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Solving A Persistent Cylinder #1 Misfire - Car Talk - Nairaland

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Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 10:44pm On May 31, 2019
Each of the combustion chambers of the various cylinders in your car's engine, goes through a series of precise combustion processes of air-fuel via the intake/exhaust valves.

With neither of the combustion chambers undergoing the processes precisely, a deficit is introduced, in terms of either a lean/rich air/fuel ratios in the valves strokes.

A distortion in the firing of the cylinder(s), quickly transcends to what we would normally called, an engine misfire.

There are misfires that can easily be tracked down, and solutions proffered in solving them, while there are others that are a pain, to track down.

Its just frustrating to have replaced all misfiring related parts, and still have the problem not solved.

Today, we'd be treating a peculiar sort of misfire, that has caused a new client thousands in costs of parts replacement and labour.

If you're ready, here we go!

CASE STUDY

CAR TYPE: Toyota Corolla 2010
ENGINE TYPE: 2ZR-FE
TRANSMISSION TYPE: Automatic drive

COMPLAINTS

According to client:
1. Car has being parked for about six months
2. Returned from a journey, and tried starting the car.
3. Engine started finally, but suddenly started experiencing some sort of engine misfires.
4. My mechanic has done all what he could do to fix the problem, but without success.
5. I retrieved a P0301 misfire code with my Bluetooth code reader.
6. I'm scared of driving the car down to your shop Joe!
Could you come pick it up?

VERIFICATION OF CUSTOMER'S COMPLAINTS ONSITE

1. Started vehicle, and confirmed there was a terrible misfire occurring in the engine.
Engine was basically "dancing".
2. Observed excessive black smoke, and foul odour of petrol from the exhaust tailpipe.
3. Personally scanned the car with a professional scan tool, and confirmed same code present.

DIAGNOSIS and FIX
1. Drove the car to the shop, with the hazard light on

2. Because of the violent nature of the misfires, there was a lot of sort of engine knocked kind of noise from the engine.

3. The car was driven, at 30mph, to reduced the load on the engine.

4. Interchanged the ignition coils of #1 and #4, to see if the coils were the culprit.
That didn't solved the problem.

5. Next was to have those spark plugs also replaced, with some sets of test spark plugs I had in the shop, instead of buying new ones.

This also didn't take care of the problem.
This tells me its not an ignition system related problem.

6. I opted to have the fuel injectors serviced, and also interchanged.
I noticed something astonishing during servicing the injectors with carb cleaner.

They were totally clogged with carbon deposits.
The injector on #1 cylinder, had a greater %of carbon buildup on the injector pintle.

That was obstructing the free flow of fuel, and subsequently reducing the fuel pressure on the cylinders.

7. Cleaned up the fuel injectors, and fixed them back; started the engine, there was not improvement.

8. Got a test lamp and a digital multimeter to test the fuel injector's power and ground circuits for either of an open or a short circuits problems.

All the injector power feeds were intact, including the grounds.

With this test, I was able to isolate any ECU related causes.

9. Now, what was in my mind was that this particular problem, is a mechanically induced one, that is narrowed down only to cylinder #1.

Since I have had experiences like these before,
I had already began narrowing down the likely causes to the following:

a) bad top cylinder gasket, due to overheating, can cause the valves to stick in their bores.
b) broken, or worn faulty valves, stems, guides, etc.
broken piston compression rings on cylinder #1.

10. What we saw, opening up the valve cover, with the intention of dismantling the top cylinder head, was surprising.

11. The inlet rocker arms on cylinder #1, were all dislodged from their positions on the pushrods.
This was the actual reason, that cylinder was misfiring, and loosing power.

12. Timed the engine, and had the top cylinder removed and taken to a machinist, for machining.

13. Replaced top cylinder gasket with a composite one, instead of the multilayered one that was originally on the car.

14. Dressed the deck of the engine block, cylinder head, and installed the head, after modifying the gasket.

ANALYSIS OF CAUSES OF THE MISFIRE
1. Closely looking at the valve train components in the cylinder head, and how clean they were, suggested to us that the client must have being properly maintaining his car, and that engine oil degradation was not to blamed for the problem.

