I am glad to help if you can be reasonable. I will fall on my sword immediately, issue a public apology, and get you set up with whatever hardware will make it right if you can prove that there's a legitimate hardware problem. But right now, I'm struggling because you're attacking me and my company. You're not looking for solutions to troubleshoot your problem -- you're attempting to condemn the DIYPNP and DIYAutoTune.com for a problem that you have not shown to exist. Taking an antagonistic attitude towards the people you are asking for help is not productive.

The DIYPNP is only sold as a user assembled kit. The hardware is robust and well tested. It's one of our better selling kits, and of the various versions the N76 kit is the best seller. This is no doubt due to how popular they are with the Miata crowd.

I've been running a DIYPNP in my own car (turbo Miata, basically same application as you) for several years. I've built unkown dozens of them for various applications, including for enduro racers. I built many before I started working for DIYAutoTune.com, and I've built many after being hired on. I have never had a problem with one I've built. We have no QC issues with this product.

The weakest link in this product is the quality of assembly, and that's something we have no control over. This is no different than any other DIY oriented kit. Stray solder, incorrect connections, or poor solder joints can wreak havoc. Those are the typical issues, and they're all user error. A cold solder joint may only show up when the joint gets hot. If that happens, it's certainly not our fault in any way -- the fault is on the person who assembled it, as we are not responsible for the user's workmanship. You can buy materials to build a barn at Home Depot, but if the barn is poorly built, falls, and crushes your prize pig, is that Home Depot's fault?

I'm sorry that something happened while you were on track, but that "something" could have been any number of things. From the evidence you have supplied, that something does not appear to be a problem with a map sensor. The only problems I can find with the map sensor is your incorrect understanding of how the sensor works -- your interpretation of the reading was incorrect, your interpretation of troubleshooting the ADC circuit was incorrect, and your understanding of how to wire an analog device to the ECU is incorrect.

The datalog screenshot you provided shows the sensor working and showing reasonable values. Posting an actual datalog .msl file is much more useful than a screenshot, but the map sensor is clearly working in the image you provided. It is clearly showing 137 kPa absolute. That is 5.5 psi of boost, NOT 19 psi of boost (that would be 235 kPa).

The map sensor itself is generally extremely reliable. It is more likely to damage or dislodge the tube that feeds the map sensor its pressure signal than for the sensor itself to fail. Did you check the tube for obstructions?

If I had a turbo Miata that suddenly fell on its face when hot, under high load, and at high RPM, the first place I would look is at the ignition system. As it gets hot, it has a harder time firing the spark (high resistance due to higher heat). As ignition components wear over time, the typical failure mode is to first break up under high heat, high load, high RPM. Over time, it will start breaking up under lighter heat and load conditions.

It's fair to say that something failed on you at the track. I don't think it's the map sensor that came with your DIYPNP or the other sensor that you replaced it with. I think it's something else. We'll help you, but you'll have to help us to help you. Part of that is not throwing mud.

What Ben said. As the founder/owner here, I've got to say he's right on, that said, our policy is pretty much 'the reasonable customer is always right'. We want to help you, but right from the get go- there was blame and attack straight from the video. Let's figure out what went wrong, and help you make it right? Maybe there's a problem with the ECU, maybe it was something else, either way, we're your friend, not your enemy, and we'll help you figure it out.

I had very similar symptoms years ago with another MS install while on the track. Minor difference, mine only showed up when I made a hard left turn with a passenger in the car. Root cause, the vacuum line to the MAP sensor was getting pinched when my passenger braced and pushed against the firewall, that was locking my map reading in one place by pinching off the line, and i fell on my face. Easy fix, reroute the map sensor's vacuum line somewhere it won't get stepped on ;).

If the map sensor IS reading off, the first place to look is the calibration. We can support any MAP sensor in the world with a 0-5v output. That means it's up to the person who built the ECU to calibrate it. It defaults to use the MPX4250 which is a 2.5 bar map sensor, anything else will require calibration to match the voltage output curve of the sensor to the ECU so the ECU can correctly interpret the output from the sensor.

