Power Brake Booster

ChemCool · Post by **ChemCool** » Fri Mar 07, 2008 12:06 pm

This is the next piece of 17 year old crap that is busy scratching my ass!!!

Why? This thing, when we brake, and the revs go down to like 200 or 300 RPM and some times the sx dies, I suspect the brake booster. When you brake, the engine can only deliver so much vacuum, and when the booster is not ok, like leaking, then this can happen. I checked the vacuum pipes for leaks and brittleness towards the brake booster. They look ok to me.

What are you members thinking?

Can we replace the inside diaphragm? Replacement kits available? Can the bloody thing be opened so that our overhaul experience can utilized again?

Chem

ChemCool · Post by **ChemCool** » Fri Mar 07, 2008 12:43 pm

When the sx is standing put and idling, and you hit the brake pedal, all is fine. Not the same as when you approach a stop street.
Question is: while standing and idle the brake booster is sealed of with the one way vacuum valve in line. So while idling the result is not the same??
I dont know.
Any body out there with a vacuum tester. Then I need to link that in line and observe the vacuum drop?
Chem

veecee · Post by **veecee** » Fri Mar 07, 2008 1:45 pm

you can test the one way valve with your big fat lips!!!

hahahah!

Toby · Post by **Toby** » Fri Mar 07, 2008 4:01 pm

Doesn't the idle drop even if you don't brake? If so, why suspect the brake booster?

Doctor G · Post by **Doctor G** » Fri Mar 07, 2008 4:22 pm

My money is on the IACV (Idle Air Control Valve).

They get dirty with age. Take it off. Clean it, then set the idle with the car at riding temperature and with the IACV disconnected. Then connect it afterwards.

veecee · Post by **veecee** » Fri Mar 07, 2008 5:03 pm

Doctor G wrote:My money is on the IACV (Idle Air Control Valve).

just throw the damned thing in the dustbin!

ChemCool · Post by **ChemCool** » Sat Mar 08, 2008 4:33 pm

just throw the damned thing in the dustbin! Wink Wink

Done that. AAC valve out!!!! Still the problem or fault is there. Idles still drop down to 200/300 and eves the sx engine dies some times.

Next one please?

Chem

ChemCool · Post by **ChemCool** » Sat Mar 08, 2008 4:34 pm

you can test the one way valve with your big fat lips!!!

Done, and still no joy.

Chem

ChemCool · Post by **ChemCool** » Sat Mar 08, 2008 4:35 pm

Any money on the TPS??

widowmaker · Post by **widowmaker** » Sat Mar 08, 2008 6:41 pm

get new battery

Doctor G · Post by **Doctor G** » Sat Mar 08, 2008 7:20 pm

ChemCool wrote:
just throw the damned thing in the dustbin! Wink Wink
Done that.

Maybe thats the problem then.

If you suspect the TPS then stick the prongs from a voltmerer in there and check the idle and WOT voltages. Not sure what the readings are meant to be for CA's though. FSM.

ChemCool · Post by **ChemCool** » Sun Mar 09, 2008 6:09 pm

If you suspect the TPS then stick the prongs from a voltmerer in there and check the idle and WOT voltages. Not sure what the readings are meant to be for CA's though. FSM.

Thanks, done that. TPS is fine. I now went the VC route. AAC valve in the dustbin. The method works fine. Idle switch on an off checked and throttle sensor checked=fine.

But problem of stop and idle drop is still there.

Chem

Gary57 · Post by **Gary57** » Mon Mar 10, 2008 9:00 am

How is the tuning chem??

Doctor G · Post by **Doctor G** » Mon Mar 10, 2008 9:31 am

Earth Wires?

ChemCool · Post by **ChemCool** » Mon Mar 10, 2008 10:15 am

Ok, this problem of idle drop down to 200/300rpms, when approaching a stop, and then rpm goes back to normal, or the sx engine will stall, is a common situation with a lot of different cars. I picked this one up on internet.

It happens a lot with s13's and with s13's even with sr20 motors and with KA's

The most common advice is the AAC Valve. Clean it ! Replace it! That is the common answer/advice.

But that is not really to say it resolves the problem.

I have removed the AAC valve. And the problem still persists. If the AAC valve is the culprit, then VC 's sx should experience the same problem(cause he is running without the AAC valve too).

On the moment, my sx is idling perfect via the TB butterfly. All idling crap is removed and AAC valved removed too as mentioned.

Now: This is the other advice from internet:

1.Air trapped in air coolant???
2.Vacuum leak
3.Cleaning the TB
4.Feul filter
5.Throttel cable settings
6.clutch switch???
7.Clogged or dirty injectors
8.TPS
9.AFM
10. Engine temp sensor

And no one on internet has come back and said prominently that this or that was the solution to it. Nothing.

I feel the one about the dirty injector/s is getting my attention?

And of course, it all boils down to elimination again.

Chem