2. The absence of an open or short circuit problems on the injector power/ground harnesses, proved that the ECU, and it's wiring, were functional, and there was no need to other a "Brainbox"!

3. Inspecting the inlet port on the cylinder #1 alone as compared to others, showed a huge volume of raw petrol dumped in there.
Obviously, this points to either a valve is not opening at all, or ...

I did conclude that why the rocker arms fell off from their positions in the engine, was basically a buildup of carbon deposits in the bore of the valves on the inlet sides of #1cylinder.

HOW TO PREVENT PROBLEMS LIKE THIS
If you intend to prevent instances such as this, ensured;
1. Engine oils are replaced as at when due.
Not replacing when its due, introduces impurities in the valve train, and cause problems.
2. Use fuel additives, devoid of sulphur contents at least once a month.
This would take care of fuel related carbon deposits on the fuel injector pintle.
3. If this isn't feasible, use carb cleaner to manually clean the injectors.
4. Don't rev your engine when its idling.
This would put more stress on the engine, and cause internal engine problems, such as rocker arm failures, if your engine is equipped with one.
5. Always replace old fuel from a car that has stayed longer than three months.
An j complete combustion process, as a result of bad gasoline, would exert stresses on the rocker arms, and cause lags in the combustion strokes.


PS:
Engines with rocker arm designs, or overhead camshafts (OHC), are known to exhibit problems of rocker arms falling off of their positions on the pushrods, or even falling off and exploding, causing severe engine problems, and suddenly stalling in motions.

This, I have seen on some 2004 Ford Explorers, where the rocker arms are dislodged, and caused an engine to seize entirely.

Well, that ended up having the entire engine replaced.






Regards,
Joseph
DW Nig Ltd
Isolo,
Lagos
www.dxta.com.ng
08066643532

3 Likes

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 10:46pm On May 31, 2019
Intake manifold removed, exposing the inlet valves

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 10:49pm On May 31, 2019
A closer look at the intake manifold port from #1, shows how wet it is, as compared to others.
When we removed the intake manifold, there was unburnt fuel on that section of the port.

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 10:52pm On May 31, 2019
Valve cover opened, exposing some of the valve train components, like the rocker arms, pushrods, camshafts, timing chains, etc.

Re: Solving A Persistent Cylinder #1 Misfire by Nobody: 10:52pm On May 31, 2019
Good read
TRYGO:
Each of the combustion chambers of the various cylinders in your car's engine, goes through a series of precise combustion processes of air-fuel via the intake/exhaust valves.

With neither of the combustion chambers undergoing the processes precisely, a deficit is introduced, in terms of either a lean/rich air/fuel ratios in the valves strokes.

A distortion in the firing of the cylinder(s), quickly transcends to what we would normally called, an engine misfire.

There are misfires that can easily be tracked down, and solutions proffered in solving them, while there are others that are a pain, to track down.

Its just frustrating to have replaced all misfiring related parts, and still have the problem not solved.

Today, we'd be treating a peculiar sort of misfire, that has caused a new client thousands in costs of parts replacement and labour.

If you're ready, here we go!

CASE STUDY

CAR TYPE: Toyota Corolla 2010
ENGINE TYPE: 2ZR-FE
TRANSMISSION TYPE: Automatic drive

COMPLAINTS

According to client:
1. Car has being parked for about six months
2. Returned from a journey, and tried starting the car.
3. Engine started finally, but suddenly started experiencing some sort of engine misfires.
4. My mechanic has done all what he could do to fix the problem, but without success.
5. I retrieved a P0301 misfire code with my Bluetooth code reader.
6. I'm scared of driving the car down to your shop Joe!
Could you come pick it up?

VERIFICATION OF CUSTOMER'S COMPLAINTS ONSITE

1. Started vehicle, and confirmed there was a terrible misfire occurring in the engine.
Engine was basically "dancing".
2. Observed excessive black smoke, and foul odour of petrol from the exhaust tailpipe.
3. Personally scanned the car with a professional scan tool, and confirmed same code present.

DIAGNOSIS and FIX
1. Drove the car to the shop, with the hazard light on

2. Because of the violent nature of the misfires, there was a lot of sort of engine knocked kind of noise from the engine.

