[deezee18]

Not quite sure how to explain this but Ill try my best.

2007 BMW 328xi E90

Whenever I accelerate strongly, the car will accelerate and then pause for less than half a second, then continue. This happens about 2 or 3 times per gear before it shifts. Everytime the car hesitates it jerks, making it really annoying.

There are no codes showing up.

Any help would be greatly appreciated.

[CTinline-six]

How many miles (or KM's)on the car and has the fluid and filter ever been changed?

The 328i's have a GM transmission, GA6L45R, and GM specifies the fluid be changed every 50-60k miles or so with Dex VI fluid, contrary to BMW's "lifetime" fluid recommendation.

I'd start there.

[deezee18]

Originally Posted by CTinline-six

How many miles (or KM's)on the car and has the fluid and filter ever been changed?

The 328i's have a GM transmission, GA6L45R, and GM specifies the fluid be changed every 50-60k miles or so with Dex VI fluid, contrary to BMW's "lifetime" fluid recommendation.

I'd start there.

Car just hit about 163,000km (approx 100,000 miles).

Transmission fluid and transmission filter were change about 10,000km ago using Dex VI

[jt335i]

Were the solenoids checked/replaced when the transmission fluid and transmission filter was changed? If not, may need to do it. You may want to have the torque converter checked as well just to be sure.

[e90yyc]

6L45R does not have user-replaceable solenoids in the same fashion that the ZF 6HP unit does.

The solenoids are, for all intents and purposes, sealed within the TEHCM (mechatronics) unit. This can be replaced separately from the valve body, but it's pricey. And it may not necessarily solve the problems OP is having. ~160,000 kms is fairly low. My car has over 280,000 kms and while the transmission is far from perfect, it's not causing me major grief.

• Short of WOT acceleration, is transmission shift quality acceptable?
• I assume this issue was present prior to fluid change as well?
• When the car hesitates, do RPM's flare or stay static until acceleration resumes?
• Did you happen to note the condition of the fluid you replaced? Was it burnt, contaminated with metal shavings, or did it look okay?

[deezee18]

Originally Posted by e90yyc

6L45R does not have user-replaceable solenoids in the same fashion that the ZF 6HP unit does.

The solenoids are, for all intents and purposes, sealed within the TEHCM (mechatronics) unit. This can be replaced separately from the valve body, but it's pricey. And it may not necessarily solve the problems OP is having. ~160,000 kms is fairly low. My car has over 280,000 kms and while the transmission is far from perfect, it's not causing me major grief.

• Short of WOT acceleration, is transmission shift quality acceptable?
• I assume this issue was present prior to fluid change as well?
• When the car hesitates, do RPM's flare or stay static until acceleration resumes?
• Did you happen to note the condition of the fluid you replaced? Was it burnt, contaminated with metal shavings, or did it look okay?

- Having a small rough shift sometimes from 1st to 2nd..
- The issue was not present before the fluid change, but it did not start right after the change.
- RPMs stays in its spot
- Fluid looked fine, not too dirty and barely any metal shavings found in the fluid or on the magnet

[e90yyc]

Hmm!

So unless you’ve got the pedal to the floor, things are mostly okay? (Sorry - re-read your post and it sounds like it’s not necessarily full throttle, just strong acceleration; correct me if I’m mistaken)

I was going to ask you if it feels like the transmission is slipping, but if RPM’s are staying static, that wouldn’t really make sense...

How soon after fluid change did this start, and did it just suddenly begin at its current intensity, or did it start small and get progressively worse?

And if you keep constant throttle input, will this occur from gears 1 through 6?

How about using “manual” mode; does the jerking still happen, and if so, is it typically at same RPM’s each time?

Btw, where in Canada are you?

[3srsntswngr]

Not to sound dumb, but could this be NOT transmission related? I thought it may be a misfire hesitation before the codes show up. Mine did that for a bit, before i forced it to throw codes by heavily inducing the symptom.

[gbalthrop]

Originally Posted by deezee18

...2007 BMW 328xi E90 Whenever I accelerate strongly, the car will accelerate and then pause for less than half a second, then continue. This happens about 2 or 3 times per gear before it shifts. Everytime the car hesitates it jerks, making it really annoying. There are no codes showing up.

What did you use to read codes? Did you use INPA/ISTA or BMW-specific software that can read codes in ALL modules (such as Functional Jobs in INPA)? Did you specifically connect with the TCM and the Transfer case modules and read codes?

Without ALL available diagnostics, we can only guess, but you may have a problem with communication between the DME and the TCM, such as the TCM is NOT getting good, consistent RPM or load data from the DME. If the shifts are normal and positive at half of accelerator pedal travel, and only get ragged with MORE pedal travel, what about if you use Manual Shift mode (steptronic)?

George

[e90yyc]

Originally Posted by 3srsntswngr

Not to sound dumb, but could this be NOT transmission related? I thought it may be a misfire hesitation before the codes show up. Mine did that for a bit, before i forced it to throw codes by heavily inducing the symptom.

Yeah it’s definitely possible by the sounds of it, which is why I’m asking so many questions in order to *try* to rule some things out.

[deezee18]

Originally Posted by e90yyc

Hmm!

