Technical Correct spark plugs for 1.1 - 2006

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Technical Correct spark plugs for 1.1 - 2006

Wasgehabendas

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Recently I changed the spark plugs from NGK R to DCPR7E-N-10 (4983) for my 1.1 2006 (January 2016) and car started to misfire on low rpm while accelerating.

Old: NGK R, there wasn't a problem with them.

New: DCPR7E-N-10 (4983), misfire on low rpm while accelerating
Manual: BKR5EZ

Old and new spark plugs differ from those in the manual because of the thread size and gap. There is a big confusion about these spark plugs and I see that many questions are asked on this forum about them. I couldn't get a definite answer.

These DCPR7E-N-10 (4983) are everywhere listed as correct ones but misfire started right after they were fitted. What could went wrong? Can someone help me with correct ones?
 
Sometime around the end of 2005 or the beginning of 2006 the plugs changed to ones with a smaller thread diameter, on 1.1 and 1.2. This may have happened at the same time as the change from square to round oil cap, but that's just a guess. The handbooks, as always take some time to catch up, mine also states the old ones, although the engine takes the new ones. I've been replacing these annually for the last ten years without any problems. Your new plugs are unlikely to be the cause of your problems.

When you changed the plugs, you did not remove BKR5EZ so that you could fit DCPR7E-N-10. The ones you removed must have been DCPR7E-N-10, or equivalent form another manufacturer.

All Panda and Punto 8v engines suffer from ageing plug leads. They deteriorate, and break down, eventually causing a misfire, which can destroy the coil if left unfixed. They tend to stick to the plugs and be difficult to remove, so at plug change time, disturbing them could be the trigger for them to fail. It might be as simple as them not being attached to the plugs securely. If the plug cover has moved along the cable, the connector may not be secure, or even touching the plug terminal, so the spark has to jump that gap before it reaches the plug electrode gap. That'll strain the coils very quickly.

Are the plugs fitted properly? I have seen plugs that have not been tightened properly. The gasket washer does nto just seal the plug, but is an important part of the heat path to maintian correct plug running temperature. A gasket that is not squashed properly can make a plug run hotter than it should, which can lead to a holed piston. Do not overcompensate and overtighten.

Why did you change the plugs? Was this a routine service, or was there a problem ther already, and is not fixed, but you are focussing on the only new part?

"NGK R" may be a plug type, but is not a specific part number. Whatever they are must have at least been the correct thread size. Perhaps some more detail of those might be useful, and the reason not to replace like with like. Had those been fitted by you, or a previous owner to try to 'fix' a misfire?

If you need help, give us the detail we need.
 
if you are fitting DCPR7E-N-10 plugs
and the recommend in the manual is BKR5EZ
then the plugs you have fitted are 2 levels to cold, this means the tip will not retain the heat required for optimum cumbustion, spark plugs not only act as a spark producer but also keep the cumbustion temp to a set level keeping the engine clear of soot and other particles.
A cold plug will create a missfire as much as an overheating plug will.

this might explain it
/https://www.ngkntk.in/ngk-technology/importance-of-heat-range/
 
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if you are fitting DCPR7E-N-10 plugs
and the recommend in the manual is BKR5EZ
then the plugs you have fitted are 2 levels to cold

BKR5EZ has a 14mm thread diameter
DCPR7E-N-10 has a 12mm thread diameter

Might be quite a struggle to get the DCPR to stay in the head, or a struggle to get the BKR into the smaller hole.

I think the key issue here is why the plugs were changed, and if to cure a problem, why the new plugs are being suggested as the cause.

A low speed misfire is more likely an HT issue, with leads or coils, or perhaps a head gasket problem. Could also be mechanical, with valve seating issues, or piston ring failure, but much less likely on a FIRE engine.
 
I strongly agree with Portland bill,

Change your plug leads and see if that is the cause of problem.

If problem still there you may have a faulty new plug, that said I have never had a faulty ngk spark plug.

Good idea from koala too try old plugs if you have them, What type are the old plugs?
 
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Sorry for the late reply I was away for some time.

I did change the plug leads but everything is same, no changes. Mechanic said coils are fine too.

Last time car was running normal was on:

DCPR7E (3932) spark plugs, fitted by FIAT dealer. In the first post I mentioned them as NGK R because I didn't know the correct type.


Difference between DCPR7E (3932) and DCPR7E-N-10 (4983) is the gap - 0.8 mm vs 1.00 mm.


After fitting these 4983 engine started to shake, muffler too, strong misfire at idle, knocking sound from the engine and jerky acceleration and deceleration. Are these things possible from this "small mistake"?

@portland_bill I did change the spark plugs as part of a routine service.
 
