NB2 Project from Cheltenham

Hi everybody! Here’s my NB2.5, its a pheonix edition with the 1.8 vvt and torsen dif. I’ve had it for about a year and a half now. Im seriously in love with it and the MX5 community!

As my second car my plans are to track it and drift it (hopefully not break it!). So far modifications include…

-From the previous owner
K&N Typhoon induction kit
Unknown brand back box
JVC head unit and fancy footwell LEDs

-By myself
Maxpeedingrods coilovers (sh!t I know, but I’m poor)
Hard top

I’ve managed to take it to one track day so far and was pleasantly surprised how well it hand on the budget coilovers. I was just let down a bit by the old stock size tyre. Definitely after a nice wheel and tyre package next!

I’m in the process of fixing some issues with it at the moment. It’s throwing a couple fault codes…

P0172 - System too rich
P1498 - EGR Valve Motor Coil ‘3’ Open or Shorted

It has a droopy idle and runs ritch. I think i may have diagnosed it as a faulty ECU. Unfortunately after I fitted a new EGR valve, cleaned intake manifold and EGR pipe, cleaned air filter and tuned mechanical idle. Im going to make aother thread in a more appropriate section to ask for some ECU help.

But yea! Watch this space! I plan to make a little weapon out of her :v: Cheers!


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Hi Shinobi.
North Place car park?
You’ll probably recognise this location : Favourite MX-5 Photo (gallery thread - no chat) - #844 by AndyGadget

Nice looking car and what you’re planning to do to it sounds interesting, I’ll look out for it.
And welcome to the forum.

(A bit outside Cheltenham on the Oxford side, off the A436.)


Hi Andy, thanks!
Yep that’s North Place, Cheltenham is awesome for graffiti. I love that shot, your car looks so smart. That’s High street car park right?

Tidy, I actually live in Brockworth now, bought a house there just over a year ago… but its easier to say Cheltenham still because more people know it (and its nicer than Gloucester :joy:). I’ll keep an eye out for you too!

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My shot was Henrietta Street car park, down the end of the lower High Street.
I was just lucky with the photo. The car was pretty dirty but it doesn’t show :smiley:

Yea thats the one! I’ve got a nice shot of my daily (Audi A4 avant) in front of the mural at Hardwick Campus. But I won’t bore people here with that :sweat_smile:

Lucky! It looks well nice :ok_hand:

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A bit off topic but is there a good garage you would recommend in the area? Would like to start modding my PRHT 1.8, with the aim to start learning to drift. But first of all need to have it checked out for rust etc before I invest the money into it


Also looking for a a recommended garage in the Cheltenham area for my Nc. Any suggestions?

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It’s be interested as well.
I have used J-Worx in Bourton on the Water for some brake work who were good to deal with. They also do restorations and engine work but I can’t give a recommendation 'cos I haven’t tried those services.

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I use a small garage just outside Evesham. It’s near my work yard so it’s convenient for me, the owner is a great guy who appreciates MX5’s.
Quality honest mechanic.
He’s a very busy one man band and is getting on a bit now. He’s trying to slow down so don’t expect to be booked in urgently. but if anyone is interested the company is called…

Auto Enginuity
South Littleton
01386 761664

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So… bit of an update. I noticed that the vacuum pipe from my intake manifold to the MAP sensor was missing and the intake was plugged. I purchased and fitted a new MAP sensor and vacuum hose. After doing this, the car continued to idle poorly. I checked for codes. The previous codes I had have now cleared and I have four new codes, written below. If anybody has a clue what is going on I’d mega appreciate some help. My MOT is coming up in a month and I’m at a total loss :melting_face::face_with_spiral_eyes: thanks!

P0010 - A camshaft position actuator circuit / open bank 1

P0107 - Manifold absolute pressure / Barometric pressure circuit low

P0113 - Intake air temperature sensor 1 circuit high

P0123 - Throttle / Pedel position sensor / Switch A circuit high

FML. Further down the rabbit hole I go…
Using the process of elimination I continue to diagnose and fix any of the issues relating to the idle droop and rich air/fuel ratio.

