2003 Buick Park Avenue 3800 Series II hard to start

buick
parkavenue

#1

The problem occurs under all conditions, cold start, hot start, weather doesn’t play a factor. When you turn the key it will sometimes fire right away and then die or you’ll have to turn it over for a few seconds. I now just rest my foot on the gas and press it slightly the second that it fires. It will sort of stumble and surge for a second or two and then it is fine. A few times it has died at a stop light, although not recently. It has has 45,000 miles and isn’t driven very often. I’ve scoured the internet and have come to the conclusion that it is getting too much fuel, hence when pressing the gas to open the throttle body to let more air in helps. It seems to be a rather common problem with this engine but I can’t seem to find an actual smoking gun fix posted anywhere. Some suggest the fuel pressure regulator. I don’t have a fuel pressure tester but I the regulator isn’t leaking out of the vent tube. Coolant temp sensor maybe? Anyone have any ideas? Thanks!!


#2

Cleaning the maf sensor is my first thought, second thought throttle body needs cleaning.


#3

The problem might be with the Idle Air Control valve. The IAC valve is what allows the engine to idle under all conditions.

The next time you go to start the engine, slightly step on the accelerator. This will substitute for the IAC valve. If the engine starts replace the IAC valve.

Tester


#4

A vacuum leak is a possibility but odds are more towards an Idle Air Control valve problem. Cleaning the throttle body and IAC may help.


#5

I actually did look for the MAF but couldn’t find/identify it. It doesn’t look like the inline unit I’ve seen on my other cars. The throttle body has a weird honey comb disc where the air hose attaches. I haven’t seen this before so I was hesitant to spray it down with cleaner.

I didn’t think about the IAC. My daily driver is a '96 Accord. I replaced the throttle body with a bigger one and the aftermarket unit doesn’t accept an IAC. It starts just fine, although idles a little erratically sometimes, obviously. I just now started the Buick with my foot lightly on the gas and it seemed to start a little better. I’ll try this over the next few days and see if it’s consistent.

I should also note that other than the starting issue it runs great around town and on the highway. It still gets 30+ mpg on the highway too.

Thanks!


#6

That weird honey comb disc is the MAF sensor.

Follow the hose from the MAF sensor to the back of the engine, and that’s the throttle body.

Tester


#7

Hmm, the MAF is then attached directly to the front of the throttle body, almost like it’s built into it.

I’ve tried resting my foot on the gas peddle over the past few days and it starts every time with no problem. So this is a sure sign of a bad IAC?


#8

The MAF is attached to the top of the throttle body with two TT20 screws, has an electrical connector labeled ABC where it plugs in. The MAF can be removed to make for easy throttle body/ IAC cleaning. Simply spray cleaner through the hole. And while the MAF is out it can be cleaned with electrical cleaner. Be careful not to damage the elements.