We want to help-- please help us help you.

Ben, you are right on some points you have made, I have been shooting off words without organizing my thoughts. But you seem to have missed some important points that I have also made, and only pointed out the flaws in my arguement.

I haven't responded yet because I haven't been able to do the testing that DIYAutotune has requested (via email) or what Reverant has suggested due to Father's Day events and working a busy week. Hopefully I will have some time tomorrow to put together a coherant response and try to address the mistakes I have made in some previous posts.

Having a hard time locating Pin 3, maybe my eyes are just not working right, mind circling the general location?

Pin 3 is right next to pin 1 on the 50-way connector.

I get 1.8V at this point.


With the sensor hooked up to 5V and SG GND, I get 1.8V as well. Seems like the map sensor itself is fine.

Does the voltage change if you apply vacuum to the sensor?

Yes, while blowing into the sensor I can see the voltage fluctuate.

Get a syringe, remove the needle and replace it with a small piece of vacuum tubing. Apply vacuum/boost to the sensor, and make sure the voltage goes from approx 0.2V to 4.8V.

Yep, works for both the DIYPNP map sensor and GM 3bar. Also borrowed a friend's GM 3bar out of his running car and they all seem to be working fine.

Do you see the MAP reading in the tuning software moving up and down during these tests?

Tried to plug in the laptop today to verify the map and fuel loads as per DIY's email response today and I was unable to connect to the laptop.

But to answer your question, based on past testing the logs show that there is map activity but it is very non-linear.

https://www.miataturbo.net/attachmen...ine=1372708191

Notice a few things here: Map signal is moving but looks way off compared to the log below. Someone mentioned how my map signal moving before rpm does is related to slow throttle response. Bullshit. Look at the log below.

https://www.miataturbo.net/attachmen...ine=1372708191

There was a comment earlier about how my "map sensor issue" was related to slow throttle response. This is just not the case. Look at how my map slowly increases as rpm increases. Everything here is coming on smooth, no random spikes like in the log above.

I understand these screenshots are hard to interpret due to scaling, etc. I'm more than happy to post the log for those still not convinced that there is something seriously wrong with the DIYPNP.

Could it be that you have a blockage/kink in the hose to the MAP sensor? That would explain things.

Hose to the map sensor is fine and clear. I blew through them to make sure they were clean at track. No kinks as the hose lengths are pretty short, I tried to reduce the amount of hose as much as possible, hence why the sensors are mounted in the engine bay, and not on the diypnp board. I pulled 6 wires through the firewall.

Then I'd disconnect the sensor and use a potentiometer instead. See if that speeds up the response. Just turn it left-right and see if the MAP-reading in TS changes instantaneously.
If it looks OK with the potentiometer, your MAP sensor is shot. Replace it.
If not, attach the potentiometer directly at the MS and not via the wires going into the engine compartment. Disconnect everything else to eliminate interference from other areas. Make sure to use sensor ground as reference and not some random ground found on the chassis.
If the potentiometer attached directly to MS gives you slow responses, then I'd say something is wrong with your MS. If the responses are immediate, your problem is likely in the wiring.

BTW: the potentiometer should be rated at similar resistance as your MAP sensor. Doesn't need to be the same- just similar.

BTW2: If you attach screenshots of logs, trying to troubleshoot MAP issues, TP-data would help. For all I know, the slow ramping-up of MAP could be related to throttle-movement. And a description of conditions. Were you free-revving? Accelerating hard in low gear?

I'm still trying to figure out why the MSQ and log files still haven't been posted.

QFT.

There is a lot of talk of logs and looking at them, but a screen dump does not = an actual log.

In for PEBKAC.

Because no one asked for them, although I have said numerous times that they are readily available. This goes for the tune file as well. With my dealings with the tech support @ DIYAutotune, they were not asked for as well.

Post #21 begs to differ

Mention of log: