Blew my motor yesterday....tuner says AEM wideband 02 sensor flatlined

[Maple Valley NSX]

Hello Prime Members,
Yesterday was a bad day for my ’93 NSX.
About 2 years ago, in anticipation of adding a supercharger someday, I installed an AEM ECU, Wideband UEGO with Bosch 02 sensors , AEM air sensor kit, 3.5 bar map sensor, and 725 cc balanced injector dynamics injectors. My N/A beauty already had a CT air box, SOS cams and throttle body, CT headers and the sweet GT-1 exhaust from Umbrella. The car was tuned and made an impressive 278 rwhp N/A.
About a year ago I had a top local shop (Acura of Lynwood) install a 1.7 liter CT Supercharger, Laminova intercooler (SOS) and updated lost motion assembly (also from SOS).
I am certain that all the suppliers and installed parts were of top quality.
After setting this project aside for another 12 months I finally found a tuner that I had confidence in and set up the appointment.
Well…..yesterday after spending many hours carefully building and perfecting the various tuning maps on his laptop and on the Dyno, my motor failed on a final run. It had just cooled off from a 374 rwhp run and was performing perfectly (and sounding amazing).
I am no expert on this but the tuner is saying that an 02 sensor flat lined and sent the wrong information to the ECU which led to a lean out @ WOT….=….motor failure.
After removing the plugs, we found 3 “affected” cylinders. The motor will have to come out and rebuilt or my pristine garage queen will be a display piece only.
In your collective experience, is 02 sensor failure the likely scenario to cause this, or is it something else?
I guess that this question may lead to other questions…..but I just needed to share with someone who may care, my brothers on Prime.
Short of shipping the car to Acura of Lynwood, can anyone recommend an independent shop is Seattle area to (carefully) drop the motor so I can get it rebuilt?
I have had excellent experience with SOS, so I may opt for their forced induction rebuild, but right now my head is still spinning and the thought of blowing another motor due to sensor failure gets me in PTSD.
Thanks for reading/commenting on this.
Brian P.

 

[BobK]

I had an AEM FIC fail as the map sensor inside the fic was not reading map I sent it back and they fixed it so before you build the motor and put the same AEM parts back in I would have them checked to see if they are working properly. My motor didn't blow but it ran like crap until I got it fixed.

 

[nsxtasy]

Sorry to hear about this.

can anyone recommend an independent shop is Seattle area to (carefully) drop the motor so I can get it rebuilt?

Wouldn't the mechanic/shop that's going to rebuild the engine have the ability to drop the motor?

 

[doc_tai]

Sound like ur tuner is lazy and tune with o2 feedback on all the way to redline

 

[RYU]

In my light experience, typically this only happens when the ECU is setup to "auto-tune" where by the ECU takes active readings of the AFR (O2 widebands) and constantly makes adjustments to the fuel trims (and sometimes the timing). I was not aware the AEM had this feature. It never gets talked about so i'm not sure if your tuner is pulling a fast one on you (I don't know). It is a great feature and a very dangerous feature at the same time for exactly the reason that happened to you. The O2 sensor failed > ECU thinks car is running super rich > ECU pulls fuel > KABOOM but this is only if it has the auto-tune feature.

The HKS F-Con Vpro (big bad boy standalone) has this feature also BUT it has a built in failsafe. This failsafe can be setup whereby the adjustment the "auto-tune" feature does is limited by percentage. For example, you can setup the auto-tune to only deviate for a max of say... 25%. This way the auto-tune will only ever make, at most, a max 25% adjustment to the trim. Therefore, say you're in the mountains.. the air is thin.. boost drops, car runs rich.. the auto-tune will only pull only up to 25% of fuel or 30% or 75% or whatever you set it at. A well tuned set of compensation maps to being with should really require very little work for the auto-tune to do. It's a failsafe to prevent exactly what happened to you. I use the HKS F-Con iS "Piggyback". It's amazing and it also has this auto tune feature but does not have the 'Max correction percentage' failsafe. I'm still trying to figure out how to implement the auto-tune on this. I really want to use it but not suffer from what happened to you. Sensors fail all the time. AEM use to be notorious for having sub par hardware and buggy software but I hear their newer stuff is better.

