fiat punto 01 with juddering problem,misfire,loss of power.

[sparky1984]

my fiat punto has just started getting a problem where the engine seems like it is misfiring, juddering and losing power when pulling away. the engine management light is also coming on. when i put my foot down on the clutch there also seems to be a buzzing noise coming from the top right hand corner of the drivers side of the engine, could this be the coil packs, censor or could the ECU be at fault?
any input would be great,
thank you.

 

[Burnerman]

Coil packs are common failures on these - but failing plugs / leads (if it has leads) can also cause this.....however the fault code will be logged in the cars computer so its worth getting that read. It may help you with the diagnosis.
John

 

[sparky1984]

thanks john.
would having the ECU read cost much? and could i get it done anywhere or does it have to be done at a fiat dealer?
regards
rob

 

[Burnerman]

Hello Rob
There's no need to go to a main dealer for this, as any independant garage with the suitable diagnostic equipment can interrogate the on board computer, and give you an idea as to where the problem is.
They can then turn the lamp back off for you (they only really seem to extinguish themselves if its an exhaust lambda sensor problem) and then see if the fault comes back - which it will.
The thing is, some fault codes are retained for a long time, which can sometimes throw you off the scent if the problem happened a while back, and was then attended to.
Costs vary - £40 seems to be about the norm but often enough I don't charge for it, so long as I get the repair if I want it. Best ring around, I think.
John

 

[sparky1984]

thanks for the info john, much appreciated.
ill give a ring around and see what i can find. luckily i have a friend that works for the RAC so im trying to get him round to plug his diagnostic comp on to it.
also could the problems iv mentioned be caused if the exhaust comes away from any joints? the rear engine mount is in need of changing and it keeps pulling the exhaust forward which keeps loosening the rear exhaust bracket and i thought that maybe the exhaust itself has pulled away from any joints.

Regards,
Rob.[/b]

 

[Burnerman]

This would probably annoy the lambda sensor, just before the catalytic converter and that could upset the fuelling to a small degree, but I can't really see why this would cause misfiring......anyway, with a mate working for the RAC I'm sure he'll get it right!
Be lucky!
John

 

[sparky1984]

thanks again john, your infon has been much appreciated.

regards,
Rob.

 

[sparky1984]

well i went out today and got a replacement coil pack, fitted it and tried the car once again, to my displeasure the problem was still there. now all i can think to do is to get a proper diagnosis done on it. would anyone know of a decent cheap place in middlesex?

 

[Burnerman]

I'm sure the shop will take the coil pack back, Rob.
So, a genuine constant misfire has to be either ignition or fuel, so assuming the plugs are ok its back to fuel.....from time to time I do replace the odd fuel injector but its vital to get a diagnostic check done because the shops don't like taking them back.
I've no idea about the buzzing you refer to, but ECU's do tend to chirp a bit, even after the engine is switched off. It could be worth a chat with a Fiat service manager if there is a dealership nearby - a good person will have seen this all before.
John

 

[sparky1984]

Thanks john,
im gonna try and get my mate to come round with his RAC computer and diagnose it for me it i cant get him to do that then ill have to bite the bullet and get it taken to a garage and have it seen to that way, not really what i wanted to do but i don't want the car off the road that long.
regards
Rob

 

[Belle427]

as said get the codes read as your just guessing. maf sensor can cause these type of symptoms too, try disconnecting it and taking it for a run see if it performs any better. This works with some cars

 

[Mickymoody]

An ECU code read is cryptic, but reveals all, but it's usually something very simple that causes a fault. ie the fuel filter could be blocked, they are often overlooked on servicing.

I can obtain my ECU error codes manually, is this not possible on other older cars? (Not saying your Punto is old, but is there a mechanism in place to read the codes, without buying expensive kit)..

I just short out te1 and e1 in the fusebox, and the car tells me if it is ill. paperclip technology. I then look up a table, that tells me whats wrong.

 

[jetex]

Mickeymoody, you can do this with some older Vauxhalls and Volvos. The problem with the Punto may be the E.C.U as it's a common problem. Unplug both connections to the coil packs and bridge one plug with an L.E.D test lamp (or noid light if you have one).Ask someone to crank the engine, and the L.E.D should flash. Try this with the other plug. If one doesn't flash, it's an E.C.U fault. The E.C.U is located as part of the throttle body. You can fit a new or second hand one without the need to programme it. You may put the management light on by doing this, but if it's on anyway you're not adding to the problem.

 

[Mickymoody]

Mickeymoody, you can do this with some older Vauxhalls and Volvos. The problem with the Punto may be the E.C.U as it's a common problem. Unplug both connections to the coil packs and bridge one plug with an L.E.D test lamp (or noid light if you have one).Ask someone to crank the engine, and the L.E.D should flash. Try this with the other plug. If one doesn't flash, it's an E.C.U fault. The E.C.U is located as part of the throttle body. You can fit a new or second hand one without the need to programme it. You may put the management light on by doing this, but if it's on anyway you're not adding to the problem.

I can do this on a Toyota. From the late '80's I was recoding ECU chips for the Ford Cosworth engine, generic, not system built, as the technology for feedback never existed. Many engines blew, as it was a generic code, dependant on the customer spec. Never had any returns. I never saw an ECU return in 20 years. Either OE or modified.

If a Punto has an ECU fault, it would be the 1st I heard of. Sensors and connections are more likely candidates.

 

[jetex]

Micky, I'm a Patrol with a motoring organisation and have seen plebty of Punto ECU failures. We don't see so many now, but they're easy to check using a noid light or L.E.D testlamp. Don't use a bulb type testlamp as the current draw for the bulb is too much for the ECU, and can blow it.