Vaccuum Leak?
#1
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Vaccuum Leak?
I got a new (to me) s2k on monday for a daily driver. its an MY00 with 83k.
I have noticed that when braking gently to a stop you can feel the car lurch a little bit, also the engine at times stumbles a little bit at idle. I've given the map the obligitory whack.
I haven't looked yet, but the odd "lurch" under light braking feels like that I'm losing some vacuum and I lose the power brakes for a second.
Any ideas before I go investigating?
I have noticed that when braking gently to a stop you can feel the car lurch a little bit, also the engine at times stumbles a little bit at idle. I've given the map the obligitory whack.
I haven't looked yet, but the odd "lurch" under light braking feels like that I'm losing some vacuum and I lose the power brakes for a second.
Any ideas before I go investigating?
#2
The "lurk" under light braking could also be related to the brakes. You could have a slightly warped rotor or grabby brake pads. With that many miles on it, this is a distinct possibility.
As for the vacuum leak, start by examining all the vacuum hoses and lines for cracks or holes. Look at each end of each run of hose to see if the ends are loose/cracked. A quick tug and a wiggle should be revealing.
Look at the throttle cable slack. Is the throttle plate area really grungy? The plate may not be sealing properly when closed. Check the Idle Air Control assembly for any weird clicking noises and see if all those coolant lines are good.
Of course, then there's all the ignition and fuel stuff - plugs, injectors, fuel pressure. How about the air filter? Really clogged?
Diagnosing this one is going to be hit and miss. You'll more likely come across the fix purely by fluke.
As for the vacuum leak, start by examining all the vacuum hoses and lines for cracks or holes. Look at each end of each run of hose to see if the ends are loose/cracked. A quick tug and a wiggle should be revealing.
Look at the throttle cable slack. Is the throttle plate area really grungy? The plate may not be sealing properly when closed. Check the Idle Air Control assembly for any weird clicking noises and see if all those coolant lines are good.
Of course, then there's all the ignition and fuel stuff - plugs, injectors, fuel pressure. How about the air filter? Really clogged?
Diagnosing this one is going to be hit and miss. You'll more likely come across the fix purely by fluke.
#3
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When braking to a stop try doing it two ways. One with the car in gear and the other with the car in neutral and rpm at idle.
With the car decellerating in gear the vacuum should be very consistant from high rpm down to about 1500rpm at which point the idle air control valve will start doing its thing. If you notice variation in braking effort before 1500rpm then chances are you are dealing with a vaccum leak.
With the car decellerating in neutral the vacuum generated will be dependant on the rpm the idle air control maintains. I believe that should be around 1200 to 1500 rpm until the speed drops to well below 10mph. If you notice variations in braking effort check to see if there are also variations in rpm associated with it. If so you may need to check for a faulty idle air control valve.
With the car decellerating in gear the vacuum should be very consistant from high rpm down to about 1500rpm at which point the idle air control valve will start doing its thing. If you notice variation in braking effort before 1500rpm then chances are you are dealing with a vaccum leak.
With the car decellerating in neutral the vacuum generated will be dependant on the rpm the idle air control maintains. I believe that should be around 1200 to 1500 rpm until the speed drops to well below 10mph. If you notice variations in braking effort check to see if there are also variations in rpm associated with it. If so you may need to check for a faulty idle air control valve.
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