I have to say that painted one hell of a picture :D

 

forgot to mention that fuel pressure and spark were checked early on. fuel pressure was also checked overnight and at time of start-up.

I'm not saying cat was the problem. In fact it really isn't. It appears that answering this post and responding to a grease monkey jinxed me.

issue occured today...after several months. blast you scionlife! I suppose this is an omen for the rest of summer until September..more on that prediction later.

I am experiencing the same issue as tc4italy, and the same as the guy in CT and TX...

so again for the folks suggesting to check this and check that...here is the friggin run down again. Without talking first hand with t4italy i would be willing to bet dollars to donuts she has the same issue:

1. A/T
2. S/C dealer installed
3. My car it seems only had the first flash and not the A/T flash done by the dealer..learned this 4 months later. Had the second reflash done and no fix to cold start issue. (special case for me I suppose...but possible red herring since 2nd flash is supposed to be shift point related...and as you will see later, ECU was eliminated as issue).

4. With warm weather (> 45 degrees), car will stumble on first start. Full lights on the dash, voltage good on battery. Crank it again and she fires like no problem and like any other day.
5. No Codes.
6. No idling issue once running.
7. Car must sit about 4-6 hours until you experience the issue again. Could be overnight...could be all day..key here is either relative climate or humidity...this is not a "cold weather" issue. In the winter this does not happen.
Essentially engine has not had a heat soak from long running but ambient temp is warm enough that car gets to operating temp with seconds. That's why this problem will go away as it eventually gets cooler in the Fall/Winter. If this was pure heat soak related I might be tempted to say head gasket..

8. "Priming the pump" with key to acc prior to ignition DOES nothing.
9. While dying, feathering the pedal MAY allow start up (99% of the time) without having to recrank. As priming does nothing it seems that fuel is not needed here...maybe air.

So tc4italy can tell me what I got right there.

Let's get to the suggestions...and while intended well, I will dispel these AGAIN.
1. For the folks suggesting the MAF and throttlebody...I had both cleaned, and then both replaced.
2. Battery replaced..But if the battery is dying it will NEVER start the car..so scrap that idea. Even still, the battery doesn't decide to give you a second chance. If it won't start, it won't start. The first attempt doesn't "charge" it.
3. ECU replaced and reflashed. That should take care of the "was it the missing flash question" i guess
4. Spark plugs checked and then replaced
5. Compression test (mostly great, one a little high), only told us that there was another problem with the cat and it now appears this was a red herring.
6. Fuel pressure, as mentioned earlier checked.. And if fuel pump was going I would be seeing other.
7. O2 sensor checked
And no cold start plug on the tC to check.
To engifineer, switching A/C when idling provides no change in behavior.

At 20k miles and this whack-a-mole approach by the dealer I had more swapped out on this car so parts either were or now are CLEAN. Nothing to really clean on the TB anyway. And the fella in TX had his entire S/C replaced but his problem reoccurred. Only thing had me scratching my head was he is 5 speed...
Oh yeah, and not like I had carbon buildup, but seafoam didn't do anything either.

Dealership threw up their hands after that. Third party mechanic said the next thing to do was to leave the car overnight and when they try to start it up have it on a computer and check hydrocarbons. But got tired of leaving the car overnight and then magically fall appeared...

I may just have to go this route, but since you only have 1 shot to see the issue and you have to wait 6 hours to get lucky...it's tough.

Since we have 4 known cases with nearly exact same setup I can only surmise this is a result of incorrect cold start map provided by TRD reflash. It's a stab, but it's the only thing we really have in common.
Other than the CPS there aren't many other sensors to check on this car so it's pretty f'n puzzling.

 

it must be the reflash because whenever my car first starts up the idle starts and stumbles at 500rpm and then increases to about 680rpm. im guessing its the way trd flashed our ecu to do this. car used to stall but cleaned throttle body, hasn't stalled since. drive an AT 2006 dealer installed s/c.

