Hi everyone, newbie here! Hope I'm posting this in the right place...

We have a fiat Punto GO! petrol (2001). When travelling on motorways when we reach 70mpg the EOBD starts flashing (amber in colour).

When we lift off the accerlerator, after around 10 flashes or 30 seconds, the light stops flashing.

We've taken it in to a local garage (they're quite old fashioned and have no up to date equipment by the looks of thing) and they can't advise us at to what the problem might be.

Has anybody experienced this or know what it may be?

Please help as we're a little worried about driving, but around town no light, so it's just when you get to 70mph.

Thanks

flashing normally means a missfire,

True Dave, but flashing at 3k rpm suggests it wants a phonic wheel learn (I bet the cambelt was replaced before this fault occured and it's now detecting a 'false' misfire).

Been covered many times in the Punto section.

https://www.fiatforum.com/punto/228660-flashing-engine-light-afer-new-cambelt.html

cambelt

Hi everybody - thanks for the replies

Hi danny thanks for the further link.. I've read it and will give the "The phonic wheel learn procedure" a whirl (warm-up engine, floor to 5000rpm x 3)

I also posted this thread in the Punto section last night but it appears to have been removed. A posted (calls 'Brin'?) kindly responded to. I had said this only happens around 70mph but I think it may be 'rpm' related just that when we're doing less than 70mph the rpms are low and hence no flashing light .. I think that's what Brin was hinting at as he said to rev it to see if that triggers a flashing light at say 35mph.

It terms of 'drive' .. I'm not an expert but it seems to drive fine, even with the light on.

In terms of when we first noticed it.. it was 2009.. the temperature gauge was going VERY high.. we put the car in to Garage and they said head gasget had started to go (not fully gone) ... anyway after the car came out, the light started to flash aorund 70mph. When we took it back, the Garage said they couldnt explain why it continued to flash! but it was sound as far as they were concered!

Sorry if that doesn't make much sense, my mind's a little blank.

thanks again for your help

D4nny8oy said:

True Dave, but flashing at 3k rpm suggests it wants a phonic wheel learn (I bet the cambelt was replaced before this fault occured and it's now detecting a 'false' misfire).

Been covered many times in the Punto section.

https://www.fiatforum.com/punto/228660-flashing-engine-light-afer-new-cambelt.html

Click to expand...

I think you only do the phonic wheel trick when the ecu is replaced...

Beavis64 said:

I think you only do the phonic wheel trick when the ecu is replaced...

Click to expand...

The phonic wheel learn should be performed whenever the self adaptive parameters have been reset (or if ECU has been replaced), or if any operation has been performed on the engine which involves the valve timing.

When everything is ok, the crank and cam signals are synchronised and accelerate/decelerate evenly. When a misfire occurs, the two are a fraction out as the top and bottom-end rotate slightly differently for a split second- this is how it detects it. Even if the new belt is fitted seemingly perfectly, there's still a likelyhood the two signals aren't exactly where they were before, and so a false misfire gets picked-up, almost always at 3000rpm/70mph.

birdietrail- If it's not flashing with the engine idling, you'll probably need a garage (or Dealer) who can reset the ECU parameters and allow the phonic wheel learn to be performed.

Danny thanks again for taking the time to help..

I kinda followed what you were saying (I say kinda, as I'm an office boy who would love to being able to know what's going on under the bonnet, but it's a confidence thing!)

I will give the Fiat garage near me a ring as they are bound to know about the ECU parameters.. fingers crossed it's a £25 quid job! :slayer:

I'm still going to try and reach 3000rpm at say 35mph to see if it's a rpm thing as I discounted rpms and just thought it was speed related (>70mph)

Thanks again skin

I'd see if the garage who did the work would be willing to pay, or at least reimburse you, as they haven't finished the job you paid them to do. If they don't want to pay for even vaguely upto date ECU reading/diagnostic software (we're talking nearly 10 years old here!), then that's their problem. They should've taken it to the Dealer themselves once they'd finished the headgasket job.