3. The car was driven, at 30mph, to reduced the load on the engine.

4. Interchanged the ignition coils of #1 and #4, to see if the coils were the culprit.
That didn't solved the problem.

5. Next was to have those spark plugs also replaced, with some sets of test spark plugs I had in the shop, instead of buying new ones.

This also didn't take care of the problem.
This tells me its not an ignition system related problem.

6. I opted to have the fuel injectors serviced, and also interchanged.
I noticed something astonishing during servicing the injectors with carb cleaner.

They were totally clogged with carbon deposits.
The injector on #1 cylinder, had a greater %of carbon buildup on the injector pintle.

That was obstructing the free flow of fuel, and subsequently reducing the fuel pressure on the cylinders.

7. Cleaned up the fuel injectors, and fixed them back; started the engine, there was not improvement.

8. Got a test lamp and a digital multimeter to test the fuel injector's power and ground circuits for either of an open or a short circuits problems.

All the injector power feeds were intact, including the grounds.

With this test, I was able to isolate any ECU related causes.

9. Now, what was in my mind was that this particular problem, is a mechanically induced one, that is narrowed down only to cylinder #1.

Since I have had experiences like these before,
I had already began narrowing down the likely causes to the following:

a) bad top cylinder gasket, due to overheating, can cause the valves to stick in their bores.
b) broken, or worn faulty valves, stems, guides, etc.
broken piston compression rings on cylinder #1.

10. What we saw, opening up the valve cover, with the intention of dismantling the top cylinder head, was surprising.

11. The inlet rocker arms on cylinder #1, were all dislodged from their positions on the pushrods.
This was the actual reason, that cylinder was misfiring, and loosing power.

12. Timed the engine, and had the top cylinder removed and taken to a machinist, for machining.

13. Replaced top cylinder gasket with a composite one, instead of the multilayered one that was originally on the car.

14. Dressed the deck of the engine block, cylinder head, and installed the head, after modifying the gasket.

ANALYSIS OF CAUSES OF THE MISFIRE
1. Closely looking at the valve train components in the cylinder head, and how clean they were, suggested to us that the client must have being properly maintaining his car, and that engine oil degradation was not to blamed for the problem.

2. The absence of an open or short circuit problems on the injector power/ground harnesses, proved that the ECU, and it's wiring, were functional, and there was no need to other a "Brainbox"!

3. Inspecting the inlet port on the cylinder #1 alone as compared to others, showed a huge volume of raw petrol dumped in there.
Obviously, this points to either a valve is not opening at all, or ...

I did conclude that why the rocker arms fell off from their positions in the engine, was basically a buildup of carbon deposits in the bore of the valves on the inlet sides of #1cylinder.

HOW TO PREVENT PROBLEMS LIKE THIS
If you intend to prevent instances such as this, ensured;
1. Engine oils are replaced as at when due.
Not replacing when its due, introduces impurities in the valve train, and cause problems.
2. Use fuel additives, devoid of sulphur contents at least once a month.
This would take care of fuel related carbon deposits on the fuel injector pintle.
3. If this isn't feasible, use carb cleaner to manually clean the injectors.
4. Don't rev your engine when its idling.
This would put more stress on the engine, and cause internal engine problems, such as rocker arm failures, if your engine is equipped with one.
5. Always replace old fuel from a car that has stayed longer than three months.
An j complete combustion process, as a result of bad gasoline, would exert stresses on the rocker arms, and cause lags in the combustion strokes.


PS:
Engines with rocker arm designs, or overhead camshafts (OHC), are known to exhibit problems of rocker arms falling off of their positions on the pushrods, or even falling off and exploding, causing severe engine problems, and suddenly stalling in motions.

This, I have seen on some 2004 Ford Explorers, where the rocker arms are dislodged, and caused an engine to seize entirely.

Well, that ended up having the entire engine replaced.






Regards,
Joseph
DW Nig Ltd
Isolo,
Lagos
www.dxta.com.ng
08066643532

1 Like

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 10:54pm On May 31, 2019
Pointing to directions where one of the rocker arms was thrown to.

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 10:56pm On May 31, 2019
You can see the rockers off of the valve tip

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 10:58pm On May 31, 2019
Using a white marker, to get the engine times. The Camshafts already had marks on them though.

