Car won't rev higher than 5-5.5k RPM Help!

[NormDriver]

So ever since I got my car used (2016 Fiesta ST), I have not been able to rev past around 5,000 or so rpm. When I hit 5,000 rpm the throttle cuts out and rpm drop, like it's hitting redline or something. Also after this happens the turbo won't go more than 5 pounds of boost and it acts oddly by whistling when I accelerate. I have to turn the car off for a minute and than everything is back to normal (until I do it again on accident). So I got the COBB accessport and my redline is set at 6500 rpm but this problem still occurs. The car drives normally until I floor it and it cuts off at 5k rpm (which happens easily since it spools up so fast before I realize). This is very strage and I can't seem to find anyone with the same problem. Please help, so I potentially don't blow my engine.

 

[A7xogg]

Since you have an access port, do a datalog and upload to datazap to make it easier to read

 

[D1JL]

Make sure ALL of your turbo outlet hoses/pipes are connected correctly and the clamps are tight.


Dave

 

[jtehh]

I've seen something similar pop up in here from time to time. It usually ends up being a map switching accident that is putting you into eco or valet mode. Check your map slot in the AP and make sure you are using the right tune. I believe it is quite easy to accidentally switch slots while driving.

https://www.youtube.com/watch?time_continue=50&v=vmvqXnQ48pg

 

[Sprinkle_Star]

I've seen something similar pop up in here from time to time. It usually ends up being a map switching accident that is putting you into eco or valet mode. Check your map slot in the AP and make sure you are using the right tune. I believe it is quite easy to accidentally switch slots while driving.

https://www.youtube.com/watch?time_continue=50&v=vmvqXnQ48pg

Does Valet Mode also limit the vehicle's power? I just thought it locked SYNC 3. Cool!

 

[jtehh]

Does Valet Mode also limit the vehicle's power? I just thought it locked SYNC 3. Cool!

Valet mode via Sync is different from Cobb's valet mode map. The one using Sync doesn't do much. Cobb's mode will limit boost and rev to make it less fun for the valet (or your teenage son) to hoon.

 

[Bosnian Fiesta]

Check to make sure you don't have a fuel starvation issue. Use the AP to log your FRP Desired & FRP Actual to see if the car is actually hitting its fueling targets. If you're coming up short, the PCM sends the car into limp mode to save the engine. Fuel Rail Pressure should be ~600psi in hot idle & 2200psi+ at high load.

I recently had my High Pressure Fuel Pump go and it presented similar problems (albeit at a lower RPM).

 

[NormDriver]

Alright I'll try all of these suggestions and get back to you guys.

 

[DEss]

I've seen something similar pop up in here from time to time. It usually ends up being a map switching accident that is putting you into eco or valet mode. Check your map slot in the AP and make sure you are using the right tune. I believe it is quite easy to accidentally switch slots while driving.

https://www.youtube.com/watch?time_continue=50&v=vmvqXnQ48pg

Doubt it's an inadvertant map switch, since op states it happened even before the ap install.

 

[jtehh]

Doubt it's an inadvertant map switch, since op states it happened even before the ap install.

Yeah, it wasn't entirely clear that he was saying he only added the AP after the issue. But also, he bought used from somewhere - maybe there was a previous AP install in there.

I was just going with the most common solution I've seen here in the forums for similar issues. I think at least three times over the last few months (or year) someone complained that they basically went into a limp mode with no warning lights or overheating and it was later determined that they were flipping into the wrong map slot. Guess we'll wait and see. Hope one of the suggestions above helps him out.

