Technical Ignition (Coil) problem on startup

[YiannisAth]

Hi everyone,

Last couple of weeks I have a problem on my 2003 Panda 1.2 8v where ignition coil 1 does not fire on startup initially leaving the car to idle on the 2 cylinders left. Revving to 2-3k rpm solves the problem (But leaves check light on).

This appears mostly with cold engine maybe 3 out of 4 startups - So far have tried the following

Faults detected so far
- MES gave error P0351 for Coil Pack 1
- Coil 1 charge time 4.5 ms and Coil 2 was 2.5 ms
- Some oil at spark plug 4 (Connected to coil 1)
-Maybe slightly down on power

Checked ok
- All 4 injectors resistance within spec
- Injectors had similar cone pattern, nothing seemed clogged and no streaks
-Run tank with injecor cleaner nevertheless
- Coils are probably fine as swapping each other didnt move the problem to coil 2 (Error P0352)
-Installed new NGK spark plugs (Maybe overdue but didnt look in terrible state)
-Spark leads look in ok condition, were changed 3 years ago and couldn't detect any spark leaks.
-ECU to coils harness probably not faulty as jerking it with engine running didnt cause misfires
-Disconnected related connectors (ECU, coils, injectors, earth under battery) and cleaned with contact spray which fixed for 2-3 days.

So I am left with no ideas, hoping I dont have a faulty ECU, my question is, what else can I test, or get from MES that might be helpful and how can I be sure my ECU is dying?

PS Budget is limited -only for necessary tools/parts- but my time at the moment isnt so anything you come up with, within reason can be tested. Photos of everything I have tested so far are available.

 

[Greasytrucker]

Is the mileage 220,000 or is that a typo? If so i’d be starting with a compression test i think, especially as you said it’s down on power

 

[YiannisAth]

Is the mileage 220,000 or is that a typo? If so i’d be starting with a compression test i think, especially as you said it’s down on power

Thank you for the reply, It is in km, so almost 140.000 miles, still a good idea, will take it to a garage to test and follow up.

 

[DTanner]

@YiannisAth sounds like you have taken a good approach so not sure I can help much.

I had a ignition coil issue recently that I covered on this post: Link
It will not be super valuable to you but maybe the labelling of the coil packs will be and some coil tests. On mine the error code was P0351 which is Ignition Coil “A”, which is the coil further into the engine bay (closer to the boot/trunk).

So if I have read your post correctly you had the issue persist despite:
+ Changing to new spark plugs
+ Swapping the coil packs ("A" for "B" and "B" for "A")

Is this correct?
Did you physically interchange the two coil packs - and did not reuse any leads of connections? This is really important as if only the coil pack was changed in the whole circuit and the code was again thrown for the same coil pack, this sets a strong direction for troubleshooting.
Did you clear the error code and ensure it was regenerated following both of these with the same error code? Just a check but again want to double check you erased the code before checking after the swap.

As the error code relates to ignition circuitry I would focus on things that affect this, i.e., not the fueling system, injectors, etc. just the supporting electrical system (battery and ground paths), and ECU, Wire Harnessing, Ignition Coils, HT Leads and Spark Plugs.

So what would I do?

1) Listen for firing: Can you listen near the Coil Packs when the engine is showing the issue. Do you hear a clicking sound that shows the Coils are trying to fire? This is subjective but may help.

2) Check what cylinders are not working: confirm that it is definitely two cylinders not working and specifically which two they are. Are they both connected to the same ignition coil?
a) Remove a HT Lead from a spark plug (ensure it is secure and away from the metal of the engine)
b) Start the engine - assess if the engine was running worse or the same
c) Stop the engine
d) Replace the HT Lead
e) Repeat these steps for all HT Leads
The point here is to check which specific cylinders are not running and what ignition coil it/they are connected to.
Cylinder 1 and Cylinder 4 (outside cylinders) are connected to Coil Pack "A" (P0351)
Cylinder 2 and Cylinder 3 are connected to Coil Pack "B" (P0352)

Make sure you know what cylinders are not firing and what ignition coils they are connected to.

