Behavior after DOD swap and cam upgrade

[JKaechler]

So, This past week we did the DOD cam swap on my Tahoe.
lots of hard work but it idles smooth and has a small lope as hoped for.

I used the Comp Cams single bolt cam that keeps the VVT
Camshaft Specs: Dur. @ .050" 214/228 | Lift .559"/.571" | LSA 114

Oil pressure from a new pump is slightly higher than before, and of course the new green o-ring on the pickup tube.
All seems to be well after the first road test.

here is the question:
When you are sitting still in drive, with foot on break it idles fine. when you take foot off brake, it gently accelerates up to about 1500rpm ish (not positive on the rpm here) and then it calmly shifts into second gear. None of this is done with any drama, and it leads me to believe that its either some kind of re-learn thing or maybe a transmission computer adjustment is needed. maybe its just that much of a power difference.

Has anyone experienced something like this?

My last step will be to do a datalog and send the info off to BlackBear for a final tune. Maybe that will address it.

 

[Dustin Jackson]

@JKaechler Never heard of anything like this. So without doing anything your tahoe will go fast enough to reach 2nd gear?

 

[JKaechler]

Yep. My current suspicion is that the BlackBear 'startup tune' for a new cam has the in-drive idle set pretty high. I will be sending them the datalog later today anyways.

 

[Dustin Jackson]

@JKaechler If you are in the middle of the tune with BlackBear I say work with them on this and then come back here if the problem isn't resolved through them. If you do fix the problem please update your post here in case anyone else has this problem we can tell them where to start looking.

 

[RVTSP21K]

I'll probably get flamed for this since everyone here is diehard BlackBear but, don't count on a mailed tune. Sure, it's a great baseline but, find a local GM tuner and get it on a dyno to perfect the tuning. There is no replacement for a tuning expert watching live data and adjusting YOUR Tahoe's parameters accordingly.

 

[JKaechler]

I'll probably get flamed for this since everyone here is diehard BlackBear but, don't count on a mailed tune. Sure, it's a great baseline but, find a local GM tuner and get it on a dyno to perfect the tuning. There is no replacement for a tuning expert watching live data and adjusting YOUR Tahoe's parameters accordingly.

You are likely technically correct.... however. there are a whole load of practicalities that make BlackBear a better option.
- what local GM tuner? There appear not to be any in rural central texas
- sending files too and from BlackBear does not require me to take time off work (which i already had to do to rebuild the engine)
- BlackBear is a known cost. Easier to plan for than a shop who may or may not tack on extra charges because they need to make the payment on their boat.
- It gets the job done. I am not looking for some kind of razor edge performance perfection. Just a bit better than stock is ok with me.

Thats just the top-of-mind response.

 

[Charlie207]

I'll probably get flamed for this since everyone here is diehard BlackBear but, don't count on a mailed tune. Sure, it's a great baseline but, find a local GM tuner and get it on a dyno to perfect the tuning. There is no replacement for a tuning expert watching live data and adjusting YOUR Tahoe's parameters accordingly.

I've yet to find anyone near me that will even respond to my emails. Imagine having a hand full of $$$ and people just ghost you.

 

[Geotrash]

Yep. My current suspicion is that the BlackBear 'startup tune' for a new cam has the in-drive idle set pretty high. I will be sending them the datalog later today anyways.

This was not the case for my new cam startup tune from Blackbear. I suspect either a different cause or an error in the tune.

 

[Geotrash]

I'll probably get flamed for this since everyone here is diehard BlackBear but, don't count on a mailed tune. Sure, it's a great baseline but, find a local GM tuner and get it on a dyno to perfect the tuning. There is no replacement for a tuning expert watching live data and adjusting YOUR Tahoe's parameters accordingly.

I've had three GM large SUV's tuned by them and they did a great job, so that's my basis. One of those required three different tunes for three different cams, and they did each of them perfectly, such that they ran exactly as I'd asked for (.e.g lope, no lope, etc.). Part of the Blackbear process is to capture 20-30 minutes of live data through a range of prescribed driving scenarios, which allows Justin to play it back and set up the tune from the data. One could argue it's better than a dyno because it's a sample from real driving on real roads, which more closely matches the reality the vehicle will be driving around through.

 

[RVTSP21K]

You are likely technically correct.... however. there are a whole load of practicalities that make BlackBear a better option.
- what local GM tuner? There appear not to be any in rural central texas
- sending files too and from BlackBear does not require me to take time off work (which i already had to do to rebuild the engine)
- BlackBear is a known cost. Easier to plan for than a shop who may or may not tack on extra charges because they need to make the payment on their boat.
- It gets the job done. I am not looking for some kind of razor edge performance perfection. Just a bit better than stock is ok with me.

Thats just the top-of-mind response.

I completely understand where you're coming from. My post was just from personal experiences that I am still salty about. Not with BlackBear, but with a very well known Ford tuning company when I did some performance upgrades to a Mustang I had. Everyone swore by this company and their tunes. Well, their "Max-Performance" tune (written for my mods) was so pig rich it blew gasoline out of my tailpipes and made 175 whp on a dyno.

 

[Marky Dissod]

When you are sitting still in drive, with foot on break it idles fine.
when you take foot off brake, it gently accelerates up to about 1500rpm ish (not positive on the rpm here) and then it calmly shifts into second gear.
None of this is done with any drama, and it leads me to believe that its either some kind of re-learn thing or maybe a transmission computer adjustment is needed. maybe its just that much of a power difference.

Has anyone experienced something like this?

My last step will be to do a datalog and send the info off to BlackBear for a final tune. Maybe that will address it.

By the way, I have this exact same problem with my BONE STOCK '02 Tahoe; it behaved this way before the tune,
and my tuner was not able to ameliorate this odd behavior with the tune despite several attempts. In other words, it may not be the tune?

Drive normally in such a way as to make the fault-behavior more likely to present itself,
so BlackBear can get the relevant data.
If the behavior presents itself during a very-cold-warmup, show him that too.
If it only presents itself once fully warmed up, then just show him that.

Forced to guess, I'd clean the MAF, IAC ... you don't have an IAC ...
clean the throttlebody, then recalibrate it ...
Is your engine FlexFuel-ible?