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If you changed the PCV valve is it the chrome version? The black one is for the Manual IS250.
Also check that the vacuum switch on the intake manifold is not stuck open. Pull the hose that's coming under the intake pipe. Then disconnect the plug from the switch. If it has vacuum at the port it's open. Should be closed with no power to the switch.
It does seem like something is not getting metered behind the MAF. Searching I found on the Cobalt forums. The guy had a crack on the air cooler. They couldn't figure it out. P0101 kept on coming back up constantly.
As you said you didn't see any vacuum leaks before. You wouldn't be able to catch the switch with hoses hooked up. Again this is just trouble shooting.
Okay so i check vacuum switch later but now i check maf. Engine off, only ignition on. My maf rate is 0.46 g/sec to 0.48 g/sec. Normal value?
I'd say reset the ECU pull the negative on the battery. 15 minutes is all it takes. Then the long term fuel trims learned are at 0. Then go from there if the banks go rich immediately, and throws a cel. Something is definitely wrong somewhere.
Remember after ECU reset the car won't start on the first try. If it's too fast the car will stall first. I normally hit the ignition to the on position wait until the AC does the cycle check for the servos. At this point I put my foot on the break pedal and start the car. Then the car won't stall out. After it starts let it idle until the rpms stablize. Which in turn is about 10-15 minutes from a cold start. Don't touch the gas pedal.
Check your readings once it stabilizes.
Here's a good read about resetting fuel trims from the Volvo forums.
I disconnect negative from battery and leave car for 30 min and after this i turn on engine. Wait 20 min and have this:
I disconnect pipe from vacuum switch like you say and dont have any vacuum. I replace it and now it opens and closes quickly but fuel trims look like always.
So i disconnect again pipe what you say and look at fuel trims. Without this hose its look like in idle:
short bank1 = ~ +4% - 10% (always positive value)
long bank1 = ~ -24%
short bank2 = ~ +4 % - 12% (always positive value)
long bank2 = ~ -22%
Maf rate are around 3.68 g/sec
For what is this hose?
edit 2nd
When i disconnect this hose from other side vacuum switch i get this value
Last edited by wieszkto; Feb 23, 2019 at 02:10 PM.
The hose is for the fuel Vapor. Coming from the EVAP canister. If you enduced a vacuum leak. All the numbers should be high positive numbers. Your's seem to stay relatively low. That vacuum leak at that position should've of pegged them out at +20 or more easily.
Nobody can help me so i go to dealer. Dealer said my throttlw body is real dirty so he clean it, check wires and said now must be okey. But now after 15-20 miles i got new code P0172 and P0175. I disconnect battery and after 15 min run car. Now before code show i have high rpm! Like ~1800 rpm in idle and code p0101, p0172, p0175. I reset code drive 40 miles and now have 800 rpm and p0101 and p0172 only code. What is going on with this car?
Nobody can help me so i go to dealer. Dealer said my throttlw body is real dirty so he clean it, check wires and said now must be okey. But now after 15-20 miles i got new code P0172 and P0175. I disconnect battery and after 15 min run car. Now before code show i have high rpm! Like ~1800 rpm in idle and code p0101, p0172, p0175. I reset code drive 40 miles and now have 800 rpm and p0101 and p0172 only code. What is going on with this car?