3) Check the HT Leads: Not sure how possible it is but if you know that cylinder(s) are not firing would it be possible to interchange the leads temporarily to see if it resolves the issue on the cylinder. I would consider just buying new leads (around £20) but there is a chance it would not help. Maybe temporarily swapping them may help explore they would not route well but may allow you to test. The HT Leads seems less likely to me if Step 1 shows that two cylinders are affected and much more if only one is affected. Note: interchanging a good and bad lead may move the problem so it may not be obvious that it has changed check that the same cylinder is affected.

4) Measure Coil resistance: measure the primary and secondary coil pack resistance for both coils. I suggest this as it is very easy to do if you have a good multimeter - see my post for details: Link. I would measure from cold as this appears to be where you have the issue

Other odd thoughts are:
Could it be a broader electrical issue that one coil is more susceptible to? How old is the battery and what is its condition? What is the state of the earth strap?

Caveat - I am certainly not an expert and just wanted to share some thoughts as I had some recent experience with ignition coil issues. Use your judgement over mine.

 

[YiannisAth]

@YiannisAth sounds like you have taken a good approach so not sure I can help much.

I had a ignition coil issue recently that I covered on this post: Link
It will not be super valuable to you but maybe the labelling of the coil packs will be and some coil tests. On mine the error code was P0351 which is Ignition Coil “A”, which is the coil further into the engine bay (closer to the boot/trunk).

So if I have read your post correctly you had the issue persist despite:
+ Changing to new spark plugs
+ Swapping the coil packs ("A" for "B" and "B" for "A")

Is this correct?
Did you physically interchange the two coil packs - and did not reuse any leads of connections? This is really important as if only the coil pack was changed in the whole circuit and the code was again thrown for the same coil pack, this sets a strong direction for troubleshooting.
Did you clear the error code and ensure it was regenerated following both of these with the same error code? Just a check but again want to double check you erased the code before checking after the swap.

As the error code relates to ignition circuitry I would focus on things that affect this, i.e., not the fueling system, injectors, etc. just the supporting electrical system (battery and ground paths), and ECU, Wire Harnessing, Ignition Coils, HT Leads and Spark Plugs.

So what would I do?

1) Listen for firing: Can you listen near the Coil Packs when the engine is showing the issue. Do you hear a clicking sound that shows the Coils are trying to fire? This is subjective but may help.

2) Check what cylinders are not working: confirm that it is definitely two cylinders not working and specifically which two they are. Are they both connected to the same ignition coil?
a) Remove a HT Lead from a spark plug (ensure it is secure and away from the metal of the engine)
b) Start the engine - assess if the engine was running worse or the same
c) Stop the engine
d) Replace the HT Lead
e) Repeat these steps for all HT Leads
The point here is to check which specific cylinders are not running and what ignition coil it/they are connected to.
Cylinder 1 and Cylinder 4 (outside cylinders) are connected to Coil Pack "A" (P0351)
Cylinder 2 and Cylinder 3 are connected to Coil Pack "B" (P0352)

Make sure you know what cylinders are not firing and what ignition coils they are connected to.

3) Check the HT Leads: Not sure how possible it is but if you know that cylinder(s) are not firing would it be possible to interchange the leads temporarily to see if it resolves the issue on the cylinder. I would consider just buying new leads (around £20) but there is a chance it would not help. Maybe temporarily swapping them may help explore they would not route well but may allow you to test. The HT Leads seems less likely to me if Step 1 shows that two cylinders are affected and much more if only one is affected. Note: interchanging a good and bad lead may move the problem so it may not be obvious that it has changed check that the same cylinder is affected.

