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Old 07-03-2012   #1
max76
 
Join Date: Apr 2009
Location: ITALY
Posts: 264
Default idle problem

Hi guys....
i have a little problem with my 1990 zr-1.
When i start the engine it's run great...but after some minutes it run bad...it's seem like lose rpm and it's shake for few second, after it run ok...and after few minute it run bad for few seconds.
if i push oh the accellerator pedal the engine run good.
I change: Spark and fuel filter.
I test the fule pressure and it's ok...50 psi on both pumps without run engine.
What can i check???
Thanks to all!!!!
Max
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Old 07-03-2012   #2
scottfab
 
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Location: Portland Oregon metro area (Washington side)
Posts: 3,207
Default Re: idle problem

Quote:
Originally Posted by max76 View Post
Hi guys....
i have a little problem with my 1990 zr-1.
When i start the engine it's run great...but after some minutes it run bad...it's seem like lose rpm and it's shake for few second, after it run ok...and after few minute it run bad for few seconds.
if i push oh the accellerator pedal the engine run good.
I change: Spark and fuel filter.
I test the fule pressure and it's ok...50 psi on both pumps without run engine.
What can i check???
Thanks to all!!!!
Max
I may know but to make my guess I'd like to hear it run.
Can you make a sound recording of it while running rough?
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Old 07-03-2012   #3
ZZZZZR1
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Default Re: idle problem

Max,

To help the experts (not me) diagnose your problem, give us some more info.

What have you done to your car recently?

Have you changed injectors? (are they original)

Do you drive your Z regularly? (once a week, two weeks, month?)



David
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Old 07-03-2012   #4
zrwhat
 
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Location: Maryland
Posts: 119
Default Re: idle problem

Sounds like a ignition coil going south, breaking down and coming back randomely or fuel contamination, water in the fuel will make the thing run real ugly at times, water tends to not burn very well for some reason!!!!!

New fuel filter will catch particles of crud but will still allow water to be squeezed through it and will stumble all over the place until corrected.

Have you tried any fuel conditioner or fuel drier which seperates the larger water puddles and keeps the water in smaller amounts so it will pass more easily?

Did the problem start to happen shortly after filling up the petrol tank recently?

Good luck

Gibby
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Old 07-04-2012   #5
max76
 
Join Date: Apr 2009
Location: ITALY
Posts: 264
Default Re: idle problem

Quote:
Originally Posted by ZZZZZR1 View Post
Max,

To help the experts (not me) diagnose your problem, give us some more info.

What have you done to your car recently?

Have you changed injectors? (are they original)

Do you drive your Z regularly? (once a week, two weeks, month?)



David
Hi zzzzr1...
i have original injectors (the car have 18500miles)
I drive the car sometimes...also once two or three weeks....
:-)
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Old 07-04-2012   #6
WB9MCW
 
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Default Re: idle problem

test injectors
http://www.zr1.net/forum/showthread.php?p=17299

test coils
http://www.zr1.net/forum/showthread.php?p=70781

Use Solutions to help get to your problems and fix them
http://www.zr1.net/forum/showthread.php?t=16778
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Old 07-04-2012   #7
max76
 
Join Date: Apr 2009
Location: ITALY
Posts: 264
Default Re: idle problem

Hi zrwhat...
i think is an alimention problem too...i have leave the car sit down for about 45 days and after this sometimes run bad at idle...iill try to add a gasoline cleaner
;-)
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Old 07-04-2012   #8
max76
 
Join Date: Apr 2009
Location: ITALY
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Default Re: idle problem

Quote:
Originally Posted by WB9MCW View Post


Hi...very interesting post!!!!
I'll read all when i have just a little time!!!
Thanks
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