HKS also has a Knock Amplifier. It's basically an amp that sends to the tuner the audible Knock picked up by the knock sensors. Yes, you can actually hear it with a pair of earphones but you have to know what you're hearing. It can be setup to pull timing or richen fuel if a knock condition is experienced. It's the best way to tune at the limits in my opinion. It's kind of old school but it works. There is a chance that your tuner could have heard the engine start to knock that brief moment and pull back on the throttle had the AEM had this feature.

Sorry to hear about your engine. Man that really really sucks. When i'm on the dyno with my motor i'm always on edge. Hope some of this information can better equip you for your next dyno day.

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Sound like ur tuner is lazy and tune with o2 feedback on all the way to redline

+1

So it does have some kind of "auto-tune". Well, a good tuner doesn't typically turn this on until you're well on your way but a conservative tuner would have told you of the potential for this. Good tuners are conservative in my experience. They can get max power out of your engine but it's usually attached to a huge disclaimer which the owner has to understand. If most owners understand they'll easily be happy with the 350whp at a safe tune than a 380whp at a really edgy tune.

 

[d_prada1]

In my light experience, typically this only happens when the ECU is setup to "auto-tune" where by the ECU takes active readings of the AFR (O2 widebands) and constantly makes adjustments to the fuel trims (and sometimes the timing). I was not aware the AEM had this feature. It never gets talked about so i'm not sure if your tuner is pulling a fast one on you (I don't know). It is a great feature and a very dangerous feature at the same time for exactly the reason that happened to you. The O2 sensor failed > ECU thinks car is running super rich > ECU pulls fuel > KABOOM but this is only if it has the auto-tune feature.

The HKS F-Con Vpro (big bad boy standalone) has this feature also BUT it has a built in failsafe. This failsafe can be setup whereby the adjustment the "auto-tune" feature does is limited by percentage. For example, you can setup the auto-tune to only deviate for a max of say... 25%. This way the auto-tune will only ever make, at most, a max 25% adjustment to the trim. Therefore, say you're in the mountains.. the air is thin.. boost drops, car runs rich.. the auto-tune will only pull only up to 25% of fuel or 30% or 75% or whatever you set it at. A well tuned set of compensation maps to being with should really require very little work for the auto-tune to do. It's a failsafe to prevent exactly what happened to you. I use the HKS F-Con iS "Piggyback". It's amazing and it also has this auto tune feature but does not have the 'Max correction percentage' failsafe. I'm still trying to figure out how to implement the auto-tune on this. I really want to use it but not suffer from what happened to you. Sensors fail all the time. AEM use to be notorious for having sub par hardware and buggy software but I hear their newer stuff is better.

HKS also has a Knock Amplifier. It's basically an amp that sends to the tuner the audible Knock picked up by the knock sensors. Yes, you can actually hear it with a pair of earphones but you have to know what you're hearing. It can be setup to pull timing or richen fuel if a knock condition is experienced. It's the best way to tune at the limits in my opinion. It's kind of old school but it works. There is a chance that your tuner could have heard the engine start to knock that brief moment and pull back on the throttle had the AEM had this feature.

Sorry to hear about your engine. Man that really really sucks. When i'm on the dyno with my motor i'm always on edge. Hope some of this information can better equip you for your next dyno day.

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+1

So it does have some kind of "auto-tune". Well, a good tuner doesn't typically turn this on until you're well on your way but a conservative tuner would have told you of the potential for this. Good tuners are conservative in my experience. They can get max power out of your engine but it's usually attached to a huge disclaimer which the owner has to understand. If most owners understand they'll easily be happy with the 350whp at a safe tune than a 380whp at a really edgy tune.

yea I have an aem series 1 and i have my auto tune setup for 15% deviation at wot. I have heard horror stories of said "tuners" that just use aem auto tune features, record the fuel trims and copy and paste the data log in a sense. I would never rely on a sensor to do all the work/corrections in my tune. Still need a decent base fuel and ignition map for a failsafe. Pretty much how an oem ecu runs.