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 10:59pm On May 31, 2019
Plan view of the camshaft gears being marked

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 11:01pm On May 31, 2019
On assessment of the various vve train components exposed here, you could see how clean, this engine is.
This tells us that the misfire it had wasn't as a result of oil sludges, but rather something else.

Re: Solving A Persistent Cylinder #1 Misfire by HeavenlyBang(m): 11:04pm On May 31, 2019
Good work! Cartalk needs more content like this.

3 Likes

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 11:04pm On May 31, 2019
That's how a rocker arm looks like on this engine.
Tiny of some sort, but does a whole lot of important functions.
It was its distortion, that resulted into a single cylinder misfiring persistently..

1 Like

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 11:06pm On May 31, 2019
Showing the pistons in the engine block

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 11:08pm On May 31, 2019
Look at the differences between the valves in each cylinder and compared.
Cylinder on left is #1 cylinder with the. problem, while the next is cylinder #2.
Noticed how brownish cylinder #1 looks like.

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 11:12pm On May 31, 2019
Comparing the old top cylinder gasket and the new one, for any differences in orientations, and water channel ports.
On the stock multilayered(iron) gasket, it had only two water channel openings one a particular side, while the new composite gasket(paper), had only one.
Provision was made already for more openings to be made on it.

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 11:14pm On May 31, 2019
After top cylinder was mounted, the pushrods, are being fixes in their various positions, after bring lubricated with fresh engine oil.

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 11:15pm On May 31, 2019
Be careful when fixing the rocker arm on the pushrods

1 Like

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 11:20pm On May 31, 2019
Camshafts mounted, after rocker arms installation. Apply engine oil before turning the camshafts

Re: Solving A Persistent Cylinder #1 Misfire by tensazangetsu20(m): 11:37pm On May 31, 2019
Do you think if you had ran a compression test immediately after servicing the injectors. You would have had normal compression values for this engine. I always run a compression test for misfiring issues once I noticed the problem isn't the coil or the plug.
Re: Solving A Persistent Cylinder #1 Misfire by CocoaOla: 5:42am On Jun 01, 2019
TRYGO:
Each of the combustion chambers of the various cylinders in your car's engine, goes through a series of precise combustion processes of air-fuel via the intake/exhaust valves.

With neither of the combustion chambers undergoing the processes precisely, a deficit is introduced, in terms of either a lean/rich air/fuel ratios in the valves strokes.

A distortion in the firing of the cylinder(s), quickly transcends to what we would normally called, an engine misfire.

There are misfires that can easily be tracked down, and solutions proffered in solving them, while there are others that are a pain, to track down.

Its just frustrating to have replaced all misfiring related parts, and still have the problem not solved.

Today, we'd be treating a peculiar sort of misfire, that has caused a new client thousands in costs of parts replacement and labour.

If you're ready, here we go!

CASE STUDY

CAR TYPE: Toyota Corolla 2010
ENGINE TYPE: 2ZR-FE
TRANSMISSION TYPE: Automatic drive

COMPLAINTS

According to client:
1. Car has being parked for about six months
2. Returned from a journey, and tried starting the car.
3. Engine started finally, but suddenly started experiencing some sort of engine misfires.
4. My mechanic has done all what he could do to fix the problem, but without success.
5. I retrieved a P0301 misfire code with my Bluetooth code reader.
6. I'm scared of driving the car down to your shop Joe!
Could you come pick it up?

VERIFICATION OF CUSTOMER'S COMPLAINTS ONSITE

1. Started vehicle, and confirmed there was a terrible misfire occurring in the engine.
Engine was basically "dancing".
2. Observed excessive black smoke, and foul odour of petrol from the exhaust tailpipe.
3. Personally scanned the car with a professional scan tool, and confirmed same code present.

DIAGNOSIS and FIX
1. Drove the car to the shop, with the hazard light on

2. Because of the violent nature of the misfires, there was a lot of sort of engine knocked kind of noise from the engine.

3. The car was driven, at 30mph, to reduced the load on the engine.

4. Interchanged the ignition coils of #1 and #4, to see if the coils were the culprit.
That didn't solved the problem.

5. Next was to have those spark plugs also replaced, with some sets of test spark plugs I had in the shop, instead of buying new ones.

