Help! Boost just cut off

clio 480 turbo · Post by **clio 480 turbo** » Thu Apr 12, 2007 7:59 pm

Can anyone help. My car seems to pick up on boost then just drops right off. The turbo just starts to come in then the boost drops right off. I'm running 10psi

owen080808 · Post by **owen080808** » Fri Apr 13, 2007 12:22 pm

It could be any number of things: boost leak, faulty wastegate, faulty dump valve, boost solenoid problems, incorrect/old sparkplugs/ignition components...

I assume this is an engine transplant into a clio? How does the car run when not in boost? are you using an MBC or a chipped ecu or just standard? has it recently been swapped or has it been running fine for a while and now you have problems?

Try searching the forum too, you might get some ideas from people who have had similar symptoms before...

clio 480 turbo · Post by **clio 480 turbo** » Fri Apr 13, 2007 4:11 pm

bought the car off some guy, he said it was running mint then a week before i bought it the problem accurred. running a standard ecu for now anyway.

dave · Post by **dave** » Fri Apr 13, 2007 4:16 pm

Standard ECU will only allow 6-7 psi then will cut off. Turn the boost down to that and see how it is.

I had a problem with my actuator, replaced it with a standard one and runs ok.

JohnTurbo · Post by **JohnTurbo** » Mon Apr 16, 2007 9:31 am

Should get at least 13-14 psi before the ecu interveens.

owen080808 · Post by **owen080808** » Mon Apr 16, 2007 2:53 pm

JohnTurbo wrote:Should get at least 13-14 psi before the ecu interveens.

thats what i thought, i guess it could just be the gague? its hard to know when there's no mention of how the car runs the rest of the time...

JohnTurbo · Post by **JohnTurbo** » Mon Apr 16, 2007 3:00 pm

Clio person, for me to be of any help you need to be super decriptive.

The boost dropping off is too vague.

What happens exactly, does the car violently decelerate? or are you sitting there with your foot wedged to the floor on zero psi smoothly cruising along albeit with pretty piss poor acceleration?

clio 480 turbo · Post by **clio 480 turbo** » Mon Apr 16, 2007 8:35 pm

once i try to accelerate the turbo will just start to boost then all of a suddern the boost will drop right off , just as the car's about to take off the boost will drop off as if its under fueling.

JohnTurbo · Post by **JohnTurbo** » Mon Apr 16, 2007 8:40 pm

How many psi does it build? How fast does it build?

Does the car shake when it happens?

clio 480 turbo · Post by **clio 480 turbo** » Sat Apr 21, 2007 9:27 pm

it will boost to 10psi on the gauge but the car is not performing, it seems to run fine on low boost but when i try to get over 5-7 psi the car has no power. could it be under fueling?

JohnTurbo · Post by **JohnTurbo** » Wed Apr 25, 2007 8:30 pm

Its possible. This rings a little bell in my head that says "your fuel pump is under spec"

What fuel pump are you using?

haz@nocturnal_development · Post by **haz@nocturnal_development** » Sun May 13, 2007 5:31 pm

the ecu starts to retard boost at 8psi and keeps retardin. the ecu doesn't interveen at 14psi, thats when the injectors are on max cycle so will start to run lean if most boost is reached. if its the ecu boost limit bein reached then it will misfire.
if the car is goin flat then its prob got an rt pump on it, check that.
also the actuator, if std, is too weak so will spike high then drop off.
sounds like the car is std, the chap has tried to up the boost then gave up n sold it on. its always suspect when the car developes issues 'just' before a sale

BNZ · Post by **BNZ** » Sun May 13, 2007 9:16 pm

If the car shakes when building boost its the pump,i have the same pb.Gonna change the pump tomorrow and see what's what !

Also another symptom for low fuel pressure is engine choke-up if u push the acceleration quick to the floor it,even in neutral.

Duke of Cruel · Post by **Duke of Cruel** » Fri Jun 22, 2007 1:52 pm

clio 480 turbo wrote:once i try to accelerate the turbo will just start to boost then all of a suddern the boost will drop right off , just as the car's about to take off the boost will drop off as if its under fueling.

Sounds like too low octane, or dodgy cat. Just a few of many possibilities.
DoC

Volvo 480 Club Europe

Help! Boost just cut off

Help! Boost just cut off

drops off on boost

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