Turbo F22b1 on Neptune, is occasionally logging a fuel cut or ignition cut between 4600-5000rpm. It does not always log it as such but the misfire/break-up/power loss is 100% repeatable and happens every single time the engine is revved north of 4500rpm!? Also, and I find this very significant, the BATTERY light is flashing sporadically as the misfire/break-up begins. The coil/igniter are good, they both spec out to a "T", although I did order a new one just in case. I also have a High-output alternator built by Mike Singer, which as far as I know is still in excellent condition..? I have a relatively high wattage stereo and I NEVER see voltages under 14.2v (engine on) even with the amps/stereo on full tilt. So I'm hoping it's not that? Idk? ANY feedback, ideas, experience with a similar issue, etc... anything!....would be great and very much appreciated. Thx in advance to any and all who reply.

 

launch control turned on?

 

Battery light flashing is more than likely the alternator. High output or not. You have a log manifold and a turbo right next to it. That's a massive heat source and that stuff gets hot as hell. One of the biggest issues I had with my turbo F series setup was the constant death of alternators. It happened every 6-10 months without a doubt. The radiant heat from the turbo setup destroys the voltage regulators. It literally melts the insides of them together and ruins them. It will start showing the battery light at high rpm(voltage will appear fine) and one day you'll be sitting in traffic(happened to me at fast food lines mostly) when everything is heatsoaked and the alternator will take a dump leaving you to run on straight battery until you can pull off and let the car cool down. You might get lucky and make it home after it cools down a bit if it decides to return to working order. It's a common but not so talked about problem with turbo F series. You don't have to replace the whole alternator when it dies, just the voltage regulator. I tried heat wrap on the downpipe, dump tube, etc and a turbo blanket to keep the heat away from it but nothing completely remedied the issue. Some people fab up a heat shield for the alt and that seems to work well enough.


For the rev limit, check what 2kdrift said. If your VSS is not functioning properly you will hit launch control in gear at whatever rpm it's set to activate. Otherwise, check for any stored codes as you could be going into limp mode.

 

Not that I know of... no?

I was afraid someone might say this. My dp is literally directly up against the plug going into the alt. And I already did the heat wraps and turbo blanket because I could tell from the very first start up that heat was going to be a huge issue. I guess the next step will be fabbing up some type of heat shield for it but regardless at this point it's already too late. From the sound of your reply though, you don't seem to think the 2 issues are related? Like, they're literally happening together... one doesn't happen w/o the other. And it doesn't really act like a rev limit, it's more like it begins to misfire? But occasionally Neptune will log it as a fuel cut... yet no limiters or cuts are in place!? As a matter of fact, iirc, we turned the limiters up to the max to see if it would change position on the rev scale and it still happened, everytime, in the same RPM range? Weird right!? Also when we tried setting the rev limit to the max, rather than log it as a fuel cut, Neptune logged an ignition cut! ...But still in that same RPM range between 4600-5k? Oh and I forgot to mention this earlier... we tried it with 2 completely different ECU's both using their own Demon's! So 2 separate ECU's, 2 separate Demon's, exact same results. Which to me crosses off any possibility of it being hardware/software related and that led me to the mechanical options at which point I started with the distributor, BUT then I realized the battery light was coming on while it was happening. See I never noticed it before because I was staring at the laptop and dyno screens the whole time, but now I'm thinking the alt is the main culprit... is that a possibility? Could the issue with the alt be causing this inability to rev beyond 5k? Lmk what you think?

And thank you both for your replies!

 

are you logging battery voltage when this happens?
EDIT: missed the part where aradin, said voltage will appear to be fine, He knows alot more then I do especially with H/F series and hes a tuner just trying to throw ideas out there

I know my launch control was set around 5k, thats why I asked about that, I was wondering why I couldn't rev past 5k (this only happens in neutral) then I find that my tuner had launch control enabled

 

I don't believe the alternator itself would cause an inability to rev or cause a rev limit at all really unless you're seeing heavy voltage drop which you stated you're not. The battery light flashing is not likely to be the root cause of your rev limiter. If you're not seeing any actual voltage fluctuation then I would start looking else. The dummy light seems to be overly sensitive and will trip way before the voltage regulator dies. I could usually get about another month out of them once the light started coming on and not have any other issues.

You can try unchecking the "cut fuel" & "cut ignition" boxes under the rev limiter part of Neptune. That will remove all of the ECU controlled rev limiters so be careful. By all I mean, your actual rev limiter, launch control/anti-lag, full throttle shift, limp mode, etc. If that doesn't remedy the issue then you need to start looking at hardware. Are your plugs gapped tight enough? And other things along those lines.

