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Yeah, but a jack can be super useful, not just for my car.
Like when the suspension falls out of someones BMW...
I just went and checked an a legit Hi-Lift 36" HL-364 is ~$100 MSRP. Rated for 4,660lbs and weights only 25lbs. I honestly thought they were more expensive and I've never seen one that small.
During the rally, Gesso and I noticed that there were times when the car would be making 3-4psi of boost on the gauge, yet the wideband display was flip-flopping from 14.x:1 and probably 12.x:1 AFR (with occasional trips into the 15.x range) but anything above around 4.5ps the AFRs would plummet into the 10.x:1 range. At RPMs above 6k it was churning out 7psi (up to 8!) and the AFRs were in the 9s because that JR RRFPR was definitely doing work.
So too much fuel on the top end, and not enough fuel on the bottom end. Kinda. What do?
I think the top end fueling is simply a result of the RRFPR rate simply being too high. I have no idea what the rate actually is and you can't change it in this unit (with any reasonable effort) so it is what it is. This might be a FPR for a 1.6 kit. Or maybe its setup for the "big boost" upgrade. Who the hell knows at this point nearly 20 years after its manufacture. The solution might be to just make more boost to try to use up the fuel
The low boost fueling is a little unnerving. One would imagine the FPR would have surely kicked in by 4psi and would be cranking up the fuel pressure but we aren't seeing it consistently in the AFRs. After repeatedly watching the transition very closely (and believe me, I had ample time to do that in the 30+ hours I spent in the car during the rally) and doing some reading here and on m.net about how the factory ECU is programmed, I'm pretty sure what we are seeing is the closed loop/open loop transition. By way of explanation, I found a great quote:
Originally Posted by Savington
I'm drunk, so excuse the absurd pre-school style conversations.
open loop
ECU: Sup O2 sensor.
O2 sensor: Sup ECU. You're a little too lean.
ECU: No **** you O2 sensor.
closed loop
ECU: Sup O2 sensor.
O2 sensor: Sup ECU. You're a little too lean.
ECU: OK, we'll add some fuel to that ****.
O2 sensor. C00l.
The OBD1 NA8 ECU in my 95 is fairly rudimentary but it still uses this same type of logic. When the ECU transitions between the two is the subject of much stupid debate, but on the NA8 it happens around ~4000RPM. Its not nearly that simple as its got a whole bunch of other parameters like MAF input, coolant temp, throttle position, load, etc all in a table but the generic RPM number works when explaining this to the smoothbrains in the back of the class. Below 4k the system is in closed loop and the ECU is paying attention to the o2 sensor, above 4k it goes open loop and its ignoring the o2 sensor and running off an internal table. Wouldn't you know it? Around 4k is where the system is making around 4psi of boost. The RRFPR is working but the ECU is reading the o2 sensor and pulling the extra fuel OUT because its still in closed loop. Its actively FIGHTING the RRFPR by reducing the injector DC to keep the AFRs in check until it goes open loop and gives up, then we get ALLOFIT for fuel.
If only there was a way to create a simple device that would fool the ECU into thinking there wasn't additional fuel, or perhaps taking the signal and modifying it in such a way that under boost conditions we could hide the extra fuel until we hit open loop?
Fortunately, a great many people recognized this issue in the aeons that have preceded us and several marvels of industrial oddware were cobbled together to meet this very need. One of primogenitors of such arcane technology was @olderguy who's name is inextricably linked with the O2 Clamp: a clever device that went through many revisions, but was, in the broadest terms, a pressure switch coupled to some electronics that allowed you to set an output voltage to the ECU via the O2 sensor signal wire. Flyin' Miata had a similar unit which they called the "FM O2 Pressure Switch" that also supplied an user adjustable output voltage. I'm not sure when Olderguy removed his thread from the classified section here on MT where he used to sell the things, and the last of the adjustable output units from FM were sold out around late '07 to early '08. I did an excruciating amount of reading about both units and Olderguy was kind enough to reply to a couple of my PMs about it. I believe that I could reasonably reproduce one but there is some risk of damaging the ECU if I get it wrong, so even though I bought parts to do it I'm probably not going to try because I found another solution.
In my never ending to acquiring more trash to plug into this car to support the stock ECU, I bring to you...
The Flyin' Miata o2 Signal Modifier!
