How serious are my 172s problems?

[bbess]

Hi,

First time post, so hello all

I bought a Monaco blue PH2 172 52 plate on Saturday. 66K, clean on outside, no obvious issues under the bonnet and it test drove well.

After getting used to it today, I've noticed a few problems:

1. It is very lumpy at idle. It feels like it is on the edge of stalling and will bounce me up and down slightly in traffic. Edging forward in traffic with no throttle (just gently off the clutch) stalls the car, even downhill! At low revs (below about 2,000 rpm) it feels lumpy too; rev it harder and its fine, pulls well and smoothly. Bonnet open at idle, the engine shakes like it is going to cut out.

2. When trying emergency stops (testing the brakes to see what they're like), the brakes are quite good and responsive until the ABS kicks in. Once I can hear and feel the ABS, the braking is not good. The pedal feels like pressing against a brick wall. Surely the brakes should continue to slow you down once the ABS kicks in? Is there anyway to disconnect ABS, so that I can see if the brakes are any good without it?

3. Crazy torque steer.

4. When the car is above 60mph, it feels like there is a swirling wind outside making it sway slightly, and twitch.

Over a very, very steady 65 mile round trip (included 50 mins of stop-start traffic, around town driving and 25 miles of dual-carriageway), I got 37 MPG. Is this normal?

Thanks in advance for your replies. My main worry is the engine at idle

Blake

 

[Nik]

Welcome to the forum, bbess!

 

[bbess]

Hi!

These problems have taken the shine off me getting my new car a bit

 

[loggyboy]

1. It is very lumpy at idle. It feels like it is on the edge of stalling and will bounce me up and down slightly in traffic. Edging forward in traffic with no throttle (just gently off the clutch) stalls the car, even downhill! At low revs (below about 2,000 rpm) it feels lumpy too; rev it harder and its fine, pulls well and smoothly. Bonnet open at idle, the engine shakes like it is going to cut out.
Lumpy idle when cold is fairly common, but a shaky engine at low revs would point to a ignition issue. check the HT leads for splits and connections, Dispac and consider new sparkplugs. A wobbly engine could also be the dogbone mount at the lower rear of the gearbox. Some just come loose.

2. When trying emergency stops (testing the brakes to see what they're like), the brakes are quite good and responsive until the ABS kicks in. Once I can hear and feel the ABS, the braking is not good. The pedal feels like pressing against a brick wall. Surely the brakes should continue to slow you down once the ABS kicks in? Is there anyway to disconnect ABS, so that I can see if the brakes are any good without it?
Fairly common for ABS rings (small metal toothed rings around the cv joints) to come loose or split. or could simply be dirty sensors.

3. Crazy torque steer.
High BHP and FWD this is par for the course. However if you had high power FWD cars and it feels worse than normal then could be geometry and/or worn/loose wishbones/trackrods etc.

4. When the car is above 60mph, it feels like there is a swirling wind outside making it sway slightly, and twitch.Twitching and swaying points to geometry and suspension. Wind noise is unlikely to be unrealted.

Over a very, very steady 65 mile round trip (included 50 mins of stop-start traffic, around town driving and 25 miles of dual-carriageway), I got 37 MPG. Is this normal?Thats good - spirted driving should give 20-25 - super frugal motorways may give 45.

 

[bbess]

Thanks for your reply!

The car has had a service in the last 2000 miles. The service book shows that the spark plugs have been done. Looked at the HT leads and they look brand new as well. I've read that some people suggest Super Unleaded (Shell particularly), I only have Sainsbury's standard Unleaded in mine - is this likely to make a difference?

I'll have a look at the ABS tomorrow.

Over bumps in the road, the car becomes unsettled. Is this a potential rear shock issue?

I'm used to a 65 MPG diesel , so it was quite a shock!

 

[...]

The feeling you experience when the ABS kicks in is exactly what ABS feels like ....... wait till you drive in snow LOL

 

[Naith]

mines running well and sounds like its in worse shape than yours!

 

[bbess]

Sounds fun!

The car hardly slows down when the ABS kicks in though..

 

[Tin cup]

If you don't like the Abs then the 172 cup doesn't have Abs so can't be to hard to swap over, start a post asking for some one with a dianostics like one called Clip which is a renault one would save time and money with a few fault codes

 

[Addicted]

Try Ron98/99, should feel a lot better, made mine alot smoother.

If that makes the difference, then also look at a RSTuner 98 Ron map - smooths out the lumpy idle on startup nicely, assuming you fix the issues first

 

[bbess]

How lumpy is normal? Can you pull away with no throttle? (Gently?) Mine has just enough revs to keep it going.

Some people suggest cleaning the throttle body. Is this easy? DIY job?

 

[Tin cup]

Yes I'd say easy, but I'd change the plugs leads, clean the crank sensor then if no joy I'd get a used coil pack

 

[bbess]

Thanks for your advice. What are the costs of these fixes?

Also, would an oil change help (should have been done recently though).

It has a cone/pod filter fitted. Could this be causing problems?

 

[Tin cup]

Can't see the filter doing that, best thing to do is join as a full member only £12 and you can see in the for sale section and traders that give you discount as well as welcome pack, genuine plugs are about £35 unless you rafter cheapie stuff

 

[bbess]

I just want it to run smoothly. Whatever is recommended.

These are marked as being changed 2,000 miles ago, though...

Is an incorrectly timed cambelt a potential reason for the problems?

Thanks for your help Tin Cup.

 

[Tin cup]

You could make sure the cam belt isn't damaged or that it has slipped, try and upload a video the engine on tick over

 

[bbess]

Will try tomorrow, thanks.