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Old 7th January 2020, 15:43   #1
Ravinder
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Default Missfire - 75 1.8 turbo

Hi guys,

Noticed when flooring the car in fourth gear the other day, the car missfired briefly. Any idea what would caused this?
Thanks.
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Old 7th January 2020, 16:18   #2
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My 1.8T has done this for years!
I've replaced plugs, leads, coil packs and even had a new turbo💨 over the years but it still persists. I have learned to drive it accordingly and don't get tempted to floor it in too high a gear. The bonus being a much improved mpg!

I await suggestions on how to to solve this.🙂
Chris.
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Old 7th January 2020, 16:19   #3
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Plugs or leads breaking down under load would be my best bet, assuming that you don't have any smoke, noises etc.
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Old 7th January 2020, 16:36   #4
Ravinder
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No noises and no smoke as far as I know. Might change the plugs and see if it makes a difference.
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First name and forum name: Ravinder

Rover 75 2.0 CDT Connoisseur SE 116 (160 remap)
Royal Blue (JFM)

This vehicle was the 50,481st 75 to run off the production line, out of 112,381
This vehicle was the 2,238th 75 CDT Connoisseur SE to be made out of 3,775
This vehicle was the 5,002nd 75 in Royal Blue (code: JFM) to be made out of 14,420 Royal Blue 75s
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Old 7th January 2020, 17:27   #5
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Could it be hitting the rev limit?

The boost control valve on the airbox is also a possible known cause of missfire when they get (tired).
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Old 7th January 2020, 17:38   #6
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Have you tried a reduced spark gap for the plugs? Usual suggestion is to set the gap at 0.7 - 0.5mm depending on who you ask. Try 0.6mm.


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Old 7th January 2020, 17:59   #7
Ravinder
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Quote:
Originally Posted by VVC-Geeza View Post
Could it be hitting the rev limit?

The boost control valve on the airbox is also a possible known cause of missfire when they get (tired).
Do you mean boost cut? Didn’t think of this but I guess it could be....

Quote:
Originally Posted by T-Cut View Post
Have you tried a reduced spark gap for the plugs? Usual suggestion is to set the gap at 0.7 - 0.5mm depending on who you ask. Try 0.6mm.


TC
I’ve not checked the gaps but the car was bought from a well known genius on the forum. I’d be very surprised if they weren’t gapped correctly.
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First name and forum name: Ravinder

Rover 75 2.0 CDT Connoisseur SE 116 (160 remap)
Royal Blue (JFM)

This vehicle was the 50,481st 75 to run off the production line, out of 112,381
This vehicle was the 2,238th 75 CDT Connoisseur SE to be made out of 3,775
This vehicle was the 5,002nd 75 in Royal Blue (code: JFM) to be made out of 14,420 Royal Blue 75s
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Old 7th January 2020, 18:25   #8
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Quote:
Originally Posted by Ravinder View Post
No noises and no smoke as far as I know. Might change the plugs and see if it makes a difference.
A spray of WD40 (water displacer) over the leads may help in the wet weather but new leads would probably cure it if the plugs don't.
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Old 7th January 2020, 20:04   #9
VVC-Geeza
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Quote:
Originally Posted by Ravinder View Post
Do you mean boost cut? Didn’t think of this but I guess it could be....
Yes,they are a known weak point.Not too expensive to replace and see if it cures it.I would re-gap the plugs first though as TC suggests if you haven't already done so.
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Old 7th January 2020, 20:45   #10
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Quote:
Originally Posted by Ravinder View Post
I’ve not checked the gaps but the car was bought from a well known genius on the forum.

Perhaps he'll know what's up?


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