4) Measure Coil resistance: measure the primary and secondary coil pack resistance for both coils. I suggest this as it is very easy to do if you have a good multimeter - see my post for details: Link. I would measure from cold as this appears to be where you have the issue

Other odd thoughts are:
Could it be a broader electrical issue that one coil is more susceptible to? How old is the battery and what is its condition? What is the state of the earth strap?

Caveat - I am certainly not an expert and just wanted to share some thoughts as I had some recent experience with ignition coil issues. Use your judgement over mine.

I remember your thread and it helped me very much with the methodology, even though eventually we have different causes.

So first off, yes with coil 1/A I also mean the one towards the firewall, powering the outer cylinders.

Yes the problem persisted exactly as it was even after new spark plugs and the coil swap.

For the coil swap I physically exchanged the coils' position (the low voltage connectors were not long enough to just change those) and of course the connectors from the ECU. The leads and circuitry were left as they were. Deleted the codes, which in fact I did multiple times these days, and still got P0351, code did not follow the Coil A.

On which cylinders are not firing, I am sure exactly 1 and 4 are not firing following a similar tactic. With the issue present - reminder it comes and goes - unplugging any of 1 or 4 made no change to the engine's attitude and unplugging 2 (or 3 i dont remember) stalled it immediately.

I am personally not very suspicious of HT leads as the issue is traced to 2 cylinders at the same time, connected fo the same coil. Unfortunately there was no way to route them in a differently way to check. If I am left with no option I will buy new ones but for now I am assuming they work. Same with the battery, it is less than a year old and Bosch branded, will also assume is not causing the issue.

When I find the time tomorrow I will measure the coil circuits resistance according to your link, even though finding a fault there will further confuse me and complicate my life. Will also check with more caution the earth points.

Thank you for the detailed answer.

 

[DTanner]

@YiannisAth,

Unfortunately I agree with everything you have said. If the fault affect running of two cylinders on the same ignition coil it feels like it must be on originating on the coils or earlier in the ignition circuitry.

Given what you have done the only areas I can think to check are (sorry it is a brain dump):
1) The HT Leads - though I agree that two bad ones seems very unlikely
2) The Harnessing - I would gently inspect the harness for any issues, between the ignition coil and the ECU. You can gently open in any suspect places. And wiggle the harnessing as the car is running to see if you can stimulate rough running (though I think you did this)
3) The ECU - I don't know enough to help here
4) The Battery - I wonder if the MES can give you a good reading on battery health - like voltage drop / min voltage during cranking and voltage when idling
5) The earth strap - If you have a multimeter set it to resistance and probe between the battery negative clamp and a couple of metal points on the body of the engine (near the coils). This should read a low resistance (close to 0 ohms)
6) The coils - though I agree that I cannot see how it would be relevant given you interchanged them and the issue did not move. However, I would measure the coil resistances anyway as they are easily accessible and may turn something up

Note: Sorry to ask, but this is the biggest part of the testing you did - are you confident that you actually interchanged the coils in the test you did. I ask only as the Coil is an obvious part to fail here and easy to replace. I am also biased towards this as it is the problem I had.

I think you need more help than I can offer - @koalar are you about or anyone else?

 

[Greasytrucker]

-Disconnected related connectors (ECU, coils, injectors, earth under battery) and cleaned with contact spray which fixed for 2-3 days.

After reading your original post in detail again, this part says to me you have a wiring issue, as disturbing various connectors has temporarily fixed the issue

 

[DTanner]

@YiannisAth check out this post. I recommend you read the whole thread. They describe some issues very similar to yours:

ECU COIL ISSUE

 

[koalar]

Has the code really been cleared

If you clear the code

Switch the ignition off and back on without starting the car

Reread the code

Is it still present

 

[koalar]

Assuming that clears

Put a 12V test light on the control pin of coil 1 and crank the car,bodies it flicker

However it doesn't sound like your average faulty coil, which are normally worse when hot ior higher RPM

Control circuits normally don't clear themselves


Any blue smoke on start up