I'm really sorry to hear about your blown motor. Best of luck!

 

[Levworks]

02 feedback should only correct the map ever so slightly for changes in weather etc. So, for the tuner to allow it to change the fuel map so bad that it leans out a cylinder to the point of mechanical damage is pretty bad in my opinion.

Inspecting the engine internals once the engine is removed and apart will help you understand what was the actual cause of the failure. Even posting pictures of the internals on here if you aren't sure what you are looking for could help you out.

 

[E-Nough Logic]

Hello Prime Members,
Yesterday was a bad day for my ’93 NSX.
About 2 years ago, in anticipation of adding a supercharger someday, I installed an AEM ECU, Wideband UEGO with Bosch 02 sensors , AEM air sensor kit, 3.5 bar map sensor, and 725 cc balanced injector dynamics injectors. My N/A beauty already had a CT air box, SOS cams and throttle body, CT headers and the sweet GT-1 exhaust from Umbrella. The car was tuned and made an impressive 278 rwhp N/A.
About a year ago I had a top local shop (Acura of Lynwood) install a 1.7 liter CT Supercharger, Laminova intercooler (SOS) and updated lost motion assembly (also from SOS).
I am certain that all the suppliers and installed parts were of top quality.
After setting this project aside for another 12 months I finally found a tuner that I had confidence in and set up the appointment.
Well…..yesterday after spending many hours carefully building and perfecting the various tuning maps on his laptop and on the Dyno, my motor failed on a final run. It had just cooled off from a 374 rwhp run and was performing perfectly (and sounding amazing).
I am no expert on this but the tuner is saying that an 02 sensor flat lined and sent the wrong information to the ECU which led to a lean out @ WOT….=….motor failure.
After removing the plugs, we found 3 “affected” cylinders. The motor will have to come out and rebuilt or my pristine garage queen will be a display piece only.
In your collective experience, is 02 sensor failure the likely scenario to cause this, or is it something else?
I guess that this question may lead to other questions…..but I just needed to share with someone who may care, my brothers on Prime.
Short of shipping the car to Acura of Lynwood, can anyone recommend an independent shop is Seattle area to (carefully) drop the motor so I can get it rebuilt?
I have had excellent experience with SOS, so I may opt for their forced induction rebuild, but right now my head is still spinning and the thought of blowing another motor due to sensor failure gets me in PTSD.
Thanks for reading/commenting on this.
Brian P.

It can but only if the tuner lets it happen IMO. The big thing here is that you had 2 oxygen sensors, this is a huge advantage to prevent something like this from happening. If you have one sensor and it fails you have no immediate frame of reference to know it failed but with 2 sensors quite the contrary.

I know many tuners have different strategies some monitor the o2 feedback trims and use it to apply changes permanent changes, and some disable it and monitor the AFR's themselves. I prefer the latter. Are you on a series 1 or Series 2 AEM EMS? Were both o2 sensors wired up to the EMS? Did this failure happen all within one dyno pull or did it seem to fail over several? I see 2 potential faults here, the first one being the max trims/gains were so high that it allowed the ECU to pull too much fuel during one single pull, or he failed to monitor a huge trim being applied after the sensor failed over several pulls, as well as the difference between the oxygen sensors.

Shameless plug: My Digital Display can easily be setup to detect variations between o2 sensors and trims and warn you if such a condition exists automatically.

 

[TURBO2GO]

So who is responsible when this happens?

 

[E-Nough Logic]

In my light experience, typically this only happens when the ECU is setup to "auto-tune" where by the ECU takes active readings of the AFR (O2 widebands) and constantly makes adjustments to the fuel trims (and sometimes the timing). I was not aware the AEM had this feature. It never gets talked about so i'm not sure if your tuner is pulling a fast one on you (I don't know). It is a great feature and a very dangerous feature at the same time for exactly the reason that happened to you. The O2 sensor failed > ECU thinks car is running super rich > ECU pulls fuel > KABOOM but this is only if it has the auto-tune feature.