So unless you’ve got the pedal to the floor, things are mostly okay? (Sorry - re-read your post and it sounds like it’s not necessarily full throttle, just strong acceleration; correct me if I’m mistaken)

I was going to ask you if it feels like the transmission is slipping, but if RPM’s are staying static, that wouldn’t really make sense...

How soon after fluid change did this start, and did it just suddenly begin at its current intensity, or did it start small and get progressively worse?

And if you keep constant throttle input, will this occur from gears 1 through 6?

How about using “manual” mode; does the jerking still happen, and if so, is it typically at same RPM’s each time?

Btw, where in Canada are you?

Not necessarily 'to the floor' but enough so that the car starts shifting near the red line (so about 75%+). So yeah youre correct.

I want to say it started about a month after the fluid change. Its been pretty consistent since it first started, hasn't really gotten worse.

As far as I can tell it happens mostly in the first couple of gears but I havent really had the oppurtunity to get into 6th gear and floor it lol.

Still happens in manual mode. Based on my memory its at about 4000 RPM, 5000RPM and then maybe at 6000 RPM but Ill need to double check

Im in Ottawa

[deezee18]

Originally Posted by 3srsntswngr

Not to sound dumb, but could this be NOT transmission related? I thought it may be a misfire hesitation before the codes show up. Mine did that for a bit, before i forced it to throw codes by heavily inducing the symptom.

Had the shop check my sparkplugs and they all seemed fine. Did you just continually floor it until codes showed up?

[deezee18]

Originally Posted by gbalthrop

What did you use to read codes? Did you use INPA/ISTA or BMW-specific software that can read codes in ALL modules (such as Functional Jobs in INPA)? Did you specifically connect with the TCM and the Transfer case modules and read codes?

Without ALL available diagnostics, we can only guess, but you may have a problem with communication between the DME and the TCM, such as the TCM is NOT getting good, consistent RPM or load data from the DME. If the shifts are normal and positive at half of accelerator pedal travel, and only get ragged with MORE pedal travel, what about if you use Manual Shift mode (steptronic)?

George

Had my local shop take a look with their scanner and they stated there was nothing. From what I remember it was the ipad looking snap on scanner.

Still happens when I use Manual mode

[e90yyc]

Scanner should be good. It’ll be able to address all the individual modules.

Thanks for providing all these details. Am currently thinking!

[adam_c]

Can that scanner show shadow codes?

Example I bought an OBD2 scanner and everything was ok

I then bought a kcan cable and scanner with inpa and found codes that were not showing on the obd2 scanner as well saw some codes that occurred in the cars past that didn’t generate a SES

[e90yyc]

Originally Posted by adam_c

Can that scanner show shadow codes?

Example I bought an OBD2 scanner and everything was ok

I then bought a kcan cable and scanner with inpa and found codes that were not showing on the obd2 scanner as well saw some codes that occurred in the cars past that didn’t generate a SES

The Snap-On scanner I have used in the past was able to, yes. I’d imagine they all can, as they aren’t just your average OBD scanner, but I could be wrong.

[adam_c]

Originally Posted by e90yyc

The Snap-On scanner I have used in the past was able to, yes. I’d imagine they all can, as they aren’t just your average OBD scanner, but I could be wrong.

If you still have it we could test it one day

[franksinatra]

I had this exact same issue but maybe not as apparent. I would have to be in a high gear and accelerate, but not enough that it changes gears and the car would stutter until I gave it more gas and it downshifted. It was worse when the AC was on or when I was going uphill. I ended up replacing all my coil packs and spark plugs which resolved it for me. Just my two cents!

[deezee18]

Originally Posted by adam_c

Can that scanner show shadow codes?

Example I bought an OBD2 scanner and everything was ok

I then bought a kcan cable and scanner with inpa and found codes that were not showing on the obd2 scanner as well saw some codes that occurred in the cars past that didn’t generate a SES

Yea it shows codes in memory and a bunch of other things. Its a pretty legit scanner

[deezee18]

Originally Posted by franksinatra

I had this exact same issue but maybe not as apparent. I would have to be in a high gear and accelerate, but not enough that it changes gears and the car would stutter until I gave it more gas and it downshifted. It was worse when the AC was on or when I was going uphill. I ended up replacing all my coil packs and spark plugs which resolved it for me. Just my two cents!

Did you have any codes being thrown? Correct me if Im wrong but I feel like anything related to the coil packs or sparkplugs should throw a code right away

[3srsntswngr]

Originally Posted by deezee18

Had the shop check my sparkplugs and they all seemed fine. Did you just continually floor it until codes showed up?

Basically, yes. Those misfires happened more in low rev, high load situations though. Yours dont quite fit that situation. But yeah, I put it in a higher gear and gave it lots of right pedal at low rpms and after a lot of hesitations in a short amount of time the light came on and i got misfire codes

[Bmw_Crazy]

Originally Posted by deezee18

Not quite sure how to explain this but Ill try my best.

2007 BMW 328xi E90

Whenever I accelerate strongly, the car will accelerate and then pause for less than half a second, then continue. This happens about 2 or 3 times per gear before it shifts. Everytime the car hesitates it jerks, making it really annoying.

There are no codes showing up.

Any help would be greatly appreciated.

Check your coils