2006 Lacrosse 3.8 Starting issue: videos this time

[TmanP]

I posted a while back about my 3800 starting issue. Since then, I replaced the plugs and wires, cleaned the MAF sensor and replaced the air filter. I think it's getting progressively worse. Often, when I restart the engine after it has been sitting for a while (never completely cold or warm), it takes 2-4, but usually 3 tries to start it. It starts then seems to starve off and die. When it's running it runs fine. The car has 140k miles and is in good shape, so I want to figure this out, and any help would be very appreciated!! I took a couple videos so you could see the problem. Links are below:


Two different days:

Video #1- Buick starting problem




Video #2- Buick starting problem


What I've done:

-New ACDelco Iridium plugs & ACDelco wires

-New air filter

-Cleaned MAF sensor

-Ran Techron through the gas

-Pulled negative battery cable for 20 minutes to let it relearn idle (per GM instructions)

-Took it out for a longer highway trip to burn through the Techron



-the car DOES NOT HAVE an IAC valve. I know that's a logical solution but it doesn't have one.

-If it matters, the car is drive-by-wire so it's mostly computerized.



Thank you so much everybody! This forum is great!

 

[dan_erickson]

Maybe it is a problem with the drive by wire throttle body. Is the throttle body blade completely stuck shut upon startup?

 

[Warstud]

I think you may have a weak fuel pump. Have someone spray some Starting Fluid into the throttle body while cranking it over. If it stays running with the SF... then you probably have a fuel problem. Then check the fuel pressure with a gauge.

 

[TmanP]

The thing is, it's hard to replicate. It doesn't always do it. Oh, and also, the battery is a newer ACDelco. Voltage looks good. And the alternator is a newer Bosch.

 

[Warstud]

That video would have been better if you would have filmed it outside the car with the hood open as you were cranking it over. But I'm guessing its a weak Fuel Pump. Which sometimes can work perfectly fine and other times be a pain to start. Just do what I said in the previous post and report back.

 

[Gasbuggy]

Hook a gauge up to the fuel rail. change your fuel filter

 

[901Memphis]

Common issues with those are fuel pumps and ignition coils too

 

[Dan55]

Coolant Temp Sensor ,ignition control module

 

[Trav]

Originally Posted By: TmanP
The thing is, it's hard to replicate. It doesn't always do it.

I ran into this once on a Pontiac, it had something to do with the anti theft system.
Sometimes a faulty ignition switch can cause these sort of intermittent issues without tripping a CEL or code.

Depending on the circuit it may not be powering up something when you turn the switch to crank.
Checking the fuel pressure and sensors if the key isn't being read correctly or the switch is defective may disable those.

Drive by wire uses dual TPS units so anything faulty in that system will throw a code. If the pedal position and throttle plate position don't match its an automatic CEL and limp home mode.

Being intermittent i am seriously looking at the ignition switch. Was this car recalled for ignition switch? If it was did the problem start after having the work done or before?

Edit: I just checked out the video on my PC, if the battery is good and the connections and grounds are okay i would say you are almost certainly looking at a switch problem.
Have you tried the other key when it does this?

 

[TmanP]

The car doesn't have a fuel filter. But you think the pump is bad?

 

[ls1mike]

I agree with Trav, looks like an ignition switch issue to me. I have seen it on few different 3800 powered cars.

 

[TmanP]

All right, I'll use my other key for a while and see what that does. Thanks. Or would you carry the other key and use it when the other one has trouble starting it?

 

[TmanP]

I used the other key, it still did the same thing. No codes.

 

[TmanP]

Okay everybody... I cleaned the throttle body (took it off and used a whole can of CRC throttle body cleaner and a toothbrush). It was filthy. It seems to have been the problem. It runs and starts great now! Not a bad $5 fix for an hour of my time. Thanks for all of your help. I appreciate it.