Ideas why i need to add 25% VE after rebuild?

[kidglok]

Like the title states, replaced my melted block with a fresh one, new pistons because this block is .030 vs .020. New champion heads (same as old motor), everything else is the same.

Fire it up yesterday with the same tune that was in the box and she needed 25% added to the whole VE table. Fuel pressure reads the same, alky is the same (although it shouldnt matter under 7psi) but she was maxing out the correction untill we highlited the whole table and added +25%. Now she runs fine.

any ideas?

 

[TurboBob]

idle, part throttle, WOT??

Fuel pressure, MAP sensor, coolant or air temp sensor, wrong tune?? wrong fuel?? (e85/gas), installed different injectors?

Got some old vs new logs to compare? Perhaps the issue was with the old engine, and its corrected now....

Bob

 

[kidglok]

idle, part throttle, WOT??

Fuel pressure, MAP sensor, coolant or air temp sensor, wrong tune?? wrong fuel?? (e85/gas), installed different injectors?

Got some old vs new logs to compare? Perhaps the issue was with the old engine, and its corrected now....

Bob

fuel pressure is the same, map sensor reading accurately, coolant and air temp are working correctly. Cant be the wrong tune its the same one from the track before i parked it to rebuild it, plus i looked into the tune it was the same. Injectors are the same.

i took a log but it was on my buddys laptop so it didnt log the things i wanted to see, just looked over the tune to make sure nothing weird was going on which it wasnt, just had to add 25%

i had to add this to the whole VE table, idle part throttle and WOT

 

[HighPSI]

You mentioned this is the same tune as before when you melted the block. Perhaps the tune was off before the rebuild? Where did you get the tune from?

 

[kidglok]

You mentioned this is the same tune as before when you melted the block. Perhaps the tune was off before the rebuild? Where did you get the tune from?

tuning was done by me. corrections were all within 5%, VE numbers were low 50's at around 25psi, now at 20psi the VE is around 63. Number 2 let go last time when i was trying to get the tune right, so it was hurt by the time i made this pass. this is a screen shot of the pass i made before i parked it for the rebuild

 

[TurboBob]

tuning was done by me. corrections were all within 5%, VE numbers were low 50's at around 25psi, now at 20psi the VE is around 63. Number 2 let go last time when i was trying to get the tune right, so it was hurt by the time i made this pass. this is a screen shot of the pass i made before i parked it for the rebuild

that doesn't seem right......

 

[TurboBob]

oh, you were compensating for the alky........

slippery slope there..

B

 

[kidglok]

oh, you were compensating for the alky........

slippery slope there..

B

Correct. And the correction was +-3%@50VE Now the correction is the same, but I had to change the numbers to 63

 

[TurboBob]

so, assuming that the rest of the parameters are unchanged (tune/temperature) then the XFI is delivering more fuel.

So either the engine wants more fuel, your alky kit is putting out a lot less (which would not explain idle), or the amount of fuel you think is going to the engine is not actually going to the engine.

25% is a LOT of fuel....

Bob

 

[HighPSI]

Even with a dual alky kit, 50's are kinda low at 25 psi. 60's seem more reasonable. By any chance, are you going to be at Atco tomorrow?

 

[kidglok]

Even with a dual alky kit, 50's are kinda low at 25 psi. 60's seem more reasonable. By any chance, are you going to be at Atco tomorrow?

Wish i was going to be there, gotta work

we always wondered why my VE numbers were soo low, but it worked so we didnt go crazy over it

 

[turbobitt]

Wish i was going to be there, gotta work

Dam, I'm stuck working to...
Was hoping to get some expertise on my tune.

Allan G.

 

[kidglok]

cal, how long you in jersey for?

 

[SloGN]

Can you take a look and make sure the energy constant is set correctly? Also is the engine running like it's lean? You may be tring to compensate for a wideband thats going bad.


Also i noticed that the bat voltage is reading 15.4 is this normal ?

 

[kidglok]

Can you take a look and make sure the energy constant is set correctly? Also is the engine running like it's lean? You may be tring to compensate for a wideband thats going bad.

thats a good point, but the injector dutycycle hasnt changed much, maybe 2%. Energy constant is at 1.00 like it always has. I noticed the engine hunting during the warmup routine, once it was up to operating temp closed loop was maxed out at 25% positive correction at idle, and the wideband was at 14.5. The positive correction stayed constant throughout the VE map.

 

[SloGN]

whats the kpa at idle?

 

[kidglok]

whats the kpa at idle?

46-50

 

[HighPSI]

cal, how long you in jersey for?

Just tomorrow, then headed north for the weekend

 

[norbs]

I;ve never seen a program in the 50;s at WOT with alky you should be in the 70's.......A non alky tune average is 85-95 approx..

 

[kidglok]

I;ve never seen a program in the 50;s at WOT with alky you should be in the 70's.......A non alky tune average is 85-95 approx..

you have the gct and the logs of mine