High rpm bogging
 

Long history in a short period. NA engine rebuilt after rocker arm/timing chain issue. What would cause the ignition timing advance to drop at wot? Still waiting for my tuner to get back to me.



https://datazap.me/u/blsfrs/log-1644...&data=10-20-21

Funnier behavior. If I push the pedal 3/4 (under load, 2nd and 3rd gear pulls) to the floor, the rpms go from 3000 to 7300, no problem.



If I push the pedal 4/4, at around 5000, the engine bogs like hitting a rev limiter and my ignition advance drops to 3*-5*. The point that the advance drops can vary from 4500 to 7000.


Are there any diagnostics I can do while waiting to hear back from my tuner, Said he's going to look at my logs this weekend.

Did something get changed in the tune recently or is this just since the rebuild?

is it running lean??? or rich??? when you go to full throttle it uses a different part of the map, but something physical or in the tune is off.... not getting enough fuel???

Here's the timeline (and I didn't even mention the broken driveshaft).


March 2021: Ingested something in #3. Ejected intake rocker arms, broke timing chain. Complete rebuild by Cody Dawson. Injectors serviced by Injector Pulse. Engine reinstalled September 2021



PROBLEMS SINCE REINSTALL


Intermittent P0219a and P0119f (AFR codes) and decreased power.



Replaced: MAF, MAP, upstream 02 sensor. No change.


January 2022: PTuning: No problems found. Retuned. NEW PROBLEM: Upon picking car up, found bogging at 5500-6500rpm. On the way to Charlottesville the CEL for secondary 02 came on but hasn't come on again. No improvement with replacement of throttle body.


February-March 2022; Bogging/decreased power worsened to the point where the car wouldn't go over 35-40 mph. Upstream cat removed after temp/back pressure tests. Immediate improvement in power up to 6000rpm then bogs like hitting rev limiter. Sometimes improves with 3-4 3rd gear pulls but bogging returns next drive cycle. Installed Nameless 2.5" catted midpipe: No change in bogging. CEL for P0219a and P0119f came on last week.


A couple of weeks ago went back to PTing. Their guy could not reproduce bogging. He then rode with me and I reproduced it with him in the car. He and their tuner went out to data log but could not reproduce bogging. I finally was able to send them an Ecutek datalog and am waiting to hear back from them.

Tuner at Ptuning says everything looks good.

Can you log what the sensor voltage outputs are in Ecutek? I wonder if you have something going out or range on the higher end. Also hard to tell if it is picking up any knock and that is why it is pulling timing, though I doubt this is the case. I'd imagine the PT gus have looked at that already. It's hard to tell what's the chicken/egg.

Here is the Ecutek log. I mostly don't know what I'm looking for but I can see the ig timing drop. Any Ideas? Thanks



https://datazap.me/u/blsfrs/log-1651...og=0&data=7-12

That is strange. I was hoping to see a hardware issue pop out but maf is stable as is afr so I doubt the O2 is acting up. KC is 0 with a tiny bit of KC learned. We are over my head. Maybe Tomm or Steve will chime in. I wonder if something else is causing the timing compensation table to wig out and drop out the advance. Any missfires? It for sure can't rev out with it pulling timing that far out.

Lately this car has cornered the market on strange. I get no indication of missfires. As I said earlier, if I hold the pedal at 3/4, it will rev to 7300rpm. If I really floor it , it bogs.


I noticed that none of the PTuning drivers seemed to change my seat position. I have long legs. So, I question if those drivers could push the gas pedal as far as I can. Also, the car was tuned with a failing cat.

AFR looks too rich at high RPM. Way beyond needed. Out of the range that the stock O2 sensor can handle.

What is going on with the DI from 4.5 to 5.5 seconds into that log? Fuel rail pressure too. Like an intermittent electrical something cutting out from vibration. Red herring? it doesn't happen in the second pull. I'm always afraid to join in on these discussions.

Something is quite off mechanically/electronically, also we can t see the tune or if he used custom maps too so really can t help, just look to me that something is too off to be tune related

Good observation. I didn't see that before. It looks like the afr goes rich when the timing advance drops. Maybe it unburnt fuel as a result of lack late spark?

When I first got the engine in the car, I was a little low on power (160ish hp on the dyno) and would get intermittent P0219a and P0119f codes but it would rev to 7300 without bogging. I took the car PTuning for diagnostic work and they said it needed tuning. Their printout showed 198hp after tuning The bogging problem did not manifest until after having it tuned.



I'd really like to rule out a mechanical problem.

and how does it work with oem tune?

I could see that at the top of the pull. You lifted off the throttle a bit and the timing went up to 21. Really strange.

I saw that too but wasn't sure what to make of it.

^^ this. It's too weird to be tune.

I was thinking hardware too, but I am not sure what sensor input(s) would cause a timing reduction without an associated code. It doesn't show knock correction happening. There are timing compensation tables for things like IAT, and coolant temp. We can see IAT and coolant temp in the log and they look fine. There may be others in Ecutek, I dunno :iono: The timing drop with full throttle is weird. Hopefully the issue gets found so we can learn something new.


...oh, and blsfrs have his issue resolved.

OK, Noob question, can I switch to the oem tune by fiddling with the criuse lever? Map 1 vs map 2? Or is this something different?


The tuner is scratching his head too. Asked for another datalog looking at VVT. I thought that was on when I did the last log but apparently not. I hope to post the new log this evening.


Thank you all for imput.

without having the opened tune on hands is not easy to understand everything, and your log seems to have few values logged, are you logging from the dashboard on the ecutek app?
you could try logging much more values like every custom map output, speed desnity value if present etc and see if we could understand the tune more.. so log many more values

also,... try oem tune

you can t have both tune on hands with the xruise, you need to flash back to stock tune then you can go back to your usual tune when you want

now that i rrmember,
it could be that you get VVT disabled during wot pulls
This sometimes happens when 40 of cam intake is requested
40 is too much for many cars, the fix is to set 39 on tune instead of 40
It could then trigger Base timing A map to be used, ence the reduced timings on your log

Log Please vvt enabled value, together with all vvt values and ask tuner to set 39 of max cam intake advance instead of 40

i once got a guy tuned by Fensport having vvt disabling on wot and i fixed it just by set 39 instead of 40

Does your tune have FFS flat foot upshift enabled ? if so it migh be the clutch detection switch faulty trigging the FFS function, or your resting foot slightly on clutch trigfering the FFS function when throttle is 100%

I'll check on FFS. I didn't know it was a thing. Didn't get a log yesterday, my assistant was busy. Will try tonight. I'll make sure I'm not unconsciously resting my foot on the clutch.

make sure to log clutch switch with the other things

@steve99, I think you are an absolute GENIUS! I took a lunchtime test drive and NO BOGGING!! It took an extreme amount of concentration for me NOT to rest my foot on the clutch in prep for shifting but by not touching the pedal the car performed perfectly. Now I will test again on my commute home just to make sure and report back. Thanks again to everyone.

You can adjist the clutch detect switch to be lessxsensitive, its the one thats at the start of clutch operation ie at top , fhe one that detects if clutch on floor is the start safety switch.


Or if you never use flat foot shift get tuner to disable it in tune

I drove home this afternoon and was able to do a couple of pulls and VOILA', no bog. I experimented with the cruise control. The slightest touch on the clutch pedal turned it off. As per @steve99, I will have the tuner disable FFS since these transmissions would probably go bang after 2-3 FFS's. Thanks again.

This is one of the most interesting solves in a while. Just last weekend, my wife re-told the story of how her dad would call her out for resting her foot on the clutch.

10/10 thread.

good steve finds always a way, he s the best:)

i got confused by the fact his. log didn t have all the normal values logged by default by ecutek, but now we know it s kind of easier to spot from the afr target he gets too

steve we love. you

+1 Steve. Even took the time to mostly spell-check. Maybe someone hacked his account. ;)

I was thinking that it would be interesting to log everything while playing with the switch, but it already makes perfect sense in hindsight.

yes when you log clutch switch (it s not default value) it shows immediately as clutch switch value would jump to 1 when it starts the bog

Yeah, that was a good one :thumbsup:

Finally putting this one to bed. PTuning sent me an update which turned off ffs and P0420. I can drive my car with my foot touching (but not riding, since I don't want to piss off @ultramoon's father in law)) the clutch before I shift. What a joy.

the standard ecutek FFS setup is quite harsh as it actually hold the rpm 200 rpm above the rpm clutch was pressed. for smooth shifts you want to have the rpm hold between 200 less to 1200 rpm less than when clutch pressed ( depending on the rpm of shift, i calculated this of the average gear ratio change and this produces very smooth shifts like an auto actually smoother than you can do yourself.

On the dyno, it actually looks fairly smooth.


https://www.youtube.com/watch?v=BA8qrWMwYH8

That's terrible! Why even bother having the feature?

that' s terrible for the clutch and transmission. but allows for the quickest shift, as it "pushes" the car forward as you change gears


Wouldn t use it anyway. i put the rpm lower always like steve said

I have had the same problem with my car. Sudden cut of between 5 and 7k rpm about 5 times now. I went out driving today and tested the cruise. It took an unbelievably baby push on the clutch to turn it off. I usually run my car with the tune that includes racerom features. I like the auto blip.

So I tried to replicate the cutoff. Couldn't do it. Now going to run the tune without racerom and see if it happens again.