6 cyl vacuum problem - Toyota Nation Forum : Toyota Car and Truck Forums

gduguid · 10-29-2011, 06:45 PM

I have been having a problem with a hard cold start for a while. So far fuel pump, fuel regulator, fuel filter, and a coil have been replaced. I thoroughly cleaned the throttle body, iac, and egr valve. Today i did a vacuum test on the engine and had no vacuum to the map sensor. I saw that i had about 2 lbs going into the vacuum canister, and none coming out of the vsv on the canister. What is the probably the problem lies in the canister, or if it lies in the vsv valve/switch?

gduguid · 10-29-2011, 06:57 PM

Failed to mention that there are no cel's and during initial start up that it is rough but smooths out after about 10-15 seconds.

dorifuto.boi · 10-30-2011, 01:25 AM

the MAP sensor isn't reading any vacuum at idle ?

Stillrunning · 10-30-2011, 06:39 AM

Quote:

Originally Posted by gduguid

6 cyl vacuum problemToday i did a vacuum test on the engine and had no vacuum to the map sensor.

6cyl should have MAF not MAP??

gduguid · 10-30-2011, 07:32 AM

what ever sensor that is on the firewall next to the brake booster has no vacuum going to it. at idle or 2k rpm. there is a vsv that is on top of the vacuum canister which i have vacuum going into but none coming out. the one side of the vsv is fed by the vacuum canister, and the other side has 2 outlets the first going to the sensor on the firewall, and the second feeding back into the canister.

gduguid · 10-30-2011, 07:36 AM

it does have a maf that is located in between the air filter housing and intake. i was told that the sensor on the firewall has a electrical connection and then one vacuum line is the map sensor.

Stillrunning · 10-30-2011, 07:55 AM

Quote:

Originally Posted by gduguid

there is a vsv that is on top of the vacuum canister which i have vacuum going into but none coming out. the one side of the vsv is fed by the vacuum canister, and the other side has 2 outlets the first going to the sensor on the firewall, and the second feeding back into the canister.

Do you mean the charcoal canister for evap emissions?

gduguid · 10-30-2011, 08:01 AM

i guess thats what it is. on the diagram on the car it calls it the vacuum canister.

gduguid · 10-30-2011, 08:06 AM

i just know that i have been having a hard time with cold start and cant seem to figure out what it is. so far i have changed the fuel pump, fule pressure regulator, a coil, and cleaned the whole throttle body. nothing has seemed to work.

gduguid · 10-30-2011, 08:45 AM

i was told it might be the temp sensor, and have not checked that out yet. can i put a jumper on the temp sensor switch or the vsv switch to test to see if that is it?

gduguid · 10-30-2011, 08:53 AM

ok the switch on the firewall is the vapor pressure assy, and it just says canister on the diagram

gduguid · 10-30-2011, 08:53 AM

any thoughts if i am diagnosing the right things or if i need to check something else?

Stillrunning · 10-30-2011, 10:06 AM

Quote:

Originally Posted by gduguid

i just know that i have been having a hard time with cold start

More detailed description of symptoms please.

gduguid · 10-30-2011, 10:45 AM

hard cold start. turns over great. rough idle when does start for about 15 seconds and then runs fine. starts good when engine is hot. sometimes smoke comes out and smells like unburned gas. i am starting to lean to the ect

gduguid · 10-30-2011, 10:47 AM

cant do any testing due to all my tools being at work. i'm a small engine mechanic and i have tried to replace and test all the logical things to me