Topic: Sluggish on start up after tune

[lil goat]

Over on the other forum someone asked about why the GXP/RL's are sluggish until they get warmed up after pretty much any tune, even the GMPP. Martin from GMR decides he would answer the question, I have never gotten along with him but, that is another story, so I question what he posted, pretty much always do. I understood the issue to be caused by the cat being cold basically. I asked Lyndon. GMR posted it was a cam phasing issue that changes after the car is warm, while that is true it is not really relevant and certainly not the whole story as he never explained why. Here is what I got from Lyndon and I quote when I asked about the cam phasing and in general why this happens.

No...it's because of timing retard to get the catalyst temp up. first response

There 'is' a cam phasing table for catalyst warmup, too....but that's not the only thing that occurs. Second response Log the startup timing.

OK everyone got that!

If you have an HPT and are adept at using it and have a 2007 GXP or RL, log the startup timing, send it in and maybe Lyndon can fix this for us, he can do the 2008 himself.

So the bottom line, it is because the timing is retarded, CENSORED are you feeling the love.

For those of us with a catless down pipe like myself and SOB, and soon JM.  We should be able to eliminate almost all of this I hope.

[DeepBlueGXP]

Interesting.  I'll have to log mine as I see the same problem for about the first 30 seconds or so.  I can't hit hard until it has warmed up.

[lil goat]

It would seem even the folks with the pure GMPP tune see this, not sure much can be done on a car with a cat, but maybe, you know if anyone can figure it out it would be Lyndon.

[Critterman]

I have never noticed it, but I always let my car idle for 30-60 seconds on start up and then do slow pulls to 3k in 1st and 2nd until I get to the main road. I never mash the gas until the engine is up to temp.

[U4EA]

My 07 GXP has always done this, before and after GMPP Tune. Start it up, let it warm till BOV whistles, tap the throttle, idles down, put it in gear and chug down the driveway to the stop sign.

[lil goat]

I have never noticed it, but I always let my car idle for 30-60 seconds on start up and then do slow pulls to 3k in 1st and 2nd until I get to the main road. I never mash the gas until the engine is up to temp.

I don't remember it ever happening on my NA, but has done it ever since I put the tune on the car, obviously worse in winter.

[lil goat]

I just got a new tune from the Maestro, I will install it tonight and see what happens. It is a no cat tune but we may learn something that will apply more universally.

[BigSal]

I have a similar issue until car comes up to running temp, If I hit it (which I try not to do) it bogs down at around 3K rpm.  Thought it was just my car.

BigSal

[HAMMER DOWN]

I haven't felt no power loss when cold, all the power is their from start. With stock tune & GMPP tune. Like Critterman, I always let my car idle for 30-60 seconds on start up. 

[lil goat]

Stock tune there is no issue, some people see it with the GMPP, but if you let the car warm up, you won't see it unless you flog it really hard right away. I have a new tune we shall see in the morning if it is improved.

[LatinVenom]

My car never leaves the garage until the DIC reads 165 then it does not leave the driveway until it reads 180.
I do not have the problem, do to the above procedure.

[jonymac]

Hmmmmm... I had wondered about that - although (and I am sure I will be pummeled by the purists) I had attributed it recently to my Sprintbooster install...

I have noticed that the SB exaggerates the bogginess early in my drive cycle.  It takes a good couple of minutes - sometimes more - before I can properly feather first gear with the SB in place.  I will have shifted into first, eased off the clutch and try to accelerate with no clutch riding and the car begins to buck even though there is no clutch involved (embarrassingly so).  After 4 or 5 minutes maybe, doing the same procedure works fine - no bucking.  Maybe it is related and exaggerated in some way.

My catless DP goes in next week rather than this weekend (long and preferably non-public story...) so we will see if this affects the bogginess.  I had attributed it to me not being skillful enough with the clutch when I first got in the car - and have found that if I ride the clutch from parked to 1st to 2nd, I can get past the bucking problem without slopping coffee all over the car.  This also may be two problems superimposed - and the SB issue may be a new thread... 

Ahhhh... Just like a woman, when you think you have them all figured out, they throw you a curve ball - that is what life is about I guess - wouldn't change it for the world...

