Car: 2004 Z06 w/ 16,000 miles (~2,000 miles on new cam)
Mods: Longtubes; no cats; Magicstick 4 cam kit & custom tune from TSP
Problem: Every start is rough and sometimes dies
Cam: http://www.texas-speed.com/p-1153-te...-camshaft.aspx
Tune: Mail order from Texas Speed for my setup & cam

UPDATE: After good forum feedback I will be taking it to get a custom tune @ West Bend Dyno in Wisconsin. I will post additional updates next weekend

VIDEO - hot start, no throttle, no AC, 74*F ambient:
What I've tried so far: Checked for vacuum leaks 4 times (engine running +felt for leaks). Removed and checked entire intake system for holes or lose clamps. Checked MAF & Throttle Body - clean and undamaged. Checked DIC error codes - No PCM codes (only some traction and abs codes). Checked every electrical connection I find. Finally called TSP for advice, they want me to mail back the PCM for re-tuning.

Detailed problem: Every time the car is started the car has a hard time idling and sometimes dies but after about 15 seconds will adapt and then will run OK from then on most of the time. Outside temp doesn't matter, car can be cold or hot - every start even repeated starts after good idle is attained. Clutch starts or neutral starts doesn't matter. Using throttle helps but takes much longer to attain good idle (1-2 minutes sometimes). Sometimes while driving car will not come to an idle and battles to keep running at stop lights (usually when car is stopped). Sometimes when shifting up will also nearly stall. Also there is a pretty heavy fuel odder from the exhaust after every start, might be OK since no cats. Oh and if I try to start it with the AC running it dies every time without some good throttle.

My thoughts: I know it is a huge cam and expect rough idles and some cam surge, but this is not normal - I've had LT1's with cams almost thing big and didn't have any idle issues at all. I spoke with TSP and they just thought to check for vacuum leaks otherwise send PCM in for re-tune, I want to save this as a last resort since it causes long downtime and really don't see how they could have miss-tuned the startup idle so bad but rest of the tune seems pretty good.

 

What is a huge cam? Specs?

And idle and drive ability is all tune. ( if there is no mechanical problems) Enough time and know how can make a monster solid roller drive like a Buick.

Check the pcv system and if it hooked up correctly. If I read right you are sending the ecu off to be tuned? Mail order stuff is a joke. Go to a good tuner and have them do some street tuning.

 

It is a Texas Speed Magic Stick 4 with their tune to go along with it... http://www.texas-speed.com/p-1153-te...-camshaft.aspx

 

Go to a real tuner man...skip that mail order crap. That cam is decent size for a 346. Get some street tuning done. Any good shops around you?

 

Would probably have to go to Chicago area, about 2.5 hours away which is doable. I will seriously consider doing that if I am sure I've ruled everything else out.

 

Thats a lot of cam for a mail order tune. Its never gonna drive like a stock car(for better and worse) but it shouldnt be too tough to clean that up assuming all is good mechanically. Had some similar issues with a g5x2(good bit smaller)...tuner cleaned it up in a few minutes.

Fuel/exhaust smell is part of the game with that kind of overlap and no cats.

 

I have the MS3 in my car. The first time I had it tuned it took my tuner a good hour and a half to set it up. I had a some problems like you're having afterwards and he tuned on it some more about a week later. Now the car runs great. I bet you can solve your issues with a custom tune. It takes some skill and some time for a tuner to get a big cam running well.

 

You have to have a dyno'd tune!!!

 

I have the ms4 in my 04 z ce too. Awesome cam drives pretty Dame good to for a big lumpy cam. But get a dyno tune not a mail order tune. Make sure they are a reputable tuner as well and do a street ability tuning after dynoing the car. Good luck

 

By the way that cam is a stinky smelling cam especially if you don't have cats. I have cats on mine. And on cold start it stinks up the garage. It's not tune related either just the nature of that cam.

 

Thanks guys for the feedback!

I feel much better about going and spending $400+ on a custom tune now. Not sure if i'll get to it this year or not since I may want to do a few more mods over the winter.

I'll probably let this thread go without updating it with the solution if I wait that long to tune it

 

Definitely need to adjust the tune. Your idle airflow is probably screwed up. The ac issues can be resolved in the tune as well. You need to have a few parameters modified to account for the big cam.

 

Yep, big cam needs dyno end and street tune.

I talked with Doug at east coast and he said he could do a mail order tune to get my car to a shop for a decent tune, as cam goin in my car won't even start once cam is in, Lg gx3.

 

OK, between all the help you guys gave me and the crazy annoying start idle I have gone ahead and setup a custom tune appointment

Next week I drop my car off @ West Bend Dyno in Wisconsin for a few days of tuning, likely ending in a $650 bill I am hoping for an end result of 430+rwhp w/ a MS4 cam, CAI, LongTubes & no cats .

Spending this weekend changing spark plugs and going over the car. Will post results next weekend when I get the car back.

 

Good deal bud. Just to give you a comparison mine made 435whp and 394 torque. Then with under drive pulley ported fast 92 and ported ls2 tb it made 452whp and 393tq and I'm out of injector now.

 

TUNE!!

Good job checking for leaks - this is always good to do. My car had/has similar issue; needs tune.

One thing I did that helped a lot was to slightly enlarge the idle hole in the throttle body blade. Caution: this is considered 'bad form' and 'shadetree' by many. However it reduced my engine's surge/dying @ stoplights by 80% or more. If you mess up it's a $20 plate, no biggie.

The 'right' way to do it is still a tune.

 

With MS4 cam & stock LS6 heads?

 

Yes sir . 1 7/8 arh headers catted x pipe too.

 

 

Sounds right on par with dyno tuning cost. When you go there make sure and let them know what you are looking for. Communication on your part will help ensure the best tune. I would also ask if there is any warranty per say. Will they do adjustments for x amount of days after the dyno? You want to make sure you can bring it back if it needs some minor tweaking.