spectre6000

iTrader: (1)

Ah. I figure it shouldn't be too different from any sensor though. As long as the ranges are in the right... range it shouldn't matter what it came from. Since the MAF is thoroughly removed from any other hard components and there's lots of leeway in terms of real estate, there should be multiple options available. Hell, I'll bet Felix could throw together a little box that will translate whatever signal into whatever other signal I want in an afternoon using the crap he sweeps off the floor of his garage. That's the sort of project he's always looking for.

clokker

iTrader: (2)

Here's the swap schematic:

Again let me say that this is a controversial "mod", but in this case it's not being done as a performance move, more to just get running better.
Anyway, I'll bring the MAF and airbox Sat. and we can see.

If Felix really can do a translator box so easily, we need to look into a hot wire AFM and better TPS modules. A smaller, more accurate AFM in particular would really open up some packaging opportunities.

j9fd3s

iTrader: (3)

the AFM to hotwire or even MAP sensor has been done.

https://www.hks-power.co.jp/usa/prod...=858_more.html

spectre6000

iTrader: (1)

What's controversial about it?

clokker

iTrader: (2)

There seems a wide range of disparate opinions about whether it works at all, if there's any performance change and whether it's worth losing the fuel cut switch for.

Unlike the S4 part, the S5 is position agnostic, weighs significantly less and with it's round ends, easier to package.

None of this is really germane though.
The point here is to cobble in another meter and see what symptoms continue/disappear.
I've always been struck by the similarity between the stock Z MAF and the S4s.
They are schematically identical (even have the fuel switch) and the plugs are the same.
The only apparent difference is the Z does not have the flanged inlet, it's round on both ends.
Which is a good thing.
So that might be an option as well.

spectre6000

iTrader: (1)

Whether or not it works should be easy enough to suss out. It's not like the fuel pump has any real reason to shut off as long as the injectors don't leak. That's how pretty much every rattle pump works, and if that's how they did it in the S5, as far as I'm concerned it shouldn't have any negative consequences. Hell, might even be useful for instances like priming the fuel system a la last weekend's fuel injector adventure. The other specs are easily compared with a multimeter. No need to even guess. I imagine one could just look at the manuals for the different generations and compare specs and parameters to see if that lines up. If the Z unit is the same (wouldn't be surprised if it is minus some dimensional changes given the way the industry operates), I could swap the guts easily enough if a Z car MAF is easier to get a hold of or substantially cheaper. The temp part of the unit is held in with one or two screws; the only challenge is that the potentiometer board section with the off switch would have to come out to gain access to it.

clokker

iTrader: (2)

The specs are easily available in the FSMs, comparing the two should be cake.
My operating theory re: Z MAF is that it is the same part and you'd just drop it in, no gut swapping required.
The specs for that are also in the Z manual, it'd be easy to cross reference.

How sure are you that your unit is actually bad?

spectre6000

iTrader: (1)

The MAF temp sensor tested bad at the ECU, so I took the MAF out, took it apart and tested it more thoroughly and directly. It tested bad. Just the temperature sensor though, the rest is fine.

When I was out driving a bit ago, I had a new fun thing happen. I was on the highway, going slightly up hill, and wanted to pass someone. I was at such a speed that downshifting needed to happen, so I did and accelerated accordingly. At about 3500 RPM, it seems like the fuel cut out and stuttered as if it had a rev limiter. I tried it again a little later, and there was a lesser cut at about 3800 RPM (transition to secondaries). I tried it a third time (in first maybe?) and it was back to normal. Additionally and seemingly concurrently, my upshift light didn't illuminate. I think I've probably got a few things going on there... I haven't had time to dig too deep into this yet (at some point I'm just going to have to sit down and read the manual cover to cover), but I can't imagine any link between the light and anything actually involved in forward motion; though I could be wrong. The 3800 RPM stumble was the first time that's happened, and would seem to be obvious in origin were in not for the 3500 RPM stutter almost immediately prior. It felt fuel related more than anything, and since I know my injectors are brand new, as are the lines, I'm thinking fuel filter, pump, or something computer related (primarily because I still haven't figured out how everything relates electronically). Fun times... I really need to get some work done. Work has been slow this week, but I've been more distracted than it's been slow.

j9fd3s

iTrader: (3)

iirc the temp sensor in the AFM comes right out, so while a new part is the whole assembly, a good used temp sensor can be installed in the old AFM.

the upshift light might no be directly hooked to the pressure sensor, but its part of the equation.

spectre6000

iTrader: (1)

The only question with removing the temp sensor from the MAF is how easy it is to disassemble. The temp sensor is under the swept plate, so that would have to be removed first. I'm not sure how easy it'll be to do so without doing any damage to the rest of the MAF. That aside, it's only held in with one or two screws, and the wires are on skinny spade connectors, so the temp sensor itself would be a cinch. Since you're deep in Mazda land, do you know of any alternate vehicles that used the same temp sensor?

