mashimario

Hi all,

Today I took apart the air intake case and manifold to clean the EGR port. I also disconnect the EGR valve and cleaned it. After I put everything back, I turned on the car. The cat started to idle at 1.25k rpm, then after a while, the rpm jumps between 1.25k and 1.75k. I thought there was some vacuum leak and replace one hose I thought might be the problem, but the problem still there. I really don't know what the problem is.

Is there anyway to find a vacuum leak by ourselves?

Thanks a lot for any help.


-mm

richardparker

iTrader: (7)

I'm pretty sure you can use carb spray.
The engine running condition will change spraying the leak.

fsttyms1

Still sounds like a vacuum leak. Did you take the throttle body off? Llike richardparker said. Take some carb cleaner and spray it near the parts you took off and see if the idle changes. If it does thats your leak

phee

iTrader: (5)

did you tighten the intake manifold all the way?

was the gasket put on?

did you remove the throttle body and break that gasket?

its def a vacuum leak if its bouncing. if it stays high then its your IACV

mashimario

I first tightened the manifold bolts evenly to certain level, then used the torque wrench to tighten them to 16 lb-ft in the order from the manual.

I pretty sure the gasket is on. Do I need to clean it?

I didn't take off the throttle body.

mashimario

Will throttle body cleaner work?

fsttyms1

Also make sure EVERY thing is plugged in. Make sure you reattached the plug for the IACV

mashimario

One more question, if the EGR valve joint is leaking, will it cause same problem or not?

fsttyms1

yes, without it the intake has open vacuum. Spray some carb cleaner there with the motor running and see if the idle changes

mashimario

I just spray the throttle body cleaner on the EGR valve joint, no luck.

Do I need to clean the manifold surface really well before putting it back?

mashimario

guys, when you say the idle changing after spraying the carb cleaner, do you mean the idle becoming better or worse? Or, whatever, as long as there is a change, I can tell there is a leak?

01tl4tl

when carb cleaner/tb cleaner hits the leak it raises the rpm noticably in most cases- it may make it stumble--so any change indicates you found the spot

when you install the top cover gasket it can go on upside down and look like its on correctly
but it wont seal until you take it back off and flip over
Set it to match the top cover-not the engine side
there is a port that gets blocked by the gasket when on wrong

mashimario

I took apart everything again and checked all the vacuum hoses. The hoses look perfect. I cleaned the gasket and joints.

There are three sensors on the throttle body (one top, one bottom, one side). When I disconnected the side one (I don't what the sensor is), the idle was high around 2k rpm stably. Then I hooked it back, the car started to shake again between 1k-1.5k rpm with low frequency. Then I sprayed some Carb cleaner around the EGR valve joint, after a while the rpm jump around 1.5k with very high frequency and very small amplitude.

Can I say the leak is the EGR joint?

Thanks all.

fsttyms1

Did you take the EGR off? Did you get a new gasket?

mashimario

I did take the EGR valve off, also put a new gasket from the local auto store.

I just turned on the car again. Now the rpm is low between 700 rpm to 1k rpm, but I can feel the idle is not smooth at all, feel like misfiring or something. The CEL is on, so I will read the code to find out tomorrow.

One more question, I didn't clean the EGR mounting place on the engine very clean coz I am not sure if I can spray the T/B cleaner on that place. Is it ok if the cleaner flows into the engine?

Thanks a lot

01tl4tl

it will be fine with TB spray in there- it burns
you can spray that stuff thru the TB with engine running or not- its a cleaner

careful on the torque on egr valve bolts- too tight can make a bad seal

and you say the top cover gasket is correctly installed- you matched all the holes and cutouts with it - both ways- to see which is right?
This seems like one of those freaky stupid problems like an upside down gasket

01tl4tl

all gasket surfaces must be clean before assembly, even metal ones should be wiped clean
no old fabric gasket material left,, or it will leak there for sure