Tip In response.

[Rickerbucks]

When I tip in at idle or at cruise, I get a lean - rich - lean spike. It happens very quickly and I cannot feel it driving, but it bothers me that it happens. I presume that the "AE vs TPS rate of change" and the "AE ve MAP rate of change" are the tables to play with but after much messing around, nothing seems to be better.

I have seen two other tunes and they have a gently rising curve that flattens out as you move from left to right.

Is this reaction normal and not to be worried about do I not have the shape right?

 

[bobc455]

My opinion: if your VE tables are accurate and your drivability is okay, then don't worry about it.

The O2 sensor is not a perfect/exact indicator of what's happening in the combustion chamber, it is subject to slight delays and weird readings reacting to quick/small changes. Consider the O2 sensor just to be a "steady state" reading, don't worry about having it react instantly/perfectly to sudden changes.

-Bob C.

 

[Craig Smith]

I agree with Bob 100%. How the car reacts is definitely more important than how the data logger reacts in this instance.

A/F ratio spikes are normal when the speed or load changes suddenly, like a gear shift or stabbing the gas. As long as it feels OK, you are in good shape in my opinion!

 

[Rickerbucks]

TY guys. That puts my mind at rest.

 

[mustangmike]

i'm having a tip in problem from an idle and can't get it figured out. this is only happening during idle and it almost stalls, it also stalls when i'm coming up to a stop a light or wants to if i let off the accel. quickly. i've tried to adjust the ae vs map rate of change and the ae vs tps rate of change and nothing got any better. any ideas?

 

[bruce]

Originally posted by Rickerbucks
When I tip in at idle or at cruise, I get a lean - rich - lean spike. It happens very quickly and I cannot feel it driving, but it bothers me that it happens. I presume that the "AE vs TPS rate of change" and the "AE ve MAP rate of change" are the tables to play with but after much messing around, nothing seems to be better.

I have seen two other tunes and they have a gently rising curve that flattens out as you move from left to right.

Is this reaction normal and not to be worried about do I not have the shape right?

It is important to get right.
That lean rich lean is the perfect setup for trace detonation.

If you get to where fueling changes don't change the fueling, the timing might be off.

Take the time and get rid of it would be my advise.

WAY too often guys get way too hung up with running as much timing as possible in idle, cruise, light load, and while if your going for a lean burn and mileage that's fine, but for engine life, there are better strategies.

While I tend to run real low timing chips, at 70 MPH I'm only running 26d of timing, and 13.8-14.2 AFR. Your combo will vary.

 

[Big88]

Tip in

Tip in problem
Im having just about the same problem. When the engine is at nomal operating temp, It tries to stall when i tip in. When its cold it doesnt do it. This is kind of a pain when your trying to stage the car and it tries to stall. What should i look for?

Tom

 

[bruce]

First table is spark, multiply by .352 to see it in degrees.
Second table is VE.

At a glance it looks very different then what your used too, but the shape of the tables, and the way the timing ramps out, and VE increases are the areas of interest.

Part of the secret is keeping any excessive heat off the piston crwon when not in PE. So a lil rich with a few degrees less timing help. It also keeps some heat out of the oil and reduces blow by slightly. Any one item by itself is no biggy, but when you add up the details it all gets important.

The AE stuff should rather quickly fall into place once you have the timing and VE correct. IMO, anyway.

; 3 BAR 45 75 100 125 150 175 200 225 250 275 300
FCB 61,61,61,61,45,34,28,28,28,28,28,28,28,17,17,17,17 ; 600
FCB 61,61,61,57,45,34,28,28,28,28,28,28,28,17,17,17,17 ; 800
FCB 42,42,61,57,52,48,31,28,28,26,26,26,21,21,17,17,17 ; 1000
FCB 32,42,68,68,63,48,37,28,28,26,26,26,21,21,17,17,17 ; 1200
FCB 32,42,71,71,68,61,60,48,28,26,26,26,21,21,17,17,17 ; 1400
FCB 32,42,74,74,68,63,48,48,48,33,31,26,23,23,23,23,23 ; 1600
FCB 32,42,74,74,68,63,51,48,48,33,31,28,28,26,26,26,26 ; 2000
FCB 32,42,74,74,68,63,58,53,51,43,31,28,25,25,25,23,23 ; 2400
FCB 32,42,74,74,68,68,63,57,54,43,38,38,34,34,34,34,34 ; 2800
FCB 32,42,74,74,68,68,63,62,54,51,49,46,46,42,42,42,42 ; 3200
FCB 32,42,74,74,68,68,68,68,60,54,54,48,48,48,46,46,46 ; 3600
FCB 32,42,68,68,68,68,68,68,65,65,63,57,57,51,51,51,51 ; 4000
FCB 32,42,68,68,68,68,68,68,65,65,63,57,57,51,51,51,51 ; 4400
FCB 32,42,68,68,68,68,68,68,65,65,63,57,57,51,51,51,51 ; 4800

FCB100,100,100,100,100,100,100,100,105,105,110,130,130,130,140,140,150 ; 400 RPM
FCB100,100,100,100,100,100,100,100,100,100,110,130,140,140,150,150,150 ; 600
FCB100,100,100,100,100,100,100,100,100,105,110,130,140,140,150,150,160 ; 800
FCB30, ,30,100,115,115,115,110,115,110,115,145,150,155,160,160,170 ; 1000
FCB30, 30, 125,125,130,135,140,145,155,155,160,165,170,170,170 ; 1200
FCB 30, 30,100,130,135,135,140,145,150,155,165,170,175,180,190,190,200 ; 1400
FCB 30, 30,100,130,135,140,145,145,150,155,165,170,180,185,190,210,220 ; 1600
FCB 30, 30,100,135,140,150,150,155,155,160,165,170,180,185,190,210,220 ; 1800
FCB 30, 30,100,135,140,150,155,155,155,160,165,175,180,190,190,210,220 ; 2000
FCB 30, 30,105,135,145,150,155,160,155,165,165,175,185,200,190,210,220 ; 2200
FCB 30, 30,105,135,145,150,155,160,155,165,165,175,185,200,190,210,220 ; 2400
FCB 30, 30,105,135,150,150,160,165,160,165,170,175,185,200,200,220,220 ; 2800
FCB 30, 30,105,135,150,150,160,165,165,170,175,175,185,200,200,220,220 ; 3200
FCB 30, 30,105,135,150,150,165,165,165,175,175,175,190,200,200,220,220 ; 3600
FCB 30, 30,105,135,150,150,165,165,165,175,175,175,190,200,200,220,220 ; 4000
FCB 50, 60,105,135,150,150,165,165,165,175,175,175,190,200,200,220,220 ; 4400
FCB 50, 60,105,135,150,150,165,165,160,175,175,175,190,200,200,220,220 ; 4800

I'd show you the AE stuff, but then I'd have to put contracts out on ya,,,,,,,

This is all from what I've found to work for me.
Your results, and tables will be different.
Educational purposes only
Not to be attempted without adult supervision, yada yada
HTH