Boost stops at 0.5bar
#1
Boost stops at 0.5bar
Recently fitted a defi boost gauge and when putting foot down the boost gauge gets to +0.5 and won't go higher is that correct.
And idle is below the 0 at 0.6.
Car is a uk classic with a vf35.
Thanks
And idle is below the 0 at 0.6.
Car is a uk classic with a vf35.
Thanks
#2
However, maximum boost isnt going to be achieved unless the engine is under load. If you have measured 0.5 bar under load then it seems too low. I would be expecting 1.0 bar in a classic or 1.2 in a PPP classic. Take the car to a place where the engine will run on full load, up an incline is good as you will see full boost if you floor it in top gear with the car gaining speed and wait for the boost to rise. If boost remains at 0.5 bar then common fault would be wastegate actuator not working or car in limp home mode. We take it you have no Engine Management light showing and speedometer is working.
In relation to minus 0.6 bar on idle, yes this is normal due to vacuum in manifold.
#3
You dont mention year of model which i think is important as boost varies over miodel year, and also we dont know where you have attached the boost gauge.
However, maximum boost isnt going to be achieved unless the engine is under load. If you have measured 0.5 bar under load then it seems too low. I would be expecting 1.0 bar in a classic or 1.2 in a PPP classic. Take the car to a place where the engine will run on full load, up an incline is good as you will see full boost if you floor it in top gear with the car gaining speed and wait for the boost to rise. If boost remains at 0.5 bar then common fault would be wastegate actuator not working or car in limp home mode. We take it you have no Engine Management light showing and speedometer is working.
In relation to minus 0.6 bar on idle, yes this is normal due to vacuum in manifold.
However, maximum boost isnt going to be achieved unless the engine is under load. If you have measured 0.5 bar under load then it seems too low. I would be expecting 1.0 bar in a classic or 1.2 in a PPP classic. Take the car to a place where the engine will run on full load, up an incline is good as you will see full boost if you floor it in top gear with the car gaining speed and wait for the boost to rise. If boost remains at 0.5 bar then common fault would be wastegate actuator not working or car in limp home mode. We take it you have no Engine Management light showing and speedometer is working.
In relation to minus 0.6 bar on idle, yes this is normal due to vacuum in manifold.
The car still feels to pull so wouldn't think it's in limp mode and speedo works.
How would I check waste gate when I put my foot down and release I hear a small dv type noise is that related.
Thanks
#5
Hi thanks for your reply the car is a my00 and I've tried it under full load up a hill and it hits 0.5 and stops.
The car still feels to pull so wouldn't think it's in limp mode and speedo works.
How would I check waste gate when I put my foot down and release I hear a small dv type noise is that related.
Thanks
The car still feels to pull so wouldn't think it's in limp mode and speedo works.
How would I check waste gate when I put my foot down and release I hear a small dv type noise is that related.
Thanks
I assume if you have a MY 2000 that you connected the boost gauge to the spare nipple on the inlet manifold.
Its possible that someone has fiddled with the boost control. Even with the pill out you should see full boost. You are around 3000 to 3500 revs up this hill right? (Full boost area)
Another possibility is that your boost gauge is not reading right. Can you check using another gauge? Is it connected to the correct port on the defi controller (if you have one). Did you tee in when you fitted your gauge, can you show us where by posting a picture?
Can you look at the boost pipework and see if any modifications or disconnection? It was common in 2000 to fit a Dawes device which allowed boost to be tweaked up. This is basically a needle valve, look for a small brass valve and report if fitted.
Check the pipe to the wastegate actuator to see if that has somehow become disconnected, although that should give you maximum boost . I say that because 0.5 bar is boost pressure normally achieved when the wastegate is not working. Check the wastegate moves by moving the arm, it could be seized open which normally results in boost of 7.5psi or about 0.5 bar.
Dump valve noise sounds normal, Is it standard recirc type or aftermarket?
Last edited by Beastie; 25 July 2013 at 12:07 PM.
#6
Hi beastie thanks again.