Since my last update I have installed a new MAP sensor and re-plugged the vacuum hose on the intake manifold as it should have always been. The previous codes disappeared and were replaced by Oxygen sensor fault codes.

I cleaned the oxygen sensors. No luck.

The car failed its MOT. Turns out it had a de-cat installed. I had no idea :upside_down_face:
I installed a 200 cell sports cat and new oxygen sensors but the poor idle persists.

Oxygen sensor codes have now been replaced with ‘P0037 - Heater Control Circuit Low Bank 1 Sensor 2’

This code specificly relates to the heater element inside the rear oxygen sensor. First I used a multimeter to check the resistance from sensor heater element, which was a healthy 14.8. I then checked that the sensor plug received battery voltage when the ignition was on, which it does. Next I tried to diagnose a faulty return wire to the PCM but unfortunately that appaears to be functioning perfectly too.

I know that my PCM is healthy as I have recently sent it off for examination and no faults were found.

If anybody has any suggestions on how to sort this out I would really appreciated it!

A lot of aftermarket oxygen sensors throw an error code on the MX-5.

Also in Cheltenham (well bishops cleeve), but i’m also having issues with droopy idle on my Mk2 1999. I’ve changed quite a few sensors, checked for vacuum leaks, replaced gaskets etc. Still having slight issues.

I’ve raised up the base idle slightly to compensate, but it’s not really a proper fix.

Any close to finding the fix?


Why hello there… it’s been a while. Since the last time I posted here a few fun things have changed, stuff has been fixed and stuff has been broken again :slight_smile:

Let’s start with the fun stuff. I finally got some decent wheels and tyres.
7twenty Style 51, 15x8, et10 rear, et20 front.
Toyo Proxes TR1 205/45/15.
I think it needs lowering a tiny bit more, especially on the back. But overall I’m very happy with the fitment. No rubbing, no spacers, no arch modification!
Let me know what you think!

I also got myself a new steering wheel and quick release hub. Nothing fancy but I’m really happy with the quality and being able to move my legs without hitting the wheel!

I messed up the horn button so I just have a sticker on there :upside_down_face: I still need to sort this out and install a resistor to bypass the airbag light.

And finally some technical updates…

I resolved the rough idle / idle droop by simply installing a new MAF sensor. This was a relief but also very frustrating after going on a wild goose chase, fixing everything else but the root cause as the original MAF wasn’t throwing a code or showing any signs of malfunctioning. But she runs (ran) sweet so I’m not complaining!

I replaced the de-cat with a 200 cell sports cat. (De-cat is for sale if anybody wants it!)

Removed the soft top entirely. Installed hard top brackets, replacing the oem clips. No more wind noise, less weight and increased rigidity overall :ok_hand:

So yea, well chuffed with all of that stuff!


But now I have a new pain in the ar$e…

I parked the car up for a couple of months over winter and forgot to unplug the battery. Upon first attempted fire up the other day there was no response at all. No attempt to turn over, silence. I trickle charged it for 30mins and it fired up… Great! I thought…

After an hours drive that night, it didn’t fire up the next morning. Battery was reading 13.6 volts. Not the best but it should have been enough to fire it up. I tried to jump start it, wouldn’t work. So I went and bought a new battery…

First turn of the key with a new battery, nothing.
Second, nothing.
Third, held the key turned for a few seconds longer, fires up!:thinking:

Drove it for an hour and had a similar issue again before driving home.

It wouldn’t fire up at all earlier today, I checked for codes but there aren’t any. I was just about to give up and come inside but I tried it one last time and it fired up! Very confusing!

Could I have an issue with my starter motor? Ignition switch?

I’m going to check voltages at the alternator and starter motor tomorrow in the daylight. In the meantime, if anyone has any idea as to what is going on… your help would be greatly appreciated!


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Hi Graham, nice to hear from another local owner. Have you tried the MAF sensor yet? It resolved the issue for me, but as I mentioned in my last reply, I wasnt expecting it to do so…

I’d suspect the ignition switch before the starter motor.