flat spot

[mark]

Hi,

Just bought a p reg brava really good nick except that in 1st when you floor it the revs drop off for about 1 sec then go again any ideas???

It can be a bit scary joining a busy roundabout!

 

[Daz155HGT]

I had exactly what you are describing with my 2.0 HGT.

When i used to pull off, the car seemed to have no power, then pick-up as normal.

A few people had a look at it, with no luck (even the all-knowing Tom )

As a last resort i reset the ECU, it is easily done by disconnecting the battery overnight...

It will take a hundred or so miles to reconfigure itself, but it sorted out my problem once and for all.

Hopefully you have the same problem as me, if you have its very simple to fix...and best of all its free!

Hope this helps you...

Daz

 

[mark]

i will try that

Thanks , i will try that, what side effects if any does resetting the ECU have?

Mark

 

[Tom]

What engine size, milage etc..

 

[Mark]

car

Brava
1.4sx
69000 miles
New exaust and timing belt

It is strange , it is almost like the car stops to think the goes, if you apply accelerator and release clutch slowly you can avoid it but on a hill start it happens 9 out of ten times.

Mark

 

[Daz155HGT]

Re: i will try that

I dont think there are any, but my fuel economy did get worse for the first 50 or so miles, but then it was better than when i had the problem.

Fuel Economy:
Before ECU was reset: 24mpg
First 50 or so miles after reset: 20mpg
After ECU was reset: 29mpg

I have recently had the car off the road for 5 days, and left the battery off.

I now get about 32mpg, which isnt bad for the 2.0.

Daz

 

[Daz155HGT]

Re: car

sounds exactly the same as what i had...

The car lacks power until you get upto about 1500rpm???

Daz

 

[Tom]

Re: car

Probably throttle pot.

 

[Daz155HGT]

Re: Re: car

Thats your answer to every bravo problem...lol

a bit like me with my ECU's

Daz

 

[Mark]

thanks

Thanks for help, i will try the ECU , any other ideas?
I thought it might be dodgy lamba sensor?

 

[Daz155HGT]

Re: thanks

If you go to Fiat, i expect that is what they will tell you...it's thier answer to everything.

I believe that if the lambda sensor was the problem it would show up on the dash?

Tom will correct me on this if i am incorrect.

Like i mentioned before, it wont do any harm to the car by resetting the ECU, plus its free, so its a good place to start.

Daz

 

[Tom]

Re: Re: thanks

Lambda sensor would only show up when the car is hot. For about the first 10mins the lamda sensor is ignored by the ECU as its too cold.

The throttle pot is a common failure on old cars, it gets alot of use. The other thing could be manifold pressure sensor. the ECU is not registering the opening of the throttle straight away hence the drop in revs as its not adding fuel.

A reset won't hurt.
I'm not sure if the fiat diags can show sensor values, if it can you should be able to see what happens when you boot it.