Hesitation During Acceleration - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

WhoMadeWho · 08-16-2011, 01:42 AM

Hey guys,
Here's my situation. I had an LS3 376ci with an upgraded cam and Whipple SC in my 2010 Camaro. It ran great until an exhaust valve dropped and tore up the engine. So, I had Livernois build a stroked LS3 with forged internals and better heads as a replacement. The engine went from 376ci at 10.7:1 to 419ci at 9.7:1. The cam profiles are the same except the new motor has a narrower LSA of 114. The other change is that I installed a set of Injector Dynamic's ID850 injectors as part of the new engine reassembly.

To get the car running, I used my previous tune as a basis and changed the fuel injector values as recommended by ID using the data they provide on their website. Other than that, I've not changed anything.

The car fired up and idled fine, the initial break in procedure (driving it and varying between 1500-2500 rpm for about 2 minutes) it seemed to run ok. For the second stage of the break in they recommend driving the car and varying the rpm from 2500-5000rpm while gradually increasing the load via 50% throttle to 90% throttle. This is where the problems surfaced; the engine hesitates/cuts out during moderate to heavy throttle up transitions. I also notice much more deceleration popping from the exhaust.

I was scanning during the break-in runs and did not notice anything out of whack, except the AFR was a bit lean at times (14-15) but nothing too bad.

There are no miss fire DTC's, which surprised me since the hesitation under acceleration feels like a miss fire.

Streetsweepergto · 08-16-2011, 09:52 AM

What are your wot afr's?
Any throttle position over 60% generally is pe/wot

Did you also change the displacement value of the motor in the tune?

Lean or rich af's can cause hesitation sometimes it will bring back firing and kr.
It may not pull a misfire dtc because it needs to surpass the cycles.
If your too rich your dousing the flame, too lean may not have enough torque and it will always feel like a misfire.

Post a log of the situation.

Your ve and maf will need readjusting.

WhoMadeWho · 08-16-2011, 10:06 PM

Quote:

Originally Posted by Streetsweepergto

What are your wot afr's?
Any throttle position over 60% generally is pe/wot

Did you also change the displacement value of the motor in the tune?

Lean or rich af's can cause hesitation sometimes it will bring back firing and kr.
It may not pull a misfire dtc because it needs to surpass the cycles.
If your too rich your dousing the flame, too lean may not have enough torque and it will always feel like a misfire.

Post a log of the situation.

Your ve and maf will need readjusting.

Thanks for the response....problem turned out to be a bad plug wire. It was intermittently arcing to the header

Streetsweepergto · 08-17-2011, 08:44 AM

Glad to hear!

Always assume what I wrote only if everything is mechanically sound!

08-16-2011, 01:42 AM	#1
WhoMadeWho Liberty vs Tyranny Drives: 2010 SS/RS M6 Inferno Orange Join Date: Jul 2011 Location: Florida Posts: 98	Hesitation During Acceleration Hey guys, Here's my situation. I had an LS3 376ci with an upgraded cam and Whipple SC in my 2010 Camaro. It ran great until an exhaust valve dropped and tore up the engine. So, I had Livernois build a stroked LS3 with forged internals and better heads as a replacement. The engine went from 376ci at 10.7:1 to 419ci at 9.7:1. The cam profiles are the same except the new motor has a narrower LSA of 114. The other change is that I installed a set of Injector Dynamic's ID850 injectors as part of the new engine reassembly. To get the car running, I used my previous tune as a basis and changed the fuel injector values as recommended by ID using the data they provide on their website. Other than that, I've not changed anything. The car fired up and idled fine, the initial break in procedure (driving it and varying between 1500-2500 rpm for about 2 minutes) it seemed to run ok. For the second stage of the break in they recommend driving the car and varying the rpm from 2500-5000rpm while gradually increasing the load via 50% throttle to 90% throttle. This is where the problems surfaced; the engine hesitates/cuts out during moderate to heavy throttle up transitions. I also notice much more deceleration popping from the exhaust. I was scanning during the break-in runs and did not notice anything out of whack, except the AFR was a bit lean at times (14-15) but nothing too bad. There are no miss fire DTC's, which surprised me since the hesitation under acceleration feels like a miss fire.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Top Fuel Acceleration Facts..OMG!	H3LL1ON	General Automotive + Other Cars Discussion	19	05-02-2012 10:24 AM
Hesitation when Accelerating	speedbrds	Camaro Issues / Problems \| Warranty Discussions \| TSB and Recalls	22	03-11-2012 11:56 PM
Acceleration problem with my new Camaro	maverickmage	5th Gen Camaro SS LS LT General Discussions	17	07-04-2011 11:49 AM
The true definition of acceleration	BlaSSt Off	5th Gen Camaro SS LS LT General Discussions	7	06-22-2010 12:39 AM
DEFINITION OF ACCELERATION	HALFFAST	Off-topic Discussions	12	08-14-2009 08:42 AM

08-16-2011, 09:52 AM	#2
Streetsweepergto Drives: CTSV Join Date: Feb 2011 Location: CT Posts: 80	What are your wot afr's? Any throttle position over 60% generally is pe/wot Did you also change the displacement value of the motor in the tune? Lean or rich af's can cause hesitation sometimes it will bring back firing and kr. It may not pull a misfire dtc because it needs to surpass the cycles. If your too rich your dousing the flame, too lean may not have enough torque and it will always feel like a misfire. Post a log of the situation. Your ve and maf will need readjusting.

08-17-2011, 08:44 AM	#4
Streetsweepergto Drives: CTSV Join Date: Feb 2011 Location: CT Posts: 80	Glad to hear! Always assume what I wrote only if everything is mechanically sound!