The HKS F-Con Vpro (big bad boy standalone) has this feature also BUT it has a built in failsafe. This failsafe can be setup whereby the adjustment the "auto-tune" feature does is limited by percentage. For example, you can setup the auto-tune to only deviate for a max of say... 25%. This way the auto-tune will only ever make, at most, a max 25% adjustment to the trim. Therefore, say you're in the mountains.. the air is thin.. boost drops, car runs rich.. the auto-tune will only pull only up to 25% of fuel or 30% or 75% or whatever you set it at. A well tuned set of compensation maps to being with should really require very little work for the auto-tune to do. It's a failsafe to prevent exactly what happened to you. I use the HKS F-Con iS "Piggyback". It's amazing and it also has this auto tune feature but does not have the 'Max correction percentage' failsafe. I'm still trying to figure out how to implement the auto-tune on this. I really want to use it but not suffer from what happened to you. Sensors fail all the time. AEM use to be notorious for having sub par hardware and buggy software but I hear their newer stuff is better.

HKS also has a Knock Amplifier. It's basically an amp that sends to the tuner the audible Knock picked up by the knock sensors. Yes, you can actually hear it with a pair of earphones but you have to know what you're hearing. It can be setup to pull timing or richen fuel if a knock condition is experienced. It's the best way to tune at the limits in my opinion. It's kind of old school but it works. There is a chance that your tuner could have heard the engine start to knock that brief moment and pull back on the throttle had the AEM had this feature.

Sorry to hear about your engine. Man that really really sucks. When i'm on the dyno with my motor i'm always on edge. Hope some of this information can better equip you for your next dyno day.

- - - Updated - - -


+1

So it does have some kind of "auto-tune". Well, a good tuner doesn't typically turn this on until you're well on your way but a conservative tuner would have told you of the potential for this. Good tuners are conservative in my experience. They can get max power out of your engine but it's usually attached to a huge disclaimer which the owner has to understand. If most owners understand they'll easily be happy with the 350whp at a safe tune than a 380whp at a really edgy tune.

Yes AEM has normal o2 feedback trimming which are variable and temporary, as well as auto-tune which is permanent. The fuel trims are typically turned on most of the time, meanwhile the auto-tune is a feature some use during the tuning process. Very dangerous feature indeed. Changes should be small and monitored vigorously. Both the auto-tune, and normal o2 feedback fuel trim have max limitations that can be setup, as well as a gains that affects how quickly the changes can be applied.

 

[doc_tai]

Auto tune come in handy when u try to tune part throttle in vacuum by urself on the street. O2 feedback should be set to do very little fuel trim(+-10% or less) for weather or humidity change in vaccum or little boost(under 2psi) in part throttle or cruise. That's how I use those features to tune my car

 

[Ponyboy]

I'm not going to delve into the why as others more knowledgeable can wade into it. However, I've been where you're at and while I blew my engine at the track, the sinking feeling - I'm sure - is the same.

Take a deep breath. Take another one. For me, the best thing to do was to put some distance b/t me and the blown to smithereens engine. Once your head is not spinning - then assess where you're at and what you want to do. Widen your framework - is there an option you haven't thought of? Reality test your options - are those options genuinely doable? Attain some distance - take a few days to think about it again. Prepare to be wrong - what would be the obstacle(s) to keep you from the option you've chosen?

It's a suck situation to be sure. But you're in good company (I've done it twice!). Keep your chin up - it gets better.

 

[d_prada1]

I'm not going to delve into the why as others more knowledgeable can wade into it. However, I've been where you're at and while I blew my engine at the track, the sinking feeling - I'm sure - is the same.

Take a deep breath. Take another one. For me, the best thing to do was to put some distance b/t me and the blown to smithereens engine. Once your head is not spinning - then assess where you're at and what you want to do. Widen your framework - is there an option you haven't thought of? Reality test your options - are those options genuinely doable? Attain some distance - take a few days to think about it again. Prepare to be wrong - what would be the obstacle(s) to keep you from the option you've chosen?

