65mojoe

I just swapped the inlet tube on my vortech mongoose kit to a 4" boost pipe from MPH. Now in the mornings on first fire up, when I come to the first stop leaving my neighborhood I am getting a very strong surging effect that lasts for about 3-5 seconds. The rpm's will drop down to almost stalling and then jump back up to idle (~850). It will do this about 3 or 4 times and then it will level off normal. Has anyone experienced this before?

**car is a 2004, s/c is the vortech v2-sq (mongoose kit)

RuffCat

My car has done that even after going to the dyno and getting a custom tune. It does it on clod start-ups regardless if it's 80* outside. First time start-up on a cold block it has done it since day one. I have a Steeda Powerpipe kit.
It moves more air into the supercharger and it causes the MAF to have a different reading so it causes the injectors to pulse fater for more fuel and in turn it gives too much and that's why you experience the dying effect because it gets loaded up primarily due to the fact that on cold starts the ecu promps the car to run rich until a certain temp!

65mojoe

Thanks for the reply. I figured it was choking on too much air, never thought about it running fat.! Now that you mention it, ever since the powerpipe install, i've noticed a richer smell in the morning on startup. Thanks and glad to hear im not the only one.

RuffCat

Yeah, my car was stalling on the way to the dyno session. He did the best he could to make it run the smoothest however, the car is always warm-hot when it's strapped down. I'm sure that the car would run into problems if he corrected that for cold starts which would most likely lean it out on hot runs at idle. My idle is pretty choppy for th first 10seconds and then smooths right out. It'll surge for the first few mintes if I take right off and pull outta my garage. After that time has passed, runs like a rapedate and idles super smooth! It's a small price to pay to gain from midrange-top end. I bet you can actually feel it pull noticeably harder!

jbors1

its all normal

mylongvictor

Thats wha mines does.... Then again I need new ignition coils and spark plugs....

lizzyfan

Did you move the position of the MAF??