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Discussion Starter #1
Hi guys

Probably not a new issue as in the subject.
I started engine after a few days of big raining and it has unstable rpm on idle gear. Same situation appears during smooth driving up to 2,5-3k rpm. Sometimes during acceleration on 1st and 2nd gear the car "jumps" as if choking

I suppose something electronic got wet. Any idea what would be the first to check?

Thanks
 

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Hi guys

Probably not a new issue as in the subject.
I started engine after a few days of big raining and it has unstable rpm on idle gear. Same situation appears during smooth driving up to 2,5-3k rpm. Sometimes during acceleration on 1st and 2nd gear the car "jumps" as if choking

I suppose some electonic got wet. Any idea what would be the first to check?

Thanks
What year is your car? Do you have the metal bracket over the TCM?


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Discussion Starter #3
What year is your car? Do you have the metal bracket over the TCM?


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Yes I have ;) 2018

My first thought was wet spark plug wires or the flowmeter issue because car behaves like there is some electric puncture.
Above 3k rpm or during fast acceleration there is everything ok
 

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did problem go away after engine bay area warmed up?
 

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Discussion Starter #5
did problem go away after engine bay area warmed up?
No. The worst was when I started cold engine after 3 days of raining. The vibration was terible. After few minutes was much better and after 150km of driving there is still unstable (jerking) acceleration up to 3000 rpm when I want to accelerate slow and smooth.
 

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Had the same problem on a Opel speedster turbo. Bad grounds. Had to replace the whole electric loom.
Also tested: coilpack,Maf sensor,plugs, nothing worked.
The speedster was 10 years old...

If i can remeber , a member from this club noticed the grounds on this car were weak? 4C-ophe maybe ????
 

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Hi Remik,

If it's not throwing up any Check Engine Light - CEL Codes, then it's less likely to be an electrical fault and more likely to be a fuel fault.

As it is worse after rain, is there any possibility that water is getting into your fuel tank via the filler cap? I would be checking the little rubber seal on the door flap to make sure it is covering the fuel filler hole as a starting point.

Can you drain a sample of fuel / siphon some out and have a look at it? Free water will separate from the fuel and be clearly visible.

If it is water in the fuel, putting an ethanol blended fuel (while maintaining the correct MON/RON rating of the fuel) will absorb the water into the ethanol and that will then get consumed in the engine rather than sloshing around in the fuel tank as free water (due to the different densities between fuel and water).

If the fuel tank is badly contaminated, you will need completely drain the fuel tank and it will need a fuel filter replacement too if you want to be sure you are getting unrestricted fuel flow (water can clog fuel filters leading to reduced max fuel flow).

I would advise you against continuing to drive it if you have a misfire like this as it cannot be good for the engine.

If you can rule out fuel related issues, you can then then chase electric gremlins, which usually begins with the battery itself and cleaning the + & - terminals.

Good luck, and please let us know what you find.

Cheers,

Alf.
 

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Discussion Starter #8
Hi Remik,

If it's not throwing up any Check Engine Light - CEL Codes, then it's less likely to be an electrical fault and more likely to be a fuel fault.

As it is worse after rain, is there any possibility that water is getting into your fuel tank via the filler cap? I would be checking the little rubber seal on the door flap to make sure it is covering the fuel filler hole as a starting point.

Can you drain a sample of fuel / siphon some out and have a look at it? Free water will separate from the fuel and be clearly visible.

If it is water in the fuel, putting an ethanol blended fuel (while maintaining the correct MON/RON rating of the fuel) will absorb the water into the ethanol and that will then get consumed in the engine rather than sloshing around in the fuel tank as free water (due to the different densities between fuel and water).

If the fuel tank is badly contaminated, you will need completely drain the fuel tank and it will need a fuel filter replacement too if you want to be sure you are getting unrestricted fuel flow (water can clog fuel filters leading to reduced max fuel flow).

I would advise you against continuing to drive it if you have a misfire like this as it cannot be good for the engine.

If you can rule out fuel related issues, you can then then chase electric gremlins, which usually begins with the battery itself and cleaning the + & - terminals.

Good luck, and please let us know what you find.

Cheers,

Alf.

Thanks a lot for all suggestions.
The problem has been already fixed. The first cylinder had an issue as there was bad connection in coil with spark plug.
And moreover the spark plugs were in terrible condition as shown below.

For all of you guys to know my Alfa has only 10k km so I suggest to check and change the spark plugs quite often ;)

107966
 

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Thanks a lot for all suggestions.
The problem has been already fixed. The first cylinder had an issue as there was bad connection in coil with spark plug.
And moreover the spark plugs were in terrible condition as shown below.

For all of you guys to know my Alfa has only 10k km so I suggest to check and change the spark plugs quite often ;)

View attachment 107966
Those are not the oem spark plugs .... Maybe they are the wrong 'heat' range??

 

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I think you may have the colder range plugs sold through some after market vendors FOR TRACK use. They will not be a good choice for street use.
 

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Hi Remik,

Thanks for the feedback.

My fault diagnosis was way off :ROFLMAO:

Glad you solved the problem.

Cheers,

Alf.
 

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Discussion Starter #12
Thanks Guys! ;)

Yes it looks like the previous owner wanted to put better sport spark plugs but he was wrong as this Brisk ones aren't good.

Now I've put the correct ones NGK ILKAR7D6G as shown below and it's much better!
108069
 
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