In the future if you have issues you believe are related to Neptune, the best place to go are the forums at HRTuning.com

 

I should've stated this in my last post but, my tuner and James (HRtuning) are completely stumped on this. We did however try removing all "cuts" and we still got the same result. I'm not 100% sure we were logging voltage but I'll check the logs and let yall know? The next thing we tried was the coil and now I'm waiting on a new dizzy altogether. i also sent an email out to Singer about the alt but chances are the expense may be too great so I may just wind up replacing the regulator and brushes myself. On the mechanical side is there anything else You can see as being a possible culprit of this particular type of issue? Like, what's the first thing that comes to mind?... aside from the obvious hardware/software (ECU/Neptune). I'm just trying to brainstorm as many heads together as possible on this one. And thx again

 

I still haven't gotten this issue resolved but the voltage is holding between 14.4-14.8 while it's happening so I don't think the alt is the issue? Also just replaced the entire distributor with a high quality refurbed Hitachi (everything's to spec even the oddball ignition coil), along with new iridium plugs, and NGK "Blues" HE73's and I'm still getting the same result!? So ignition system, alt, and ECU/Software are all off the table as possible causes... Any more suggestions or possibilities anyone can think of?

 

Are you pushing the car beyond the 4500-5000 breakup? Does it clear up after that? Or are you unable to go further than that point...

And secondly, how is it being logged as a fuel/ignition cut? I guess I don't know enough about Neptune (or any other software for that matter) to understand this. Could it be a mechanical issue? Fuel deprivation? Spark blowout?

I'm curious to know what you find so definitely post the solution once you find it

 

Do you have a screen shot of a data log when this is happening to post? Look in the the data window that shows every sensor and check for any strange readings. What's your actual timing showing when this happens? Double check all your compensations that affect timing and make sure nothing got changed to a weird value on accident.

I had a similar problem when I was adjusting the iat timing compensations, for some reason it would randomly pull crazy amount of timing and misfire even though the perameters were set in a way that it should not happen. It ended up getting resolved from uploading the tune again, I think it was just a corrupt upload of something.

 

No...it's logging as a HARD fuel cut, and we cannot push through it. It also drops out of boost etc..
Second, the reason I posted it as "fuel/ignition" is because when my tuner attempted to remove any and all fuel related limiters and it still had the same result but then logged it as an ignition cut!? And YES I'm positive that it is something mechanical or at least something happening from the harness forward. The problem is I've got NO IDEA what that is? lol! I think I may have to rephrase the question to something like: "What systems/sensors can trigger a hard fuel cut around 5000rpm?"... Or, "What failsafes are hardwired into the ecm that would cause this and what sensors trigger them?"
You know something like that? Thanks for your reply

So here's the craZY part.... nothing else is out of the ordinary!? Everything else is checking out!? I'd be glad to send you the logs if you'd like to have a look at them tho? So far no one has been able to find anything in the datalogs that would point to a possible cause and this includes the man himself James (creator of Neptune) so we're all really stumped at this point. And this is why I said above that I may need to rephrase the question because this certainly seems like something that needs a much different perspective. And what I mean by that is, maybe the perspective of someone that has a very deep understanding of Honda's fundamental engine functions, sensors, etc... Like, let's completely forget that the car's boosted, has a particular ecm and engine mgmt, etc, etc.... Let's not look at all the typical/obvious reasons this would happen on a turbocharged engine with all this extra ****, And instead say: what triggers a fuel cut like this, at this rpm on a bone stock Honda motor? And I believe the key word there is "triggers" because we all know the ecm actually controls it but what is it that TELLs the ecm, "hey man cut the fuel NOW!"? I myself have no idea? But I can't stop until I get this sorted out because I surely haven't come this far to let this happen... I didn't build this engine to stop at my current power level when I know she's got WAY more in her.
Lastly, it's funny you brought up the timing, because I literally just reset the timing when I installed the new distributor and I'm still having an identical result...? At this point I'm pretty much positive it's not the ignition system, unless it's something in the wiring sending a fudged up signal but if that were the case why is it only happening in that very specific rpm range? Again bro if you'd like to take a look at the logs that would be excellent? PM me your email address and I'll send them right over to you. And thank you for your reply

 

Wow dude this is crazy. I highly doubt I'll see anything in your data logs that these other more experienced tuners didn't. I would start going through all the wiring, check the pins that plug into the ecu, maybe even try a different engine wiring harness. Keep us updated.

 

does it do this in neutral? It might be worth a shot to get a stock ECU, and disconnect a boost line just to test, it still sounds like the ecu is cutting it if its saved in the logs, otherwise I dont think it would log it as a cut

 

You know something that's a REALLY good question!? I've honestly never tried doing it in neutral, let alone any other gears, besides 3rd!? I'll have to give that a shot just to see what happens... is there ANY reason NOT to try this though? Like, is there any reason I shouldn't rev the motor that high without a load on it? lmk...?

 

its tuned correct? should be able to rev fine without load. yah definitely should try other gears just giving you some ideas to try nothing to lose at this point. I was thinking boost cut but I kinda figured you tried different gears etc

 

Yea it's tuned GREAT!... up to that point. lol! But seriously though it runs like a savage until it hit's that hard fuel cut, and the worst part is NOBODY has a clue wth's causing it?

