VS stalls when breaking

[finch21]

Can anyone help me i have a 96 vs ute and it stalls whenever i have to brake hard but only when the tank is above 3/4s full, Ive been reading up and from what ive read sounds like it might be a vacuum leak. it also has very poor fuel consumption only get 320kms out of each tank

Has anyone else had this problem before

Cheers

[greenacc]

try cleaning the IAC valve and port.
Does it idle smoothly ? If its a vacuum leak it should not matter what the fuel level is, unless it is the fuel pressure regulator. Check the vacuum hose on the regulator for leaking fuel - indicating its stuffed.

[grnvs]

How'd you go with this one? My car is doing similar stuff on some occasions except it only almost stalls! I was think on the same lines, vacuum leak or fuel pressure regulator maybe.

[brewerboy]

I had an auto V6 VP that started doing this. When i braked the engine would cut out and it ended up being a fualty throttly bedy position sensor.

The engine management light came on on the dash the the holden computer spat out the code that pointed to the culprit.

dont know if this helps of not

cheers

[clubby_you]

sound like a brake booster leak to me

[grnvs]

Is there an easy way to check for vacuum leaks / brake booster leaks?

[clubby_you]

1*
start the car and put your head under the dash and put your hand on the brake pedal can you hear a sucking noise ..?

2*
start the car put your foot on the brake and turn the car off does the brake pedal start coming up even tho your pushing on it if the booster is ok should be able to hold vacuum for at leasr an hour so if it come up quickly it's stuffed

3*
sparay some carby clean around the engine bay like at all the vacuam lines and around the inlet manifold see if the idle speed changes when you do

cheers doug

[grnvs]

cool thanks for that! i'll give it a go!

[grnvs]

Checked brake booster all sweet, and couldn't find any vacuum leaks. I have also driven around with the IAC valve unplugged and still does it so it aint the problem either. I have also had fuel pressure and flow tested recently and that was good. Put the multimeter on the TPS and the voltage went up smoothly, so i'm guessing its ok too.

Are there any other things I should check because its kind of got me stumped! Is there anything else I should do before I take the car to a mechanic?

Cheers

[MADVRSS]

hey just take your fuse out of your brake lightes see if that chages any thing, it might be pulling voltage from the ecu ,,,, worth a try

[greenacc]

hmmm yeah, or u could try pulling the engine fuse out too, that ought to save lots of voltage. NOT.

[grnvs]

I've also figured out its not just playing up when i brake. If i'm driving along and pop it into neutral and roll for a bit, the engine wont sit at idle speed, it jumps around between 500 and 1000rpm. But if car is parked the idle is okay!

The engine does have a really loud tick which I assume is a hydraulic lifter not opperating properly. I've tried lifter free ect but wont go away. Is it possible that the lifter is not opening the valve enough? Could that cause the engine to idle badly after deceleration?

Cheers

[grnvs]

Dodgy IAC valve was the culprit. It was working, but was not working properly. The mechanic set it back to zero and said if it starts playing up again to put a new one in. Glad it wasn't anything major.