe the wastgate has sheared internally stoppping the turbo pressure building up. has anyone seen anything like this?