[lil goat]

I tested the newest catless tune from Lyndon today, it has far less sluggishness. I am pretty sure the Sprint Booster would make it worse, it amplifies the pedal position sensor signal, so the car would read more pedal and that is what makes it bog. It won;t get any better remove the cat as the computer doesn't know it's not there, it is still trying to heat it up. Lyndon is dealing with it in the tune for the catless anyway. By the way the latest tune has some new stuff in it WOW!

[baconbits]

"My car never leaves the garage until the DIC reads 165 then it does not leave the driveway until it reads 180.
I do not have the problem, do to the above procedure"..

If I did this LV I would leave the driveway till mid July...

[Sol Asylum]

"My car never leaves the garage until the DIC reads 165 then it does not leave the driveway until it reads 180.
I do not have the problem, do to the above procedure"..

If I did this LV I would leave the driveway till mid July...

Wow how long is your driveway?

Yes I know.... you live in Canada.

[KWhale]

Esay you crack me up man.  I thought I had a wise crackin mouth on me, and you could out do me in your sleep dude.  You should move to Canada!

[Sol Asylum]

I think I would get deported.

[KWhale]

You can't get kicked out of Canada!  If we don't like you, we make you become a politician, and then we vote for you because even though we might not like you, but you're still better than the other jerk that's running against you LOL

[G8TR]

Y'all should know by now how this is, LV and I both live in Florida. Start the car, wait 1 minute and you're sitting at 150 or more on the DIC already. Yesterday, going from Tampa to St. Pete the ambient temperature was reading 96*. It's only the first week in May  . We may be in for a scorcher this year.
I'm going to have to pack a heavy coat for Mecca. I see it's going to drop into the 50s at night. 

[Sol Asylum]

You can't get kicked out of Canada!  If we don't like you, we make you become a politician, and then we vote for you because even though we might not like you, but you're still better than the other jerk that's running against you LOL

So are you saying I'm a jerk?....That might be the nicest thing I have been called recently.

Actually I have been to Canada a few times, it was summer and the temps were much nicer then they are here during the summer.  However I would rather be here then in Florida during the summer its not the heat its the humidity that I hate.  Personally I'm not much for going to the beach and getting sun burnt I would much rather go hiking in the mountains of Colorado.  So instead I live in central Hellinois where there are no beaches and cow pies are the highest natural features within 100 miles, 95% of our roads are either straight north/south or east/west.  When I learned how to fly I never needed to look at a compass I would just look at where the sun was and what time of day and then look at the roads below.

[lil goat]

Well the newest tune from Lyndon for us fellows that hate cats is much better, I am sure it will translate over to the cat tunes soon, hmmm why did that last statement make me start humming a cat food commercial, meow, meow, meow, meow OK now the damn thing is stuck in my head.

[jonymac]

BTW Goat - although I received my catless DP late last week, I won't be installing it until maybe this coming weds or thurs night cuz (and I will never admit this in public on a forum such as this one) s o m e b o d y threw out the box with the $35 copper gasket that comes with the DP!  When I called to talk to Eloy he said he would send me another - should be here by tuesday-ish.  Hoping to get some emotional support, I said I bet this happens a lot - he said, "No, maybe 2 out of 100 times." Soooo anyhoooo.....

On the positive side, after talking with Eloy, I decided to wrap the DP and exhaust with DEI Titanium wrap and it should be coming in today too, so that's cool.

[lil goat]

I just wrapped mine in an a header blanket, and I didn't throw away the gasket, car should run fine until you get the tune, we need to meet up so I can read your tune and email it to Lyndon, so he can email the new one to DBG for the meet.

[jonymac]

How does Weds night look for you?  I could leave DC early - need to stop by one of our data centers in ashburn and could be home by 5:30ish. Dinner and beer on me!  How long does it take for the engine to cool enough to work on the the DP?  (It's my DD...)

[lil goat]

I think Wednesday is fine, I get off around 3:30 usually home by 4:15 I would not want to work on the Cat that same day, I always do first thing in the morning when it's cold, if you have the factory cat it can take a while to get it out, you have to jack the engine up. I will take about 20 minutes to read your tune for Lyndon. Then I can just email it.