 

UPDATE: https://www.scionlife.com/forums/vie...258&highlight=

 

Hi, did you get this fixed? I am having the same issue. I just took my car back to near stock from a turbo kit. I have the problem of having to pump the gas while turning the car on to get it to start. I have to do this every time i start the car, but it takes more pumps of the accelerator when i have left the car for a few hours or overnight. I have taken it to the dealership twice and they say i might need new plugs. I use bosch platinum fusions as of this moment and have tried many in between. The tech guy that i spoke with said that scions are rated to use denso iridiums with a double electrode. Have you had issues with their spark plugs or something similar.

 

Defiently go back to stokc plugs...they are as good as it gets really...

check the updatedlink

On a side note....dont call yourself a tech if you cant diagnose problems at least across one manufacturer....Im not even ASE certified, and i work on my scion, my chevy, my parents chevy's, my friends Ford...

granted it is hard to work with "it wont start"....but its your job to help these idiots that dont know a spark plug from a crankshaft...if you dont like it, i suggest a different profession

 

Nope, issue is still there but car is running lol
Everything has been documented

 

I appreciate the advice, but i didn't call myself a tech, I do work on my own car and used the current plugs with my turbo kit for a while and this is a recent issue. i just asked if anyone could reply with advice. I have tried multiple plugs and have similar problems. If scion tcs are meant to have just one type of plug then it should be implied when we go do a tune up and purchase plugs and you have so many options.

 

hm.......... interesting!!! i dont have s/c but IHE and my idle is BAAAAAAD rpm goes up and down between ~400-700

the car died once today when i was rolling backwards

 

Hi, i have had this problem with many vehicles, typically warrants fuel injection service, which is easiest done with Sea Foam- an engine detergent/degreaser that can go in the gas tank or through the vacuum line between the vacuum switching valve and the throttle body. Just let the vacuum pull enough liquid into the throttle body because if you do too much the car will stall. Over the five minutes you do this the car will produce a lot of smoke. After u are done turn the car off and let sit for 5 minutes. Turn the car on and go for a drive to get rid of the smoke or just run it at high rpms before you get on the road. Good luck.

 

thx for the info! if i put it that in the gastank my car will produce smoke until i empty my tank?

 

^
no, just for the first few moments of burn. Then it diminishes.

 

cool

can you send me a link what do i need.. tried to find something in google but im not sure what do i need to look for

is this that STP engine cleaner what they sell in most auto stores?

 

Actually it is a white cylindrical bottle found in most auto part stores. It is called Sea Foam. The directions for doing what i told you are implied on the side. You can put it in your gas and it cleans your injectors . If you put it in the vacuum line it will clean the valves. I usually do this myself after every oil change. It is around 13 for the two bottles, much cheaper than the 80-90 dollars you fork over to do it at the shop. Good luck- Discount auto parts, pepboys and auto zone should have this product.

 

my apologies for that coming off as an attack towards you...\


well, hope this eventually works its way out...

as for stalling while rolling backwards, i have done that once trying to back out too quick...

 

had engine check light come on so i took it to dealership (I knew it wasn't because of the oil cap). They said it's due to my busted front catalytic converter not properly 'detecting' oxygen/fuel. So....maybe once that's fixed the stalling will go away?

 

I noticed from you tcitaly, and jetlounge that both of you have 2006's. This must be a problem with the first generation of tC's. Is anyone having this problem with their 07 or 08?

 

Most of the S/C issues were sorted out when they changed the S/C for 07+.

 

Claudia.. can you tell us exactly what code they said it was? The reason I ask is becase the cat doesnt detect anything.

The 2nd O2 sensor detects a difference in emission components after the primary cat (the cat built into the header). If the code was related to that, it can mean that that cat is not doing its job, or that the O2 is no good.

 

cold start...I would think its the flash. I know that you need to squirt a lot of fuel for the ignition to take. Maybe that was ironed out in the new version.

Solution #1
aftermarket ECU. Have a tuning guru give you a flawless tune.

Solution #2 (maybe)
an engine block heater. I dont know what temp they bring it to , but it might help those cold starts. See if they have that option for the tundra/taco/titan and have them install it in your car.

Sorry girlie I wish I could help out more.