[Jordii]

Recently got my 335d remapped and haven’t really had time to thrash it until early this week. Noticed an odd thing happen when in higher mph ( between 80-120mph). At full throttle the car will pull very hard up until these speeds then falls off and goes in a sort of limp mode ( low power ) and won’t pull any further but no lights come on the dash. It’s stuck in this limp mode until you stop the car and turn it off and on again. Then it’s back to pulling like a train until it goes into limp mode again.

But the odd thing is if you don’t go full throttle it will pull well onto the speed limiter with no issues. I’m unsure if this problem is to do with the tune or something that’s happened that’s nothing to do with the remap.

Wonder if anyone’s encountered this problem. Thinking about going back to the tuner and seeing if it’s their fault.

TIA

[RL18]

Some others that are smarter than me will chime in but you should do a 4th gear pull from 1,500-redline on some type of logging program like testo or torque and log boost actual vs requested, Maybe fuel rail pressure, rpm, speed, and graph it. That'll tell you more what's going on

[Deftronix]

Check all your boost hose connections. I had this issue when my chargepipe turbo side wasn't 100% seated properly. On stock map, it didn't happen but after going stage 1 it did.

The remap is most likely now requesting more boost and the variance of what it's actually getting is out of threshold because of a leak and causing dde to go low power.

Could definitely be a tune issue as well if it is not one of the "mainstream" maps but would start by checking your chargepipes / vacuum system before asking the tuner to fix.

[FlaPatsFan]

Jordii, I had a similar issue. However I have a 328i. Basically after I got my second tune done after catless header install I was experiencing a “limp” mode at high RPMs. Car shut down into a protection mode. Restart car and was fine.

Ultimately it turned out to be a faulty alternator sending high/low voltage confusing the ECU. I replaced the alternator and problem solved. Car running great. Not sure this applies to your 335 but thought I would chime in.

[VladPC]

The fault should be very high exhaust temperature.
Who tuned your car didn't monitor the exhaust temperature and added too much fuel. He compensated with too much mg/stroke...and I will tell you why. It's because the high pressure fuel pump limited his tune. He should reduce the fuel compensation (mg/stroke).

Bring the car back to your tuner, tell him to go for a drive with you in the passanger seat, make him bring his diagnostics tools with him and have him monitor exhaust temperature while you thrash your car as when it went into limp mode.

Please let us know what you have done and how did you fix it, eventually. Thank you!

[Owen81]

Just do some logs first, most likely a boost or fueling issue

[Jordii]

Thanks for the help. I’ll do a boost leak test and see what I find. I replaced the common leak problem off the red pipe going into the intercooler thinking it may be that but it’s still there. What logging/monitoring software would people recommend ?

[Owen81]

ProTool, Testo, Torque with the DWR PIDs

[Jordii]

fault found
Only just got round to doing some investigation to what the problem is. Done a boost leak test with no leaks found. When inspecting round the engine noticed a lot of the vacuum pipes are in very bad condition. With one been snapped in half all together. Pipe at the front drivers side of the engine just as it goes into the ‘pouch’ thing that holds the pipes together.. Didn’t have any new hose so put a temporary fix in. Took it out and performs great no limp mode at full throttle and pulls well in all the gears. Also noticed a drastic increase in fuel economy. I saw a thread about replacing the vacuum hoses but it was from a while ago. Anyone recommend what hose would be best to replace the original ones ?


Thanks again

[Deftronix]

Glad you were able to get to the bottom of it!

https://www.tunemyeuro.com/cloth-cov...i-bmw-engines/

[Jordii]

Originally Posted by Deftronix

Glad you were able to get to the bottom of it!

https://www.tunemyeuro.com/cloth-cov...i-bmw-engines/

Great thanks. Hopefully get round to fitting them this weekend. Wonder how many more leaks I find