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Drives like crap when cold

Posted: Wed Jun 02, 2010 12:09 am
by TieNN89
Does anyone know what is going on with my MX5

It drives like crap when its cold

When I pull up at a set of lights the revs just drop to 500rpm and kicks back up to 850rpm where it should be then when I take off the revs just drops and comes back to life again :S

It idles at 850rpm

Drives like crap when cold

Posted: Wed Jun 02, 2010 10:03 am
by project.r.racing
the idle drop when braking sounds like the IAC valve.

How long do you allow it to warm up before driving?

Drives like crap when cold

Posted: Wed Jun 02, 2010 7:18 pm
by Regie
mine was doing this a few weeks ago.

I ran some injector cleaner though it and it fixed itself :)

Drives like crap when cold

Posted: Wed Jun 02, 2010 7:18 pm
by TieNN89
not long

not even a minute

I try to let it run longer when I can though


Regie, what brand injector fluid did you use?

Drives like crap when cold

Posted: Wed Jun 02, 2010 11:24 pm
by Regie
TieNN89 wrote:not long

not even a minute

I try to let it run longer when I can though


Regie, what brand injector fluid did you use?


good question, but i remember it was red and treated 2 tanks....i just put the whole bottle in :P

Drives like crap when cold

Posted: Wed Jun 02, 2010 11:47 pm
by manga_blue
Engine coolant temp (ECT) sensor failure? ECU defaulting to engine hottish.
ECT test.jpg

Re: Drives like crap when cold

Posted: Thu Jun 03, 2010 11:41 am
by Alex

Re: Drives like crap when cold

Posted: Thu Jun 03, 2010 7:05 pm
by TieNN89
manga_blue wrote:Engine coolant temp (ECT) sensor failure? ECU defaulting to engine hottish.
ECT test.jpg


Would this be the same sensor that tells me how hot it is on the instruments?

If so it looks to be working fine


It also idles higher when cold as normal

Re: Drives like crap when cold

Posted: Sat Jun 05, 2010 6:23 pm
by 93_Clubman
NA6 B6 engine used to have an extra sensor at the rear of the head, but from memory NA8 & NB8 BP engine just has the one sensor at the rear of the head.