Very high LTFTs

[tomasidris]

Double check the pid trigger sampling time: every 1sec, or pid frame? Slow sampling time can cause missing pulses on O2 sensor signals (and other pids).

Well finally was able to replace that boot, cleared adaptations and went for a quick drive then logged this at hot idle: https://datazap.me/u/tomasidris/hot-...-12&solo=2-4-8

Looks a lot better already though time will tell when the adaptations start adjusting. I do notice a weird stutter now in 3rd at partial throttle, only 3rd too.

[sapote]

Well finally was able to replace that boot, cleared adaptations and went for a quick drive then logged this at hot idle: https://datazap.me/u/tomasidris/hot-...-12&solo=2-4-8

Looks a lot better already though time will tell when the adaptations start adjusting. I do notice a weird stutter now in 3rd at partial throttle, only 3rd too.

You did a great job!
LTFT went from over 18 to 1.5; MAF went from very low to proper around 4.5 g/s idling.
Sampling time is faster and O2 signals are switching faster as should be.

This engine is in great shape with perfectly low and even LTFt, how many miles on engine?

You accidentaly deleted coolant temperature in the log.

[tomasidris]

You did a great job!
LTFT went from over 18 to 1.5; MAF went from very low to proper around 4.5 g/s idling.
Sampling time is faster and O2 signals are switching faster as should be.

This engine is in great shape with perfectly low and even LTFt, how many miles on engine?

You accidentaly deleted coolant temperature in the log.

Ah, ill add that back. Sweet man yeah def feels noticeably better. At 231k miles rn and dont plan on stopping anytime soon lol.

[BL92]

What are you logging with ?

[tomasidris]

What are you logging with ?

Obd fusion app and a vepeak obd adapter

[tomasidris]

You did a great job!
LTFT went from over 18 to 1.5; MAF went from very low to proper around 4.5 g/s idling.
Sampling time is faster and O2 signals are switching faster as should be.

This engine is in great shape with perfectly low and even LTFt, how many miles on engine?

You accidentaly deleted coolant temperature in the log.

Aight little update, fuel trims now show over +20 again and am now getting a bank 1 too rich code which makes no sense this car is driving me crazy lol

[sapote]

Aight little update, fuel trims now show over +20 again and am now getting a bank 1 too rich code which makes no sense this car is driving me crazy lol

Post a new hot idle log with coolant T

[tomasidris]

Post a new hot idle log with coolant T

I selected coolant temp but ig it didnt register but heres the log: https://datazap.me/u/tomasidris/e46-...e?log=0&data=6

I was monitoring it the whole time though and it sat right at 82 C which is normal so.

[sapote]

I selected coolant temp but ig it didnt register but heres the log: https://datazap.me/u/tomasidris/e46-...e?log=0&data=6

I was monitoring it the whole time though and it sat right at 82 C which is normal so.

It must have a big intake air leak, as MAF is low, should be around 4.7g/s. Some thing popped out.

[tomasidris]

It must have a big intake air leak, as MAF is low, should be around 4.7g/s. Some thing popped out.

Leak tested everything past the maf and everythings tight. I do have an eventuri intake, could that affect anything?

[sapote]

Leak tested everything past the maf and everythings tight. I do have an eventuri intake, could that affect anything?

How do you know if the brake booster/hose are tight, no leak? Its check valve won't leak smoke from intake to fill in.

Ventui doesn't cuase air leak.

[y2k_o__o]

My 2002 M3 (130k miles) is also having the same issues in these 2 years, same high LTFT (15-20%, but no CEL) and did smoke test and no results, so today I decided to replace all my vacuum-related lines with new BMW parts in (documented in my E46 fanatics post) and I hope this is going to fix my leak.



1. airbox to oil pan drain hose (known to crack easily)
2. sucking jet line to brake booster
3. IACV elbow hose
4. cyclone to airbox cross tube
5. SAP to head hose
6. brake booster to jet sucking line grommet

Prior to this, I have also replaced my coil, plugs, fuel pump, cleaned my fuel injectors, new both pre-cat O2 sensors, new injector & air connection pipe seals & o-ring, replaced the cyclone, valve cover seals & gaskets and etc..... basically anything that has a SEAL involved, I have already replaced. This is driving me nut but I am not giving up.
I removed my catch can and reseted my adaptation (basically my setup is stock) and drove 20km today the LTFT is starting to climb up to 6-8% in both banks, but will report here again after 200km.

I swear if these measures can't fix this, my last resort will be replacing the brake booster.

[ATB88]

I've been here: replaced literally every sensor, hose, fuel part I could imagine (and even the brake booster) and could not get rid of my high LTFTs. Eventually just gave up :/

[y2k_o__o]

I've been here: replaced literally every sensor, hose, fuel part I could imagine (and even the brake booster) and could not get rid of my high LTFTs. Eventually just gave up :/

how high is your LTFT ? does it flare up the CEL ?

[ATB88]

IIRC they were sitting around 10-14ish, no CEL. Also did compression + leakdown test at that time which came back flawless. This was with a completely stock setup. Since giving up on chasing down the LTFTs, I've gone to a modded tuned setup (CSL box, SSV1 headers + cats, HTE dyno tune, SAP delete), so I'm not sure checking them now would be so meaningful. Car also has an extremely intermittent hard start issue that I was never able to figure out/solve despite changing every possible part one could imagine. I've always wondered if they were related.