Northern Auto Tech - ECU and Blue & Me Repairs

Technical Bad missfire/hesitation/power loss

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Technical Bad missfire/hesitation/power loss

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iffy

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May 15, 2009
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At idle the car missfires, and in every gear I can feel hesitation when applying power, although the powerloss is more evident in second gear. What you guys think it could be? Car is a punto 1.2 8v 2000 reg.
Also can anyone tell me where the diagnostic port is on this car?
 
Hi mate.
Our cars are famous for coil failure leading to spiked ECU/Ecu damage.
If you use the search button on here i'm sure you'll read plenty about it all and how to test for ignition output from the ECU itself.

As for diagnostic port, its located in the fuse panel where your right knee is when sat behind the wheel. Couple of quarter turn screws and your in.

Good luck with it mate, worth looking on here as lots of info and knowledge available (y)
 
The other thing that could cause the issues are lambda related, or a vacum leak.

Do you have an EOBD tester that can record data on the move. This will help to track down the problem.

A lot of things can create misfires, but not all of them are straight forward.

PS I have a good set of coils for a cheap price if required.
 
Last edited:
mk2 punto rarely have coil problems, untrained techs/people with code readers rely too much on the coil errors given when infact its not the coils at fault....hence diagnostics is more than simply reading a code reader.

https://www.fiatforum.com/punto-guides/52068-punto-coil-ecu-checks.html

The fault is actually the coil drivers insde the ECU not the coils, think I have changed one coil in 6 years. Also disregard what people say about changing the coils with the ECU at same time (unless you have a fault in the coil obviously) again I have never done this in 6 years and never had a customer return.

My advice (to save money/grief) is to follow the guide above or take to someone with more than just a code reader, i.e. oscilliscope.
 
Nice answer T14086, however I think that using data from scanners, can be very helpful in diagnostics if used with care.

An example attached below is helping me to get to grips with my particular problem.....

View attachment Punto_Data_01.pdf

Although I am not taking the results as an exact cause of the fault, I think it is pointing me in the right direction.

Any tool in the wrong hands can be bad, but furnished with a little bit of information it can help with hard to trace errors.

The next attachment shows when the MIL light comes on....

View attachment Punto_P0300.pdf

The result of this is a MIL with a P0302.

One thing to remember though is that T14086 has a cracking knowledge and I for one would trust what he says. :worship:
 
oh I agree absolutely 100%. I use a code reader on non-fiat cars & find it extremely useful (especially ones with freeze data) & helpful.

It's easy to think to oneself "oh I have seen this before so I know what it is" which in some cases can be useful but potentially dangerous in others. A good blend of knowlege, experience,the ability to read information provided (from readers etc) and from the customer him/her self combines to make a good allround diagnostic technician....lets also not forget common sense aswell.

Fiat techs (especially DET's) are trained to have a 70% 'idea' of the fault before they have even got in the car, all of this comes from experience,customers description of fault & training.

However rule number one is never assume! ...lets face it we have all been caught out many times:eek: My 'gripe' so to speak is large dealership chains not letting techs have sufficient time to diagnose problems correctly/accurately, something we see many customers complain about on this and other forums.
 
T14086 said:
oh I agree absolutely 100%. I use a code reader on non-fiat cars & find it extremely useful (especially ones with freeze data) & helpful.

It's easy to think to oneself "oh I have seen this before so I know what it is" which in some cases can be useful but potentially dangerous in others. A good blend of knowlege, experience,the ability to read information provided (from readers etc) and from the customer him/her self combines to make a good allround diagnostic technician....lets also not forget common sense aswell.

Fiat techs (especially DET's) are trained to have a 70% 'idea' of the fault before they have even got in the car, all of this comes from experience,customers description of fault & training.

However rule number one is never assume! ...lets face it we have all been caught out many times:eek: My 'gripe' so to speak is large dealership chains not letting techs have sufficient time to diagnose problems correctly/accurately, something we see many customers complain about on this and other forums.
Click to expand...

I agree with your DEALERSHIP phrase, boils down ££ at the end of the day.

Iam currently help with a 2003 PUNTO 1.2 16v with a missfire problem,i have 3 codes,all missfire codes,300,302 & 304 but after 20 seconds aprox, the AIR INTAKE TEMP stops reading according to my 'solus',so some digging to do,may be puting a link on here for comments.
 
I am sure if you post the info then there are some cleaver people on here who will help.

I have found that by collating info into graphs/charts can help as a problem will seem clearer when presented in an uncomplicated way - unlike this sentence.
 
Now we digress, but Ace is clean and rocking again, new album out soon and not playing in Kiss.......(y)


However, Iffy - have you got any further with the issue? My misfire looks like it is CAT/Lambda related. The error code is not always direct to the problem. More info could help, ie is the car cutting out, etc?
 
Well,thats my punto sorted :p :D :D

Set of plugs, my diagnostic tool said sparkplugs and other items, so thought i would have a indepth play,made me look good :D infront of my friend :ROFLMAO:
 
good stuff(y)

one point if you changed plugs is make sure they are not non-resistive type (like alot of shops list them as) as you will kill the ecu, genuine plugs are just as cheap so best play it safe(y)
 
T14086 said:
good stuff(y)

one point if you changed plugs is make sure they are not non-resistive type (like alot of shops list them as) as you will kill the ecu, genuine plugs are just as cheap so best play it safe(y)
Click to expand...


You mention kills ECU's, :confused:
I still have the box for the plugs fitted and receipt,i supplied the FIATpart number from around the chrome hexagonal fitting of the plug to my local motor factors, and they supplied the only plug listed.

Plugs fitted: NGK-DCPR8E-N.

I take it you are a dealership techy ?, i've not herd of plugs killing ECU's before.

NGK havent let me down yet, unlike champion.

usefull bit of info to know, cheers.

Andy
d'ship techy
 
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