Due to "emissions regulation pressure" FM is no longer willing sell these to the general public, and the "FM Voodoo Box" includes circuitry that emulates this device so there is really no reason for them to even list them on the website. They sold A LOT of these to the 04/05 MSM guys to try to band-aid the horrible programming Mazda put on the MSM ECU, but they work on other NA & NB systems as well. The only place I can find this unit on the current website is as part of their MSM "Little Enchilada" kit, currently listed at $2,449 (though it was $1939 as recently as 2015) and they won't sell you this as a replacement component unless you are in their system as having purchased one in the past. Trust me, I've asked.
The best way to explain this thing is to let FM do it in their own words, I snipped and edited/reformatted this from the installation instructions PDF that still exist because the internet never forgets:
I do not like the language FM uses regarding "lean tip in" because this device isn't going to do anything for that issue unless you are in boost so I consider that description a little clunky. So as you can see by the revision date, FM has been selling these for quite some time. It's clear that FM was very proud of these devices and as of 2015 these were retailing for $125
I still think that price is a little dear, but FM is selling actually selling more than just a pressure switch.
Part of the label is ground off, and the hole for the adjustment screw and a couple of the contacts have been potted, and a couple wires added.
I like to test used things to make sure they work properly, so out came the Motive Bleeder and the Fluke DMM
And let me tell you, this thing is on a hair trigger. A single pump on the Motive was enough to trip it over.
The switches are the easy part, its the additional components inside that are the challenge.
A word of warning/advice:
The PN for the switch is easy-peasy, FM included that in some of the images in their product documentation. Hell, I ordered 2x of them from Newark some months ago. There is a certain group of people who think that FM is JUST selling a switch at incredible markup, but I can tell you that assertion is 100% false. There is even an instructional video of some smoothbrain on YouTube just ... installing the same model pressure switch on the sensor wire for his o2 sensor. Watching him try to solder directly to the stainless wire in the sensor is definitely worth a chuckle but I won't bother posting a link because I don't want to encourage that particular brand of oxygen thievery. I'm sure he's making money on that video distributing potentially damaging information which really drives me up the wall. Don't assume everyone on the internet knows what the **** they are talking about. Including me.
Anyway, this thing might help or it might make things much worse. It might be that the ECU is saving us from running horrifically rich while in boost and closed loop. Maybe it'll smooth out the AFRs and we won't get that weird stumble anymore. I honestly don't know, but I'm going to install it on my extension harness and report back as to how it goes.
That's a hideous "oil drain plug repair sleeve" thing.
I believe the way it works is that once you strip out the threads you drill out the pan to some nominal size, and then you blast that thing in there and hope for the best. God forbid you actually re-tap the pan, so that super shallow external "thread" is supposed to self tap into the aluminum and then it's threaded on the inside for a standard M14x1.5 drain plug. It's OD is small enough that it's still covered by the drain plug gasket so it doesn't leak. That is... if the sleeve stays in place. Which clearly it didn't.
No idea how long that's been in there but seeing as I just changed the oil, and it's holding oil, I'm going to let it be for now. Next time I change the oil I'll be prepared to re-tap the pan for Timesert or Helicoil, or maybe just blast some M16 threads in there and get a larger plug. Oh man, oil changes are going to be high speed!
I'd also like to point out that none of the 3 previous POs of this vehicle owned up to this madness 😆
If you remember back to the beginning of this thread, I mentioned the oil drain plug was loose and it was a couple quarts low when the car showed up. This would 100% be the root cause of that issue. The plug looked really funny with the big 18mm chrome head so I figured something was up, but I didn't expect this
I'd just like to note that I really like keenserts, but they're probably not the right thread repair insert for this application.
Also as the furthest removed PO (aside from you and the diamond man), I feel like my claim to having no knowledge of this atrocity is the most legitimate.
I'd like to update that I finally bought a decent relay to replace the super crap one that Moss shipped with the kit.
Stupid bastard expensive OE BMW relay is expensive, but also the only one I could find that looks like it'll work.
It's BMW PN# 61 36 1 729 004. It weighs about 6x what the original weights. Weight is a sign of reliability. If it does not work, you can always hit him with it.
I need to build a new harness and socket for this guy and put it on a dash switch. Hell, I should plug it in and see if it even works
Hah! Unfortunately that's a biiiiit of a haul for me, but I will have to get this thing out to the monthly Cars & Coffee at some point. I'll try to park it next to something expensive and get some pics.
11-19-2021, 05:38 PM
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