It's a suck situation to be sure. But you're in good company (I've done it twice!). Keep your chin up - it gets better.

great advice

 

[docjohn]

rebuilding an engine may seem cheaper but you should also research buying a complete motor which in the long run imho will last longer,because it is all original....ie factory matched.

 

[nsxtasy]

rebuilding an engine may seem cheaper but you should also research buying a complete motor which in the long run imho will last longer,because it is all original....ie factory matched.

Buying a used motor may also be more cost-effective, once you factor in the cost of labor as well as of any parts you'll need. When my engine needed replacing, I estimated the cost both ways, and found it would cost less to replace my engine with a used one than to rebuild it. (Note, in my case, it was a stock engine.) Don't forget to include all the costs when estimating - the cost of parts or the engine, shipping costs (which can be significant for shipping an engine cross-country), and what you may get back if you sell the block or other parts from your blown engine.

One other point on the costs (and this applies to a rebuild as well as a replacement) - unless the timing belt and water pump are new, you may as well get new ones installed at this time, when the engine is out anyway. (And consider new cooling system hoses as well.) This will save you most of the cost of the timing belt job, which you then won't need for another 6 years or 90K miles.

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So who is responsible when this happens?

The following answer is not intended to apply to this specific incident, but rather, for any incident in which a car incurs mechanical damage.

The car owner is usually responsible. If the shop admits that their work and decisions caused the damage (or played a role in it), they may pick up part or all of the cost of the repair needed to restore the car to its previous condition. If the owner and the shop disagree regarding whether the shop caused the damage, you can try to work together to come up with a solution you can both live with, but if you can't, you can take it to court. Hopefully that happens only as a last resort and you can work something out.

In my experience, as long as both sides are reasonable as far as understanding how it happened and the work that needs to be done, you can figure out a way of handling it; typically the owner still pays for most of the repair but the shop provides some relief (discounts) on the labor rates, parts costs, etc. This is how I've seen it handled most often.

 

[J KRIB]

Is o2 sensor feedback not usually shut off when on the dyno and doing hard pulls. I figured a tuner should build a MAP that is reliable and produce a decent amount of power then turn feedback control on for fine tuning after a good base MAP is completed. Sorry to hear about your motor but there is 'J' motor buzz going around on Prime if you are not in a rush to get a 'C' motor back in your car.

 

[Vega$ NSX]

Sorry to hear. Welcome to the club:

Unofficial How Many Times You've Blown Up Your Engine Thread

It's not a club most people want to be in, but at least you can take comfort that there are others and they have felt your pain too.

Most of the people already hit the nail on the head, but your tuner should have had a base map that he should have loaded as a starting point. Then he should have then slowly tweaked performance on multiple dyno runs. Then tweaked the drive-ability and idle using street tuning and then finally used the "auto-tuning" to fill in very minor gaps.

 

[Elite]

Is o2 sensor feedback not usually shut off when on the dyno and doing hard pulls. I figured a tuner should build a MAP that is reliable and produce a decent amount of power then turn feedback control on for fine tuning after a good base MAP is completed. Sorry to hear about your motor but there is 'J' motor buzz going around on Prime if you are not in a rush to get a 'C' motor back in your car.

Sorry to hear. Welcome to the club:

Unofficial How Many Times You've Blown Up Your Engine Thread

It's not a club most people want to be in, but at least you can take comfort that there are others and they have felt your pain too.

Most of the people already hit the nail on the head, but your tuner should have had a base map that he should have loaded as a starting point. Then he should have then slowly tweaked performance on multiple dyno runs. Then tweaked the drive-ability and idle using street tuning and then finally used the "auto-tuning" to fill in very minor gaps.

Agree with what these guys said.

 

[ScienceofSpeed]

Sorry to hear about this. Typically, this should never be an issue because the sensor has a voltage error mode (if it is out of the range of .5 - 4.5V, it will go to a default mode which will result in fuel being added, not removed). In addition, the sensor is typically only given a very range to subtract fuel. Also, most tuners will not enable closed loop (02 sensor reading) if the car is under full load. That being said, all of these options are programmable by the tuner and can result in damage if not programmed correctly.

Regardless, we're here to help. We're happy to repair the engine for you, and have significant amount of experience so that the job is done right. Feel free to give us a call if you have any questions.

 

[cptnsx]

First auto tune is terrible and should never be used. Everything I've read about it details how it can really screw things up and most tuners recommend against using it. I have had an intercooled supercharged car since 2009 and have over 200 to 300 logs.

Second, dual O2 feedback is a good thing and can be necessary for the NSX. Because of the way our engine is mounted we don't have a single company that produces good equal length headers with the proper collector (for stock cars) that flow evenly from a bank perspective. The twists and turns required for the headers at the rear of the car affects flow. This has an impact on the AFR at various RPM from bank to bank due to exhaust wave tuning. I have a great tune from UMS but they still use a -/+ 13% correction.

At first I was concerned when I saw this but after logging and logging run after run, I discovered that my rear bank is more efficient around 4-4.5K ie O2 feedback would add 12% to the rear bank and subtract 10% from the front. I saw the reverse around 3.5K although not at severe. Things would even out at higher RPMs. Most people would then say just offset the fuel per bank at those RPMs, but with the AEM EMS this is a global setting and would be wrong because these flow issues only occur at part throttle and low to mid load. At high load or WOT the flow is pretty much even which I assume is either the supercharger making the exhaust tuning irrelevant or just the high amount of flow at WOT negating those issues. So in some cases you need O2 Feedback to be around 15%.

So what is the solution. You don't run O2 feedback at high loads or WOT and run a table that is slightly rich (where possible) so at low to medium load fuel is being pulled. If the sensor fails and causes max fuel pull you will at most lean out .5 AFR which is not catastrophic at those load levels. I run off my fuel tables at high loads and WOT. I have added fuel at 3.5 and 4-4.5k at low to medium low with the expectation that the O2 feedback will reduce it for the inefficient bank and add a little fuel for the more efficient (actually UMS set it up this way).

The next part of the solution is to frequently replace the AEM UEGO sensors. I change mine every two years. Overkill just like changing my iridium spark plugs every year but that money is nothing compared to the costs if they fail and their inspection can be very helpful.

Finally set up a monitoring system. I'm looking at adding the digital logic system but I already connect a laptop to the AEM and then connect this to a monitor. Really nothing will help if you are WOT since things happen so fast but by constant monitoring you can at least see what your AFR is doing especially at low or mid loads. These sensors show signs that they are starting to go. If you constantly watch them, then you can recognize the symptoms which are typically slower and slower response especially from on throttle to off throttle.

Basically if you let SoS fix your car let UMS tune it. As they are doing this learn as much as you can about the AEM EMS and tuning because you should be logging your car and reading those logs as much as possible plus you may have to make some minor changes to your tune as the weather changes. Because UMS is really good the only thing you would have to the change is the AIT tables as the temperature drastically changes i.e. tuned at 100F and now you are driving at 50-60F.

 

[RYU]

Going to go OT because not sure the OP even cares about this thread

cptnsx - Question for you please. What kind of cooling are you seeing in your IAT? Is it always relative to ambient? Say... your cooler will always cool IAT to +/- XX F degrees consistently regardless of ambient temps?

Here's my latest data points from my most recent track events this year.

- Streets of Willow ambient 110F/38C. With water injection resulted in IATs of 125F/52C. Delta 15F/14C
- Buttonwillow ambient 75F/24C. With water injection resulted in IATs of 100F/42C. Delta 25F/18C <<<---- This as today

I've been logging some amazing results especially today. I easily record deltas of 100F with the water injection turned off so only a 25F delta is more than I expected. The interesting surprise is I logged .5-1psi of increased boost today. My Autorotor typically maxes out at 7.1lbs in a typical sea level day. I was hitting near 8lbs of boost today at Buttonwillow. I recorded 38C of IAT at the time my boost is at it's highest. The water chilled air may have had a lot to do with it. Had to retune that section of the fuel map because didn't really expect it! I also thought the additional water would kill my HP but it seemed to have power for days. Car felt great all day long.

What's interesting is when it's off boost and the IAT begins to heat soak. I'll see cruising IATs of 60-65C.

Please share your results. My biggest concern is if my IATs are too cold. I might be willing to give up some cooler IAT if it means I dump less water into the cylinders. I believe you're on the SOS Laminova? If you're seeing this cool of IATs on your engine, it would make me feel better about a safety buffer in mine

 

[cptnsx]

My delta is 35-40F between ambient and highest temp; however, with the SOS Laminova not only is the IAT sensor different from stock but is also in a different location. Personally everything I have seen and read with Mustangs that use Meth or water cooling maxes out around 20-30 degrees.. maybe you're able to get better results or you could be over cooling the sensor. I have never seen that type of reduction. If your AFR still looks good and you are not bogging then you are not dumping too much water, technically this is suppose to reduce power since water does not burn.

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One way to test the IAT is to do about two to three third gear runs without the water injection and log your AFR. Then do about two to three with water injection and log your AFR. If you are getting a reduction of 75F then your AFR should be off by about a point ie your off injection should be richer by about a point.

 

[RYU]

thanks for the spot check cpt. i think you might be onto something in regards to the sensor overcooling. however, i'm not sure how to verify that. I'm reading from two IAT sensors. The OEM unit in the stock location via the CTSC manifold and an open element via one of the side ports connected to my Zeitronix data logger. The OEM is much slower moving but they both tend to get to the same delta. I'll have to trust it for now I reckon.

My AFR readings are a bit more inconsistent at WOT which might be due to too much water or maybe a worn out O2 WB sensor. I did experience some bog yesterday and turned down the water flow. So you're right there also. I think i'll be happy with a 30F delta so I need to order a couple more smaller nozzles. After turning down the spray and still getting only a 25F delta the car ran great and the AFR was more consistent. If I was lazy I'd be ok with keeping it as is but i'd like to turn up the pump voltage to max but maximize atomization with a smaller nozzle.

Thanks again!

 

[cptnsx]

thanks for the spot check cpt. i think you might be onto something in regards to the sensor overcooling. however, i'm not sure how to verify that. I'm reading from two IAT sensors. The OEM unit in the stock location via the CTSC manifold and an open element via one of the side ports connected to my Zeitronix data logger. The OEM is much slower moving but they both tend to get to the same delta. I'll have to trust it for now I reckon.

My AFR readings are a bit more inconsistent at WOT which might be due to too much water or maybe a worn out O2 WB sensor. I did experience some bog yesterday and turned down the water flow. So you're right there also. I think i'll be happy with a 30F delta so I need to order a couple more smaller nozzles. After turning down the spray and still getting only a 25F delta the car ran great and the AFR was more consistent. If I was lazy I'd be ok with keeping it as is but i'd like to turn up the pump voltage to max but maximize atomization with a smaller nozzle.

Thanks again!

Good to hear. I just changed out my wideband O2 sensors. I have heard that the AEM ones don't last a long time. I'm also running the iridium 8s with no problems. They have superior anti-fouling characteristics so you can get away with that. I've always heard run the coldest spark that does not foul to get extra detonation prevention headroom plus I mix 100 race gas with 91 to give me 93. I believe this 91 we get (probably from Cali) is not good. My G37S will lightly ping on it at low RPM. If I mix to get 92 or 93 for that car, everything is fine.

 

[Maple Valley NSX]

Thank You Prime Members!

This has become a lively discussion and extremely informative. I have had to set this aside for the last 2 weeks as I took the earlier advise to heart and just "chilled" on this for a while. I am going to try to get the tune file/data logging from the AEM. Is there a member that can objectively evaluate this tune forensically?
I am trying to make a decision on rebuilding and to what extent and most certainly do not want a repeat of this tragedy.

Thanks again for all the support and advise, genuinely appreciated!

Brian P.