So guys I have had this issue for a while now. It first happened at the dragstrip last year after having my car retuned on e85 (stock turbo)

I would somewhat launch the car, and after a hard shift into 3rd gear the car falls flat on its face for about a half second then kicks back in.

I can NOT get to the bottom of it.. I've changed the plugs, gapped and regapped them. Checked for disconnected hoses, etc etc etc.

I had the car retuned with my new turbo setup a few weeks ago and was hopeful that maybe it was a kink in the tune that got worked out.

Well it happened again the other day. and it hurt my E/T really bad at the track last time so I need to get it figured out.

Any ideas? I am still on MAF. I have a turbosmart dual port bov. Could that be causing an issue? I haven't heard of any of these bovs causing things like this..

Here is a video from the track last year that best shows it. Keep an eye on the 2nd - 3rd shift.

 

Your car has a the Tephra No-lift-to-shift patch?

 

No I don't have that

 

bump?

 

Dang. Over 350 views but no luck.

Guess I'll start by swapping back to my oem 9 dv and see how it does

 

You could be setting off the knock sensor and it pulls timing if it sees knock. Do you have a datalog?

 

Could be an issue with the throttle cable as well. Through I'd suspect it happen in all gears you never know

 

I don't have have any logs unfortunately. My tuner is about 2 hours away but he said he looked through the tune and found nothing that should cause this

 

How can I rule that out? Throttle cable itself looks good just from the top view however I guess the end connections or something could be what you're talking about?

It's only a 50k mile car

 

Need some suggestions! I'm lost. It's so frustrating. I can't get a clean 1/4 pass because the hesitation cuts literally a half second off the e/t.

Am I wrong in thinking the 50/50 vta/recirc bov could be causing it? Because whenever I mention that nobody really responds

 

It is possible that the 50/50 is causing the car to run rich and bog. The system assumes there is a certain amount of air in it and puts in a pre-determined amount of fuel. Less air than assumed = more fuel = bog. Not sure why it would only be happening in 3rd but I would definitely switch to the full recirc DV and see if that helps at all.

 

Okay. I have a forge recirc dv and my oem ix dv (not crushed). I guess I'll throw the forge on there and see if I can make it happen again. Just hated how much the forge fluttered lol.

Thanks though!

 

What happens if you just do a 3rd gear pull?

Also, is it doing this after every hard shift into 3rd or only sometimes?

 

The car rarely does it. It only happens after a long 1-3rd or 4th pull. Or so it has only happened that way thus far. From a 3rd gear pull its fine.

 

Very strange indeed. I dont really have than many great ideas for you. If there was something knocking around the car would pull timing but it would still pull smoothly albiet feel like its way down on power. What yours sounds like is a misfire almost.

Whats the deal with the DV? If you have a couple others to try out I'd go that route for starters. Maybe the thing is sticking sometimes frmo a quick shift and it stays open and thats causing the bogging? IDK man purely speculation. But start eliminating variables.