New FD owner, have a few questions regarding coils

[Jit]

No I don’t think that’s the correct steering wheel for a 97 car. Seems as though someone’s gone to the trouble to replace an aftermarket wheel with a stock one only to put the wrong one on.

 

[Jit]

You should have one of these wheels if I’m not mistaken

 

[Om7]

Ah, that would make sense I guess. Would a '97 import have an airbag? I believe that in Japan they don't have the same laws as us so post '96 cars didn't require an airbag where as the UK spec ones would have. Do you know if the splines for the steering wheel on the FD are the same as the NA MX5? I can get my hands on both the MOMO airbag and none airbag steering wheel but they would both be from the MX5 and not an FD.

Strange that the airbag fault has only appeared now. Though the misfire only occurred after I got it back so I kinda guess that a couple of things were covered up so that I could get it home before they showed themselves. Not a problem as the price was right and the initial plan was to buy one that required a rebuild, so the fact this one already runs and drives is a bonus. Just a few problems to sort out now!

Thanks Jit!

 

[Jit]

Fairly certain splines on mx5 are the same. Ceylon will be along to confirm soon enough. I think there is a small tab on the FD indicator stalk that you have to break off when installing an MX5 wheel. Again don’t quote me on that. Ceylon is your man.
The airbag fault is an odd one hence why I suspected possibly the clockspring

 

[Om7]

Thanks again for all of your help Jit. I didn't get chance to work on the FD last week but had it up on the ramp last night and managed to try a few things.

First of all I removed the wheel and found this:

I assume the yellow box which tricks the car into thinking it has an airbag has failed. I tried installing a late NB MX5 steering wheel and although the splines are correct the squib isn't the same. I'm not sure whether it is worth trying to modify the squib with an NB MX5 squib to make it work? Should I be playing with airbags?

We also pulled the coils and leads and tested their resistance. The coils were between 0.6 and 0.8 ohms which I assume is fine but the leads weren't great at around 26 ohms per metre when Mazda recommend 16 ohms per metre maximum. Which leads are recommended? These are cheap after market red ones so I would like to replace them with something decent.

I changed the fuel filter too, which wasn't as bad as I was expecting but it didn't make a lot of difference. Ran out of time so I didn't get chance to pull the cat but I want to replace it with a decat pipe when I do anyway. Where can I buy a decat pipe? The only one I can find is on the JapSpeed site but they seem to be discontinued.

After all of this the car still misfires and I'm sure it's getting worse. The manifold still glows bright red and I realised the other day it boils the washer fluid it gets that hot!

Thanks again!

Edit: Also, the guy from the unit next door popped in while it was running and says it sounds like it's burnt a valve. Something worth thinking about.

 

[Matt]

I changed the fuel filter too, which wasn't as bad as I was expecting but it didn't make a lot of difference. Ran out of time so I didn't get chance to pull the cat but I want to replace it with a decat pipe when I do anyway. Where can I buy a decat pipe? The only one I can find is on the JapSpeed site but they seem to be discontinued.

@Topgears should be the man for that and you're not a million miles away so its a no brainier.

https://tgsexhausts.co.uk/product/t...exhaust-system-decat-racepipe-mazda-rx7-fd3s/

 

[Jit]

Decat wise I’d just find a cheap one that fits just to help you rule out the cat (although it could very well be this). Have you checked that the car is also not in limp home mode? Series 7 and 8 cars don’t take much to go into limp mode. Leads wise I’ve always just gone with stock Mazda. Can’t remember what they were off the top of my head but I’m sure it wasn’t too offensive.
I’ve got a known good set of coils/leads on a series 7/8 plate (so in the correct orientation) I can lend you to try out if you want?

 

[Jit]

Decat wise I’d just find a cheap one that fits just to help you rule out the cat (although it could very well be this). Have you checked that the car is also not in limp home mode? Series 7 and 8 cars don’t take much to go into limp mode. Leads wise I’ve always just gone with stock Mazda. Can’t remember what they were off the top of my head but I’m sure it wasn’t too offensive.
I’ve got a known good set of coils/leads on a series 7/8 plate (so in the correct orientation) I can lend you to try out if you want?

Also steering wheel wise, can you take a pic of the set up with the wheel off.

 

[Om7]

Matt: I had a Top Gear exhaust on my first S13 years ago and it was great but at the moment I'm just problem solving and don't want to throw large amounts of money at it to try and fix things. Definitely interested in the future though so thank you for the link.

Jit: I had assumed the cat was in the down pipe but after looking it would appear the down pipe is straight through and then the mid section has a cat. I seem to have an after market sports cat here with some form of sensor welded in so I plan to remove the exhaust after the down pipe and run it straight to atmosphere and see if that helps at all. Hopefully I will be able to see most of the way up the down pipe to the turbo to check that it is clear here and go from there.

Regarding the steering wheel I plan to drill the back slightly so that the blue section of the airbag squib can fit properly and the try and dismantle an NB squib to try and make it work with the FD squib. I should get chance to do this tomorrow evening so I'll put some pictures up of the setup and if it works or not.

Thanks again for your help!

Edit 10/04/18:

I didn't get chance to look tonight and I'm going away for a few days tomorrow so it will be next week now until I can get it back on the ramp. While I remember I should have mentioned this before:

I asked a friend and he says the green label says 'Murayama Special'. I had a Google and couldn't find a lot on these guys, if that is what it says. They seem to have a couple of videos on YouTube but no real information.

