Slow Start/ Hot Soak Problem on 2004 Vibe

[flowdam]

Hello All,My Vibe- (2004 base model) has been running great with no problems. Recently though, it has started what appears to be a hot soak issue. When the vehicle is cold and has sat for a while it starts up fairly quickly, but if the vehicle is still warm and only been off for a short while it takes sometimes 5-10 seconds of turning the engine over for it to finally start. I have the following questions: > There is a TSB apparently that says it is fixed by replacing the PCM (powertrain control module. If my vehicle is no longer under warranty I assume this would be something I would have to pay for...Yes or No?> The bulletin is pretty old, so I hesistate to just automatically assume this is the problem. Anyone have any troubleshooting help that could help diagnose this for sure?>Anyone else recently have this problem, and if so how did you fix it? Thanks in Advance!!

[frankiemenz]

I don't know as far as a pcm recall/tsb for this. I had almost the exact symptoms on my brothers 2000 Camry Le, 2.2 liter. The problem on his turned out to be the fuel pump/regulator assembly. He lived in Florida at the time and I was on vacay there and his pump assembly was easily changed from the back seat with the tank remaining in the car, simply remove rear seat cushion. I was able to make this determination by cranking the engine when hot(after a 15 minute or so off time) just a second and allowing the fuel pump to run, then trying it again for just a second and allowing the fuel pump to run again, since this doesn't prime with key on engine off like a l,ot of other cars, you have to engage the starter for a secong to activate the fuel pump, after this the car would start much more easily, like you said no problem starting when cold. There is no easy port to put a fuel pressure gauge on and the dealer pump, fuel press. regulator and cover, which they fit into, were very expensive parts. What happens is the fuel drains off past the check valve or regulator allowing pressure to drop and form a vapor lock on a hot engine, when cool the fuel would liquify and cause no noticeable starting problem, since it is a returnless fuel system the vapor has to push through the injectors and liquid fuel must re-pressurize the fuel rail. We bought a used fuel pump assembly from LKQ in Orlando and I put it in the car in his driveway/carport. This fixed his problem for $35.00, I am not a fan of used fuel system parts but the dealer parts were big bucks, @$600.00+. I figured for the used stuff we could make a cheaper diagnosis and then replace the cheap parts eventually if they failed with better quality new parts. HTH--Frank

[flowdam]

frankie- wow, I can't believe you found this post almost 6 months later. Thanks for your info and ideas though. Fortunately for me, this problem disappeared about two weeks after I posted this. Who knows maybe there was trash in the check valve. I'm going to put this info in the vault though in case this problem returns.I know I have an O2 sensor that occasionally acts up. I'll get a check engine light on maybe once every six months. I've had the code pulled and it says O2 sensor. Usually within a day or two it goes away so I've put off changing it. Still getting the same gas mileage so why bother. My check engine light wasn't on when I was having the hot soak problem though so I don't know if the two are related or not.