PCV w/AT backfires under acceleration

Reply Subscribe

Thread Tools

Search this Thread

Jul 25, 2009 | 07:53 PM

bstewart71

Thread Starter

Intermediate

Joined: Jun 2007

Posts: 38

Likes: 0

From: Kansas

UPDATED PCV w/AT backfires under acceleration

Hi all, just recently got 1000 miles on the 09 SG and have had the PCV and AT on it for about 300 miles, running SE Air, Dyno Jackpot touring mufflers, map from fuel moto. Problem occured today on highway under hard acceleration coming off an entrance ramp the bike back fired a few times and at one point shut off completely! nearly through me forward, got home and hooked up laptop and I am seeing the afr on cylinder 2 at 16 to 17 at idle! rolling the throttle up through the rpm range it has showed a few numbers in the 20's on the rear cyl only. checked all connections and reloaded map to base before trim values. Running better but still have abnormally high afr on cyl 2. Any ideas? Should I disable the autotune feature to ride after it has made initial adjustments? Thanks!!

Last edited by bstewart71; Aug 25, 2009 at 04:55 PM. Reason: Updated

Jul 25, 2009 | 08:04 PM

street_glider

Road Warrior

Joined: Nov 2008

Posts: 1,636

Likes: 7

From: Jackson, Michigan

PM iClick - he knows these things backwards!

Jul 25, 2009 | 08:24 PM

OG1

Road Master

Joined: Apr 2008

Posts: 897

Likes: 10

From: Oregon

couple questions:

did you use the o2 sensor eliminators on the FACTORY o2 sensor harnesses?
did you modify your target AFR's at idle?

it is not adviseable to have any target afr specified at idle RPM's, so theoretically the auto tune shouldnt be making adjustments at idle.

Jul 25, 2009 | 09:23 PM

iclick

Extreme HDF Member

Joined: Sep 2005

Posts: 11,615

Likes: 50

From: Baton Rouge, LA

Quote:

Originally Posted by bstewart71

Problem occured today on highway under hard acceleration coming off an entrance ramp the bike back fired a few times and at one point shut off completely! nearly through me forward, got home and hooked up laptop and I am seeing the afr on cylinder 2 at 16 to 17 at idle! rolling the throttle up through the rpm range it has showed a few numbers in the 20's on the rear cyl only.

If you don't mind, send your map to my email address so I can take a look at it. I assume you have target AFR's set to zero around idle (750 to at least 1500 @ 0% TP), which is the way it was programmed at Fuel Moto. If you are seeing 16-17:1 at idle there is something amiss unless the base map is way off, which is doubtful. What comes to mind is an intake leak, which could be letting too much air in the combustion chamber.

Was the hesitation and rough running you had today when the bike was at or near 0% TP, as in decelerating off the ramp? I wouldn't worry too much about different values on the two cylinders, expecially if you have aftermarket cams installed. When you say "rolling the throttle up through the rpm range it has showed a few numbers in the 20's on the rear cyl only" do you mean that you're seeing 20:1 AFR's or is that the number in the display for fuel values? Looking at your map will help.

Quote:

Should I disable the autotune feature to ride after it has made initial adjustments? Thanks!!

I don't know yet, as I don't know enough about what's going on. Did you change any of the target AFR's after receiving the PCV? Did this behavior just start today after running well for 300 miles?

Jul 26, 2009 | 07:47 AM

rodeking

Tourer

Joined: Jun 2007

Posts: 279

Likes: 3

From: N. Alabama

Quote:

Originally Posted by bstewart71

His bike must be stock and new except for the FM package. Also reads like he is hooked up and stationary. Would the AFR be correct if he is just blipping the throttle? Would #2 even fire at 20:1? On My maiden run of 1200 miles with the PCV/AT I had the engine hiccup three times at cruise speed. Speedometer would fall and come back instantly. I don't know if it was the PCV/AT or the calibration of the speedometer to match the GPS. I think it was the ECU reacting to "dead on" speedometer because it only did it on cruise control. Also my idle is at -27 at 1000 and 1250. I have to run -27 fuel for two seconds at start up to made hot starts.

Last edited by rodeking; Jul 26, 2009 at 07:53 AM. Reason: adding sentence

Jul 26, 2009 | 11:40 AM

bstewart71

Thread Starter

Intermediate

Joined: Jun 2007

Posts: 38

Likes: 0

From: Kansas

Well, here's an update, I get the Dumb@ss award for the day, the rear cyl O2 "faker" was not plugged into factory harness. Damn i'm glad nothing seems to be hurt. strange that the plugs looked perfect and no check engine light came on? Reloaded base map from fuel moto and everything seems to be running much better. Will await info from iclick if he has anything to add to this. Thanks for the help guys.

Jul 26, 2009 | 12:00 PM

iclick

Extreme HDF Member

Joined: Sep 2005

Posts: 11,615

Likes: 50

From: Baton Rouge, LA

Quote:

Originally Posted by bstewart71

I sent you an email this AM after looking over your map, and I see nothing that would cause me great alarm. I would like for you to spot-check it at various RPM/TP areas (e.g. 2500 @ 10%) and compare the computer readout to the target AFR's. It will fluctuate quite a bit, especially at idle, but remember that idle is set to 0, so it is not running in closed-loop mode (AT). If you are seeing leanness at idle adjust according to the procedure in my email, which is to adjust the base map values at idle and "send map" on the fly, repeating until it is where you want. Remember that at idle the AFR readout will jump around quite a bit, so just get it to average about 14.0 or wherever you want it.

7 Times Harley-Davidson Chucked Tradition Out the Window

Verdad Gallardo

7 Surprising Harley-Davidson Products that Are Not Motorcycles

Verdad Gallardo

8 Best Harley-Davidson Motorcycles Ever

Pouria Savadkouei

10 Worst Harley-Davidson Motorcycles Ever

Pouria Savadkouei

Killer Custom's Jail Break Is The Breakout That Refused to Blend In

Verdad Gallardo

Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

Verdad Gallardo

Harley-Davidson Reveals Super Cool Cafe Racer Concept

Verdad Gallardo

Engraved Rebellion: Inside Bundnerbike's Glam Rock II

Verdad Gallardo

10 Motorcycles You Should Never Buy

Joe Kucinski

10 Things Harley-Davidson Needs to Fix in 2026

Verdad Gallardo

Aug 25, 2009 | 04:12 PM

bstewart71

Thread Starter

Intermediate

Joined: Jun 2007

Posts: 38

Likes: 0

From: Kansas

Update on the PCV with Auto tune. Have reviewed the trim values for the base map and found that the front cyclinder hardly needed any trim, BUT, the rear cylinder is trimming to +18 on everything under 20% throttle. My thought is reversion issues with stock head pipe and DT Jackpots. Checked with Fuelmoto and confirmed that this appears to be the issue and is also why I was still seeing abnormally high AFR readings (lean) on the rear cyl. Will reset the base map and ZERO out all AFR numbers under 20% throttle where the trim was abnormally high. This is the temporary fix for now suggested by both Powercommander and Fuelmoto. Will keep this post updated when I can.

Aug 26, 2009 | 08:40 PM

#10

street_glider

Road Warrior

Joined: Nov 2008

Posts: 1,636

Likes: 7

From: Jackson, Michigan

Ain't it grand?

I have been riding for a few hundred miles and I think I'll get out the computer and play with things a bit, based upon the experiences in this and other posts.

Thanks All!