[Anthonyd335]

My car is a 2015 335i fbo stage 2 bm3 and stage 2 xhp as well. 69k miles

For the past few months I’ve been noticing something odd with my car, it seems to happen mostly when im lugging the engine a bit while trying to pass cars. If I have it in manual mode and don’t downshift before accelerating occasionally I’ll get a strange jolt or hiccup which was fine initially because I don’t ever lug the engine on purpose so I started to change my habits to make sure I’m in drive mode or sport.

Recently it has started happening more and more often when I’m accelerating hard, usually happens right after I hit the gas and doesn’t happen during a long pull. If it happens and I push through it will keep jolting and jerking but If I let off the gas and slowly roll back into it it will go away

I’ve had another issue which I’m not sure but could be related. It seemed to start after I had an issue with my car misfiring randomly (turned out injectors were bad) after I fixed it I started to notice right around the top of the rpm range just before shifting at WOT I get a few small pulses from what seems to be the drivetrain as the motor doesn’t drop in rpm at all.

I’m starting to think that my Torque converter lockup clutch could be slipping. Just want some more opinions before I start looking for an upgraded converter.

My plan for now is to do a fluid and filter change and see what happens from there. Doesn’t happen all the time so I’m not too worried about it yet but Better to be prepared.

I know the zf8 is a bit more complicated than a standard automatic so I’m hoping maybe my problem could be elsewhere but I do drive it hard so I wouldn’t be too surprised if my converter was failing.

Thanks in advance.

[Pussiwillow]

When was the last time you did spark plugs

Also, usually when trouble shooting the consensus is, revert back to stock tunes and see if the problem goes away

[435gc]

And a log por favor

[Anthonyd335]

Originally Posted by Pussiwillow

When was the last time you did spark plugs

Also, usually when trouble shooting the consensus is, revert back to stock tunes and see if the problem goes away

I did plugs about 5k miles ago gapped to .022 for the tune

[Anthonyd335]

Originally Posted by 435gc

And a log por favor

I’ll try and get a log it can be hard to replicate the problem and my obd cable is finicky haha

[ctt300]

Bet this is misfires. I'd gap larger like .027 or a bit larger and also try diff gas. But get some logs in 4th gear 2k - 6500

[Anthonyd335]

Originally Posted by ctt300

Bet this is misfires. I'd gap larger like .027 or a bit larger and also try diff gas. But get some logs in 4th gear 2k - 6500

I had them gapped to .026 out of the box and my car was detonating and I believe that the detonation is what caused my injectors to fail

Maybe I should try like .024?

[ctt300]

Sounds like you need more octane not changing plug gap then. Look up top tier gas and use that premium fuel and might want to use a few gallons of E85 too.

Use gas buddy app to find E85. Do not lug the engine and especially on whatever gas you are using. That is the highest load you can put on an engine and you definitely do not want to be detonating in that scenario or any scenario really or you risk ring, piston, rod, rod bearing damage. Think of taking a hammer to those parts. What gas brand?

[Pray for Mojo]

Don't lug high powered turbo cars by mashing the gas at low RPM. You can induce LSPI blow them up with max torque and all the strain on components. There's a reason the car will automatically downshift when you mash the gas.

I would run a standard log to see how everything is working WOT from 3k to redline. If you have bad gas it would show up there.

[Anthonyd335]

Originally Posted by ctt300

Sounds like you need more octane not changing plug gap then. Look up top tier gas and use that premium fuel and might want to use a few gallons of E85 too.

Use gas buddy app to find E85. Do not lug the engine and especially on whatever gas you are using. That is the highest load you can put on an engine and you definitely do not want to be detonating in that scenario or any scenario really or you risk ring, piston, rod, rod bearing damage. Think of taking a hammer to those parts. What gas brand?

My friend runs e30 on the bm3 tune and it ran pretty good. Only problem is the closest e85 pump is 35 minutes away. I was hoping to wait for the customrom update for the n55 so I could use on the fly map switching before running ethanol.

I typically fill up at Cumberland farms mobil or shell gas startions. I try to not use the sketchy ones that are really cheap.

[Anthonyd335]

Originally Posted by Pray for Mojo

Don't lug high powered turbo cars by mashing the gas at low RPM. You can induce LSPI blow them up with max torque and all the strain on components. There's a reason the car will automatically downshift when you mash the gas.

