very weak warm starts
 

hello everyone, its been a while but i am back with more alero problems... so i have seen more often than not that my car during a cold start starts up perfectly fine. but after driving my alero around then starting it up again within a few minutes of shutting it off it will barely start. now my biggest lead to the problem would be computer issues with the intake air sensor, if that sensor is busted and it keeps saying its -10 degrees that would lead to my engine dumping more fuel than needed in attempt to start it, which would lead to that really weak start. has anyone else had this problem or been able to fix it?:canada: :eek:

How are you verifying your intake temp?

i haven't verified it but it seems more or less like a process of elimination. i cannot come up with any other possible cause of this.

prolly those dumb hids in stock housings, blinding every one , but you can see thats all that matters?

check your fuel pressure and get a scanner to verify iat

So u have no idea if your IAT is broke or not?

While completely ignoring the electrical side of starting up? Idk man, but I'd get the alt, starter, and battery tested just to be sure.... This would be the most "simplest" thing to eliminate. The parts store can do this for you with the alt, starter, and batt. in the car... actually it's better when it's done this way as you can see the load it carries. On another note, the Alero and Grand Am act weird when the terminals aren't serviced/cleaned.

I would clean/replace the terminals (the screws that go in the battery) and borrow a scanner from the parts store (just tell them you want to check codes and read data) so you can see what the computer sees.

Another thing. I've ran cars with bad sensors before, if the AFR is adjusted by the PCM, all it will do is run rich. It has no effect on starting the car up. The PCM orders more or less fuel to be delivered based on what it sees after the first couple seconds. This is also why engines start out somewhat revved up (go up to 1500-2000rpm then slow down to 500-700rpm). A bad IAT wouldn't have a noticeable effect as a bad MAF. The MAF is the one that makes the car die or not want to start. I would think the MAF is bad before the IAT. The PCM usually goes on the reading of the MAF first, then the IAT if it's failing (and if it will stay running, it usually runs rough and cuts off if it's bad). This is of course assuming you have the 3400 and not the 2.2 Ecotec which doesn't have a MAF.

pcm monitors intake air temp and adjusted fuel according when starting. a car is going to need a different amount of fuel to start at -40 as compared to +90. intake air is one of the few sensors that effect engine performance the second the key is set to crank.