Manual Trans Lean Spikes

[Bfisher31286]

I completed the MAF tuning using Russ K's method and I get the lean spikes when going from closed to open throttle. The problem I have is that I am driving a manual car and each time I let off the gas to shift and get back on it I get a lean spike which causes about 1 degree of KR. The car does fine if I do a WOT pull from 1500rpm but only gets the KR when I am shifting and getting back on the gas at higher RPMs. Is there a way to lower the lean spikes so I can get rid of the KR or is there something else I should be adjusting?

[Bfisher31286]

Here is my calibration file if anyone could take a look at it for me.

Fiero Spark Timing.hpt

[Bfisher31286]

To clarify this is a 2000 GTP engine in a pontiac fiero mated to a 4sp manual trans.

[Bfisher31286]

Here is a snapshot of a log with the rich/lean spikes. This was early on in the MAF tuning so I dont currently have that much KR. This was a 3rd gear wot pull followed by a gear 3-4 shift. You can see the wideband readings look pretty good at the beginning of the pull but at the shift point it dips rich and then spikes lean.

LeanSpike.png

[Bfisher31286]

Turned out to be a boost/vac leak at the oil filler cap. I found it by pressurizing the entire engine from the throttle body with a round plate and air fitting I made. Turns out to be one of the most useful tools I have. I make them for all the boosted cars Ive had and they make it a lot easier to find leaks than the spraying carb cleaner method. Got it fixed.

[5FDP]

I would have never guessed that haha.

[Bfisher31286]

Growing up, whenever I could not get an engine to start my dad would come up and say "Does it have gas in it?". Although that was never the problem it has led me to think that way when dealing with engines. Once you are thoroughly confused about something, step back and think about the simple things to check. 9 times out of 10 its the "empty gas tank" or the sensor you forgot to plug back in that is causing the problem.