I have looked I have a three port boost solenoid all seem ok no splits etc. my defi vacuum hose is from spare nipple to the receiver located near the strut top.
Will get a vacuum gauge to test the turbo actuator and the defi does have a controller and is in the correct slot.
Yes tried it up a hill in all ranges of rpm still hits +0.5 and stops.
Will try load some pics
Thanks again
I have looked I have a three port boost solenoid all seem ok no splits etc. my defi vacuum hose is from spare nipple to the receiver located near the strut top.
Will get a vacuum gauge to test the turbo actuator and the defi does have a controller and is in the correct slot.
Yes tried it up a hill in all ranges of rpm still hits +0.5 and stops.
Will try load some pics
Thanks again
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#10
Ok removed the actuator and the part on the turbo opened and closed the actuators arm was very stiff but with wd40 and moving in and out it will move but only outwards(makes rod longer) is that right and it's not pulling on vacuum.
Just when it's having air forced into it.
Also with car running the pipe to the actuator has no vacuum or pressure.
So what do you think it is.
Thanks
Just when it's having air forced into it.
Also with car running the pipe to the actuator has no vacuum or pressure.
So what do you think it is.
Thanks
#11
If the wastegate was not opening you would get full boost and then fuel cut. So I would be looking at the 3 port boost solenoid to check that it is plumbed correctly and is working correctly. At the moment I would say the 3 port is staying closed loop so that the wastegate actuator is directly working the wastegate.
#12
What I mean is you know the wastegate and actuator are working as you are getting a regulated boost. What's not working is the boost control which bleeds air out of the circuit between actuator and wastegate until the desired boost is reached.
Either that or you've got a leak in the boost pipes or intercooler somewhere.
Either that or you've got a leak in the boost pipes or intercooler somewhere.
#13
Ok I will check where each one goes to from the 3 port solinoid which is under a year old so hopefullly not that.
Also today I sprayed all hoses with brake cleaner to see and leaks which I couldn't See any but will look more into it.
Would different headers cause this?
Thanks
Also today I sprayed all hoses with brake cleaner to see and leaks which I couldn't See any but will look more into it.
Would different headers cause this?
Thanks
#18
What I mean is you know the wastegate and actuator are working as you are getting a regulated boost. What's not working is the boost control which bleeds air out of the circuit between actuator and wastegate until the desired boost is reached.
Either that or you've got a leak in the boost pipes or intercooler somewhere.
Either that or you've got a leak in the boost pipes or intercooler somewhere.
I would suggest disconnecting the boost pipe to the actuator and then seeing in one extremely brief test if boost rises over 0.5 bar. If it does then its not the actuator. Its the boost control system or map.
Alternately as i said previously could it be the gauge?
#23
Yeah, some are 3 and some are 2. Mine is 2. It's the only thing that allows the boost to rise. Do you have an aftermarket boost controller fitted or is it still the factory solenoid?
#25
I don't know about the voltage at the valve. I imagine it'll get a pulsed voltage from the ECU to regulate the opening amount rather than a straight 12V.
I read that this only happened after you fitted a boost gauge? Where did you connect the gauge to?
I read that this only happened after you fitted a boost gauge? Where did you connect the gauge to?
#26
Hi I only noticed when it had the gauge fitted as didn't know it was so low on boost. so its been like it a while I remember it pulling quick when it was mapped but until I removed the hose tonight I forgot what it should actually go like.
#29
FIXED it was a 3 port soleinoid at fault replaced it and all is good boosts to just under 1.5 bar and make me smile its like having a new car.
Anyone need a 3 port contact drewtts on here top bloke and many thanks to him it's sorted and a big thanks to the above people who helped.
Thanks
https://www.scoobynet.com/member.php?u=103389 to drewtts
Anyone need a 3 port contact drewtts on here top bloke and many thanks to him it's sorted and a big thanks to the above people who helped.
Thanks
https://www.scoobynet.com/member.php?u=103389 to drewtts
Last edited by 5cooby1; 20 August 2013 at 09:03 PM.