 

[NormDriver]

Here is a data log I did from a cold start, I push the car more at the end and tried not to go much past 5k rpm so it wouldnt cut out. Idk if theres much helpful info here since I only understand the basics. https://datazap.me/u/normdriver/wont-rev-past-5-55k-rpm?log=0&data=5-9&hg=9

 

[jtehh]

Here is a data log I did from a cold start, I push the car more at the end and tried not to go much past 5k rpm so it wouldnt cut out. Idk if theres much helpful info here since I only understand the basics. https://datazap.me/u/normdriver/wont-rev-past-5-55k-rpm?log=0&data=5-9&hg=9

I'll preface this with I'm by no means a tuning expert (or even novice). But I read a bit and learn stuff here and there. I may find more, but the first thing that stands out is your AFR. It stands out because when I get a tune from Stratified they put this in their e-mail:

Actual AFR (Air-Fuel Ratios): AFRs at constant WOT should not be leaner (higher numbers are leaner) 12.5AFR and should range between 12.2 and 11.3 AFR (Fiesta and Focus ST).

For those WOT runs where your have pedal to metal, your AFR is typically 12.4 and higher. So you may be running a bit too lean? Not sure if that will cause it to limit revs though.

 

[NormDriver]

Yeah, it wasn't entirely clear that he was saying he only added the AP after the issue. But also, he bought used from somewhere - maybe there was a previous AP install in there.

I was just going with the most common solution I've seen here in the forums for similar issues. I think at least three times over the last few months (or year) someone complained that they basically went into a limp mode with no warning lights or overheating and it was later determined that they were flipping into the wrong map slot. Guess we'll wait and see. Hope one of the suggestions above helps him out.

The guy most likely did since he had a cobb sticker on the back and had the cobb air filter.

 

[NormDriver]

I'll preface this with I'm by no means a tuning expert (or even novice). But I read a bit and learn stuff here and there. I may find more, but the first thing that stands out is your AFR. It stands out because when I get a tune from Stratified they put this in their e-mail:



For those WOT runs where your have pedal to metal, your AFR is typically 12.4 and higher. So you may be running a bit too lean? Not sure if that will cause it to limit revs though.

Ye Ive noticed that but sometimes it does go below 12, so idk whats going on

 

[jtehh]

The guy most likely did since he had a cobb sticker on the back and had the cobb air filter.

Ah - and to go along with my previous response, if you haven't already done so, either uninstall the AP or flash the stock-like Cobb tune and see if the problem remains. It is possible the previous owner had a bunch of mods that he stripped off, but left you a stock-like car on an aggressive tune.

 

[NormDriver]

Check to make sure you don't have a fuel starvation issue. Use the AP to log your FRP Desired & FRP Actual to see if the car is actually hitting its fueling targets. If you're coming up short, the PCM sends the car into limp mode to save the engine. Fuel Rail Pressure should be ~600psi in hot idle & 2200psi+ at high load.

I recently had my High Pressure Fuel Pump go and it presented similar problems (albeit at a lower RPM).

The FPR levels seem to be ok, at idle it bounces around 600 and at higher revs goes up in 2000

 

[NormDriver]

Ah - and to go along with my previous response, if you haven't already done so, either uninstall the AP or flash the stock-like Cobb tune and see if the problem remains. It is possible the previous owner had a bunch of mods that he stripped off, but left you a stock-like car on an aggressive tune.

So I loaded in the stage 0 (stock tune) and it still happens. It cut off at like 5.5k rpm and the wrench light came on and when pulled into a street and stopped the car's idle was at like 500. Here is the log I did after I reinstalled the 93 map: https://datazap.me/u/normdriver/2nd-run-cuts-55k-rpm?log=0&data=5-10&hg=2-5-10-3

 

[jtehh]

So I loaded in the stage 0 (stock tune) and it still happens. It cut off at like 5.5k rpm and the wrench light came on and when pulled into a street and stopped the car's idle was at like 500. Here is the log I did after I reinstalled the 93 map: https://datazap.me/u/normdriver/2nd-run-cuts-55k-rpm?log=0&data=5-10&hg=2-5-10-3

Any codes coming up on the AP?

 

[NormDriver]

Any codes coming up on the AP?

When I was switching to the 93 map I saw the check engine light flash and stay on but then it started to install the map and I didnt get to see if it was any codes bc the light went away when the map installed

 

[NormDriver]

Any codes coming up on the AP?

But last week I got 2 codes, P0420 and P0339. One is for the catalytic converte thte other is for the cranskshaft positioing sensor. I cleared the codes and they havent came back yet. So strange