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Discussion Starter · #1 ·
I've been getting these rather nasty large power dips at medium to light (maybe 20%) throttle (sometimes full throttle), where the engine seems to suddenly cut the boost and throttle, sometimes repeatedly in quick succession. Anyone else with the 1.4T Renegade having this problem? It is a new truck currently at about 500 miles, so it might be crap dealer gas so I'm giving it a chance for now. I have read about these engines having this issue in the past, but I have also read this has been mostly fixed (But I guess this is potential evidence of it not being fixed). Car runs fine otherwise. I guess I'll have to look into the wastegate preload adjustment if it isn't gas. Any other other is appreciated!
 

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Chrysler throttle position sensors are often uncalibrated from the factory.
This results in uneven throttle response from the pedal.

Here's the procedure swiped from another Chrysler forum.
Try it and let us know if it helps.


Throttle Calibration Procedure:

Throttle calibration can substantially improve throttle responsiveness over "factory standard." Many people notice what appears to be sluggish throttle response or a "dead area" at initial accelerator depression. Throttle calibration can take care of these.
1) Insert ignition key and turn to "ON" (not start).
2) Wait for all idiot lights to go out. Check Engine Light may remain on.
3) Slowly depress the accelerator pedal all the way to the floor.
4) Slowly release the accelerator pedal until it's all the way back up.
5) Turn the ignition key to "OFF".
6) Start the engine.
Most drivers notice an immediate change in throttle response, but depending on your driving style, you may need to repeat this procedure periodically due to the computer's adaptive programming. You likely need to repeat this procedure any time the battery is disconnected.
 

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I've been getting these rather nasty large power dips at medium to light (maybe 20%) throttle (sometimes full throttle), where the engine seems to suddenly cut the boost and throttle, sometimes repeatedly in quick succession. Anyone else with the 1.4T Renegade having this problem? It is a new truck currently at about 500 miles, so it might be crap dealer gas so I'm giving it a chance for now. I have read about these engines having this issue in the past, but I have also read this has been mostly fixed (But I guess this is potential evidence of it not being fixed). Car runs fine otherwise. I guess I'll have to look into the wastegate preload adjustment if it isn't gas. Any other other is appreciated!
If it's not wastegate then I'd take it to the dealer and have them run the scan tool on it. There could be a tell-tale fault stored on one of the many modules that wasn't bad enough to illuminate the MIL.
 

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Discussion Starter · #4 ·
Alright, I gave the calibration a try, seems to have helped. I could slightly feel it on occasion but it was far less abrupt. I think now I'll have to wait and see once I can get a tank full of 93 in there and see how it acts. That will also give the computer some more time to adjust I suppose as well. Thanks guys
 

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Alright, I gave the calibration a try, seems to have helped. I could slightly feel it on occasion but it was far less abrupt. I think now I'll have to wait and see once I can get a tank full of 93 in there and see how it acts. That will also give the computer some more time to adjust I suppose as well. Thanks guys
It may have been causing a full boost partial throttle situation. In most turbo cars this results in one of three/four things.


1) Dump lots of fuel into the cylinder to prevent detonation and reduce knock by using the increased fuel supply to pull heat out of the charge air. This usually feels like a bit of a power drop as you don't have enough air to go with if it is working. IF that doesn't reduce knock sufficiently then...

2) Pull ignition timing really hard. Which feels like a serious power drop. IF that doesn't work then...

3) Fuel cut! Turn off the injectors, because no fuel means no detonation. No detonation means your pistons live to see another day. At least in the cars I experienced this in, it was usually at uhh... highway speeds... yeah that's a suitable description.. in significantly cold weather. It feels like your car hit something without all the screaming and crunchy noises.

Newer cars may try to avoid doing number 1 for economy and emissions reasons. Newer cars also often have variable boost control which can be applied as step 0 or replace 1 - 3. It's reasonably graceful and non-violent but is a definite power loss. However, it is less likely to be effective with small turbos as they tend to suffer more from boost creep and can wind up with the wastegate being the primary boost limiter under a number of relatively common situations.

Also a weak wastegate actuator means that your wastegate may be limiting your boots to a lower PSI/bar than intended by the engineers.