Edit 2 19/04/18:

Last night I replaced the plugs and leads with NGK 9EQP plugs and Magnecore leads. Unfortunately this did nothing for my misfire. What is left other than coils? Could the small section of harness that goes to the coils cause a misfire? I opened it up as it had been clearly played with before and tidied up the wiring and re-wrapped it. Any chance this could be the problem?

I managed to pick up an FD3S5 Power FC and commander the other night too, so hopefully that will be here for the weekend. Not expecting it to sort the misfire but I know it's a better map and it will replace whatever has been modified in my current ECU.

 

[Om7]

I suppose it is time for an update now that I have managed to try a few things and my wallet is much lighter.

So far I have replaced:

• Spark plugs
• Coil packs
• Coil pack harness
• HT leads (twice)
• Igniter module
• Fit a Power FC and hand commander

Last night I started it up and it sat and idled at 2300rpm until it warmed up and the revs dropped to a hunting of 800-1500rpm (drops to 800rpm and blips itself back up to 1500rpm) and after a while that sort of sorted itself out. Is this normal? Is this the Power FC learning to idle? I'm sure I read somewhere that it has to, which is going to be annoying as I very rarely drive the car and it sits most of the time with the battery disconnected.

Secondly, I removed the air box and found an aluminium 'restrictor' in the smaller left pipe (a recirc pipe from the smaller turbo?). Basically just a spun up piece of aly with a hole in the centre. I guess this is some form of crude way of tricking the turbo to boost longer? Any ideas? I removed it anyway and the hesitation before coming on boost and the 3k rpm flat spot has gone but both of these could be the Power FC doing its thing.

Lastly, I installed a DM Motorsports coil pack relocation plate (a copy I think, but identical I guess) and removed the air con pump. I found the fit disappointing as it fouls on the bottom 'lugs' which stick out to support the air con pump. Does everyone just grind these off before fitting?

I think that is it for now. It still misfires slightly but it's much, much better than before. Sometimes only once every 10+ seconds. I guess I'll get there in the end. Took it for a spin and it feels much faster, like I imagine it should do with no hesitation - straight on boost and pulled hard to redline.

Thanks again!

 

[Spendyrx]

That ally piece is an anti moo. You need that! You run your car now and all you'll hear is moo from your air pump
Yes power fc is learning idle.
If you're still on a base map, reset it, run the car for 10 mins on idle with everything off eg, lights, heaters etc.
Then after that 10 mins, put your lights, fogs, ac and heaters on full power for 10 mins should all drop nice and sweet then

 

[Spendyrx]

Does the ally piece look like the pic?
Also, take it easy with the pfc on boost if you have an early fd! The base map isn't the best! There's a guide on how to use a 12 degree split which makes your map safer

 

[Om7]

I knew I should have taken a photo of the aly piece. It isn't like your photos, more like a solid aly piece with a hole in it rather than three smaller holes. Is this stock Mazda? I will be amazed if it is as it looks after market. My car does moo regardless as it did it before I removed it and if you rev it slightly to 3k and let off you can hear it through the air box. It also had a jubilee clip around it rather than the stock pinch clip which led me to believe someone had installed it rather than stock Mazda. I don't really understand the function of the air pump other than for the original cat so as I have no cat is it worth removing it completely?

I reset the Power FC before I first ran the car to make sure it was on the base map. If I do the sequence you mention will it remember how to idle after I remove the battery? From a quick Google the split is the firing time between the leading and trailing plugs? I'm new to rotary and learning as I go and the whole point of buying an RX7 was because I was bored of 4 stroke and wanted to learn something new so you will have to excuse my innocence and basic questions.

 

[Spendyrx]

Yes you can remove it and either buy a smaller belt or you can buy an idler pulley to sit in place of the air pump. Alot of people choose the idler I believe to stop their water pump bearing failing or high speed driving makes the water pump more effective or something like that! But... be sure that you have a decent mot man as you need to pass an emissions test of sorts still! Once the air pump is removed, you will need to get a blanking plate kit to block off the acv along with your air pump outlet pipes
Oh, I'm not sure what that is then! I'm sure someone will come along and confirm it! It's been a long time since I had a stock bay!
Haha don't worry we're all still learning!
Yes 12 degrees between leading ign and trailing ign
And yes the pfc will remember anything you do even after pulling the battery! I usually have my battery disconnected for a week or so

 

[Paulm]

Idler is best if you can fit one, larger single turbo setups can be in the way. If not an under drive pulley kit, to increase contact area between the water pump and belt. Otherwise the belt will slip, mine would scream under hard acceleration, and applying too much tension to the belt to stop the slipping will cause damage to the gears and bearings on the front of the eccentric shaft.

 

[Spendyrx]

I should really look into an idler I've not had any belt slip trouble with in though! Belts probably too tight

 

[kaeolian]

Hey bud, sorry I didn't see this earlier but I had EXACTLY the problems you are having right now and I replaced plugs / coils / leads etc and none of them fixed it.

It was actually a failing solenoid which caused this for me. I replaced my entire black solenoid box (late spec) and it resolved the issue.

 

[Paulm]

Ive jusy fitted an undeedrive kit, as mine screams it's this off. Tbh wish I'd gone idler

 

[Spendyrx]

Lol at auto correct Paul! My Mrs screams her this off at me all the time

 

[Paulm]

My wife operates at such a high frequency I no longer hear her