The difference in gap should not cause a misfire, unless it just shows a weakness elsewhere. I would have expected any weakness to show already, and the new plugs to make it worse.
Contrary to popular belief, a smaller gap does not make a better spark. A larger gap requires a higher voltage to get the spark to jump, so creates a better spark to set fire to the fuel. This does of course need the coil to be capable of creating this higher voltage, so just increasing gaps on other engines won't necessarily work.
(In the eighties, with the introduction of the Maestro and Montego, these were the first cars to arrive at Rover dealers needing larger gaps. Many mechanics promptly closed the gaps, creating misfires due to weak sparks.)
The larger gaps take a little longer for the voltage to build, so spark timing is altered to suit. So many variables illustrate why it is important to keep it all as the manufacturer intended.

Changing the plugs is almost certainly not the cause of the issue, it has merely highlighted it.

New leads still need to be checked for correct fitting.
Firstly, are they all on correctly, or is it now just running on two cylinders. Might sound silly, but a simple quick check will avoid lengthy diagnosis. (I did this early this year on mine - wouldn't start at all, but did cough a few times.)
If you've got good quality plug leads, they will be a tight fit over the ceramic. Good in one respect, but can also mask whether the connector has clicked onto the terminal properly. Check this next. Similarly, ensure they are fitted into the coils firmly.

Recheck the coil low tension connectors, and the ECU plug. There have been reports of loose terminals in ECUs. Remove the plug gently, and prod each terminal in the ECU gently to check they are firm. Do the same with the connectors in the plug, and visually check for any signs of burning indicating a poor connection.

A compression test might help, but physical damage is unlikely. A mechanical problem should have shown some symptoms before the service. Was the service done because it was due, or done because there was the start of any running problems.

Was this just a normal service, or has the cambelt been changed this time? If cambelt changed, recheck the timing.

Put the old ones back in. Does the problem disappear.
Who put the wrong ones in? You at the last service, or a previous owner?
 
The 1.1 is noted for wiring connection problems at the ECU. Faults which look like plugs and coils are one of the issues. Very carefully, check the ECU multi connector and wires going in. It's possible a broken conductor is preventing one coil from sparking.
 
The difference in gap should not cause a misfire, unless it just shows a weakness elsewhere. I would have expected any weakness to show already, and the new plugs to make it worse.
Contrary to popular belief, a smaller gap does not make a better spark. A larger gap requires a higher voltage to get the spark to jump, so creates a better spark to set fire to the fuel. This does of course need the coil to be capable of creating this higher voltage, so just increasing gaps on other engines won't necessarily work.
(In the eighties, with the introduction of the Maestro and Montego, these were the first cars to arrive at Rover dealers needing larger gaps. Many mechanics promptly closed the gaps, creating misfires due to weak sparks.)
The larger gaps take a little longer for the voltage to build, so spark timing is altered to suit. So many variables illustrate why it is important to keep it all as the manufacturer intended.

Changing the plugs is almost certainly not the cause of the issue, it has merely highlighted it.

New leads still need to be checked for correct fitting.
Firstly, are they all on correctly, or is it now just running on two cylinders. Might sound silly, but a simple quick check will avoid lengthy diagnosis. (I did this early this year on mine - wouldn't start at all, but did cough a few times.)
If you've got good quality plug leads, they will be a tight fit over the ceramic. Good in one respect, but can also mask whether the connector has clicked onto the terminal properly. Check this next. Similarly, ensure they are fitted into the coils firmly.

Recheck the coil low tension connectors, and the ECU plug. There have been reports of loose terminals in ECUs. Remove the plug gently, and prod each terminal in the ECU gently to check they are firm. Do the same with the connectors in the plug, and visually check for any signs of burning indicating a poor connection.

A compression test might help, but physical damage is unlikely. A mechanical problem should have shown some symptoms before the service. Was the service done because it was due, or done because there was the start of any running problems.

Was this just a normal service, or has the cambelt been changed this time? If cambelt changed, recheck the timing.

Put the old ones back in. Does the problem disappear.
Who put the wrong ones in? You at the last service, or a previous owner?

I checked the coils with mechanic and they are certainly not reason for the problem. He said plug leads are fine too. Service was done because there was a misfire (hiccups) at idle when engine was warm. I thought spark plugs were the culprit and I think I wasn't far away from the truth because when mechanic removed them they were almost dead.

After further investigation I am hearing a hissing sound when I open the hood. There must be some air leak that causes this. In my opinion mechanic haven't properly put back in place the hoses after clearing the throttle body with carb cleaner or when changing the spark plugs and leads.

Muffler is backfiring / detonating and when I put my nose to smell the exhaust gases there isn't a smell of petrol at all. I guess it is because the mixture is rich of air?
 
The problem was there before any work. Therefore the new plugs are not the problem.

An air leak will certainly cause problems. Gentle misfires can be caused by air leaks, but could also be a head gasket issue. Check for the leak first.

Spraying something flammable around joints will often find leaks as the engine note changes when the spray is ingested. WD40 is quite good, as it will change the engine note, but is not too flammable so is unlikely to set the car on fire. Carb cleaner will work well, but carries a greater risk. Recently one forum member described using a blowtorch, unlit, just pushing gas around the joints. Would show a leak well, but needs care near hot parts.

