| Ka Yu have just quoted me £100 plus VAT and carriage for a Roadster AFM. Ouch. Time to look around for a new one. I heard that in addition to the RX7 AFM being usuable, so was a 626 version. Is this true? (1/01) |
| I've heard that some 626 ones are, but dunno which. My 626GT (a GD, if that means anything to you!) had a hot wire sensor (still got an AFM from it). It's got a different number of connection pins - I'll take a look over the weekend - but I doubt that would work without a lot of trouble. (1/01) |
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Checked out my 626 AFM. It has 6 pins rather than 7 as on the MX-5. It is hot wire technology (like later MX-5s), and has a facility to "burn the wire" on switch off to clean it. It has an idle mixture connection (not sure what that does) no air temp sensor (that's separate in the 626GT, in the manifold air box) and no fuel cut switch. So all in all it's a completely different set-up from the MX-5. But there are many many variants of the 626 about, and they're all different!. It would probably be possible to design some interfacing jiggery-pokery, but hardly worth the effort. And I'm not convinced yet that fitting a RX-7 AFM is straightforward or worth while. (1/01) |
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Got a bit of a problem with my car. Yesterday, I decided to clean the air filter, but because it was so cold I tried to remove the Filter and the Air meter and take in inside. The mistake I made was to disconnect the electric cable from the Air Flow meter via the two screws (And not via the wrap around clip like you should) Anyway to get to the problem. The car would not start. Having removes the Black top cover and looked inside it loos as if I may have broken some of the pin contacts. There are 8 pins all together. Starting from the left as you look down. Pin 1 Black Spade connector (This one is ok as is secure and
runs to the right) So What I did: A few questions. |
| When Ifitted my induction kit I took out the two screws, then when I tried to pull it out I realised this was wrong.What I then did was to push the connecter back in little realising that the needle inside had gone the wrong side off the stop so the car would only run for a second and then stop ,you might want to have a look at this sorry I dont Know anything about the connectors.hope this helps. (1/01) |
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Oh dear! Hard to say if you've completely knackered it - as you say, they are very delicate and not to be messed with. They are also expensive - even a scrapper will be asking quite a bit (70 at a guess?) So it might be worth some more "fixing". If you do give up, you will need a replacement from a similar car - I assume you have a pre 94 1.6? (Early (1.6) cars have "moving flap" air flow meters, later ones (1.8 & 1.6) "hot wire") I think the 1.8 and 1.6 hot wire meters may have calibration differences? Try Ka Yu (024 7631 8729 or www.kayuautos.com ) You shouldn't have done any more damage, but you never know - you're getting a bit close electrically speaking to the ECU, and you don't want to damage that. No, you don't wanna. DON'T TOUCH A 5 UNLESS YOU'VE GOT A GOOD MANUAL! Most of the things which might look obvious but aren't, and might be different from usual car practice, are also very expensive, or at least potentially damaging to the pocket (eg rear brake calipers, ecu related stuff) - although most of the ecu induction/fuel/ignition system is pretty well standard Bosch derived stuff. (1/01) |
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Alternatively, treat this problem as a positive thing, and upgrade the stock AFM with an Rx7 AFM, it will give you 5hp extra at 6k + revs, and its been dynoed, airflowed and tested, 100's of people have already carried out his mod successfully. It may involve a little modification, ie just with a screwdriver nothing fancy, somtimes its just plug and play, however you would need a larger diameter pipe to connect the larger RX7 to your existing air intake.. Ive bought an Rx7 AFM (EGi 86-89 model) for 30 quid including p&p from Andrew at (Jimmys Mazda RX-7 Parts Specialists) www.jimmys-rx7.co.uk I havent yet got round to fitting my RX7 AFM but will do so, maybe this week ;o) (1/01) |
| Well, if your lucky, you may be able to solder the joints back together.... otherwise you'll have to buy another one. Don't bother going to a dealer - they'll charge you ?300 or more. Either try a breakers yard, Ka Yu autos or Jay Ng. It will still probably cost ?70 or so... (1/01) |
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I also have an RX-7 AFM awaiting fitting but will book rolling road after to check air/fuel ratio correct. As I understand it: 1. RX-7 AFM on it's own will "lean out" the mixture i.e you have to richen it. This is usually accomplished by .. 2. Fitting 1.8 size injectors. 3. On whole (but not g'teed - all vehicles different)the two together will balance each other out and you'll get more power at 6000 rpm + 4. AFM on it's own will require flapper adjustment - bit of a problem as those few still alive are in their late 90's so eyesight poor and hands shake, and scarcity means they can charge you lots ;) 5. In conjunction with 4. you may also need to fiddle with the air bypass screw on the AFM which may still be covered by a metal plug.Easy to drill out (gently) See Randy Stocker's page for details. I reckon that by attempting to "match" the flapper feel (snort)of the two AFM's you've probably allowed the larger diameter RX-7 ARM to run engine lean even more.Really you need an Air/Fuel ratio meter to check all runs as it should or rolling road used to "flapper" ARM's and adjusting them.Fortunately the one I have should be adjusted OK already as it was matched with 1.8 injectors originally.The rolling road test is primarily to check RWHP after mods but the air/fuel check will be useful. |
| Its meant to be straight forward, but I'm having a couple of problems... I bought an rx7 AFM last August, but then my daughter was born and I hadn't really got around to sorting it out! Kids 'eh. Take up too much time :o) The AFM fits on perfectly - same connectors, wired in the same manner etc... and the car starts fine.. I managed to get a little time on Sunday to have a play to get the thing working - or try to anyway. The car starts fine, but when ever I rev the car, the engine sounds lumpy - almost as if one of the cylinders is misfiring. There are two adjustments to make on the AFM...1st is to adjust the spring that controls the flapper. OK, so I adjusted that to have the same resistance as the standard AFM. Then there's the O2/CO2 adjusting screw. Well, turning that doesn't seem to change anything apart from the exhaust emissions. mmm. what now? Well, I'm not sure if its just the AFM that I've got - dunno if its broken? Or if there is anything else that needs to be tuned in... The idea came from Randy Stockers web page, where he's done the mod himself (and on his wife's '5) and he links in to a couple of other sites where other people have done it too. However, Randy doesn't reply to any emails that you send to him, so no help there... (2/01) |
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OK, so I adjusted that to have the same resistance as the standard AFM. How did you do this mate? (2/01) |
| You know when you take off the black plastic cover to look inside the AFM? You just click that spring clockwise (IIRC) by 4-8 clicks or until the resistance on the two flappers is roughly the same. All I did was put the two AFM's next to each other poked the flapper (oo-er missus!) on the standard AFM, then poked the RX7 one, adjusted the spring, poked them again etc.. until they matched!! Spent an amusing 10 mins or so poking flaps. Got a funny look of the wife too... (2/01) |
| From all the reports I've read on this mod, the majority are fine and recieve enought fuel (the mx5 runs on the rich side as standard anyhow), though Iike you I've heard if it running lean, 1.8 injectors are a good compliment to the rx7 afm. 4 1.8 injectors are about 100 quid. (2/01) |
| Your supposed to disconnect the battery for a time, the reconnect leave the car running for 15 minutes, for the ECU to learn the new air/fuel mixtures (according to the miata powerforums). Then drive the car, see what happens. If it runs ok upto about 5k, but then refuses to go past that, the flapper isnt opening fully and needs taking out some more. If while going along, the revs are bouncing all over the place, the flapper isnt tight enough and is opening and closing freely causing the revs to increase and decrease. Have you driven the car with AFM on? (2/01) |
| no I didn't drive the car - it sounded too rough so I didn't want to risk it!! I didn't disconnect the battery either...something to try next time :o) If you run the car for 15 mins, do you just leave it running at idle? or take it for a drive? (2/01) |
| leave it running at idle. (2/01) |
| Nothing will be learn at idle .. the ECU 'relearns' while you are driving around.. (2/01) |
| Anyone know how best to adjust this? Located on AFM body and normally hidden under a seal but obviously tinkered with before my time - and by me I confess. I understand it has some effect on the pick up from idle and seems to alter CO emissions. In particular is there a suggested starting point (eg screw all way in then undo three turns)?? (3/01) |
| I'm puzzled by what you mean here. There's no adjustment at the air flow meter (except by taking it apart - NOT recommended.) Do you mean the idle adjustment screw on the throttle body? That adjusts idle speed by changing the volume of air able to bypass the butterfly. All you can do is connect GND and TEN in the diagnostic connector, then screw in or out until the idle speed is 850 +/- 50. That should be fairly easy. (Do it with the engine at normal running temp) It doesn't really affect anything else except idle smoothness and droop, and it needs to be reasonably correct to get the timing right. Idle droop, varying idle speed and pick-up problems can be caused by a host of other things - sticking air and ISC valves, clogged air filter, dirty injectors, poor plugs and leads, to name but a few. (3/01) |
| Isnt there an air bypas screw of the flowmeter like on the rx7 ones? Ok your probably going to say no but least I tried ;o) (3/01) |
| You're absolutely right. I know b***** all about the by-pass adjustment on the AFM - the cap is not designed to be removed and it's obviously intended to be a once and for all adjustment, probably to adapt the AFM to different vehicle applications. Nowhere in any of my manuals does it even mention the screw, let alone how you could go about "adjusting" it. It will obviously affect CO levels and mixture strength, which will have various knock-on effects. The O2 sensor feedback will have some compensatory effects at mid throttle openings, but probably not at idle and certainly not at WOT. Possibly use of a CO meter and an Air/Fuel ratio meter would help to restore the screw to its intended setting. I have a CO meter, and even now I'm in the process of building a A/F meter. But I still won't be messing with that screw! BTW, my CO meter is a cheap one and it doesn't really measure CO at all but O2, I think. Claims to do it by measuring thermal conductivity of the exhaust gas. (3/01) |
| The screw on the AFM is under a proper seal (normally), that unless you know what you are doing should not be tampered with. It actually adjusts the tension in the clock spring inside the AFM, this clock spring is what controls how much air flowing past the flapper door affects the air flow reading. There is no easy way to recalibrate this. The screw which can be wound fully in and then out so many turns is the idle bypass screw, which is located on the side of the throttle body under a rubber bung. This controls how much air leaks past the throttle butterfly and is the one that you can adjust to set your idle, cure idle droop, etc. etc. If your clock spring screw has been messed with, you may have a problem. (3/01) |
| In that case how come on the rx7 AFM mod they advise you to adjust the internal spring by hand and then also adjust the screw if its still not right...as from what your saying they do the same thing? Am Imissing something here? (probably!) (3/01) |
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OK, the RX7 AFM is bigger than the stock 1.6 AFM, right? So, that means that the same amount of air flowing through it doesn't generate as much movement in the flapper as on the stock one. This means that the signal given to the ECU is lower (or higher - depends which way round it works) - anyway, the ECU sees you getting less air than you actually are, therefore supplies less fuel than it should, and hey presto, a lean condition = bad!! It is therefore necessary to adjust the spring setting on the RX-7 AFM so that for a given air flow, the signal generated is pretty much the same as for the stock AFM. Comprende? If the AFM screw has been adjusted on the stock AFM, it will (or at least could)( be giving dodgy signals to the ECU. This could either result in running too lean, with the potential of detonation melting your engines insidey bits, or too rich, resulting in possible meltdown of your CAT. (3/01) |
| Sorry, I meant whats the difference in moving the mechanism inside a few clicks and turning the screw adjustment screw if they both do the same thing? (3/01) |
| As far as I am aware, there is just the one screw - the one that adjusts the spring - it clicks if that helps. Not having one, I could be wrong. (3/01) |
| The lack of adjustment is (I read) because of US smog laws. User adjustable bypass of AFM would break some rule of other. The AFM seems to have two adjustments. One is the spring on the flapper, which adjusts the "gain", and the other is a bypass. Adjusting the second requires a plug to by pulled out, usually by drilling a small hole, driving in the screw, and then pulling hard! (3/01) |
| Hmm, something that hapened to one of our cars over here in Northern Ireland; a cautionary tale. The owner had a 1990 car, and fitted the UK K&N filter. Fitted it, and then the car wouldn't run. He rang me up, and I thought, uh oh, he's pulled the guts out of the AFM by mistake and raced around. Well he hadn't, not really. By the time I was round there, he had pulled the thing apart. Uh oh; you've broken the solder connections, I said. We spent hours jiggling the AFM, holding screwdrivers on the connections. Got the car to idle a few times. By about 11, we taken the AFM off the umpteenth time, and gave it a shake; something rattled. Too late to do anything more we left it, resigning ourselves to a new AFM. Took it round in the morning to an autoelectrician to check out. Well, for starters, he thought it was a bad idea to to use "normal" solder on the 3 connections in question. Apparently, its likely to fry the ECU. Also, surprise to me, these connections aren't meant to be soldered, just touching (surprising, as there was globules of solder over the ends of the prongs). The rattling was traced to a small clip that had come off the temperature sensor end of the plug, and worked its way under the base plate, resulting in a short. Put back in place, the car functioned perfectly, and no soldering was required. When he was removing the old air box, the owner found one of the bolts on the AFM was seized, and needed drilling out. This is what must have loosened the clip. One comment I have on the UK K&N 57i kit; appalingly designed. The connection from the AFM adaptor to the filter was absurdly tight. Anyone else found this. The US K&N Filtercharger has a much better connection. (6/01) |
| I found it as well. I had to 'diagonally trim' thehole on the filter to be able to get it on to the bracket. IT took a number of attempts to make it wide enough, but once there it has been alright (I've had it on for almost a year now). (6/01) |
| Apparently, its likely to fry the ECU Not if you take the ECU out it won't. (6/01) |
| Whats the difference between the uk and us spec kits? (apart from 150) (6/01) |
| My UK K&N fell off and attached itself to the manifold. I assume it was a UK one because it was difficult to fit. The previous owner had removed the heat-shield and I hadn't got around to fitting another one, so it was partly my fault that the rubber connection had melted (I deduced that this is what had happened because the clip had embedded itself into the connector) I ordered another one with a heatshield from Moss, which I guess must be the US one. As it took about half the time to fit than the other, mind you it only just fits under the strut brace. (6/01) |
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The US filtercharger (also labelled M'mms on some Jap imports) is much bigger in size than the UK version (the base is probably twice the size), and comes with a heatshield of sorts. A square-to-round adaptor is fitted to the airflow meter, like most other cone intakes for 1.6 MX5s/MR2s/Celicas, and the whole lot secured with a jubilee clip. There are also a coulple of extra brackets to make it more sturdy. No cooker ducting though....;) Ka Yu has a few of these lying around, for £25 incl. adaptor, off cars broken for parts. Only just fits under the factory brace though. The UK K&N seems to clear a low profile brace like the Cusco version ok. (6/01) |
| Ditto your experiences with the K&N kit. If I hadn't seen Gary Sereno's car with K&N fitted I wouldn't have known it could be done. The bracket that kind of holds the AFM up in the air needed lots of manipulation (read brute force and ignorance) before I got it all to come together. Still, now it's on, it's fun playing induction tunes. (6/01) |