[Sleepn]

Noise best heard around 25+ seconds

This is on a 99 2.7 w a supercharger from LCE, youtube compression messed with the audio but the noise heard is much louder. So what is leading up to this noise is slight acceleration going uphill, 0-4psi according to the MAP, open loop, 2.2k-3.2k rpm, spark advance is around 10. All is well in closed loop but after a few seconds of uphill travel the ECM will switch to open loop, drop the afr from stoich to 10-12:1 (depending on what I have the active cells set to) and make this sound, power loss the whole time. Sometimes it will even do this on flat ground and make it impossible to accelerate without coasting for a few seconds to switch back to closed loop. No ammount of timing retard or fuel cell changes makes this sound disapear, leaning out the cells seems to help with power loss but then effect afr during the first parts of WOT (16:1) for a brief moment. I've never experienced spark knock before so I'm not sure if this is what it sounds like. For anyone with experience with SplitSecond MAF/Timing controller and R4 tuning software, messing around with overboost seems to do nothing as well.

10k miles on the engine and supercharger.

 

[Gamefreakgc]

My ears can't pick up anything abnormal, I'm sure it sounds different in the vehicle. Based on the driving, I'd say it's most likely ping. What octane of fuel do you run? Try using 93 or 92 octane and see if that eliminates the sound. If you don't have that high, add a quality octane booster (usually raises 3-4 points) or a bottle of yellow HEET antifreeze treatment (it's 100% methanol) and drive the same pass again.

For AFR's under moderate boost like that, you should be shooting for a 12.5 - 13.0 AFR. If you are seeing under 12 AFR at only moderate throttle it's too rich and you'll lose power like you are experiencing. It's called combustion quench. Only at max boost and full throttle should you see 11.0 - 12.0 AFR.

 

[Sleepn]

I'll see if a gas station near me has higher than 91, or try the methanol.

An other thing I've noticed is that while in closed loop during the hill climb my timing advance is around 20, but as soon as it switches to open loop it drops to 10, could it be incomplete combustion im hearing?

An update as well, I put methanol in the tank and the noise is somewhat quieter, I've also leaned up those cells to run around 13-13.5:1, 12.5-13:1 didn't seem to change much. It does drive much better uphill but I still have the problem of it running lean during the first few seconds of WOT because of those cell changes, probably a case of I can only have it one way.

 

[Gamefreakgc]

I'll see if a gas station near me has higher than 91, or try the methanol.

An other thing I've noticed is that while in closed loop during the hill climb my timing advance is around 20, but as soon as it switches to open loop it drops to 10, could it be incomplete combustion im hearing?

An update as well, I put methanol in the tank and the noise is somewhat quieter, I've also leaned up those cells to run around 13-13.5:1, 12.5-13:1 didn't seem to change much. It does drive much better uphill but I still have the problem of it running lean during the first few seconds of WOT because of those cell changes, probably a case of I can only have it one way.

If higher octane quiets the noise, it's pinging. If your finances allow I would recommend running a higher octane on a regular basis. I always use 91 because my 4Runner (yes I know it's a Taco website but same engine) runs terrible at 10 PSI on 87 or 89 octane. As in I might damage the engine sort of terrible. I can't get 92 or 93 in CA so I had to also add a methanol injection system. I don't recommend doing that since it makes tuning even more difficult but it is an option if you are bored and want another project! Every time I drive through Oregon I put 92 or higher in and wow, what a difference. Ethanol free fuel also makes a difference for the older engines.

Does your tuning software have an "acceleration enrichment" or "tip-in enrichment" setting? That will help your initial lean condition when pushing it to WOT. That's a common issue to have.

 

[Brake Weight]

Can you retard the timing across the board and see how it acts?

Is there a small, municipal airport nearby? You may can barter or possibly buy some piston gas from there and try that.

 

[Sleepn]

If higher octane quiets the noise, it's pinging. If your finances allow I would recommend running a higher octane on a regular basis. I always use 91 because my 4Runner (yes I know it's a Taco website but same engine) runs terrible at 10 PSI on 87 or 89 octane. As in I might damage the engine sort of terrible. I can't get 92 or 93 in CA so I had to also add a methanol injection system. I don't recommend doing that since it makes tuning even more difficult but it is an option if you are bored and want another project! Every time I drive through Oregon I put 92 or higher in and wow, what a difference. Ethanol free fuel also makes a difference for the older engines.

Does your tuning software have an "acceleration enrichment" or "tip-in enrichment" setting? That will help your initial lean condition when pushing it to WOT. That's a common issue to have.

There are 2 gas stations about 40 miles from me that have 93, and I may have to just try a full tank of 93 at some point or see if an octane booster from a parts store does anything. The controller I have has the option to run an additional pump and injector, I may have to try methanol injection at some point as well.

