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Jerking in every gear (AWD tire tread?)

Started by waltong, January 29, 2019, 04:04:15 PM

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waltong

I have a 2013 ecoboost interceptor. I have a problem under light acceleration where the car jerks and rpms flutter through every gear.

I was told it might be the awd system getting confused. Tires are all 24/45/r20 but the tread depth is different:
5/32 front/right
8/32 front/left
7/32 back/left
7/32 back/right

Would this cause an issue?

Tire pressure light is on as well even though pressure is good.

Original wheels were 18", these are the 20" SHO rims on it now.  Does the computer require programming by the dealer if the wheel size is changed?

ZSHO

#1
I don't think the AWD System would cause your symptoms to flutter @ every gear..

It sounds like you have a faulty TPMS or check the Speed sensors.

Here's a good article on the AWD System. .

http://www.hendonpub.com/resources/article_archive/results/details?id=5091


2013 Performance Package SHO| Livernois Custom Methanol Tune|3-Bar Map|Reische-170-Stat|Full Race Tial-10psi BOV in Black|PPE-Gloss Black Hot Pipes|EPP Dual Intake in Gloss Black|PPE Catted DP|Corsa Sport Cat Back Exhaust|H&R Sport-Springs|CFM Performance Billet Valve Cover Breather In Gloss Black|Llumar 20%Ceramic window Tint|MSD Ignition Coils in Black|Extreme Roof Spoiler|Redline Fluids all around|Gearhead Intercooler|First-SHO With Direct Port Alky-VP-M1-100%-Methanol Injection|LMS-Custom-Dyno-Tuned @ 415whp-465wtq| Best Trap Speed of 115.54 mph|

SHOdded

If the difference in tire height is 3% on an axle, yes, it can cause AWD problems.  3% is the tolerance limit for variance.

As it sits, the tread depth difference is not significant to AWD except if it causes traction differences.  Traction differences will cause the ABS to modulate wheel speed accordingly.

Symptoms point to PTU though, especially if they occur under light throttle at cruising speeds.  I believe there is a TSB on that somewhere.

RPM flutter is a completely different animal and could point to torque converter.
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

AJP turbo

#3
That doesn't sound like a hug variation in tread depth. I would want to drain and refill the trans a few times and use a high quality fluid in the proper viscosity obviously and one that meets the oem spec. But it sounds like the torque converter a bit.

Also without working out the math I'm not sure if those overall tire diameters are the same between those 2 sizes but if there is a variation I would want to correct for that with a tune. I noticed in my IDS software that there are a couple different tire size options  that dealers can flash so if your overall diameter is different I definitely could see that affecting trans operation.

Sometimes its not clear exactly what the ECU does with all the data it gets from the sensors...There is so much today
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