This also didn't take care of the problem.
This tells me its not an ignition system related problem.

6. I opted to have the fuel injectors serviced, and also interchanged.
I noticed something astonishing during servicing the injectors with carb cleaner.

They were totally clogged with carbon deposits.
The injector on #1 cylinder, had a greater %of carbon buildup on the injector pintle.

That was obstructing the free flow of fuel, and subsequently reducing the fuel pressure on the cylinders.

7. Cleaned up the fuel injectors, and fixed them back; started the engine, there was not improvement.

8. Got a test lamp and a digital multimeter to test the fuel injector's power and ground circuits for either of an open or a short circuits problems.

All the injector power feeds were intact, including the grounds.

With this test, I was able to isolate any ECU related causes.

9. Now, what was in my mind was that this particular problem, is a mechanically induced one, that is narrowed down only to cylinder #1.

Since I have had experiences like these before,
I had already began narrowing down the likely causes to the following:

a) bad top cylinder gasket, due to overheating, can cause the valves to stick in their bores.
b) broken, or worn faulty valves, stems, guides, etc.
broken piston compression rings on cylinder #1.

10. What we saw, opening up the valve cover, with the intention of dismantling the top cylinder head, was surprising.

11. The inlet rocker arms on cylinder #1, were all dislodged from their positions on the pushrods.
This was the actual reason, that cylinder was misfiring, and loosing power.

12. Timed the engine, and had the top cylinder removed and taken to a machinist, for machining.

13. Replaced top cylinder gasket with a composite one, instead of the multilayered one that was originally on the car.

14. Dressed the deck of the engine block, cylinder head, and installed the head, after modifying the gasket.

ANALYSIS OF CAUSES OF THE MISFIRE
1. Closely looking at the valve train components in the cylinder head, and how clean they were, suggested to us that the client must have being properly maintaining his car, and that engine oil degradation was not to blamed for the problem.

2. The absence of an open or short circuit problems on the injector power/ground harnesses, proved that the ECU, and it's wiring, were functional, and there was no need to other a "Brainbox"!

3. Inspecting the inlet port on the cylinder #1 alone as compared to others, showed a huge volume of raw petrol dumped in there.
Obviously, this points to either a valve is not opening at all, or ...

I did conclude that why the rocker arms fell off from their positions in the engine, was basically a buildup of carbon deposits in the bore of the valves on the inlet sides of #1cylinder.

HOW TO PREVENT PROBLEMS LIKE THIS
If you intend to prevent instances such as this, ensured;
1. Engine oils are replaced as at when due.
Not replacing when its due, introduces impurities in the valve train, and cause problems.
2. Use fuel additives, devoid of sulphur contents at least once a month.
This would take care of fuel related carbon deposits on the fuel injector pintle.
3. If this isn't feasible, use carb cleaner to manually clean the injectors.
4. Don't rev your engine when its idling.
This would put more stress on the engine, and cause internal engine problems, such as rocker arm failures, if your engine is equipped with one.
5. Always replace old fuel from a car that has stayed longer than three months.
An j complete combustion process, as a result of bad gasoline, would exert stresses on the rocker arms, and cause lags in the combustion strokes.


PS:
Engines with rocker arm designs, or overhead camshafts (OHC), are known to exhibit problems of rocker arms falling off of their positions on the pushrods, or even falling off and exploding, causing severe engine problems, and suddenly stalling in motions.

This, I have seen on some 2004 Ford Explorers, where the rocker arms are dislodged, and caused an engine to seize entirely.

Well, that ended up having the entire engine replaced.






Regards,
Joseph
DW Nig Ltd
Isolo,
Lagos
www.dxta.com.ng
08066643532

This is the kinds of people we need in cartalks

God bless Honourable Joseph for Nigeria
Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 6:53am On Jun 01, 2019
@Tenza. This question is tricky.
The compression tests would only tell me the state of the piston ring tolerances, and not what's happening with the dislodged rocker arms(in fact, not the solution).

If one is not careful with the use of a compression tester for a case like this, the results from that tests, would make the customer assumed his engine is "dead", and a new one is required, or some of the conclusions would be that the rings are weak.

