unable to tune out ping at low (<50) map 2000-3000rpm

[jjdalynh]

11.05:1 CR static, TW-8 cams, rear cylinder running very rich from coming back from tuner and i can't it to stop pinging with lowering timing, changed to vrod plugs, gapped down to .025.  i can feel it cruising around town it feels rumbly,and when i get up over 3k it smooths out (no more knock retard registered) and really feels like it pulls strong.  timing doesn't change drastically at that rpm (a couple degrees or less).

[HD/Wrench]

So you are 100% sure the AFR is correct , cam timing is correct ?  Cannot remove ping be lower timing HMMM that does not sound right . I think you may need to have it tuned else where if there are no  mechanical issues .  11.1 with a 8 cam is stout for sure , I would think the lean AFR range which is 50 KPA ( cruise) would not want much timing .

More info on build  would be helpful


Why do you say its super rich on rear ??

[jjdalynh]

So you are 100% sure the AFR is correct , cam timing is correct ?  Cannot remove ping be lower timing HMMM that does not sound right . I think you may need to have it tuned else where if there are no  mechanical issues .  11.1 with a 8 cam is stout for sure , I would think the lean AFR range which is 50 KPA ( cruise) would not want much timing .

More info on build  would be helpful


Why do you say its super rich on rear ??

example: commanded AFR is 13.3, AFR read from PV AT Pro is 10.994 a couple ms before spark knock detected (32kpa @ 3400rpm, 6%tps).  timing is 27.5 deg.

i agree it should be pretty stout, (FM level B heads, 107").  guys at fuel moto didn't indicate it would be a problem, i know timing will need to be correct though.  93 octane around here.  probably easier if i post the tune and a sample of data logged.  IVO is set to 7, IVC 58

[HD/Wrench]

kinda confused as to how you are at 32 KPA at 3400 short of decel pretty hard to get there and in decel you can get some odd AFR readings .. light throttle cruise should be in the mid 50's   look at your log it should idling in the 35 range-40 range .

Unless you have cams out of time ??

[jjdalynh]

kinda confused as to how you are at 32 KPA at 3400 short of decel pretty hard to get there and in decel you can get some odd AFR readings .. light throttle cruise should be in the mid 50's   look at your log it should idling in the 35 range-40 range .

Unless you have cams out of time ??

you're right that was on the tail end of a decel to steady throttle.

[HD/Wrench]

 Ok so add fuel to that VE area , the AFR is showing wrong  most likely without see the map and looking to see what is going hard to know . But the Injectors may be off  or on . off is a guess but seeing the AFR hit 10 on a decel is not uncommon . Many time you will see guys posting ve tables and and the ve is 127.5 in some areas on decel .

ok but that is not 50 KPA   what am I missing here

[jjdalynh]

steady cruise @ 2800rpm, map 34ish kpa, 5%tps, Commanded AFR mid 12s, rear AFR 10.7, timing down to 20 deg, 4 deg spark knock.  (limited to 4 right now)

[jjdalynh]

Ok so add fuel to that VE area , the AFR is showing wrong  most likely without see the map and looking to see what is going hard to know . But the Injectors may be off  or on . off is a guess but seeing the AFR hit 10 on a decel is not uncommon . Many time you will see guys posting ve tables and and the ve is 127.5 in some areas on decel .

ok but that is not 50 KPA   what am I missing here

can't imagine the cams are off, i've done them before (these are gears,BTW) and it dynoed at 112/110 (which i thought was a bit low)

[Hossamania]

For peace of mind, maybe do a compression check just to verify cam timing? I have no tuning advice, just the "keep it simple to start troubleshooting" principle.

[jjdalynh]

For peace of mind, maybe do a compression check just to verify cam timing? I have no tuning advice, just the "keep it simple to start troubleshooting" principle.

good advice, i'll do that. 

[jjdalynh]

more info: HPI 55mm Tb, 6.2 injectors (i know they are a bit large for this application, it's what i had) dragos 2:1 2.55" baffle exh.

