What do you mean by smoothed? Did you use the actual smoothing feature like what is done in the timing tables? I heard that is a big no-no.

I have been using GMTech's cam tables for a few months now with no issue... until this little problem started.

 

My **** just got a lot worse.

Went to lunch and decided to retune the fuel trims again. This requires to unplug the purge solenoid to get it tuned correctly. I did so and there was no change in my startup issue.

BUT, this time I noticed a lot of white smoke out the exhaust as the car stumbled at idle. Smelled a ton like fuel too... White smoke leads me to beleive I may have a failing head gasket. Although there is no noticeable loss of coolant and I haven't checked my oil yet.

My theory is the head gasket isn't that bad yet... I think this because the car will run mint once it has started to warm up - pulls hard and true. However, I feel that once I turn off the car and let it sit, the coolant pressure is greater than cylinder pressure and a bit of coolant seeps into the cylinders. This, in turn, causes my rough stumbling idle and white smoke on startup.

I'm going to diagnose some more, but I am so pissed right now.

 

damn bro, i hope its not your head gasket, my buddy just had this problem on his sky redline, only had 5600 miles, head gasket failed, the dealership even fixed it under warranty with all his mods and tune!

 

I wonder if the dealer will fix mine

 

I spent the last few hours diagnosing my car and verifying if this is a head gasket or not.

I've come to the conclusion that it is NOT a head gasket.

I took out the spark plugs and they have some black soot on them indicating a rich condition. THEY ARE BRAND NEW... I think it's because something is going on in cold start up where the injectors are dumping fuel until the motor has idled for about 45 seconds. I found no vacuum leaks, no coolant loss, no oil milkshake, no bubbles in coolant tank and no more white smoke... it was just that one time I guess. Upon further inspection of the exhaust at this cold start, I see puffs of black smoke which also shows it's just dumping fuel until the engine idles for about 45 seconds. It's almost the same exact time every time.

While data logging, the MAF is perfect, the O2 sensor is perfect, the fuel trims are near perfect now, and I see the commanded as well as the commanded AFR once it enters closed loop... which makes me believe this is an open loop issue... I saw that the injectore pulse was about 2.0msec on first cold start up and the idle is rough.

Here is a video and a picture of the spark plugs.... I noticed my boost gauge would rise and hold towards 0 and then slowly come back down into proper vacuum. Maybe my wastegate is sticking? I'm going through things one by one at this point. I'm just relieved it's not a head gasket!




i don't touch the gas pedal at all... the car idles up and then stumbles all on its own. Then it levels out and idles fine after about 45 seconds.

 

Mine did this at cold start with HP tune and cat delete when I still had my cats on. I got retuned to a more conservative tune with cat warm up and bumped up my timing and my car idles just like it did when it was stock, 1400 to 1000 to 800 fully warm

Nevermind mine did not do that, when I had the cat delete it idled at 1100 to 1000 Wich made it feel like it had a cam but never went down like yours. That sucks man and also scares me when it comes to being tuned

 

Good news man, i hope you will find it, i see more and more people with this issue.
I got retuned today and asked Vince if he could look for anything weird, i told him about the problem, i sent the log and also made a log on idle , everything is fine from what he said.

Let us know if you find the problem, mine does the exact same thing, the small black puff on startup too.

 

Thats how mine sound... almost stall on worst day. (at 1:30min)

‪stock downpipe vs catless downpipe sound‬‏ - YouTube

 

What's your timing bumped to and where?

So he see's nothing wrong? Weird. I tried to look at my own logs and I just see it kinda hunting for idle for a few seconds.

Funny thing is, the car runs mint as soon as it gets warmed up a bit after the cold start. It pulls strong, everything is in line and it'll idle perfect after warm.

I'll keep digging to find an answer.

 

I think it's +12? I'm a noob when it comes to this tuning stuff but the guy who tuned me has tuned a **** ton

 

hmmm, must mean WOT timing. I thought you meant he adjusted timing at idle enough to rid the problem.. But I don't know how that could work.

 

ohhhh my bad, ya its at wot. if you think it came from the tune just throw your stock tune back on, if you saved the file and if its still acting up bring it to the dealer

 

The log was when the car was warmed up unfortunatly...

 

Alright if you have been tuning your car i am assuming you turned off CAT..... Which will cause the car to idle hunt and ect.. You need to tune the cold start timing for cat warmup and ect.!!! If fuel trims are staying wacked out do this... With your maf correction factor map just make it all 1s again and from there log and collect your data and do not change your maf correction just yet. Do it the second time or third and when you do it multiply the data you collected by 50% and the second time you data log for the maf correction multiply it .25% using your excel sheet and ect. and from there the trims should all get back to where they should be! Now you also need to transfer the data from stft/ltft*maf and ect so dont forget. You can do the stft/ltft* maf the same way as maf correction 50% then 25% and so on and so forth! It works for me great!!

