running on 3 cyls when cold.

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gslender
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Re: running on 3 cyls when cold.

Postby gslender » Thu Oct 02, 2014 8:15 am

JBT raises a good point. Stuck HLA could be it


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MX5 91 NA6 LE completely stock and loving it!
MX5 92 NA8/ITBs Silver "aka Track Beeotch"

4sfed5
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Re: running on 3 cyls when cold.

Postby 4sfed5 » Thu Oct 02, 2014 9:54 am

Would't a stuck Hla tick though?? apart from the chug there's no ticking or knocking
red'90 vf10 turbo. FMIC,dual feed fuel rail, E Manage, "330cc" injectors.16" ADVAN RG wheels, http://www.cardomain.com/ride/264041/6

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gslender
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Re: running on 3 cyls when cold.

Postby gslender » Thu Oct 02, 2014 10:42 am

4sfed5 wrote:Would't a stuck Hla tick though?? apart from the chug there's no ticking or knocking


Depends, the HLA could be just slow to return meaning the clearance is the same, but when cold it doesn't close as quickly as it should meaning you've got a cylinder with less compression and/or ineffective combustion. There are a few scenarios and worn or clogged HLAs is a reasonably common issue - even more so on a old engine.

Also, tick noise isn't always present even when you'd think it would be - example, I had my 1.8 engine (with solid lifters) have significantly incorrect shims clearance. It was way, way out of spec. It only made a really loud valve train noise when it was revving above 6,000 and after changing to within spec, the 1st start and idle still sounded the same (no more or less ticking), but I removed 6 thou in some cases which you'd think would be enough to sound more tappety at idle - but not so (or at least not over what I could hear from injectors, valves and other clatter and noise).
MX5 91 NA6 LE completely stock and loving it!
MX5 92 NA8/ITBs Silver "aka Track Beeotch"

4sfed5
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Re: running on 3 cyls when cold.

Postby 4sfed5 » Thu Oct 02, 2014 4:38 pm

i'll swap #3+4 injectors and see if the chug follows the injector or stays with the cylinder.
its due for a cambelt change and the gearbox input bearing is noisy so i guess its gonna be an engine out freshen up with head gasket/cambelt/ HLA cleanup.
red'90 vf10 turbo. FMIC,dual feed fuel rail, E Manage, "330cc" injectors.16" ADVAN RG wheels, http://www.cardomain.com/ride/264041/6

4sfed5
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Re: running on 3 cyls when cold.

Postby 4sfed5 » Fri Oct 03, 2014 2:07 pm

so i start it up this morning and..................

purrs like a kitten..... no chug at all.

so i guess the fix was to post on the internet and that makes it all ok again... :)
red'90 vf10 turbo. FMIC,dual feed fuel rail, E Manage, "330cc" injectors.16" ADVAN RG wheels, http://www.cardomain.com/ride/264041/6

squibbward
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Re: running on 3 cyls when cold.

Postby squibbward » Fri Dec 05, 2014 6:48 pm

Well you can fix a miata with only swear words i hear

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StuwieP
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Re: running on 3 cyls when cold.

Postby StuwieP » Fri Dec 05, 2014 10:15 pm

usually applied alongside a small blood sacrifice
My NA6/SE build
Engine #1 RIP 04/07/2020


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