Topic

Hello all,

My MG F Trophy has a janspeed back box on. To me it doesn't sound right. When sitting at idle every so often it has a kind of low down 'putt putt putt putt' sound. I can't seem to capture on camera as my microphone is overpowered by wind noise and engine noise. It likes to shake a bit then might settle down, then will do it again, and repeat. Revs stay the same around 850ish mark.

I took it to my local garage I've used for years. They listened and didn't think there was anything wrong with it. But you know how you are used to a car and just 'know' when something seems wrong?

Is it my paranoia, or a rough idle, or more severe problem - misfire maybe?

Regards

John

I have recorded a video. It isn't very clear through a phone's speaker, but when I have headphones on I can hear it. Hopefully it helps! It is most obvious to me from about 1:20 onwards.



Regards
John L

paranoia...

I didn't notice anything.

It is hard to hear I know, and I will try and get a better recording because it is so obvious in person but not so great on the recordings I try and do.

Was I the only one who "thinks" the exhaust is blowing?

There is definitely something up with it. It makes strange noises and the fumes don't come out smoothly, it kind of fires out in bursts.

gooseholla wrote: wrote:

There is definitely something up with it. It makes strange noises and the fumes don't come out smoothly, it kind of fires out in bursts.

Don't forget that over time carbon build up may change the sound of an exhaust's original note. Without other symptoms being evident, it's likely that you're overthinking it. It sounds nice and meaty to me.

Leigh Ping wrote: wrote:

gooseholla wrote: wrote:

There is definitely something up with it. It makes strange noises and the fumes don't come out smoothly, it kind of fires out in bursts.

Don't forget that over time carbon build up may change the sound of an exhaust's original note. Without other symptoms being evident, it's likely that you're overthinking it. It sounds nice and meaty to me.

There are a few things that might indicate it isn't just paranoia!

1.Coolant loss started with no external signs. Tried three different caps.
2. not so long ago (miles wise) previous owner had complained of poor running and garage said just keep an eye on it.
3. Not so long ago a code for a misfire on cylinder 4

I changed spark plugs and waiting for a fuel filter to change. Air filter was cleaned out. But when I first had the car after a while the IACV would need resetting as it would frequently get stuck at 1000- 1100, so I'm wondering if it is something to do with that, or if a cylinder is starting to misfire.

It is hard to explain. When you start the car up it starts about 1050 - 1100 revs and slowly drops, as I would expect. Idling at these revs the noise isn't present. As it drops to about 850 RPM that is when it starts. You get the normal noise exhaust noise then all of a sudden three or four boom booms or putt putt noises in a row where it shakes a bit. Longer you idle the more frequently the boom booms happen.

John

Hi G
Check out the inlet manifold. You probably have the plastic manifold which do warp and can lead to water loss, ie, internally and externally.
If it is leaking into a cylinder, then this could cause the problems that you have.

I have the trophy 160 so it has metal intake. Do these leak as well?

Also on a side note why is this dirt or particles suddenly appearing in my expansion bottle?

Cheers for help so far people