172 cup not running properly.

[demps23]

My cup keeps spluttering at low and high revs, mid range it pulls fine. Iv changed the spark plugs twice now and it fixes the problem for a few weeks but now its back again. It judders when u put your foot down at low revs then when it gets up the rev range to about 4500rpm the revs just stick and take an age to pull up.

Anyone else had this problem? Could it be running to rich and ruinin the plugs?

Thanks

 

[Johnc172]

Could be a number of things mate, mine was doing the same and it turned out to be a loose connection on the TB so check that.

It could also be the TB itself, also check the leads while your there

 

[Icarus]

What do the plugs you take out look like?

Cheers
M

 

[demps23]

What do the plugs you take out look like?

Cheers
M

Pretty dark, thats what makes me think its maybe running to rich?

 

[demps23]

Could be a number of things mate, mine was doing the same and it turned out to be a loose connection on the TB so check that.

It could also be the TB itself, also check the leads while your there

Cheers mate il have a look, just strange how its fine for a few weeks when i change the plugs

 

[Icarus]

Do you do lots of short journeys at low RPM/Speed as well?

Immediate thoughts are CTS failed in a way that its always on cold start or lambdas failing to swing properly but both failing in a way to cause it to overfuel are rare! Or possibly consistant spark failure but that'd be weird.

Not got a silly "power boost valve" or similar have you?

Cheers
M

 

[stan*]

What HT leads are you running?

 

[demps23]

What HT leads are you running?

Just standard I presume as I havent changed them. Sayin that it was super bosch plugs that were in so maybe they have been changed before aswell.

 

[demps23]

Do you do lots of short journeys at low RPM/Speed as well?

Immediate thoughts are CTS failed in a way that its always on cold start or lambdas failing to swing properly but both failing in a way to cause it to overfuel are rare! Or possibly consistant spark failure but that'd be weird.

Not got a silly "power boost valve" or similar have you?

Cheers
M

No my work is 22 miles away so shes always fine n warm.

No unfortunately iv not got a 'power boost valve'

Exhaust is decatted however? Could that be contributin to the problem? Never did it in the past tho and I have no warning lights on the dash.

 

[-J-]

I had the same issue with my cup... Turned out to be a build up of Carbon in the TB, Might be worth taking it off and giving it a clean.

 

[demps23]

Anyone else had this problem?

 

[Cro]

Coilpack, HT leads, Plugs are the usual suspects mate. Just fixed a cup last week with the same symptoms which turned out to be a faulty HT lead arc'ing off the body