Power pulsing while acceleration

[FiestaSTdude]

So I was driving to the NC mountains this weekend and I noticed that, when I accelerate, the power feels like its cutting out or pulsing. It happens when I'm giving it maybe 50 - 75% throttle. I have noticed it it 2nd, 3rd, 4th, and 5th gear, and it doesn't happen every time. I am aware of the issue our cars have when we fill up, and this is not it. I'm replacing the spark plugs and maybe coils soon, so i'll see if that makes it any better.

 

[TyphoonFiST]

So I was driving to the NC mountains this weekend and I noticed that, when I accelerate, the power feels like its cutting out or pulsing. It happens when I'm giving it maybe 50 - 75% throttle. I have noticed it it 2nd, 3rd, 4th, and 5th gear, and it doesn't happen every time. I am aware of the issue our cars have when we fill up, and this is not it. I'm replacing the spark plugs and maybe coils soon, so i'll see if that makes it any better.

Where you going up a grade/steep incline alot? What were the intake charge air temps?

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[FiestaSTdude]

I first noticed it while I was driving on the relatively flat piedmont. I did drive a lot of steep grades in the mountains, but that was after I first noticed the issue. How would I know the charge air temps? I don't have (but want!) an accessport yet

 

[TyphoonFiST]

I first noticed it while I was driving on the relatively flat piedmont. I did drive a lot of steep grades in the mountains, but that was after I first noticed the issue. How would I know the charge air temps? I don't have (but want!) an accessport yet

Another thing is the coolant system on A Fist is completely under sized IMO. A larger radiator will keep coolant temps down ALOT. The heat soak from going up a large incline build rapidly with a Stock CAC and Stock Radiator. I rolled stock CAC and Stock Radiator for a long time even on a tune from stratified for 20k. They are alright for street driving...Don't get me wrong. If I was you...My next step would be to buy and AP3/ Cobb accessport 3 and a tune from a Tuner of your choice or just rolling a Cobb tune is more than adequate but not as refined. You can monitor just about every aspect of importnat data of your car on one device up to 6 gauges at once also*

 

[XR650R]

So I was driving to the NC mountains this weekend and I noticed that, when I accelerate, the power feels like its cutting out or pulsing. It happens when I'm giving it maybe 50 - 75% throttle. I have noticed it it 2nd, 3rd, 4th, and 5th gear, and it doesn't happen every time. I am aware of the issue our cars have when we fill up, and this is not it. I'm replacing the spark plugs and maybe coils soon, so i'll see if that makes it any better.

Is this a stock engine? Did you buy it new or used? Mileage?

 

[FiestaSTdude]

Is this a stock engine? Did you buy it new or used? Mileage?
As far as I can tell, its stock without a tune. I bought the car at used at 43k and its now at 87k

 

[FiestaSTdude]

Another thing is the coolant system on A Fist is completely under sized IMO. A larger radiator will keep coolant temps down ALOT. The heat soak from going up a large incline build rapidly with a Stock CAC and Stock Radiator. I rolled stock CAC and Stock Radiator for a long time even on a tune from stratified for 20k. They are alright for street driving...Don't get me wrong. If I was you...My next step would be to buy and AP3/ Cobb accessport 3 and a tune from a Tuner of your choice or just rolling a Cobb tune is more than adequate but not as refined. Yo can monitor just about every aspect of importnat data of your car on one device up to 6 gauges at once also*

Maybe an accessport can be my early Christmas present t myself! Lol

 

[TyphoonFiST]

Another thing is the coolant system on A Fist is completely under sized IMO. A larger radiator will keep coolant temps down ALOT. The heat soak from going up a large incline build rapidly with a Stock CAC and Stock Radiator. I rolled stock CAC and Stock Radiator for a long time even on a tune from stratified for 20k. They are alright for street driving...Don't get me wrong. If I was you...My next step would be to buy and AP3/ Cobb accessport 3 and a tune from a Tuner of your choice or just rolling a Cobb tune is more than adequate but not as refined. Yo can monitor just about every aspect of importnat data of your car on one device up to 6 gauges at once also*

Maybe an accessport can be my early Christmas present t myself! Lol

They can be had in the forsale part of the Forum if you wanna be frugal....nothing wrong with that. I have bought most of my performance parts BNB or second hand. Saved ALOT of skrilla.

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[XR650R]

Maybe an accessport can be my early Christmas present t myself! Lol

That's a good idea. I say that because you can use it to check for codes. There are a million little sensors in there, all talking to each other, but sometimes it gets confused. The fix might be as simple as clearing some codes and starting over, seeing which codes may come back.
Another possibility might be a dirty fuel filter, or a dirty MAP sensor. I'd also check for any recalls, if you haven't yet.

 

[The_Ryan]

when's the last time plugs were done? I would start with that.

 

[FiestaSTdude]

Idk the last time the plugs were changed, I've never done it.
I'm gonna change the spark plugs and fuel filter and see if anything changes.
Thanks for the responses!

 

[Jason@dizzytuning]

My guess is you are just feeling the ECU targeting torque, which can open/close the throttle plate very abruptly. I spent a good deal of time smoothing that out on my Falsh Tune.

 

[FiestaSTdude]

I was driving the car yesterday (no accessport installed yet, I'm sitting here waiting for it to install as I write this) and I noticed a couple of things about my issue. It seems to only happen in boost. There is a rhythmic loss of power then power again. It's definitely worse in higher gears. And it doesn't happen every time I drive. It seems to only happen after I've been driving for a while (regardless of whether it's contentious or multiple trips)

 

[FiestaSTdude]

I drove for a hour after installing the accessport and it didn't act up at all.

PS coming from the stock tune, the Cobb stage 1 93 octane tune really feels fast!

 

[XR650R]

I'd use the AP to check for codes.

 

[scooter123]

They can be had in the forsale part of the Forum if you wanna be frugal....nothing wrong with that. I have bought most of my performance parts BNB or second hand. Saved ALOT of skrilla.

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A larger radiator wont just keep the engine cool and allow more timing it will also improve your fuel economy by roughly 4 MPG. Bad news that only hold true in the summer, in the winter it can slow warmup times and the Fist drinks gasoline like a drunken sod when it's cold. Last summer my mileage tattletail would show about 35.5 mpg when I minded my manners and since the cold hit I have to drive like a little old lady to see 32 mpg on that same tattletail.

 

[CarGuy]

A larger radiator wont just keep the engine cool and allow more timing it will also improve your fuel economy by roughly 4 MPG. Bad news that only hold true in the summer, in the winter it can slow warmup times and the Fist drinks gasoline like a drunken sod when it's cold. Last summer my mileage tattletail would show about 35.5 mpg when I minded my manners and since the cold hit I have to drive like a little old lady to see 32 mpg on that same tattletail.

4 mpg improvement from just a radiator replacement?

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[Intuit]

when's the last time plugs were done? I would start with that.

Yeop. Start simple. Read them plugz. This sounds like an ignition miss. You can simulate additional engine load by briefly** using the hand brake. There is never a time when checking codes is a bad idea.

** note: I say 'brief' because you don't want to get rear brake hot

 

[FiestaSTdude]

The only code the accessport showed was p0504 witch as far as I can tell has absolutely nothing to do with my issue

 

[Intuit]

Out of curiosity I'd wonder whether cruise control works, with that code being set...
https://www.obd-codes.com/p0504