96 avalon hard start (cold) - Toyota Nation Forum : Toyota Car and Truck Forums

gduguid · 10-25-2011, 05:58 PM

My original problem started out being hard start all the time and having to pump the gas...easy fix right. Replaced fuel pump and started up normally after having changed a fuel pump and fuel filter. I drove around for a while and started back up and thought my problem was fixed. Next morning hard cold start kicked in. So far I have replaced fuel pump, strainer, fuel filter, fuel pressure regulator, coils and also cleaned the throttle body. Still having problems with hard cold starts. Any suggestions of what to try next? I am clueless as to what it could be.

Thanks,
Gregg

BonzoGonzo · 10-25-2011, 08:27 PM

i would inspect the fuel injector that richens the mix for starting. i am not certain these cars do it that way... the mass air flow sensor is the other thing. it might not be working well - failing to indicate the temp of the input air... it's the thing between the big huge air cleaner and the rubber hose, leading to the throttle body. you can clean it, for starters. they sell a spray that will take the gunk off of it.

gduguid · 10-25-2011, 08:32 PM

cold start solenoid? i was thinking that or the iac but can not find either one

fourwheeler · 10-26-2011, 11:13 AM

How is the spark? Sparkplugs? Any CEL's?

gduguid · 10-26-2011, 06:06 PM

i cleaned the throttle body yesterday and that triggered the egr valve to set the cel, cleaned that today and didnt come back on. while i had the throttle body off i took all the sensors off and cleaned them thoroughly. The car started right up the first two times, but after it sat for like 45 min it went back to the same problem. Spark is good and ohmed all the coils at and all are above 3.2. Haven't taken the spark plugs out because it doesn't seem to be a spark problem. I have also noticed a cloud of smoke once the engine does start.

gduguid · 10-26-2011, 06:08 PM

Is the iac the sensor on the bottom side of the throttle body that has the 2 coolant lines and im assuming its a air line?

gduguid · 10-29-2011, 08:53 AM

ok so i think i narrowed my problem down to being a vacuum problem. i took readings from the map sensor and egr valve and had 0 vacuum. any ideas on what to check? i don't think that it would be a vacuum leak if i do not have 0 vacuum from multiple locations.

gduguid · 10-29-2011, 01:02 PM

Ok found vacuum into the canisters and going into the switch but had none going to the map sensor or to the other side of the canister. What is the probability that the whole canister assembly is faulty, or just the sensor being faulty?