Whenever I brake my car stall

[Kevdx]

Hey guys Kev here from sarawak,borneo.I'm new with this 4k engine and ive got this ke70 dx model with 4k engine too.i got this car for rm800 from a friend that have not died for years.last 2 years he bought a new carb for this car and the car was alive until the alternator died and he left it dead untill I bought it.when I bought it,got alternator change and I switch it's carb to a mitsu 4g13 carb it came back to life.the problem is every time I need to start it I have to choke the carb and floor the paddle the same time..everytime(idle at 700).then Everytime braking the car stall.ive also change the coil and distributer to electronic type which the old one still uses contact point.then got the timing for the distributer and all set properly(no misfiring) Still the same prob.ive also check if there any blockage inside the fuel tank(got it all remove actually including the pipe lines) ive tested it's brake booster one way valve.or is it something with the valve clearance or any vacuum on the engine? Really need everyone helps.totally out of idea bout this 

Edited January 21, 2018 by Kevdx

[LittleRedSpirit]

Could be anything with a carb swap and a few mods to confuse the issue. 

If it runs good at higher revs its not a fuel blockage.  That would require more fuel than idle and it does that fine so disregard that.  It could be old fuel not helping the issue, did you dump the old fuel and put in fresh when you got it running after 2 years sitting?

Likely you have a low idle setting.  Id be looking at basics, making idle adjustments, maybe trying to jet the carb, it may be jetted all wrong for a 4k.  Id be more tempted to look for a better 4k carb and work with that, at least you could rebuild it and it would probably be well matched to the motor, the 4g13 carb is unknown really, I think its a bigger motor.

Do you think the car electrically cuts out when braking or does it stall because you got off the gas and it isnt getting enough fuel and air to sustain off throttle running on decel?  It sounds more like its jetted wrong for idle and off throttle.  You dont need a lot of fuel off throttle, as long as the thing keeps running.  Any backfires?  700 is a low idle.  Id be trying to open up the idle air a bit and see if its better that way.

 

[altezzaclub]

I'm with littleredspirit, 700rpm is lower than it needs to be, and the carb may not have a good idle circuit for a 4K. Its off a Lancer isn't it?

The brakes do two things-

They allow air from the booster into the engine, so you may have a leak in the diaphram, or it may be the idle just can't handle the extra air going in & leans out.

The second thing is that the brake lights load the alternator, which makes the motor work harder. ECU-controlled cars have an idle-up valve for when the brake lights are on.

Does it die at idle if you turn on the headlights?? That will tell you that its running so lean it can't make an extra KW or two at idle..

Otherwise, wind the idle up to 900rpm and get the best idle mixture you can.

 

[rebuilder86]

if u are just sitting at idle, not moving, and push the brakes, does it stall or stumble? if so the brake booster diaphragm or seal is probably ruptured, a common issue. when u push the pedal, the seal at the back (pedal side) opens up exposing the positive side to atmosphere, which then leaks through the ruptured diaphragm and then u have a major vacuum leak.

[Kevdx]

@LittleRedSpirit @altezzaclubthanks for the reply dude I've already dump the old fuel.ive also change the carb yesterday with a running condition 4k carb still having the same problem.no back fire.sometime when you slam the throttle the car feels like as if not enough fuel going in the only thing that I did not change now is the a/c pump could it be when the car going high rev then suddenly the pump couldn't make it in time to fill the carb with enough fuel inside the carb.also today I've bought a electric fuel pump from a daihatsu hijet.and before this also no black smoke even when tune carb to rich a/f mixture.

Edited January 22, 2018 by Kevdx

[Kevdx]

@rebuilder86no bro ,no stall or stumble when you start it.also I need to chock the carb by hand Everytime I need to start it I've also check the booster still got the same prob

Edited January 22, 2018 by Kevdx

[altezzaclub]

On 22/01/2018 at 2:07 AM, Kevdx said:

I have to choke the carb and floor the paddle the same time..everytime(idle at 700).then Everytime braking the car stall.

So these are still the problems even with the 4K carb on??

Then its an airleak somewhere else in the inlet system, unless you were unlucky and both carbs had dirt in the idle circuit.  Have you checked the bolts holding the inlet  manifold on?  Any looseness there will let air slip in past the gasket, and they get loose over the years as the gasket compresses.

If the motor is down on compression it won't like to run at low speeds, can you check the compressions??  No chance of it being a head gasket is there?? Doesn't use water at all?

What happened when you turned the idle up?? Did it still stall when you stopped?

[rebuilder86]

kah ok, so would it be a correct assumption, that it is basically stalling when u are coming up to a set of traffic lights or to a stop while driving? but no problem after u start the engine and idle it?

if so, then there are a couple of possibilities.

malfunctioning fuel pump check valves are most problematic at idle, so check them. theres an "in" and an "out" inside the stock pump.

fuel pump check valves worn, - unrepairable, fuel pump must be replaced

fuel pump check valves dirty - flush with carby cleaner, then replace filter (this is common when cheaper rubber fuel hoses are used)

Other than that the float itself can stick, but this is usually tempremental and you have changed carbs allready.

but back to the brake booster,  how did u check that it was ok? it cannot be propperly tested (vacuum hold style) without the brake pedal pressed in a bit. if the brake pedal is at rest, the booster air inlet is sealed and this will mask the fact the booster is ruptured. it can be a small rupture and wont affect brake performance but will stall the engine.