Power pulsing while acceleration

[anticon]

https://dizzytuning.com/blogs/technical-documents/fiesta-st-part-throttle-surge

@Jason@dizzytuning So this can be fixed via tuning?

 

[Jason@dizzytuning]

@Jason@dizzytuning So this can be fixed via tuning?

Yes, just look at TIP Actual vs. TIP Desired in a data log. Any time the Actual exceeds Desired, the throttle closes abruptly.

 

[anticon]

Yes, just look at TIP Actual vs. TIP Desired in a data log. Any time the Actual exceeds Desired, the throttle closes abruptly.

Thanks, I'm going to go run a datalog now.

 

[FiestaSTdude]

It only does it occasionally and it's only at about 50% throttle. Tuner didn't say much either but he heard it, he sent me a new revised tune I installed it and it's still doing it. Do you have a stock or aftermarket BOV? I have aftermarket and I been reading the o rings could come loose so I'm going to check that next. If it's not that then I'm out of ideas

I think I have a stock BOV. I bought my car used and always assumed it was stock, but it could be aftermarket

 

[FiestaSTdude]

https://dizzytuning.com/blogs/technical-documents/fiesta-st-part-throttle-surge

Thanks for the article! That sounds like my issue. I'm going to have to go datalog now.

 

[DEss]

Thanks for the article! That sounds like my issue. I'm going to have to go datalog now.

Reads like you were experience this issue even on the stock tune, so the info in the article might not apply to you.

 

[FiestaSTdude]

Reads like you were experience this issue even on the stock tune, so the info in the article might not apply to you.

I'm on a Cobb stage 1 tune.

 

[DEss]

I'm on a Cobb stage 1 tune.

Didn't you report this issue even before you got the AP? Or am I misreading your second post?

 

[FiestaSTdude]

Didn't you report this issue even before you got the AP? Or am I misreading your second post?

Sorry, yes the issue has occurred on the stock tune and the Cobb stage 1 tune. The way I understand the throttle surge issue, it could happen on the stock tune because of the Ford torque targeting strategy. I could be wrong about that though.

 

[FiestaSTdude]

I just looked at a datalog I took where the surging occurred. I took this datalog in 3rd gear at around 60% throttle. When the TIP actual is greater than the TIP desired, the ETC actual switches from increasing to decreasing. When the TIP desired is greater than TIP actual, ETC actual switches back to decreasing. From what I'm seeing with this datalog, It seems likely that throttle surge is the issue I'm having with my car, but I'm still going to check my BOV when I get a chance.

 

[FiestaSTdude]

So I had the surging happen again to me on the highway last night. Even with the pedal to the floor, I could see the Accessport boost graph monitor bouncing and feel what I assume was the boost building and dropping. This occured on a Cobb stage 0 tune. So today I put in a couple gallons of 93 and when back to my dizzy 93 tune and everything felt fine. I'm going to look at and maybe replace my BOV, but I feel like it's tune related, because it so far only happens stock or with Cobb tunes.
If I figure out what's up, I'll post it on here. Right now I'm still not 100% sure what's up.

 

[TyphoonFiST]

So I had the surging happen again to me on the highway last night. Even with the pedal to the floor, I could see the Accessport boost graph monitor bouncing and feel what I assume was the boost building and dropping. This occured on a Cobb stage 0 tune. So today I put in a couple gallons of 93 and when back to my dizzy 93 tune and everything felt fine. I'm going to look at and maybe replace my BOV, but I feel like it's tune related, because it so far only happens stock or with Cobb tunes.
If I figure out what's up, I'll post it on here. Right now I'm still not 100% sure what's up.

What was the verdict?

 

[FiestaSTdude]

What was the verdict?

It still happens occasionally if I accelerate gently. It’s not nearly as bad with the dizzy tunes, so I don’t notice it much anymore