I would still not trust a compression tester tests on an OHC engine with a rocker arm/pushrod mechanism.

I'd prefer to peep through the valve cover, no matter what the tester result says.

Pls do correct if I'm wrong here.

2 Likes

Re: Solving A Persistent Cylinder #1 Misfire by TRYGO(m): 7:09am On Jun 01, 2019
Aligning the camshafts with each other before putting the timing chain on the camshafts' gears.
Without proper alignments of the gears, serious engine damages can occur.

Re: Solving A Persistent Cylinder #1 Misfire by tensazangetsu20(m): 1:55pm On Jun 01, 2019
TRYGO:
@Tenza. This question is tricky.
The compression tests would only tell me the state of the piston ring tolerances, and not what's happening with the dislodged rocker arms(in fact, not the solution).

If one is not careful with the use of a compression tester for a case like this, the results from that tests, would make the customer assumed his engine is "dead", and a new one is required, or some of the conclusions would be that the rings are weak.

I would still not trust a compression tester tests on an OHC engine with a rocker arm/pushrod mechanism.

I'd prefer to peep through the valve cover, no matter what the tester result says.

Pls do correct if I'm wrong here.

True though. I just use a compression test to ascertain if all is alright with the engine mechanically before I open up the valve covers to inspect the components. I have seen a misfire on a mercedes w205 caused by a broken piston. The whole engine had to be disassembled to see it but a compression test showed that that particular cylinder wasn't producing enough compression.

1 Like

Re: Solving A Persistent Cylinder #1 Misfire by AutoMoTech(m): 2:32pm On Jun 02, 2019
TRYGO:
Each of the combustion chambers of the various cylinders in your car's engine, goes through a series of precise combustion processes of air-fuel via the intake/exhaust valves.

With neither of the combustion chambers undergoing the processes precisely, a deficit is introduced, in terms of either a lean/rich air/fuel ratios in the valves strokes.

A distortion in the firing of the cylinder(s), quickly transcends to what we would normally called, an engine misfire.

There are misfires that can easily be tracked down, and solutions proffered in solving them, while there are others that are a pain, to track down.

Its just frustrating to have replaced all misfiring related parts, and still have the problem not solved.

Today, we'd be treating a peculiar sort of misfire, that has caused a new client thousands in costs of parts replacement and labour.

If you're ready, here we go!

CASE STUDY

CAR TYPE: Toyota Corolla 2010
ENGINE TYPE: 2ZR-FE
TRANSMISSION TYPE: Automatic drive

COMPLAINTS

According to client:
1. Car has being parked for about six months
2. Returned from a journey, and tried starting the car.
3. Engine started finally, but suddenly started experiencing some sort of engine misfires.
4. My mechanic has done all what he could do to fix the problem, but without success.
5. I retrieved a P0301 misfire code with my Bluetooth code reader.
6. I'm scared of driving the car down to your shop Joe!
Could you come pick it up?

VERIFICATION OF CUSTOMER'S COMPLAINTS ONSITE

1. Started vehicle, and confirmed there was a terrible misfire occurring in the engine.
Engine was basically "dancing".
2. Observed excessive black smoke, and foul odour of petrol from the exhaust tailpipe.
3. Personally scanned the car with a professional scan tool, and confirmed same code present.

DIAGNOSIS and FIX
1. Drove the car to the shop, with the hazard light on

2. Because of the violent nature of the misfires, there was a lot of sort of engine knocked kind of noise from the engine.

3. The car was driven, at 30mph, to reduced the load on the engine.

4. Interchanged the ignition coils of #1 and #4, to see if the coils were the culprit.
That didn't solved the problem.

5. Next was to have those spark plugs also replaced, with some sets of test spark plugs I had in the shop, instead of buying new ones.

This also didn't take care of the problem.
This tells me its not an ignition system related problem.

6. I opted to have the fuel injectors serviced, and also interchanged.
I noticed something astonishing during servicing the injectors with carb cleaner.

They were totally clogged with carbon deposits.
The injector on #1 cylinder, had a greater %of carbon buildup on the injector pintle.

That was obstructing the free flow of fuel, and subsequently reducing the fuel pressure on the cylinders.

