Hey all, been a while since I've been on the boards. I've since sold my monte and am now driving my fiancés 05' impala since she got a newer car.

That said the car runs great but for some reason I'm having a bit of trouble getting it started after it's been sitting(overnight or after work shift). I can hear the fuel pump running when I cycle the key but the engine will crank over for a few seconds before I get any light off. When it does start it stumbles to life, but once it finally makes it up to idle speed it runs fine? After the first start of the day/night it fires up perfect every time after.

I've replaced the fuel pressure regulator but that didn't seem to help. Thing is it's somewhat intermittent. Sometimes it fires right up as it should as soon as I turn the key. Other times it takes a bit. I've noticed sometimes when it tries to start I can hear a chirping sound under he hood until it's up to its normal idle speed...belt squeal maybe? I'm at a loss but have a few ideas to try. I'll clean the MAF sensor and replace the fuel filter. That should be done anyway. I'll also try and check rail pressure. Short of that I'm stuck, unless I start throwing sensors at it. TP sensor? Crank position sensor?

FWIW shifting has been off too ever since it started. The transmission shifts are very slow and lazy. I'm thinking something might be related here? I know it's not a monte but it's the same chassis...hopefully someone will still help a guy out

 

You're right, that generation Impala is near identical to the 00-05 Montes (I have an '04 Monte and my wife has an '05 Impala, I've learned they are very much alike).

As for the starting issue, I would be curious if the car is loosing fuel pressure while it sits. What you are planning to do sounds like it makes sense. Change the fuel filter (as it should be done on a regular basis), clean the MAF (I don't think this is related BUT never hurts), and check the pressure at the rail. I would assume with the car off, there should be some pressure at the rail and then when it goes to start it should increase (again, my assumption). But if you can watch a fuel pressure gauge, that will better help figure it out.

 

There is also a check valve in the fuel pump that will sometimes fail. When it does it allows the feed line from tank to regulator to lose pressure. If too much pressure isn't lost the car fires right up. If it sits for a bit it takes a couple cranks to build pressure in the feed lines so adequate pressure is available to fire the engine. You may want to take a secondary test while you have that fuel filter off just to make sure it isn't the check valve.

 

That is what it seems like, that fuel is bleeding back from the rail but I won't know til I do a pressure check. The fuel pump has been making some odd noises when you first turn the key. Sounds like a series of clunks as if it's cavitating? Hard to say. I didn't know about the check valve in the pump. Wonder if that's failed/failing. Car runs great and after my fill up today I'm still averaging 29mpg. The car also has 165k on it if it matters.

Anyone know what the nominal fuel pressure is at the rail?

 

I think the fuel pressure should be 57 psi. But don't quote me on that one. Have you checked your IAC? If it is sticking that would cause hard starts.

 

Haven't checked it but the car runs fine once it's started, if it was the iac causing issues wouldn't it have an irregular idle as well? As for the fuel pressure I still haven't got to it yet, Looks like I'll have to rent a gauge.

 

Just borrow one fromoreillys and use in park lot

 

I have the same problem with mine. I've determined its the IAC. Once it gets going its fine, but sometimes starting is hard. If you clean it it'll help, but you'll probably need to replace it at some point. I had mine working with a good cleaning every couple thousand miles but i need to change mine now. I'm waiting on one from rockauto. Using a little pressure on the gas pedal should help you start it

 

I haven't gotten around to trying to fix this thing yet. Since we've had a break in the weather I've been helping in the field before I go into work(2nd shifter) With that said last night leaving work I went to start it and it's almost like it's trying to start out of time. I hit the starter and it cranked for a bit then popped and the starter stopped. I let of and it stumbled to life like it always does, just thought it was odd. I'll look into cleaning the iac and see if that helps.
At 160k+ it's probably about time for something to fail.