As well as checking gasket joints, and that hoses are connected properly, also check the condition of all hoses, as they can crack with age and become porous.
 
The problem was there before any work. Therefore the new plugs are not the problem.

An air leak will certainly cause problems. Gentle misfires can be caused by air leaks, but could also be a head gasket issue. Check for the leak first.

Spraying something flammable around joints will often find leaks as the engine note changes when the spray is ingested. WD40 is quite good, as it will change the engine note, but is not too flammable so is unlikely to set the car on fire. Carb cleaner will work well, but carries a greater risk. Recently one forum member described using a blowtorch, unlit, just pushing gas around the joints. Would show a leak well, but needs care near hot parts.

As well as checking gasket joints, and that hoses are connected properly, also check the condition of all hoses, as they can crack with age and become porous.


I read it as it was okay

"Last time car was running normal was on: DCPR7E (3932) spark plugs, fitted by FIAT dealer."

until the plugs were changed.

I don't understand why you wouldn't put the old ones back in to see if the plugs were in fact faulty or a new fault had been induced
 
I read it as it was okay

"Last time car was running normal was on: DCPR7E (3932) spark plugs, fitted by FIAT dealer."

until the plugs were changed.

I don't understand why you wouldn't put the old ones back in to see if the plugs were in fact faulty or a new fault had been induced

I checked the coils with mechanic and they are certainly not reason for the problem. He said plug leads are fine too. Service was done because there was a misfire (hiccups) at idle when engine was warm. I thought spark plugs were the culprit and I think I wasn't far away from the truth because when mechanic removed them they were almost dead.

After further investigation I am hearing a hissing sound when I open the hood. There must be some air leak that causes this. In my opinion mechanic haven't properly put back in place the hoses after clearing the throttle body with carb cleaner or when changing the spark plugs and leads.

Muffler is backfiring / detonating and when I put my nose to smell the exhaust gases there isn't a smell of petrol at all. I guess it is because the mixture is rich of air?

I enquired as to why the plugs were changed, and this latest answer appears to say a fault was there, which is why a service was carried out.
The statement "Last time car was running normal was on: DCPR7E (3932) spark plugs, fitted by FIAT dealer." seems to contradict somewhat, but likely the car was running ok for some time on those, then developed the misfire, whilst those were still fitted. The plugs are a red herring.
 
I enquired as to why the plugs were changed, and this latest answer appears to say a fault was there, which is why a service was carried out.
The statement "Last time car was running normal was on: DCPR7E (3932) spark plugs, fitted by FIAT dealer." seems to contradict somewhat, but likely the car was running ok for some time on those, then developed the misfire, whilst those were still fitted. The plugs are a red herring.

Yes it contradicts because I haven't explain it properly. Sorry about it.

It looks like plugs were making issues because I changed them again and there isn't a misfire at idle when cold anymore.

Do you have any idea why I have been experiencing a misfire at idle when engine gets warm? It's definitely not related to spark plugs, leads or coils. No warning lights and no errors.

I want to resolve this issue for the past 2 years without success and it is getting worse over time. On cold start rpm at idle is 1000, then when engine gets warm and it drops to 750 misfire is starting. There aren't fluctuations at RPM at idle once it gets warm.

Asked hundreds of people and no one has any idea why it happens. Some people in the other thread I started mentioned crank position sensor, but if it is the culprit I wouldn't drive the car for 20k miles with a bad one.

Any help would be appreciated :)
 
Let me add one more thing.

I am hearing a clicking sound when I get under the car from the place where timing belt is fitted. Also that clicking sound can be heard inside the car, especially in 1st gear.

Do you have any experience with poorly fitted timing belt, are misfire and clicking symptoms on this 1.1 engine?
 
is it really misfiring.

can you hear it from the exhaust from the back of the car

I see you have a 1.1 might be worth disconnecting the battery and reseating the ECU

most true misfire will flag a code

there's various version of throttle bodies. Some combinations have an occasional little change in revs that some people can feel. This isn't a fault ?
 
is it really misfiring.

can you hear it from the exhaust from the back of the car

I see you have a 1.1 might be worth disconnecting the battery and reseating the ECU

most true misfire will flag a code

there's various version of throttle bodies. Some combinations have an occasional little change in revs that some people can feel. This isn't a fault ?

Yes it can be heard from the exhaust, there are detonations on every 4-5 seconds. It looks like ECU doesn't count this for misfire :D Revs are stable, they aren't going up and down.

Please look at the video, it's not mine, but exactly same issue:

https://vimeo.com/365353364
 
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well that's cleared up. Thays not a misfire but revs fluctuating

High percentage of these are nothing more than a vacuum leak.
 
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well that's cleared up. Thays not a misfire but revs fluctuating

High percentage of these are nothing more than a vacuum leak.

But revs are not going up and down. They are 750,760 all the time when it gets warm.

How to find the vacuum leak, if that is the cause? What are common vacuum leak spots for Panda?
 
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