It doesn't exactly have an enrichment function, the program calls it "overboost" so I can set it up whenever the MAF reads a specific boost number I choose, it will feed a false O2 signal to the ecm to force it into closed loop, this was their workaround for the slow response time of the older ecms and narrow band O2. I think more of the problem is that those fuel cells im changing for driveablity uphill are sooooo much leaner than the surrounding cells, 0-20 are the numerical values that can be used in the fuel map, 10.5 is what I have those problem cells set to, imediate cells around them are 11.2, its such an abrupt change I think the ECM is having trouble signaling the injectors. I wish I had more cells to work with as well, the pressure axis of the graph is great but the rpm is in increments of 500.

 

[Sleepn]

Can you retard the timing across the board and see how it acts?

Is there a small, municipal airport nearby? You may can barter or possibly buy some piston gas from there and try that.

I can try retarding the entire map to see if it helps out at all, but any changes to the cells that I'm hearing the noise at doesn't seem to do anything but kill power and cause surging. From what I was told by the company I bought the controller from, 3rz knock sensors don't do anything below 3k rpm because of engine noise from the solid lifters, it ends up changing timing below 3k based on what knock/timing threshold is above 3k. It still weirds me out that uphill in closed loop ill see 25-30 degrees advance timing but as soon as the ecm switches to open loop the timing drops to 10 advance and thats when I hear the noise. Still not entirely sure why the ECM thinks it needs to switch to open loop with no change to throttle position.

 

[Brake Weight]

Retarding the entire map may not give any results especially since it drops timing in the RPMs of interest.

 

[Gamefreakgc]

I can try retarding the entire map to see if it helps out at all, but any changes to the cells that I'm hearing the noise at doesn't seem to do anything but kill power and cause surging. From what I was told by the company I bought the controller from, 3rz knock sensors don't do anything below 3k rpm because of engine noise from the solid lifters, it ends up changing timing below 3k based on what knock/timing threshold is above 3k. It still weirds me out that uphill in closed loop ill see 25-30 degrees advance timing but as soon as the ecm switches to open loop the timing drops to 10 advance and thats when I hear the noise. Still not entirely sure why the ECM thinks it needs to switch to open loop with no change to throttle position.

You might be one of the very unlucky ones where the knock sensor picks up the supercharger rotors as knock and pulls all timing. Mine will also run up to around 28 degrees timing going uphill at 70 MPH as long as those RPM's stay under 3K. But over 3K RPM I normally see in the low 20's and if I go full throttle I see between 15-17 degrees. 10 should never occur outside of idling. There's more at play here. And before it's suggested, no it's not likely to be a faulty knock sensor, they either work or the don't. When the don't, you get a CEL.

 

[Brake Weight]

Several fingers pointing to knock sensors. What if you unbolted them one by one to see which one could be culprit or possibly all of them. Unplugging will throw a CEL.

 

[Sleepn]

You might be one of the very unlucky ones where the knock sensor picks up the supercharger rotors as knock and pulls all timing. Mine will also run up to around 28 degrees timing going uphill at 70 MPH as long as those RPM's stay under 3K. But over 3K RPM I normally see in the low 20's and if I go full throttle I see between 15-17 degrees. 10 should never occur outside of idling. There's more at play here. And before it's suggested, no it's not likely to be a faulty knock sensor, they either work or the don't. When the don't, you get a CEL.

Something to think about for sure, relocating the sensor I don't think would make a difference and if anything it will cause detonation if left unbolted from the engine. I may have to dig around and see what sensor(s) contributes to open/closed loop signal. Also my scanner is displaying it as "open loop-drive" opposed to just open loop, I assume that is WOT open loop vs warm up open loop, but maybe I am wrong.

That would really suck if its picking up the supercharger as knock.

 

[Gamefreakgc]

Something to think about for sure, relocating the sensor I don't think would make a difference and if anything it will cause detonation if left unbolted from the engine. I may have to dig around and see what sensor(s) contributes to open/closed loop signal. Also my scanner is displaying it as "open loop-drive" opposed to just open loop, I assume that is WOT open loop vs warm up open loop, but maybe I am wrong.

That would really suck if its picking up the supercharger as knock.

I believe it's based on throttle position so that would be the TPS. At what value I'm not sure, I could not pin it down in my tuning runs but it's somewhere around 60-70% throttle. Don't know what the equivalent voltage value would be though as my software sees it as a percentage. TPS sensors can go bad though and not throw a code as I just dealt with that myself. Had funny RPM issues and stalling at idle until I tested the TPS and it was out of range.

 

[Brake Weight]

Can you log throttle position real time? If so, find that sweet spot it does this and see how long it will continue into the RPMs. I’m wondering it it may be load related somehow.

If you retarded the entire map to, say 15*. Would it drop to 10* during this open loop or drop to 5*. My understanding is that open loop is a predetermined ECU map. This may be 10*. Any changes you make would be to the closed loop map. Or am I missing something?

 

[Sleepn]

I believe it's based on throttle position so that would be the TPS. At what value I'm not sure, I could not pin it down in my tuning runs but it's somewhere around 60-70% throttle. Don't know what the equivalent voltage value would be though as my software sees it as a percentage. TPS sensors can go bad though and not throw a code as I just dealt with that myself. Had funny RPM issues and stalling at idle until I tested the TPS and it was out of range.

