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Post by Jeff - jthspace on May 24, 2023 13:51:53 GMT
All of a sudden Daisy has an increased tick over either cold or hot. It may be excitement about going out or next years botox, but I fear something else. Tick over has gone up from +/- 800 to 1200 rpm. The last fill-up with E5 petrol (Sainsbury) did give some rough running but as I used it up, performance went back to normal - except the fast tick over started this week with about a third of a tank still to go. Pretty sure it's not the petrol, info given to assist in the thoughts Any ideas? Thanks, Jeff  |
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Post by mxdave on May 24, 2023 18:29:21 GMT
Could be the clutch pedal switch rubber. There’s a switch on the clutch pedal similar to the one on the brake pedal for stop light. There’s a rubber  which acts against the switch and this breaks up after many years of use. It happened on mine and I managed to get a new genuine Mazda one on eBay from Autolink, it cost £7.19. It may not be this but when mine went it caused an erratic idle, sometimes would be too high and then sometimes when I came to a stop the engine would stall. Easy to check, you do need to be a bit of a contortionist to get to look at the clutch peddle though. |
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Post by mxdave on May 24, 2023 18:31:31 GMT
It’s put a man going mad with a polisher where I wrote bu$$er.  |
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Post by Jeff - jthspace on May 24, 2023 20:32:34 GMT
Thanks, had one of those break-up a few years ago and replaced, the effect the broken one gave was fast tick-over but stalling due to sudden low revs drop when pulling up at a junction; at the moment it's just 1200 rpm all the time, great in slow moving traffic, it's like the no-stall creep you can do on the ND.
Interestingly, the fix I did originally was tape a penny over the hole while I sourced a replacement rubber bung. Why they have a hole in the clutch pedal where the switch is and then put a bung in, I don't know. They could have just had a solid pedal.........
Appreciate the hint...
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Post by RS on May 26, 2023 14:49:01 GMT
I've got no real answer to this I'm afraid, if it persists, I'd be inclined to reset the base idle by bridging GND & TEN in the diagnostic socket and bringing the idle speed back down to about 850rpm.
Might even be worth getting the ignition timing checked, manufacturers setting is 10° but can be tweaked to 12° or even 14° if it runs sweetly.
Also check for a leaky vacuum hose or intake pipe.
Check the pipe on the servo to inlet manifold for cracks.
There is also a throttle damper (it stops the throttle from snapping shut when you come off the gas) on the throttle body, make sure that's not sticking.
Thats all I can think of at the mo...
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Post by Roadie on May 26, 2023 18:41:25 GMT
Gotta love RS.
Says he's got no answer and then comes up with five suggestions.
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Post by Jeff - jthspace on May 26, 2023 19:22:39 GMT
Timing is 14 degrees and has been for the time I've owned her.
Throttle is closing fully and cable has a bit of slack (just a tad).
I'll investigate others ASAP.
Thanks for the pointers........
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Post by Jeff - jthspace on May 29, 2023 13:49:45 GMT
At Sandringham another MX5 Eunos owner had an MX5Tech OBD reader. No issues were found on the reader. MX5Tech OBD readerShorting pin 10 to ground did not reset the tick-over Temporarily adjusted tick-over down to 900/1000 rpm on the throttle body but still need to find the issue. Checked all the pipework, which was replaced 3 years ago for silicone type as the original rubber set was looking tired and flaky but I suppose a pinhole could have appeared. Will give all the associated pipes a squirt of Quick Start with the engine running to see if the revs shoot up and then identify which pipe (if any) was the culprit. After that, it's the throttle body to look at.....  |
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which acts against the switch and this 