Now if you do this a trims dont get back to-3+3 then look at your sensors. TMAP, MAP, LOOK FOR BOOST LEAKS, AND ECT!!

 

I'm tuned for CAT warm up delete. It's the same tune I've had for months. My fuel trims are perfect right now. Variations are within -5 to +5 on STFT's and my LTFT's are pretty much 0.

This is either that stupid evap sensor again or it might be mechanical with the wastegate sticking on cold start... but that one seems a little out there.

I can start the car up tomorrow morning and data log it and post my tune with the data log so you can see whats going on.

 

Well do this change ure cold idle to 1500 and progressively make it come down to 800-850 for a idle at 160 or whatever it is. And see if this helps..... If not then the tables fletch is using isn't working to great for the cat warmup delete....

 

I just saw this now and am at work already. This morning was the worst and I have it data logged. I started it up and it would stall a few seconds later. Tried it again and it stalled. I think I let it stall 3 times before I finally gave it some throttle to keep it running. I'll send you the log and tune as soon as I can. It's all on my laptop and I have no wifi at work... I'll have ot tether my phone at lunch.

As far as the tables I'm using, they've been working perfectly for months. I don't think this has to do with the tables and if I increase my cold start idle anymore, then I feel I am just masking a problem. How could it go from working perfectly to not over night? And I don't want my idle that high, it was the whole reason I disabled the cat warm-up lol.

I feel that when I seafoamed the car, that might have done something. I seafoamed it last friday after work. I did it step by step how I've always done it and it's the same way you do it in your write-up. The next day, I changed my oil, spark plugs, front O2 sensor and cleaned the MAP sensor. It ran fine for a couple days and then I was about to tune my fuel trims and I'm at where I am now.

I've set the thing back to stock and it still does the stumble and stall at cold start up. It is NOT the tune. Something mechanical is wrong. But I'll send you the tune and log and you can take a look if you want.

 

In addition, I even went as far as thinking it could possibly be bad gas. I ran her almost completely dry last night and filled up at a new station, drove it around for 70 miles and it STILL did this.

 

If u had seafoam still in the intake when.you.turned.it.off it will tarnish.the.intake thats why.it.all has to be burnt out. So if it.all wasnt out get u some distilled water about a half quart and.suck it up like u do the seafoam. Reasoning for this is it steams and.cleans so try it out and.let me know if it works.. What did u clean the map with? Because a bad map will cause.ure.issue.... It might.not even throw.the.code.....

 

I'll give the distilled water a shot too... I'll get her screaming hot first to get the "steam" effect... gotta be super careful as it's water

Nick also suggested to turn the cat warmup back on... I'm going to do that first before anything else.

I cleaned the MAP with MAF cleaner. Nothing more safe for electronic sensors than MAF cleaner And it' still good. It reads correctly and boosts perfect. Before, when my MAP would go, the first indication was that it wouldn't log boost in my HPT. Then it would set a CEL along with weird boosting issues and such.

So next steps are:
1) Turn cat warmup back on - If that doesn't work then, step 2.
2) "Steam" the intake (VERY carefully) - If that doesn't work then step 3.
3) Inspect throttle body, TPS and wastgate rod - If that doesn't work then....



4) Set it on fire

 

i havent personally messed with the cam tables myself so i cant tell you what exactly was done but got some from another member, and as soon as i did that all my problems went away. Also i didnt have any issues when cat warm up was on so i just always had it on but now that im on e and have those tables i just turned it off. My car was never like the video you poseted though it would just feel like it was about to blow up when it cold started with cat warm up delete lol, it would just drop rpms liek it was gonna stall and then pick back up.

 

This thread has gone completely over my head haha. Keep us posted if you find anything out. I'll try and record my idle tomorrow morning. I Forgot to this morning. curses

 

So uhhh... My problem is fixed.

Went out there and enabled cat warmup... didn't work.

I then took apart the BPV, removed the MAF sensor, MAP sensor, removed the brake booster vacuum line, spark plugs and then retightened my O2 sensor.

I sprayed everything down with MAF cleaner and relubed the BPV. I put everything back together and flashed the car back to a stock tune. THE IDLE WAS FINE!

Flashed my old tune back onto it and THE IDLE WAS FINE.

So, with removing and cleaning everything I could get my hands on, I did something. I don't know if there was a loose connection, vacuum line, if the BPV was sticking or WHAT, but I no longer have the problem anymore!

 

Good to know!!

Ill try the BPV first, mine sound weird with the K&N intake, that may be the problem.
Thx for sharing your progress ill let know if that solve mine too.

 

Any more specific solutions for these problems? I have the same one and I just cleaned all the sensors with no fix??