By chance do you have the testing procedure for the tps? All Data and Identifix both didn't show anything, or I couldn't find it.

 

[Sleepn]

Can you log throttle position real time? If so, find that sweet spot it does this and see how long it will continue into the RPMs. I’m wondering it it may be load related somehow.

If you retarded the entire map to, say 15*. Would it drop to 10* during this open loop or drop to 5*. My understanding is that open loop is a predetermined ECU map. This may be 10*. Any changes you make would be to the closed loop map. Or am I missing something?

I can log throttle position, I'm thinking it might be load related too, the truck is geared in 4.10 with 31x10.5x15's and there are a few charts I've seen that say that tire/gear combo would be just a little too much for the engine....how accurate those charts are, who knows. Seeing that it has a supercharger on it now and im hearing the noise uphill @ 0-3 psi the supercharger maybe drawing more hp/tq than its actually making at that point and exagerating the symptom.

As far as openloop vs closedloop timing changes im not sure, if I remember it always defaults to the 10* no matter the timing change but ill have to check again.

 

[Sleepn]

As I was typing replies, I rememberd that the orginal engine that was in it before I bought a refurb for it had a similar noise going uphill as well, I always assumed it was piston slap, when I tore down the original engine the crank and rod bearings looked great but there was scuffing on the cylinder walls and pistons. I wonder if my truck has always had some problem with a sensor, ecm, or the gear/tire combo has been an issue this whole time.

heres a pic of why I replaced the engine in the first place Picture, broken camshaft due to failed tensioner, chain bound up and snapped the chamshaft clean in 2.

 

[Brake Weight]

Crazy break there. I agree that it is an electrical issue of some sort.

Manual transmission?

 

[Sleepn]

Just as an update on this, I put 5 gallons of 100 octane in and the noise did not disapear, still had timing retard to 10* advance and a loss of power. Messing with fuel/timing map also didn't change anything other than the power gain when running leaner in the affected cells, like I mentioned in an earlier post. I'm 99% positive I have false knock, I can rule out a bad injector seeing as I only experience the noise inbetween 2500-3200 rpm, If I had fuel/spark issues I'd have problems in the top end as well. I can rule out engine failure, I've recently check compression and leak down, I've also recently checked valve lash. I have a few repairs that I've been putting off (rear u joint, trans mount, a few body mounts) that could be causing vibration that maybe the knock sensor is picking up. I'll also be calling Magnuson and LCE to see if they've had customers with similar problems. I found a user on here that has had similar issues and has a long write up on knock sensors that can be used in place of the OEM that may not be as sensitive to engine noise/vibration.

 

[Gamefreakgc]

By chance do you have the testing procedure for the tps? All Data and Identifix both didn't show anything, or I couldn't find it.

I do, you can view my recent woes here: Toyota-4Runner.org. This is for the V6 engine but I believe the sensors are identical.

That's a real bummer about the knock. I would definitely call LCE, they have been very helpful for me in the past in building my engine.

As far as timing retard goes, it's a mixed bag. In my experience with a piggyback controller, if I pull timing in closed loop it will directly affect what the ECU shows on something like a Scangauge or OBD-II reader in direct relation to how much I pulled. So if I see 30 degrees and pull -4, it now shows 26. If I pull timing in open loop, it does the opposite in most situations. The ECU will add back in the timing retard and shows a false high reading. So if I normally see 17 degrees of max timing in a 3rd gear pull and put in a safety net and pull -2 degrees of timing, I'll then see 19 degrees of max timing. The ECU will add the timing back in but not reflect the fact that I pulled some so shows a false high reading. Now if the engine knocks and pulls timing on its own, that is definitely shown in the reading and will read lower.

 

[RB3RZ]

Just as an update on this, I put 5 gallons of 100 octane in and the noise did not disapear, still had timing retard to 10* advance and a loss of power. Messing with fuel/timing map also didn't change anything other than the power gain when running leaner in the affected cells, like I mentioned in an earlier post. I'm 99% positive I have false knock, I can rule out a bad injector seeing as I only experience the noise inbetween 2500-3200 rpm, If I had fuel/spark issues I'd have problems in the top end as well. I can rule out engine failure, I've recently check compression and leak down, I've also recently checked valve lash. I have a few repairs that I've been putting off (rear u joint, trans mount, a few body mounts) that could be causing vibration that maybe the knock sensor is picking up. I'll also be calling Magnuson and LCE to see if they've had customers with similar problems. I found a user on here that has had similar issues and has a long write up on knock sensors that can be used in place of the OEM that may not be as sensitive to engine noise/vibration.

I’ve been looking for the write up on the less sensitive knock sensors. Do you by chance have a link for that write up? I believe I’m dealing with the same issues that you are. Except my timing goes all the way down to 2 and sometimes 0 going up a hill or in high wind with 33s.