Cheetah

I have a 2005 496 HO with a whipple. Runs great at high speed and high rpm. However when I idle for any length of time and try to take off it chuggs and puffs black like crazy. Once it is cleared out, It seems to run better. It has below water exhaust so I had whipple put a custom tune in which has not fixed it. I also routed the exhaust above water with a secondary 3 inch pipe that taps into the main 4 inch exhaust to try to help it breath. Not sure I am even on the right track. Any thoughts? Anyone have a used scan tool they wanna sell? I can't take this to a dealer. I am afraid they won't know where to start with the whipple installed. I have confirmed fuel pressure. Tps voltage and replaced the iac because it was cheap. Still has the same problem. Advice appreciated.

mike tkach

iTrader: (3)

maybe the injectors need to be cleaned,they can be checked and cleaned fairly cheap.

Black Baja

iTrader: (2)

Take it to someone that knows how to tune it.

TooLateVTEC

iTrader: (1)

If the fuel pressure is fine chances are the fueling at idle is too rich.

I take it the blower was just installed? If it was, the tune needs some work.

Cheetah

Is there a procedure for adjusting the blow off valve on a Whipple. There is an adjustable stop and a linkage but I have not messed with that _ (set at the factory) Just curios if it is opening and closing when it should. Any ideas?

TooLateVTEC

iTrader: (1)

Do you have a vacuum/boost gauge in the boat?

If so and the engine has vacuum at idle and its making boost then the valve is working fine.

If not, you can get a gauge cheap at the parts store and stick on there to check the vacuum, but I don't think that's your problem.

What really needs to be done it hook a wideband o2 to it and see what the AFR is at idle.

What kind of regulator is on it? Maybe you have the vacuum line for that in the wrong place and its causing the regulator to open at idle, raising the FP and causing it to load up?

pqjack

I had too much water going thru the intercooler at idle...it made the intake run too cold, telling the computer to run richer...i put a restrictor pipe in the intercooler feed line....voila!

abones

Agree with pqjack had the same issue after long idle times!

Cheetah

Thanks for all the help guys. Latest info. I changed plugs and confirmed one was actually fouled. It runs better but still really rich on idle. I am going to tap into the risers with O2 sensors. I can weld the stainless bung ports on no problem but I am a little green on the use of the fuel air reading tools. I have found many wide band kits for automotive but do I need something special for Wet exhaust? Anyone have a brand or part number they would reccomend. Also, I don't really need it all the time. Just looking for something to provide data for my tune. It looks like roughly $150 per side but let me know if you have a less expensive option

Also, PQJACK, I've heard the same things about cold water through the intercooler at idle. That makes sense as I am in WI and the water is much colder than many of you have to deal with. DId you use a low pressure valve that opens once the RPM builds or just a reducer in line. I'd like to try that first but have concerns restricting flow at high RPM. Let me know what you used. Thanks for all the help guys. Greatly appreciated.

Young Performance

We will force feed the intercooler with a transom mounted pickup. That way, it only gets water to it once the boat is on plane. There is really no need to put water through the intercooler at idle. That Cupro-Nickel intercooler is very efficient, so it will really cool the intake charge. This is especially true this time of year up north, where the water is still really cold. You can cool the charge so much that the fuel wants to come out of suspension and form droplets that will puddle in the intake.

Is this a new install? Has this been a problem since it was installed or is this a new problem on a previously installed supercharger?
Eddie