The garage is old skool, that's for sure.. all their gear is old.. e.g. car was in for MOT this month and we wanted tracking done at sametime but the guy fessed up and said, "our tracking system is years old, something I need to decide whether to invest in .. so take it to Kwik fit etc etc" also our power steering went with the red light and loss of power and he didn't have the gear to test what was wrong but did advise it probably was ECU or column.. they only just started taking payment by card etc.. but.. they're very reasonable, do a good job (bar this ECU para. reset thing) and they look after me well.. so pros and cons

but i might consider changing

when i had this missfire only at higher revs an not at tick over it turned out to be a dodgy plug.
Had same thing years ago on a rover after fitting brand new champion plugs too

dave - thanks - will mention the possibility of dodgy plug when i take it in (i assume you mean spark plug and yes that is a serious question ! :bang: )

thanks

yes spark plug, they should have been changed when head gasket was done, but even then you can still get dodgy ones

Just an update.. it seems the light flashing is deffo triggered by RPM and not MPH.

If I take the RPM to around 3,500 the EOBD light starts flashing for around 20 seconds before going out.

Not misfireing thougth.

I've phoned FIAT dealer who said they'll run some software on it and that will cost me £47, and then they will start trying to find the fault which will cost me more to find/fix it.

A local Hampshire garage has quoted £40 for a similar test.

I'm wondering if it's really worth £40/£47 (plus extra ££ when they find teh fault) when the car seem to drive fine.. but then again if we want to sell it, I wouldn't feel comfortable saying to someone there's a warning light flashing @ 3,500 RPM but car seems fine.. in case it lead to accident / major repairs...

Might be being tight but in 2009 we've shelled out £300 for some head gasket work and £300 for steering column replacement so funds are tight!

Any advice/help welcome

birdietrail said:

funds are tight!

Click to expand...

whole country is in the same boat unless your a politician (that hasn't been caught yet) or a bank manager (who hasn't lost all our money yet)

birdietrail said:

Might be being tight but in 2009 we've shelled out £300 for some head gasket work and £300 for steering column replacement so funds are tight!

Any advice/help welcome

Click to expand...

D4nny8oy said:

I'd see if the garage who did the work would be willing to pay, or at least reimburse you, as they haven't finished the job you paid them to do. If they don't want to pay for even vaguely upto date ECU reading/diagnostic software (we're talking nearly 10 years old here!), then that's their problem. They should've taken it to the Dealer themselves once they'd finished the headgasket job.

Click to expand...

Like I said, it's not your problem- the garage you paid to do the job hasn't finished it.

Running the car with a fault can end up MUCH more expensive than the diagnostics tests.

Something as "simple" as a faulty spark plug will allow unburnt fuel into the exhaust. This can ruin the catalyst = £300 plus labour - all for saving the cost of a set of plugs retailing under £20.

Best get it checked by someone who understands modern engines and seriously consider using them in future.

A word of caution though, some mechanics go for the costly fixes before checking the basics. Make sure you are clued up before agreeing to random(ish) parts swapping.

Hi, I have exactly the same issue with Seicento, just wondered if you ever found the cure?

D4nny8oy said:

The phonic wheel learn should be performed whenever the self adaptive parameters have been reset (or if ECU has been replaced), or if any operation has been performed on the engine which involves the valve timing.

When everything is ok, the crank and cam signals are synchronised and accelerate/decelerate evenly. When a misfire occurs, the two are a fraction out as the top and bottom-end rotate slightly differently for a split second- this is how it detects it. Even if the new belt is fitted seemingly perfectly, there's still a likelyhood the two signals aren't exactly where they were before, and so a false misfire gets picked-up, almost always at 3000rpm/70mph.

birdietrail- If it's not flashing with the engine idling, you'll probably need a garage (or Dealer) who can reset the ECU parameters and allow the phonic wheel learn to be performed.

Click to expand...

Do you mean the crank and cam signals go out of sync because of the misfire - or does the engine misfire because the crank and cam signals are out of sync?

Technically neither- the ECU "thinks" it sees a misfire and flags up the P0300 Generic misfire error, but it runs perfectly OK.

When a genuine misfire occurs, the ECU calculates where it is based on crank/cam position and which cylinder(s) fired at the time. Hence when the Cambelt timing isn't 100%, it gets confused.