please help regarding boost problem
13-09-2011, 07:48 PM
#1
10K+ Poster!!
Thread Starter
iTrader: (3)
Join Date: Jun 2003
Location: Hartlepool
Posts: 10,956
Likes: 0
Received 0 Likes
on
0 Posts
please help regarding boost problem
Right i took the car to get mapped a few weeks ago to get my boost sorted, as it was only making 1.3bar. Once mapping started we got the boost up to 2.0bar but soon as the car gets over 5k revs boost is dropping off to 1bar it feels like hitting a brick walk as its instant loss not just gradual. Now I've had the cr spec gt30 off and had it checked and that's fine i then found a air leak from inlet as i didn't fit o rings oops, I've since had inlet off and o rings fitted but been back out today and exactly the same problem?
Its seriously doing my head in now as I've already wasted a lot of money with fuel and mapping etc so anybody have any ideas as to why im losing so much boost?
Cheers
Its seriously doing my head in now as I've already wasted a lot of money with fuel and mapping etc so anybody have any ideas as to why im losing so much boost?
Cheers
13-09-2011, 08:32 PM
#7
stage4 2wd cosworth
Trending Topics
13-09-2011, 09:03 PM
#10
10K+ Poster!!
Thread Starter
iTrader: (3)
Join Date: Jun 2003
Location: Hartlepool
Posts: 10,956
Likes: 0
Received 0 Likes
on
0 Posts
Using the autronic boost control system. Not sure what you mean about actuator david? And yeah exhaust is deffo 2.5 all way from turbo with no boxes etc.
13-09-2011, 09:56 PM
#16
It Wasnt Me!
what happens to the boost when you disconnect it (blanking the hose) and taking it for a run...as in is the turbo capable of making the boost when it's normally dropping to 1 bar.
wastegate definately shut properly? signs its not would be boost slow to come in...
dump valve - easy to check, pull the vacuum line off and suck on it, does it hold suction on your tongue?
got to be something stupid......
14-09-2011, 07:45 AM
#18
15000
Join Date: Sep 2011
Location: scotland
Posts: 31
Likes: 0
Received 0 Likes
on
0 Posts
Sounds like the ecu is detecting a problem eg AFR's to lean or other problem, so pulling the boost. Limp mode.
The amount of boost it pulls will depend on what type of actuator your running and how its set up.
If you were running standard boost it would still probably pull 50% just would be a lower start point.
Any fault codes in the ecu ?
The amount of boost it pulls will depend on what type of actuator your running and how its set up.
If you were running standard boost it would still probably pull 50% just would be a lower start point.
Any fault codes in the ecu ?
14-09-2011, 10:17 AM
#21
10K+ Poster!!
Thread Starter
iTrader: (3)
Join Date: Jun 2003
Location: Hartlepool
Posts: 10,956
Likes: 0
Received 0 Likes
on
0 Posts
Surely mark would of picked up on that? Ill get my fuel set up fitted in boot and go from there, hopefully will pedley is gonna have a look end of month.
14-09-2011, 03:42 PM
#23
Zee Germans are coming
14-09-2011, 04:27 PM
#24
10K+ Poster!!
Thread Starter
iTrader: (3)
Join Date: Jun 2003
Location: Hartlepool
Posts: 10,956
Likes: 0
Received 0 Likes
on
0 Posts
Mark put it down to a turbo problem so i can only presume there were no faults at all? I've spoke to Joe at gs and he says sounds like big air leak still.
14-09-2011, 08:28 PM
#27
15000
Join Date: Sep 2011
Location: scotland
Posts: 31
Likes: 0
Received 0 Likes
on
0 Posts
You should be able to hear a boost leak that bad. Why not do a boost piping leak test.
Can you get full boost gradually, ie build up the load whilst not using wot. Have you tried to get boost above 5k without using wot ?
I don't see why 5k is the critical point here, unless your boost curve cant make max boost at lower revs. A boost leak will leak at 2k 3k or 7k . If you have 2 bar at 4k and suddenly not at 5k then i don't think you have a leak.
IMHO of course.
16-09-2011, 12:28 PM
#29
Advanced PassionFord User
Join Date: Jul 2005
Location: Cleveland RSOC
Posts: 1,642
Likes: 0
Received 0 Likes
on
0 Posts
16-09-2011, 06:00 PM
#31
Advanced PassionFord User
iTrader: (1)
Join Date: Mar 2005
Location: Newcastle
Posts: 1,587
Likes: 0
Received 0 Likes
on
0 Posts
You can probably rule out alot of things yourself if you think about it logicly.