 

Ok so I finally had the chance to try revving it out with no load (in neutral) and unfortunately I'm getting the same results. The battery light blinks/flashes a bit and it begins breaking up like a hard fuel cut?

 

Have any of you ever heard of this?:

"I know my S2000 limits redline based on engine temeperature. It will cut fuel if it isn't warm enough to be safe to switch to the hot cam settings. I've never run it hard when its cold, but I've read enough threads by 16 year olds wanting to know whey their car won't "veetech" straight out of the driveway on the way to school to be aware of the feature. I would assume Honda does the same thing with all their VTEC motors, but again I've never ran my cars hard when cold so I can't verify it.Anyway, if your car is warm when you're trying this, you might have a messed up sensor somewher"

Now I'm not suggesting that my engine's not up to temp while this is happening but if this is a common feature in vtec engine's/ecm's then wouldn't it be plausible that this could be caused by a bad temp sensor or possibly the fitv being removed?

 

You would see it in the logs. All that's referring to is the VTEC temp check which doesn't allow the engine to hit VTEC if it's under a certain ECT. It can be disabled in the software but if you're actually seeing it switch to the VTEC maps in the logs once it's up to temp then that's not what it is.

FITV is irrelevant.

 

Ok cool... thx for the reply I'm just checking all possibilities. You know I haven't mentioned this before but my odometer doesn't work... and I know it's connected to the VSS (in some way) do you guys think that this could be VSS related? And I completely removed the CruiseControl too.

 

Ok so I'm feeling pretty stupid right now but I MIGHT have found something. Okay, so I probably should've done this a LONG time ago but it just never dawned on me...anyway, today I went out and I did that jumper wire trick on the test harness behind the glove box, just to see if anything would come up? Well I got the code-0 (solid cel). Now Idk if this is normal when using a P28 in an Accord but normally I don't have any CEL's with the car on except for the SRS and the ABS because both of them are fkd in their own way. But the CEL never comes on. I mean when I first start the car it does but I think they all do that as the car goes through it's little system check, no? Anyway, I have a code-0 when I jump the harness and I just wanted to ask anyone knows if this is normal with a P28/NeptuneRTP setup? Also keep in mind IF this is the cause of my issue it can't actually be the ECU itself as my tuner and I tried his own personal ECU and had the same results. So if anything it's something in the wiring or wire harness, right? Plz lmk if this is nothing or if this is a clear indication of why I'm having this issue with the revs? And then of course flame me for being such a fkn idiot and not checking this earlier. Thx fellas

 

I'm not positive but the demon installed in your ecu may effect how the cel light functions. I know for sure you can check codes within the Neptune software.

But you said you are getting a 2-3 second light on the dash as you turn the car on. That's good. Generally if there was an issue, after the injectors prime and the cel light goes out, it comes right back on to indicate a problem.

I read in your other thread the concern that there may be an issue with your valvtrain not letting vtec engage. Typically this wouldn't make the engine cut out like your describing though. You would just stay on the low cam beyond the vtec engagement. Lack of power would probably be your biggest symptom. Not a harsh cutout like fuel or ignition was being cut. Someone correct me if I'm wrong.

Here's a crazy question.. Did your tuner finish out the entire low cam fuel and ignition maps? Occasionally, people neglect to finish out the high rpm segment of these maps with the arguement that the car will never see this portion of the map.

However, what happens when the vtec solenoid fails to engage? Or some other issue that prevents vtec.

The motor is forced to run on the low cam profile maps regardless of whether they were tuned or not.

Just a thought. Might be worth checking. I'd assume if you had several people looking at your tune this would have been discovered already but who knows.

 

Yes quite a few ppl have actually had a look at it thus far but nobody has said anything to that effect yet? So I'm not entirely sure? With that being said I am very confident in my tuner's abilities. Now in the other thread I think someone else had commented that the vtec engagement may have been a possibility but the vtec has been functioning fine. I know it sounds almost absurd but EVERYTHING else appears to be good if not GREAT.... except for the fact that it won't fkn rev out!? lol! If you'd like to have a look at the datalogs and calibrations I'd be happy to send them to you?

 

I'd be happy to look at them, but I'm afraid I wouldn't know what I'm looking at. Lol. I do not profess to be a tuner. I know enough to be dangerous haha.

If you notice a drastic change in cell values near your cutout rpm then it may be the issue. You should be able to identify this yourself.

How do you know vtec is engaging properly if your rpms break up at 4500-5000? Is it set lower than that?

 

I looked at his tune and data logs everything looked good except for the fuel cut. Vtec engaged at 3500rpm if I remember right, but fuel cut still happened in the log with vtec disabled. I sure it's not a tuning issue, it has to be a mechanical issue.