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Mx-5 gone, pug 107 and 300C now here.


paulplom

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On 6/12/2020 at 1:42 PM, SiC said:

I have vague recollections that bottom end can go a bit flat if the O2 sensor is knackered. Once you get above around 3k, it runs open loop hot or cold. Disconnecting the sensor will make it run open-loop all the time and may appear to fix the issue. This is possibly old enough to not need worry about a working Catalyst for MOT. Mine on K-reg was right at the edge for needing one. Will burn more fuel without it connected though. 

I've done quite a bit of googling and it looks like you're right. I'm going to unplug it when I get in from work and take it for a blast. It only hesitates when warm, never when cold or warming up.

Do you have a spare one @gm?

I'v ordered one of these too. Should be handy to keep in the glove box.

https://www.ebay.co.uk/itm/Diagnostic-connector-fault-code-reader-LED-Mazda-MX-5-mk1-mk2-Eunos-MX5/400429915759?fits=Model%3AMX-5|Plat_Gen%3ANA&hash=item5d3b7b9e6f:g:bb0AAMXQTghROKWS

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1 hour ago, paulplom said:

Do you have a spare one @gm?

Not really, there is one in the manifold on the donor engine but they tend to get destroyed when removed, better to buy a new one. There are two types, yours will likely be a single wire type, connector is behind the coil pack. 

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Wasn't bad value. £80 from JTF.

I still rage about my all my gear being stolen everytime I think about it.

30 years worth of car tools. All top gear as well. Bastards.

This stuff is just hilka bit seems pretty sturdy. It'll do for diy occasional use, I suppose.

 

 

 

 

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The kids are at my mothers, the sun is out and I have a full day to myself. Mazda fettling is a go.

This looks to be the wire from the o2 sensor. I'll disconnect it and take it for a run to see if the flat spot vanishes. Other jobs are, remove passenger doorcard and fix this bunched up window rubber. I'm going to replace the rotten drivers door with one I bought from[mention=4462]gm[/mention] e4d118355f57e200bb9de6be2edca18b.jpg

 

 

 

 

 

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I've just got in from a 110 mile hoon around Northumberland in 20° plus heat. It's proved it's reliability anyway. Two things I did discover though were the light's don't pop up anymore and the electric windows have stopped working. I'm a tit and in my haste to put it all back together earlier to go for a blast, I forgot the multi plug for the hazards/poppy up light switch and the connector for the windows.
I've just had to strip it again to connect them. Doh!

Sent from my SM-G975F using Tapatalk

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On 6/16/2020 at 1:45 PM, paulplom said:

I've managed very carefully. I've used a magnaclean magnet to extract them. The tips are very oily and two of them dripped oil as if it's running rich. Other than a blocked air filter, what could cause that? Maf or o2 sensor maybe?

I don't think these have been changed for years.

 

Sent from my SM-G975F using Tapatalk

 

 

 

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Oily plugs on these is almost always indicative of a leaking can cover gasket IME- Very common and can result in pronounced missfiring. Footnote: Only use genuine Mazda gaskets here unless you fancy doing it again in short order.

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2 hours ago, paulplom said:

in my haste to put it all back together earlier to go for a blast, I forgot the multi plug for the hazards/poppy up light switch and the connector for the windows.
I've just had to strip it again to connect them. Doh!

I think we've all done that at one time or another :) glad to hear it's running better now 

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Oily plugs on these is almost always indicative of a leaking can cover gasket IME- Very common and can result in pronounced missfiring. Footnote: Only use genuine Mazda gaskets here unless you fancy doing it again in short order.
I did notice when I removed the connector for the o2 sensor the rear of the engine was very oily. It must be what the mot tester was on about. Another one for the to do list.
I'm sunburned to feck after todays drive. Sun screen next time.

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2 hours ago, paulplom said:

I did notice when I removed the connector for the o2 sensor the rear of the engine was very oily. It must be what the mot tester was on about. Another one for the to do list.
I'm sunburned to feck after todays drive. Sun screen next time.

Sent from my SM-G975F using Tapatalk
 

^If it's down the back of things then that's almost certainly the CAS o-ring (The part the learned chap above has linked) Feel the wiring that comes from the back of the cam angle sensor, if it's wet with oil then that's definitely what that's all about. 

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34 minutes ago, xtriple said:

If it is the CAS seal, get it changed sharpish as it leaks onto a coolant pipe for the heater and rots it causing leaks. BIG leaks...

I reckon it took me about 45 minutes to get the sensor back in place with the new seal, but what a feeling when it finally clicked in! I can remember it vividly about ten years later.

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On 6/20/2020 at 10:11 AM, paulplom said:

Will leaving it unplugged till it gets here, cause any problems?

Increased fuel consumption because it's running open loop and if it's got a cat, can bugger it up running rich. However I think this age doesn't have one and certainly I don't think needs one for an MOT. Also would struggle to pass an MOT without it connected. 

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