Realisticly a leak from a pipe, intercooler, d/v, inlet isnt going to manifest suddenly at 5k, as you say the circuit is presurised well before this point with no issue. With that in mind you can probably rule out pipe collapse intake side. Its failry unlikly that having small exhaust(2.5 is really too small) is going to cause that kind of issue either.
What i would do to rule out electronic issue is bypass elec. boost control and run it up again. If its still pulling back you know its nothing to do with the ecu as it'll no longer have control.
Realisticly a leak from a pipe, intercooler, d/v, inlet isnt going to manifest suddenly at 5k, as you say the circuit is presurised well before this point with no issue. With that in mind you can probably rule out pipe collapse intake side. Its failry unlikly that having small exhaust(2.5 is really too small) is going to cause that kind of issue either.
What i would do to rule out electronic issue is bypass elec. boost control and run it up again. If its still pulling back you know its nothing to do with the ecu as it'll no longer have control.
16-09-2011, 06:27 PM
#33
I've found that life I needed.. It's HERE!!
Alright mate i would try what RS1 has said and try and take the boost control off and just put a bleed valve in. try and set it to 2 bar and see if the boost drops off to a bar. then youl see if its a ecu/boost control fault or a turbo/air leak fault.
16-09-2011, 06:35 PM
#34
15000
Join Date: Sep 2011
Location: scotland
Posts: 31
Likes: 0
Received 0 Likes
on
0 Posts
If you put the car in 4th or 5th and do some steady pulls you will definitely be able to hear a leak that drops 50% of your boost. Also in 4th & 5th things are less hectic and you will be able to achieve full boost using throttle control.
16-09-2011, 06:50 PM
#35
I've found that life I needed.. It's HERE!!
Have you tried as I mentioned, ie can you get it to boost above 5k if you don't use wot. I ask because if the ECU is pulling timing and or dropping your boost via the boost controller due to bad AFR or IAT's then don't stress the engine and see what you can get.
If you put the car in 4th or 5th and do some steady pulls you will definitely be able to hear a leak that drops 50% of your boost. Also in 4th & 5th things are less hectic and you will be able to achieve full boost using throttle control.
If you put the car in 4th or 5th and do some steady pulls you will definitely be able to hear a leak that drops 50% of your boost. Also in 4th & 5th things are less hectic and you will be able to achieve full boost using throttle control.
Is his ecu able to read AFR? may not have a lamber sencer
16-09-2011, 07:00 PM
#36
15000
Join Date: Sep 2011
Location: scotland
Posts: 31
Likes: 0
Received 0 Likes
on
0 Posts
If the ecu is open loop with no knock sensor, then no. Normally if there is a fueling problem , afr too lean, IAT problem the boost normally shuts down when a piston melts 
If you are open loop, then iirc its really only sensor failure that would cause a limp home event.
My best advice is to have a boost leak test done, as we can all be arm chair mechanics.lol but you really do need to know first of all if you have a boost leak. Personally i think its unlikely only above 5k but we all live and learn.
If you are open loop, then iirc its really only sensor failure that would cause a limp home event.
My best advice is to have a boost leak test done, as we can all be arm chair mechanics.lol but you really do need to know first of all if you have a boost leak. Personally i think its unlikely only above 5k but we all live and learn.
16-09-2011, 08:17 PM
#37
10K+ Poster!!
Thread Starter
iTrader: (3)
Join Date: Jun 2003
Location: Hartlepool
Posts: 10,956
Likes: 0
Received 0 Likes
on
0 Posts
Right been and done a leak test tonight and its losing a lot of air out the throttle body, but its on the side where the spring etc sits we took it apart and can't see any way how to cure that apart from change the very small o rings on each end of the brass bar that runs right through.
16-09-2011, 10:36 PM
#39
15000
Join Date: Sep 2011
Location: scotland
Posts: 31
Likes: 0
Received 0 Likes
on
0 Posts
Right been and done a leak test tonight and its losing a lot of air out the throttle body, but its on the side where the spring etc sits we took it apart and can't see any way how to cure that apart from change the very small o rings on each end of the brass bar that runs right through.