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cold start very poor idle after rain

PostPosted: Thu, 15 Jan 2015 2:44 +0000
by jimmy1982
Hi guys I have 1990 eunos roadster 200000km (jap import) it starting to drive me mad now when I start the car the revs show round 850 and straight away rise slowly to about 1100 but mostly when is
rainy day and the car is cold is idling very rough n revs dropping very low and its relly hard to pull off but as soon as car get warm then is fine
Now I've done following things..decat pipe, complete service with ngk iridium plugs, Jackson racing leads, new coil pack, K&N panel filter, good oil n filter n fuel filter also whole timing belt kit with new water pump n new radiator then replaced idle speed control valve as I was getting fault code which now disappeared n its fault free, also reset factory revs setting
car really improved after all that but its still not perfect when cold and there is little hesitation when pulling of from first gear
Is there anything that I mite have missed?
Can someone please help me as Im using the car on every day basis
Many thanks in advance

Re: cold start very poor idle after rain

PostPosted: Thu, 15 Jan 2015 4:53 +0000
by sti-mx5
Sorry for going off topic but where did you get the decat pipe?


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Re: cold start very poor idle after rain

PostPosted: Thu, 15 Jan 2015 7:45 +0000
by jimmy1982
Came with the car but you can get it of ebay.uk or moos Europe or mx5parts probably

Re: cold start very poor idle after rain

PostPosted: Thu, 15 Jan 2015 7:47 +0000
by jimmy1982
Same today when I started the car for the first time I could put my foot through the floor but revs wouldn't pick up for good few seconds

Re: cold start very poor idle after rain

PostPosted: Thu, 15 Jan 2015 11:55 +0000
by Yolo
check the ecu under the carpet in the passenger footwell. you say this happens after it has been wet i would suspect that water may be getting into the ecu and causing your problems. Check if the footwell is damp , you will need to check under the carpet as water will pass straight through it to the soundproofing underneath.

Re: cold start very poor idle after rain

PostPosted: Fri, 16 Jan 2015 3:09 +0000
by jimmy1982
Thanks for reply...checked n its all dry
Will upload video on youtube and share link
It does it all the time but worse when wet..I can bury my foot through the floor and revs will barely pick up
Still even when warm I think theres lack of power therevs should b much faster

Re: cold start very poor idle after rain

PostPosted: Fri, 16 Jan 2015 3:32 +0000
by jimmy1982
Theres the link in about 19th second I completely buried my foot so u can c the result

https://www.youtube.com/watch?v=sr0YmXw4kDc

Re: cold start very poor idle after rain

PostPosted: Fri, 16 Jan 2015 3:34 +0000
by gasha
Hi Jimmy have a read at this link: http://www.mx5nutz.com/forum/index.php?showtopic=170474

Unlikely but worth a read.

Also did this fault start after you done your water pump? If there is an air lock in the cooling system it will upset the engine idle, not sure about the power loss.

Hope you get it solved.

Re: cold start very poor idle after rain

PostPosted: Fri, 16 Jan 2015 4:46 +0000
by Steve
kinda sounds like its running rich...

Also, have you checked all the vac hoses & plugss on/behind the intake manifold? Might be an unmetered air leak.