XJ6 & XJ12 Series I, II & III 1968-1992
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xj6 III losing power suddenly

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Old 10-11-2017, 12:30 AM
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Default xj6 III losing power suddenly

So I Experienced this 2 times today during my commute.
Commute is 50 miles each direction.
The first time it happened it was just for 1 or 2 seconds only.
I did not even realize it was a power cut in the engine. But then it happened again in my way back engine still cold and I Was accelerating on the freeway ramp. Suddenly the engine lost power and I went from 65mph to 40mph I tried different things like pushing and releasing the throttle but the more I pushed the more the power was losing. The feeling was like when engine is running with to much gas and few air and it's not able to rev up and tend to stop, same behavior. I do not know what it could be. IT lasted for about 10 seconds and I had shivers on my spine... really feeling so bad!
After 10 seconds the engine recovered back to normality.
I do not know what it could be:
  • injection system problem (injectors) ?
  • fuel pump problem ? (it would happen more frequently eventually)
  • dirty fuel ?
  • air flow meter ? (does it exist on these engines)
I do am not able to reproduce it again. And I hope it will not show up again.

Any hints is very welcome.
 
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Old 10-11-2017, 05:59 AM
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Mine used to do that once in a while, and as younsay, it was intermittent so hars.to.find, mine turned out to be the air flow meter was sticking, got a used one.drom David Biger amd havent had a problem since. (Might have been able.to clean up mine, but i got a bit overzealous and took it apart without marking the cog and at that point i just gave up.)

Hopefully yours is sometbing simple like that too.
Good luck!
 
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Old 10-11-2017, 11:38 AM
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Originally Posted by xjfourty
So I Experienced this 2 times today during my commute.
Commute is 50 miles each direction.
The first time it happened it was just for 1 or 2 seconds only.
I did not even realize it was a power cut in the engine. But then it happened again in my way back engine still cold and I Was accelerating on the freeway ramp. Suddenly the engine lost power and I went from 65mph to 40mph I tried different things like pushing and releasing the throttle but the more I pushed the more the power was losing. The feeling was like when engine is running with to much gas and few air and it's not able to rev up and tend to stop, same behavior. I do not know what it could be. IT lasted for about 10 seconds and I had shivers on my spine... really feeling so bad!
After 10 seconds the engine recovered back to normality.
I do not know what it could be:
  • injection system problem (injectors) ?
  • fuel pump problem ? (it would happen more frequently eventually)
  • dirty fuel ?
  • air flow meter ? (does it exist on these engines)
I do am not able to reproduce it again. And I hope it will not show up again.

Any hints is very welcome.
How many miles on the car?
What items have been replaced on the car last 3 years?

Walter
 
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Old 10-11-2017, 06:23 PM
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Car has 71000mi. in the last 3 years water pump, master cylinder have been replaced,
and exhaust system too. Nothing else that I know has been replaced.
is replacing the air flow meter a DIY thing ?
 
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Old 10-11-2017, 06:30 PM
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what happens to the gauges like the tachometer and voltage gauge when it happens?

Does it feel electrical? or does it feel mechanical?

does the engine "cough" or "backfires" when it happens?
 
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Old 10-11-2017, 06:36 PM
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it's not electrical all gauges works, when it happens engine is like if gas don't arrive to injectors, and rpm start dropping down. it feels like when you run out of gas in the tank... So I was thinking to bad or dirt gas. I did gas in a place where I usually don't.
Anyway is this the air mass flow meter that I need ?

https://www.partsgeek.com/gbproducts...-07120595.html

difficult to replace ?

probably the mechanic will tell me $400 for just the replacement part.

I had this problem only the last day i used the car (yesterday). no problem at all before and I Already did 1000mi in less than 2 months.
 
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Old 10-11-2017, 09:21 PM
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Originally Posted by xjfourty
it's not electrical all gauges works, when it happens engine is like if gas don't arrive to injectors, and rpm start dropping down. it feels like when you run out of gas in the tank... So I was thinking to bad or dirt gas. I did gas in a place where I usually don't.
Anyway is this the air mass flow meter that I need ?

https://www.partsgeek.com/gbproducts...-07120595.html

difficult to replace ?

That's the one, and it's easy to replace.

No "mass" by the way. It's simply an "Air Flow Meter" or "AFM"


probably the mechanic will tell me $400 for just the replacement part.
Possibly, yes, for a new one. The Cardone unit is remanufactured



Cheers
DD
 
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Old 10-11-2017, 09:23 PM
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Originally Posted by xjfourty
it's not electrical all gauges works, when it happens engine is like if gas don't arrive to injectors, and rpm start dropping down. it feels like when you run out of gas in the tank...

Bear in mind that the fuel injection system is electronic....so a fuel problem could be electrical.

So I was thinking to bad or dirt gas.

Remove the fuel filter and empty the contents into a clean jar. What you see will dictate your next steps

Cheers
DD
 
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Old 10-11-2017, 11:13 PM
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yes good point to inspect the fuel filter I Am sure it was never changed in the last 8 years
 
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