Yea I know it’s not good for it but I usually just forget I’m in manual mode and I hit the gas. But I’ve stopped doing that since I’ve noticed this.

[Munchi435i]

Originally Posted by Anthonyd335

My friend runs e30 on the bm3 tune and it ran pretty good. Only problem is the closest e85 pump is 35 minutes away. I was hoping to wait for the customrom update for the n55 so I could use on the fly map switching before running ethanol.

I typically fill up at Cumberland farms mobil or shell gas startions. I try to not use the sketchy ones that are really cheap.

I run a custom E40 tune and similar distance to get E85. When I'm lazy I just fill up with 93 and reflash my 93 tune. Takes less than 30 seconds.

[Anthonyd335]

https://www.bootmod3.net/log?id=6056...729b1ca03c4e56

There is a link to the log I rolled into it starting at 2k rpm all the way to 7k. Everything felt fine but who knows maybe someone can gather something from this.

[thejeremyman9]

Originally Posted by Anthonyd335

I had them gapped to .026 out of the box and my car was detonating and I believe that the detonation is what caused my injectors to fail

Maybe I should try like .024?

I don't see how your plugs could have affected your injectors at all - any evidence or are you just speculating? How do you know your car was detonating with the 0.026 gap? Also, it seems you fell into the spark plug trap. Realsitically you should be totally fine with stock plugs on stock gap (~0.030-0.032). There's no reason to go to the colder plugs with small gap unless you car is having issues on the OEM ones.

Originally Posted by Anthonyd335

https://www.bootmod3.net/log?id=6056...729b1ca03c4e56

There is a link to the log I rolled into it starting at 2k rpm all the way to 7k. Everything felt fine but who knows maybe someone can gather something from this.

I took a quick look at the log. First of all you need to go WOT quickly for a "proper" 4th gear log, not roll into it. Just make sure you are at about 2500 or higher and mash the gas. You can read more in my datalogging thread here: https://f30.bimmerpost.com/forums/sh....php?t=1732327

Nonetheless, i took a quick look at the log. The most obvious thing is that your HPFP pressure is dipping pretty significantly. Not enough for a "crash" persay but more than i would run if it happens consistently. Did you add any E85 in this tank? Your trims are fairly positive if you didnt have any E85; if you added some that's expected.

You don't have any knocks, timing is ok but not great, especially cyl 3. Ideally you get 2-3 logs (spaced a bit to cool down between) so you can see if there is a pattern or if maybe this was a fluke.

Nothing else really jumps out.

[Anthonyd335]

Originally Posted by thejeremyman9

I don't see how your plugs could have affected your injectors at all - any evidence or are you just speculating? How do you know your car was detonating with the 0.026 gap? Also, it seems you fell into the spark plug trap. Realsitically you should be totally fine with stock plugs on stock gap (~0.030-0.032). There's no reason to go to the colder plugs with small gap unless you car is having issues on the OEM ones.



I took a quick look at the log. First of all you need to go WOT quickly for a "proper" 4th gear log, not roll into it. Just make sure you are at about 2500 or higher and mash the gas. You can read more in my datalogging thread here: https://f30.bimmerpost.com/forums/sh....php?t=1732327

Nonetheless, i took a quick look at the log. The most obvious thing is that your HPFP pressure is dipping pretty significantly. Not enough for a "crash" persay but more than i would run if it happens consistently. Did you add any E85 in this tank? Your trims are fairly positive if you didnt have any E85; if you added some that's expected.

You don't have any knocks, timing is ok but not great, especially cyl 3. Ideally you get 2-3 logs (spaced a bit to cool down between) so you can see if there is a pattern or if maybe this was a fluke.

Nothing else really jumps out.

I wasn’t running any e but do you think I should upgrade the hpfp?

I was speculating that maybe one time when I was getting detonation that it damaged one of the injectors but not positive.

[thejeremyman9]

Originally Posted by Anthonyd335

I wasn’t running any e but do you think I should upgrade the hpfp?

I was speculating that maybe one time when I was getting detonation that it damaged one of the injectors but not positive.

Of course you always can upgrade the HPFP but realistically you shouldnt need to on the OTS pump gas map. But if you do and run E85 mix, you at least have the 2+ map for more power.

[Anthonyd335]

Alright well I have an update with more problems.

Since I changed my transmission fluid and filter I’ve been having odd problems.