For the 1.4 turbo, given the max boost specified in the documentation on it vs. what people playing with them in other vehicles claim to be the observed behavior regarding max boost, I would say that the small turbo is indeed prone to boost creep as is common with smaller turbos due to packaging issues, or because they put a small turbo on a larger displacement engine for the size of the turbo to reduce boost lag. boost creep doesn't suck power per se. It's just an efficiency issue and heats things up resulting in 1-3 above. Boost modulation doesn't help as much with it because it is a symptom of the wastegate not being sized properly unless it is a symptom of the car's boost controller having bad software, being mis-adjusted, or just generally sucking.
 

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Discussion Starter · #6 ·
Very nice explanation. It definitely was feeling like it was pulling timing, it hasn't been doing it lately though. I still get times here and there where it feels like there is a little less power than usual.
 

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Very nice explanation. It definitely was feeling like it was pulling timing, it hasn't been doing it lately though. I still get times here and there where it feels like there is a little less power than usual.
Another cause for that can be heat soaking the intercooler. Increase the charge air temp by keeping the intercooler too hot, you can get the above. Pretty common in (and for a bit after finally escaping) stop and go traffic in warm weather.
 

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Discussion Starter · #8 ·
Well took it to the dealer and they gave it some updates. This made the power dips/ surges less noticeable. Still having the issue. Decided to take it into my own hands and found this lovely gem:

Auto part Engine Vehicle Fuel line Automotive engine part


So FCA decided to make this not serviceable. Whatever is there it is some sort of hard epoxy. So adjusting the wastegate if needed isn't going to happen.
 

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Well took it to the dealer and they gave it some updates. This made the power dips/ surges less noticeable. Still having the issue. Decided to take it into my own hands and found this lovely gem:

View attachment 20361

So FCA decided to make this not serviceable. Whatever is there it is some sort of hard epoxy. So adjusting the wastegate if needed isn't going to happen.
A lot of manufacturers have non servicable parts. You have to spent a lot of money for a part that cannot be taken apart for something that would cost pennies to replace, if you could access it.
 

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Discussion Starter · #10 ·
A lot of manufacturers have non servicable parts. You have to spent a lot of money for a part that cannot be taken apart for something that would cost pennies to replace, if you could access it.
Just gets worse and worse. Should have bought a early 2000s car lol. No wonder the dealer only wants to tackle the problem via software. Well I installed a gfb dv+ seems to help a bit (At least that wasn't locked behind a steel cage haha). Got rid of flutter I was getting with the stock valve. It still hiccups every once in awhile but at way less frequency.
 

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I believe I am experiencing a similar issue. Feels like what an older car would do with dirty fuel injectors, or air flow sensors. Most noticeable in second gear, if I start around 2000 RPM and rev up to 3500 to 4000 before shifting, no matter what % of throttle, there is little "bumps" in power at around 2500 - 3000, like not enough fuel is there, or it's stuttering. I don't have any warning lights, and it's somewhat noticeable in 1st and 3rd gear, just not as abrupt. Any ideas? With everything being drive by wire, it's hard to pinpoint the possible cause.
 

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Yep. My '15 Sport 1.4 6m does the exact same thing. Like its missing some data points in the map. Revs hard in neutral, but moderate accel in a freeway on ramp, she hits some small dead spots along the acceleration curve. And the engine software is current.

I hope the Fiat 124 doesnt act this way. It'll make you shake your head walking away.
 

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Well took it to the dealer and they gave it some updates. This made the power dips/ surges less noticeable. Still having the issue. Decided to take it into my own hands and found this lovely gem:

View attachment 20361

So FCA decided to make this not serviceable. Whatever is there it is some sort of hard epoxy. So adjusting the wastegate if needed isn't going to happen.
The waste gate is the problem...relative of mine has the same power dip problem. Waste gate pressure loss or leak error code sent to ECU makes it pull timing and fueling...to protect the motor... Result is your power dip. Had to take turbo off and recondition the waste gate with a stronger actuator.
 

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Is that a warranty item?
Yes depending on when your warranty expires.
It actually is such a prevalent problem FCMC must look at full on recall.

We all know however a recall means some powertrain engineer is going to be fired.

That is why auto companies do their very best to sweep the problem[potential recall] under the carpet-"What Problem?"
 
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