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Running Lumpy / Hesitation After Headgasket Change


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#1 baker556

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Posted 27 April 2020 - 11:58 AM

Hi,

 

I've recently swapped out the heagasket on my 1989 mk1 1.6 eunos.

 

Along with radiaator, fan switch, cambelt, pulleys, alt / p/s belt.

 

Apart from the car smoking like a gooden, it runs fine and purs up the road - but under 2k rpm it's slightly lumpy, it wasn't lumpy or rough idling before the HG change, so thinking I've not seated a wire or something back correctly.

 

Is it possible for a bad ground to cause this? Any thoughts.

 

thanks


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#2 carl s

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Posted 27 April 2020 - 05:50 PM

Have you checked the timing?  From what I remember the 1.6 ignores the engine sensors such as idle control valve, AFM etc at wide open throttle so one of them could be not connected properly but the car still run fine at WOT. Did you remember to plug the temp sender wires at the back of the engine and the Lambda sensor wire?


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mk1 1991 Eunos with RS NB drivetrain: https://www.mx5nutz....howtopic=322586

ex - mk3 2006 2.0 sport

ex - mk2 1999 1.8is JRSC


#3 baker556

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Posted 28 April 2020 - 07:56 AM

Yep temp sensor in, lambda wired in.

 

It has to be either the injectors, coil pack or spark - but everything ran fine before the HG change.

 

Thinking spark plugs from the excessive amount of smoke coming from the exhaust may have dirtied them.


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#4 dadbif

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Posted 28 April 2020 - 09:28 PM

What colour is the smoke?
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#5 baker556

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Posted 29 April 2020 - 01:43 PM

Ok so lumpy idle sorted - it was the spark plugs! They were brand new for the headgasket, I guess all the crap / soot coming out the exhaust covered them, cleaned them up and put them back in. They're fine for now but have ordered a new set.

 

The smoke is white, I think it's all the cleaning crap I used on the head - it's slowly getting less and less each time I take it out for a drive.


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#6 dadbif

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Posted 29 April 2020 - 03:01 PM

Redex used to do that!
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#7 carl s

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Posted 30 April 2020 - 09:13 AM

good to hear you've sorted it  :thumb-up:


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mk1 1991 Eunos with RS NB drivetrain: https://www.mx5nutz....howtopic=322586

ex - mk3 2006 2.0 sport

ex - mk2 1999 1.8is JRSC


#8 baker556

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Posted 30 April 2020 - 02:28 PM

Cheers Carl


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