[HD/Wrench]

Something is off , its not going to be at 34 KPA at steady cruise . That is a fact  and  that cam at that comp ratio with stock heads would make more tq than that and  most likely more Hp as well .

So  , first off make sure no intake leak ,   then do a CCP test that should make in the 200+ . 

What is the CI of the build what heads do you have on it .. A stock 103 with cam will make 95-100 Hp and 110-115 tq .. bang the comp ratio that high and it should be doing well beyond that .


tuned a 107 kit on a dyna so 46 mm T/B dd fat cat 10.1 comp ratio woods 555  101/117 .. I would think that you have ported heads as you opted for a larger TB

[jjdalynh]

Something is off , its not going to be at 34 KPA at steady cruise . That is a fact  and  that cam at that comp ratio with stock heads would make more tq than that and  most likely more Hp as well .

So  , first off make sure no intake leak ,   then do a CCP test that should make in the 200+ . 

What is the CI of the build what heads do you have on it .. A stock 103 with cam will make 95-100 Hp and 110-115 tq .. bang the comp ratio that high and it should be doing well beyond that .


tuned a 107 kit on a dyna so 46 mm T/B dd fat cat 10.1 comp ratio woods 555  101/117 .. I would think that you have ported heads as you opted for a larger TB

107"
Fuel Moto Level B heads. 
usual method of finding intake leaks (some fuel or other around the intake ports at the head?   (i've found them this way with my carbed build, i presume EFi it would be the same).

[jjdalynh]

another thing, initially the cam estimator had IVO at 8, but i had map at idle over 40 and hard starting.  when it got changed to 7, it started easier but that may been due to adjusting the cranking params and IAC. 

[HD/Wrench]

I do not have much in the 107 with the 8 cam but I have 555 with the B head and SE cnc heads etc..

but again your KPA is way off .   IVO does not effect starting in my opinion with all other items setup correctly .


Well post up your CCP  when you get it , do not forget disable ACR or un hook them   

[jjdalynh]

will do.  (it's a 2003, so manual CRs)

[jjdalynh]

looks like tomorrow is going to rain so i'll be doing some diags.  hate when i loan tools out, now i have to go get a new compression tester.  🙄

[Hossamania]

looks like tomorrow is going to rain so i'll be doing some diags.  hate when i loan tools out, now i have to go get a new compression tester.  🙄

Could you get a free loaner from an auto parts store?

[jjdalynh]

looks like tomorrow is going to rain so i'll be doing some diags.  hate when i loan tools out, now i have to go get a new compression tester.  🙄

Could you get a free loaner from an auto parts store?

yeah, but for $30-$40 id rather not have to make the return trip.  i've been meaning to replace the one that went missing anyways. 

[Hossamania]

looks like tomorrow is going to rain so i'll be doing some diags.  hate when i loan tools out, now i have to go get a new compression tester.  🙄

Could you get a free loaner from an auto parts store?

yeah, but for $30-$40 id rather not have to make the return trip.  i've been meaning to replace the one that went missing anyways.

I tend to agree with you. I'd rather just have a new one as well, though the auto parts store is only about a mile or two from my house, so pretty painless for me.

[jjdalynh]

it's at least a 15 min ride and dealing with traffic blows, sometimes it's closer to 30 on a weekend return trip with all the lights. 

quick check for intake leaks with propane and a rubber hose yeilded no results. if the idle isn't going to jump more than 50 rpm it'll be hard to tell this cam is pretty lumpety. 

wouldn't i be seeing lean conditions in my AFRs through the wideband sensors?

[jjdalynh]

compression check shows about 180psi on both cylinders. 

[HD/Wrench]

180 is a fair amount off on CCP  What is your elevation ?? you said no ACR  manual release  , they have to be closed & throttle open crank until it stops moving the needle ,... the programs are just to get you close but if your Comp ratio is that its 20+ PSI off so a tooth on the out side  retarding cam would do all kinds of crazy things .. Also that cam should have hit like a hammer out the gate for tq with a good pipe

[rigidthumper]

IMO, that combo should be closer to 210 @ sea level.

[Durwood]

compression check shows about 180psi on both cylinders.

Is this with the TB propped open?