1. I let my friends dad try launch control and it acted strange so I tried it myself and something is very wrong. When I hold the brake and gas everything is fine until I launch. After the car starts to move it will get about half way through the rev range then i feel a cut in power so I let off the gas then it shifts to second gear and makes this horrible whining noise, it goes away after you slow down and doesn’t come back until you try launch control again.

2. When you mash it in first gear about half way through the rev range there’s a weird little break in power, not sure if this is when the converter locks or what is going on but it definitely didn’t do it before

3. I decided to try and launch the car without using the actual launch control, and I was in sport shifting mode(definitely not manual mode) and when the car reaches the top of second gear it just hit the limiter and I freaked out because I didn’t want to let it rev out so high and I manually shifted it to 3rd.

First two problems have happened more than once, and the third problem only occurred one time.

If anyone has any ideas please let me know. I’m starting to regret that fluid change now but I really don’t how new fluid could’ve done this after only 70k miles.
(Also forgot to mention that I did remove and reflash my xhp trans tune and it made no difference)

[thejeremyman9]

Originally Posted by Anthonyd335

Alright well I have an update with more problems.

Since I changed my transmission fluid and filter I’ve been having odd problems.

1. I let my friends dad try launch control and it acted strange so I tried it myself and something is very wrong. When I hold the brake and gas everything is fine until I launch. After the car starts to move it will get about half way through the rev range then i feel a cut in power so I let off the gas then it shifts to second gear and makes this horrible whining noise, it goes away after you slow down and doesn’t come back until you try launch control again.

2. When you mash it in first gear about half way through the rev range there’s a weird little break in power, not sure if this is when the converter locks or what is going on but it definitely didn’t do it before

3. I decided to try and launch the car without using the actual launch control, and I was in sport shifting mode(definitely not manual mode) and when the car reaches the top of second gear it just hit the limiter and I freaked out because I didn’t want to let it rev out so high and I manually shifted it to 3rd.

First two problems have happened more than once, and the third problem only occurred one time.

If anyone has any ideas please let me know. I’m starting to regret that fluid change now but I really don’t how new fluid could’ve done this after only 70k miles.
(Also forgot to mention that I did remove and reflash my xhp trans tune and it made no difference)

Dont know why you would be launching a car that has problems lol...

Anyways how confident are you in the trans fill procedure? Did you measure the amount of fluid coming out and going in? Did you monitor trans temp, go through gears, etc?

Did you remove your BM3 tune and go back to stock and try that?

[ctt300]

Did you use the ZF Lifeguard fluid or another like Liquid Moly? I've heard that you must drain all the ZF fluid out and not to mix another brand even though both will work. You've got different chemistries at play and don't want to mix and have it not perform properly.

[Anthonyd335]

Originally Posted by thejeremyman9

Dont know why you would be launching a car that has problems lol...

Anyways how confident are you in the trans fill procedure? Did you measure the amount of fluid coming out and going in? Did you monitor trans temp, go through gears, etc?

Did you remove your BM3 tune and go back to stock and try that?

I’m decently confident on the fluid swap I didn’t measure what came out but I got about 3.5-4 qts in there (didn’t drain the converter if that’s even possible) but it was spilling out pretty good and I lowered it let the trans warm up then got another half quart in there then took it for a 10 minute drive brought it back and checked the fluid again to be sure and it was spilling out a lot and it got all over me haha so I’m pretty sure it’s full but I will definitely be checking it again to be sure.

I didn’t try removing bm3 but I will try that now

[thejeremyman9]

Originally Posted by Anthonyd335

I’m decently confident on the fluid swap I didn’t measure what came out but I got about 3.5-4 qts in there (didn’t drain the converter if that’s even possible) but it was spilling out pretty good and I lowered it let the trans warm up then got another half quart in there then took it for a 10 minute drive brought it back and checked the fluid again to be sure and it was spilling out a lot and it got all over me haha so I’m pretty sure it’s full but I will definitely be checking it again to be sure.

I didn’t try removing bm3 but I will try that now

So did you just wing it as you described or follow the actual procedure? There are specific temperatures, running through the gears in the air, etc. I wouldn't rely on guess and check.

[Anthonyd335]

Originally Posted by thejeremyman9

So did you just wing it as you described or follow the actual procedure? There are specific temperatures, running through the gears in the air, etc. I wouldn't rely on guess and check.

Yea I watched fcp euros video on it and I didn’t follow it 100% but the transmission must’ve gotten to temp because I drove it around town for about 8 miles in 65 degree weather before I check the level for the second time.