Pressure sensor?

j9fd3s

iTrader: (3)

any of the ones with the flap type AFM should use the same temp sensor. FC, 89-93 miata, 86-92 626, MPV. Clokkers datsun might even use the same one. or just find a used 86-88 NA FC afm, and put it in, they are cheap used.

the Rx7 has a Manifold Pressure sensor. one of its jobs is to run the shift light, look in the manual, there is a page to diagnose the shift light

lduley

iTrader: (1)

Ya, depending on how much you have the pedal mashed depends on if the shift light is on or not. If you feather the pedal the light will come on, but if you leave it in the same gear and push the gas some, the shift light goes out

spectre6000

iTrader: (1)

That may explain why the light went out then. Doesn't explain the fuel cutting out though... Ugh... I'll get this thing baselined eventually...

lduley

iTrader: (1)

by the time you do that, you'll have rebuilt the whole car

HRnico

iTrader: (7)

Send me $25 and I'll ship you a N326 AFM that worked fine when I removed it to install a N318 on my 86 BaseT W/Luxo package.

spectre6000

iTrader: (1)

Wouldn't be the first time... You should see my truck.


Those letters and numbers don't mean much to me... Clokker has an S5 MAF I might use. I might also junk yard up something from the list J9faoesthbaoeut23r4g203 mentioned above and just pull the temp sensor. Doubt it would cost me more than a dollar or two and would be a great excuse to observe Clokker in his natural habitat.

clokker

iTrader: (2)

Don't forget the Z part...I bet it's plug-n-play.

spectre6000

iTrader: (1)

If you're offering it, I'll certainly take you up on it. I don't want to presume anything. I feel you've been exceptionally generous toward me in the very short time I've known you. Bring it to C&C tomorrow, and I'll bring a multimeter and a socket wrench, etc.. We can test it and swap it in the parking lot.

clokker

iTrader: (2)

Sorry, the Z afm is at Sigfrid's and not in hand.
What is in hand (actually, in car now) is a S5 afm complete with airbox.
We can certainly try that (be sure to print out the diagram I supplied) but I'll have to make a special trip to get the other one.

spectre6000

iTrader: (1)

I think the challenge with the S5 in terms of what's physically available atm is going to be the plug. I don't actually have a printer (actually I do, but it's in a box in the garage buried under truck body parts), but I can pull the diagram up on my phone whenever/wherever, or just have my laptop handy with this page open (Mr. Anti-cellphone-and-anti-laptop-man). It might be that we take a field trip to a yard after C&C to see what can be pulled from a "FC, 89-93 miata, 86-92 626, MPV." I think the latter two are the only ones that would be remotely likely. I can't see any first gen Miatas wasting away in a yard... I could be wrong though, you have a lot more experience with that sort of thing than I do.

clokker

iTrader: (2)

I have the plug handled.
This will work with no modification to your wiring...at least for the "try it" phase.

spectre6000

iTrader: (1)

I'm down. I'll try to remember to bring tools. Worst case scenario, my place is on your way home. We can stop by and throw it in to see how it works.

HRnico

iTrader: (7)

70.2 degrees and 2339 ohms In range

spectre6000

iTrader: (1)

So we got back to my place after lowering the property values at C&C, and tested out Clokker's spare MAF. It tested for the same specs as the S4 (save the missing switch leads), so we rigged it into my harness temporarily. It did not want to rev well at all... All sorts of stumbling and missing. We took it out and tested the sweep, and it wasn't exactly linear... So we tested the one that came out of my car since it wasn't having issues revving, but it also wasn't what you'd call linear... So we took the MAF out of Clokker's running S5 and tested it... Also not linear, but it also didn't test to the same spec as the other S5 unit. So we put the first MAF into Clokker's S5, and it revved freely, but backfired on overrun... Interesting. Not sure what that says exactly, but interesting. In the end we just put my MAF back on, and I hit up HRnico for the used one he has. He PM'd me the spec while I was out having breakfast with my wife this morning, so I'm going to go check those specs against what I know.

I think a fuel filter, maybe a pickup sock, and a good MAF will have it running happily save maybe an exhaust leak. The exhaust is a little on the rusty side, and while I haven't found any exhaust leaks, I haven't exactly looked super hard for them and they could certainly be the source of my backfiring. Once that's done' I can shift my focus to the non-mission critical electrical stuff... The CPU is very very unhappy, the sun roof doesn't seem content with its job, and a few other little piddly things. I also need to get back to my truck at some point. It needs paint, a new electrical system (that I'm both designing and building), and a new engine all before winter... It's going to be a busy schedule there...

lduley

iTrader: (1)

An exhaust leak shouldn't give you backfiring unless its running super rich and combusting in your exhaust, even then, you should get some flames out the muffler when it does