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Good morning guys,
I have found myself in a pickle. On the way home from work yesterday, my car started doing something I have never seen or heard of before, and would love some input from you all.
To preface the scenario:
My car is an AP1 that has been turbo charged by me with a TRUST turbo kit;
the exhaust is being routed through a cat-less J's racing exhaust;
vitals are being monitored by gauges from apexi, defi and AEM;
and everything is being managed by a Haltech Platinum Pro with a street tune done by me.
I will also say that the car has been turboed for about 6 months and hasn't given me any problems (until yesterday).
SOOO, this is what happened: I started my car after work, and pulled away. When I pulled away the car stopped revving at about 2700-3000 rpm (wouldnt rev higher no matter if I opened the throttle more) but gradually built up boost (way more than the preset 8lbs btw). the only way to stop it from glitching out like this was to let off the gas, them the internal waste gate would pop open and the car would act like normal, for a bit. But, then it would go back to getting stuck at that same rpm on accel.
At first I had no idea that any of this was happening because it felt so strange. At first, I thought I was dragging a wheel or something! So i pulled over, saw everything was okay on the outside, got back in my car and pulled away. On my way home the car did this about 12 more times.
It was dark by the time I got home so not a lot of information could be gathered by looking at the engine bay, but I saw no vacuum leaks or anything out of the ordinary. I did check again before work this morning to validate this. i have heard of the Greddy Turbos internal waste gate acting up but never like this, and I'm inclined to think that that isn't the issue because it seems fully functional the rest of the time. And also I wouldn't think that a waste gate problem would cause the rpm to be stuck like that.?
honestly, I have never heard of this happening before, and am unsure what would be the cause. I would love and appreciate all the help I can get on this.
(Seriously, Ill paypal you coffee money, if you know whats up, because Im seriously befuddled by this atm.)
Rag in the intercooler or collapsed exhaust flex?
Does the wideband go rich of tuned values? Does it misfire(will then read lean.)
Give us as much detail as possible from instrumentation/what you were doing with throttle/gears etc. I have no idea whatyour car is either, manual/auto etc?
Is your boost signal from a different spot to ecu sensor/feed to waste gate pot?
Nope, no rags, and the exhaust seems good. Wideband shows correct values for I made sure to tune those parts of the map (high load, low tomorrow). No misfiring as well.
Everything acted as normal, just the rpm was, for a lack of a better term, stuck, and the boost began to rise.
The rpm seemed to always 'stick' while accelerating past 3k and sticks at around 3k. If I try to Accel past 3k, it won't change the rpm but the boost would rise proportionaly to the change in the throttle position. This would happen in any gear in my manual trans, btw. And the car is an 2000 Honda s2000.
Thanks for ur reply btw, I appreciate it! If u have any more questions about the car please don't hesitate to ask.
I would have thought a restriction would skew lambda readings, and manual trans usually wouldn't present a problem like that.
Edit: I just accidentally reported my own post
I'll try again.
Most likely an unintended ignition retard/partial cut, check all clutch input driven trims, antilag, launch control etc
Less likely but still possible is cam phase/valve lash issue giving unintended overlap/valve timing/loss of power stroke.
Today is my day off, so it was time to check out the car further. A couple of things happened that I want to make note of.
1) I went to start the car and it would only crank, no start.
I broke out the laptop and reuploaded the tune, and it fired right up. This filled me with hope that that would solve the problem and that the previous tune became corrupted somehow.
2) The problem was not solved but I did notice that the 'sticking' would always occur under 'hard' acceleration. I would say when the throttle was 30-40% or above.
as far as trims, launch control, and all other possibilities aforementioned-- I could not find fault with any of them which is even more perplexing.
Can you log ecu data whike driving? TPS, Ignition, fuel, cam phase temps etc?
Is it sucking your intake pipe closed?
Should read richer than tuned with any form of significant intake or exhaust restriction.
When you say it was building more boost than usual, could it be its overboosting and you are hitting a boost cut, hence the RPM 'hanging' and not increasing?
Can you post a log?
@Slides yes I can data log and have done! I will attach a couple of logs and pictures of the logs!
@Ducie54 I don't think so-- If I were wouldnt I still be increasing in RPM and not seeing a build in boost because of lack of air flow? I will double check my intake to make sure though.
@Rob F It only starts to build boost after the RPM hang though-- I also am not running a boost cut on this tune-- I probably should be though... And I will attach a couple of logs and pictures!
@everyone-- on second thought, HPAcademy wont let me post .dl files, so I hope some pictures will suffice...
I also want to thank everyone for taking the time to help me out-- I appreciate it immensely! Joining HPA was probably one of my better decisions.
Are you able to output a log format that will show trigger errors or limiters being active? I think for chasing weird problems like this CSV to spreadsheet type output can be more valuable than smoothed graph data.
I kind of understand limiting forum file type stuff for general purpose stuff but it makes it hard in these circumstances where people don't want to publish private contact details to email on a public visible forum instead of just being able to download and view files.
I figured out the cause of the problem!
I, stupidly, turned on Knock Control with some janky parameters. Attached is a photo of the knock controls settings. Truth be told, I'm not sure how this was causing the rev hang and boost build..? Maybe by retarding ignition so much it was acting like a rev limiter/2 step? Or maybe the load limits are incorrect and causing the ECU to freak out...?
Still though, It is puzzling how it started to act up out of the blue...
I'm just relieved that I was finally able to find the culprit!
Again, thanks a lot for helping me out, and am all ears if you know how the Knock Control was creating this problem!
That could definitely do it will a lot of retard, that is why reviewing logs with ignition timing and trim/activation status of functions can make it much faster to find things. You were basically running antilag. Some knock sensors will pick up road bumps and stuff. I think it is very car/ecu specific as to setup.
Just when I thought the headache was over and done with, I went to start the car today, so I turn the key and I hear a louder than normal but still faint-ish whistling sound. I pressed the button to crank, and it cranks but doesnt start.
This happened while I was dealing with the Ignition retard issue, the morning after it wouldnt start but upon re-upload of the map it went back to normal.
This time though my computer wont even read the ECU! It says ECU not found error!
This is when I examined the faint-ish whistling sound. It turns out it was my turbo spinning and the sound wasnt from the electronics it was the intake sucking in air! This was a real wtf moment.
Defective ECU? Thats my only guess at this point... (I have a headache lol)
I'd start by confirming the power and earth supplied to the ECU to make sure the ECU is in fact powering up. While not impossible, it's incredibly rare these days to have an ECU randomly fail.
I just got done confirming power to the ECU.
The thing that confusing me the most is the fact that the intake is sucking in air when the ignition is turned on.
Another thing to note, is when I crank, the electronics (such as dash cams and gagues) reboot.
My car is a convertible and accumulates more condensation in the cabin than other vehicles; I wonder if that could have caused damage to the ecu
Now, get this!
I went to start working on the car and really dig into the problem this morning.... and...
I switched the ignition on-- no intake sucking this time--
I decide to turn it over-- starts up right away....
Nothing was done to the car since yesterday.....
Possessed by the devil maybe?
I still think the excess condensation, with the recent weather change has had a negative affect on the ECU.
What do you guys think?
Anything using accessory switched power will drop out during cranking BTW.
If the thing fires or kicks turbo might spin for a bit and make more bearing noise if its a roller and cages haven't been flooded. Other weird noises can be generated by vapour purge system too.
Cracked solder joints, poor corroded earths moving with heat or moisture changes could be problems. Have you removed and cleaned engine loom earths?