Technical Poor acceleration from mk1 punto 55s

[MadMan0]

Hi all, I am getting poor acceleration around and above 60mph

• Compression check shows no problems.
• Fuel lines & filters are good & ran Injector Cleaner though system past 2 tanks
• Air filter is clean
• Oil is fresh within 500 miles + oil filter
• TB was cleaned and gave an improvement at lower speeds but no difference at/around 60mph+
• Sparks, HT Leads & coils are new within 1,500 miles, and all give good sparks.
• Car is standard.
• NO warning lights
• Ecu scan shows no faults
• Brakes are not binding

I suspect there is a problem in the fuel re-circulation system because the fuel box under the bonnet looks damp. Like it had been leaking, however i cannot see any leak when the engine runs.

Any thoughts?

Edit: mk1 punto (1997) 1.1L, Spi, 8v, 5 Speed Manual, 3 door, Petrol

 

[thelad]

Mite be worth checking the timing is correct and has not slipped, has it had a belt change? A fuel leak wont help and fuel is not cheap.

 

[MadMan0]

Mite be worth checking the timing is correct and has not slipped, has it had a belt change? A fuel leak wont help and fuel is not cheap.

Thanks for reply, i forgot to say.
Timing is also good, Belt was changed <1,500 miles ago (Jan 2011 I think)

Timing was actully the first thing i checked.. This Current tank looks like it will be around 60mpg again. Last tank was 38.8 mpg - when the problem first started Start of Oct 2011

 

[dumbledore]

What ever you done from last tank to the last tank must have fixed the mpg problem then. However at 60mpg you can not expect good acceleration!. Check to see if your throttle body opens OK or may be the throttle body switch indicating full throttle open is not functioning correctly and ECU is not aware you are at full throttle so it adjust the fueling for faster acceleration.

 

[MadMan0]

What ever you done from last tank to the last tank must have fixed the mpg problem then. However at 60mpg you can not expect good acceleration!. Check to see if your throttle body opens OK or may be the throttle body switch indicating full throttle open is not functioning correctly and ECU is not aware you are at full throttle so it adjust the fueling for faster acceleration.

Hmmm, i did tweak the TB & cable so that it opens fully, but maybe the throttle position sensor isn't working? Although i can't recall see where this is on my Punto? I'll try looking for it and removing it to see if things change.

I use to get mpg of 80mpg and performance was good when you wanted to put your foot down. So the mpg is down more to how you drive it, not on the engine 100%.

The sensor sounds like a possible cause. I'll try and check it out today

 

[cgarr04]

I use to get mpg of 80mpg and performance was good when you wanted to put your foot down. So the mpg is down more to how you drive it, not on the engine 100%.

Sorry, but I don't think it's possible to get 80 MPG with the punto even with the most capable driver in the world. Are you saying this based on the digital clock? 80mpg is barely achiveable even with the newest, most efficient cars such as the VW Polo Bluemotion - which has a 1.2 TDI diesel engine.

Anyway, how is the acceleration bad - can you describe it in more detail? Is there any hesitation or shakes etc?

The punto isn't exactly going to be nippy accelerating in 5th gear from 5/60mph to 7/80mph anyway. My 2003 mk2 will sit happy at 60mph but it doesn't want to go much faster than 70mph, although I can push it to about 87mph, which is really abusing it and the entire car wil shake.

 

[MadMan0]

Sorry, but I don't think it's possible to get 80 MPG with the punto even with the most capable driver in the world. Are you saying this based on the digital clock? 80mpg is barely achiveable even with the newest, most efficient cars such as the VW Polo Bluemotion - which has a 1.2 TDI diesel engine.

Anyway, how is the acceleration bad - can you describe it in more detail? Is there any hesitation or shakes etc?

The punto isn't exactly going to be nippy accelerating in 5th gear from 5/60mph to 7/80mph anyway. My 2003 mk2 will sit happy at 60mph but it doesn't want to go much faster than 70mph, although I can push it to about 87mph, which is really abusing it and the entire car wil shake.

80mpg was worked out on brimming the tank, around 600 miles on that tank, cannot remember the Fuel usage, normally around 42L a tank..

The car would normally pull upto 80mph no problems, even when sitting at 60, if i were to put foot down it would pull to 80mph.

Currently however, i put my foot down while sitting at 60mph, the nose will lift slightly and it will take along time to get to 80mph, like it's lacking power...

The car used to be nippy upto 50mph, currently it's "lagging" behind, the car is more "smooth" than it used to be when you put the foot down, it used to be a snap. i.e the car would jerk when you took foot off the gas. almost like whiplash. Now it does not do this...

 

[dumbledore]

I think the tank is about 45l. So 600 miles will be about 60mpg.
80mpg will be impossible even if you can endure driving at a constant 56mph for 800miles.

 

[MadMan0]

The tank is 47L however i don't normally have to put more than 40L in when filling up. Worse so far is putting it 45.8L - Cutting it close that time.

Get uni work slows down i'll be able to take a look at the car in some day light. At the moment it's 9:00 - 19:00, Today i have a break 18:00-19:00 then back for another 3 hours

 

[reddy4bed]

You are way out with the 80mpg, probably a poor test/calculation. Regarding the low power and poor fuel consumption, the things that can affect it are:-
Timing belt fitted wrongly.
TPS giving wrong reading - also throttle not opening fully.
Leak in pipe to MAP sensor or the sensor itself.
Temperaure sensor.

The hardest faults to locate are the ones you thought you had checked, so go over everything again. Especially check the cam timing using the hole in top of clutch housing for TDC.
Tony.

 

[MadMan0]

I changed the Airbox setting to winter and it now pulls from 60mph... Surely this can't be what was wrong?

 

[thelad]

Winter setting?

 

[sheehab]

i had the same problem its definitly one of the electric coils u have to check them