J-Rat

iTrader: (2)

So, many of you are aware of the FC hot start problem. Basically, you drive your car for a while till its nice and hot. Then you go into the store for some beer or whatever. Come back out, and BAM! You are flooded. But if the car sits for 3 hours or so, its good to go.

So you try to get the injectors cleaned.. No dice. Then figure your engine has low compression, so you test it.. Compression is good. So what gives?

I had chased this problem for ever, with little success. I had online conversations about theories surrounding this phenomenon. Leaky injectors, low compression, etc...

Then I installed a Haltech.

I was worried the entire time about the Haltech install, because once you put a Haltech in, deflooding becomes a new issue. But this car has NEVER flooded since then! Not once!

So has anyone given any thought to the "hot start" being a fault of the ECU?

Food for thought..

Rat

Icemark

actually (as I have posted many times) the ECU is the problem in about 10% of the hot start cases. There is also a well documented transistor swap for a fix on the other board.

Also more common if a test light has been used to test any underhood sensors or ECU outputs.

dennis blackstone

i had the same problem,ibought brand new injectors from marren motorsports in derby ct,my problem was solved,but i still think its the ecu,

Icemark

You put in new injectors and the problem is solved and yet you still think think it is the ECU????

Man, you make me laugh out loud.

Even more so when we all told you that the injectors would be the first thing to try and you claimed it was not the injectors.

J-Rat

iTrader: (2)

Ah, sorry icemark, I wasnt aware that you had already postulated this. Good info!

nataku

do you guys think the ECU could be attributed to my hot start problem, it's a little different than J-Rat's:

if I start the car and drive around, for any distance, and then I turn off the car, then:

a) let the car sit for a short period of time, 1-30 minutes (it varies), then my car starts fine right after. Infact it sound really strong when it starts, and the RPM's shoot right up (as it's supposed to w/ the cold start assist)

b) let the car sit for a longer period of time, 0.5-6 hours, then my car will be flooded and have problems starting. (But it will almost always start if I give it some gas, I'm pretty sure that's because of the auto-deflooding system for an S5)

c) let the car sit for a long period of time, more tha 6 hours, then my car will start up almost every time, except, it doesn't sound very strong when it starts. (the RPM's don't shoot up to 3-4k, more like creeps up slowly at 2k)


I've done searches for this and didn't find anyone with the specific problem I had. Most people had the same problem that J-Rat has where it floods when you hot start. But as I said, mine starts up fine if I do a really quick hot start.

This problem has been here even before my engine was rebuilt, so I know it's not from low compression, and I've gotten my injectors cleaned, but to no avail. I'm going to replace them soon, probably within a week, and I'll let you guys know the results, but I never thought about the ECU being the problem, does this sound like a problem that could be attributed to the ECU?

Razmus

iTrader: (2)

what do you guys mean by a "hot start"? as i was reading, i realized i had the same problem. what should i do? should i clean my injectors?any help would be cool. thanks.

nataku

a hot start is when you start your car when the engine is already warmed out (so while it's still hot)