Weak Start Up/Start Up Issues

**PontiacZack** · 04-28-2018

Hi, all

I've been having some issues lately with my 07' start up. It has been sounding weak compared to my friends 4 cylinder 😂 and the other issue is that it will start up but, then die immediately and I just had my fuel injectors cleaned. This is important to mention as well, I have to press the gas to get it to start. I've also attached a YouTube link to my cars start up if you would like to check it out. The video sounds a lot better than the actual start up.

2007 Pontiac Grand Prix Bad Start Up - YouTube

Any ideas on how to solve this issues would be greatly appreciated.

**Iceman6669** · 04-28-2018

Have you tried starting it without the MAF plugged in? That will cause a car to die right after starting sometimes.

**PontiacZack** · 04-28-2018

@Iceman6669

So, we tried unplugging the MAF and starting it up and still received a weak start up.

Here's my friends car start up for comparison. He use to own a grand prix as well and he is confused as to why the start up is so weak and his Pontiac had over 200K miles

2013 Chevy Sonic W/80K miles Start up - YouTube

**BillBoost37** · 04-28-2018

You video sounds fine to me. except that you say you are using throttle to start it.

When you did the injectors, why did you do them?
What did you take off to put them in? These are all things you should double check
Likely you moved a vacuum line etc.. check those.. a huge vac leak could cause a fire up and stall.

**PontiacZack** · 04-28-2018

@Billbost37 Before the fuel injectors cleaning, I was having a weak start up and thought cleaning the injectors would help. The work was performed by a local mechanics shop. It's actually running better now.

**Scottydoggs** · 04-28-2018

your comparing apples and a potato.

**PontiacZack** · 04-28-2018

Disregard the comparison. The issue is I have to give the car throttle to start it half the time. Could it be a fuel filter issue?

**FordMan77** · 04-28-2018

You don't have an external fuel filter. IIRC late 04+ moved it inside the tank (aka- not serviceable). Has the TB ever been cleaned? Any codes showing? When was the last time a tune-up was done? Do you know if the shop actually removed the injectors? If so they should have replaced both O-rings. And yea, that video sounds just fine for start up. Even my GT with 350K miles sounds like that. Although I don't have to give it any throttle to start it.

**WarStryker13** · 04-28-2018

The problem it's having is with the throttle body. If the TB is dirty and has a lot of build-up behind the blade, it'll cause the car to die immediately after start-up, Not sure why, could be something with the TPS built in to the TB, or the valve not returning to the exact idle position that it's expecting because of the crap blocking it...

Cleaning the TB is what I would do. If it's really nasty, be careful with the amount of TB cleaner you use, the seal between the shaft and the housing isn't the best and if any liquid gets into the housing, it'll play hell with the servo and circuits in there. I had to take mine apart and let it dry over night before it would do anything.

**PontiacZack** · 04-29-2018

@Fordman77
I don't know if the shop removed the injectors and replaced the o-rings. I would have to go back and ask them. I've only performed minimal maintence for awhile but, I'm really working hard to put some serious maintence in now.

@WarStryker13
Thank you for the info! I'm try cleaning the TB and letting it sit over night and see the results I get.

**BillBoost37** · 04-29-2018

I agree, very likely your TB is dirty.

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