7. Cleaned up the fuel injectors, and fixed them back; started the engine, there was not improvement.

8. Got a test lamp and a digital multimeter to test the fuel injector's power and ground circuits for either of an open or a short circuits problems.

All the injector power feeds were intact, including the grounds.

With this test, I was able to isolate any ECU related causes.

9. Now, what was in my mind was that this particular problem, is a mechanically induced one, that is narrowed down only to cylinder #1.

Since I have had experiences like these before,
I had already began narrowing down the likely causes to the following:

a) bad top cylinder gasket, due to overheating, can cause the valves to stick in their bores.
b) broken, or worn faulty valves, stems, guides, etc.
broken piston compression rings on cylinder #1.

10. What we saw, opening up the valve cover, with the intention of dismantling the top cylinder head, was surprising.

11. The inlet rocker arms on cylinder #1, were all dislodged from their positions on the pushrods.
This was the actual reason, that cylinder was misfiring, and loosing power.

12. Timed the engine, and had the top cylinder removed and taken to a machinist, for machining.

13. Replaced top cylinder gasket with a composite one, instead of the multilayered one that was originally on the car.

14. Dressed the deck of the engine block, cylinder head, and installed the head, after modifying the gasket.

ANALYSIS OF CAUSES OF THE MISFIRE
1. Closely looking at the valve train components in the cylinder head, and how clean they were, suggested to us that the client must have being properly maintaining his car, and that engine oil degradation was not to blamed for the problem.

2. The absence of an open or short circuit problems on the injector power/ground harnesses, proved that the ECU, and it's wiring, were functional, and there was no need to other a "Brainbox"!

3. Inspecting the inlet port on the cylinder #1 alone as compared to others, showed a huge volume of raw petrol dumped in there.
Obviously, this points to either a valve is not opening at all, or ...

I did conclude that why the rocker arms fell off from their positions in the engine, was basically a buildup of carbon deposits in the bore of the valves on the inlet sides of #1cylinder.

HOW TO PREVENT PROBLEMS LIKE THIS
If you intend to prevent instances such as this, ensured;
1. Engine oils are replaced as at when due.
Not replacing when its due, introduces impurities in the valve train, and cause problems.
2. Use fuel additives, devoid of sulphur contents at least once a month.
This would take care of fuel related carbon deposits on the fuel injector pintle.
3. If this isn't feasible, use carb cleaner to manually clean the injectors.
4. Don't rev your engine when its idling.
This would put more stress on the engine, and cause internal engine problems, such as rocker arm failures, if your engine is equipped with one.
5. Always replace old fuel from a car that has stayed longer than three months.
An j complete combustion process, as a result of bad gasoline, would exert stresses on the rocker arms, and cause lags in the combustion strokes.


PS:
Engines with rocker arm designs, or overhead camshafts (OHC), are known to exhibit problems of rocker arms falling off of their positions on the pushrods, or even falling off and exploding, causing severe engine problems, and suddenly stalling in motions.

This, I have seen on some 2004 Ford Explorers, where the rocker arms are dislodged, and caused an engine to seize entirely.

Well, that ended up having the entire engine replaced.






Regards,
Joseph
DW Nig Ltd
Isolo,
Lagos
www.dxta.com.ng
08066643532

great thought process here bro. and great job once again...
however like earlier stated. a compression test wld have told U alot. why? compression on cylinder one would most likely be lower that the rest.
dt done U kno U av a compression issue. however where wahala dey be say U will not be able to narrow down if the cylinder is leaking into the combustion chamber (via worn piston rings) or into the intake (if intake valves dont close properly) or into exhaust (exhaust valves not closing completely)
this is where a leak down tester comes into play.

men this business we need to invest in tools to make the work easier. but car owners no dey like pay at all...

would be really glad if we could share such quality knowledge here more often rather than this one dem "ogas" go about slandering eachother...

2 Likes

Re: Solving A Persistent Cylinder #1 Misfire by AutoMoTech(m): 2:35pm On Jun 02, 2019
tensazangetsu20:
Do you think if you had ran a compression test immediately after servicing the injectors. You would have had normal compression values for this engine. I always run a compression test for misfiring issues once I noticed the problem isn't the coil or the plug.
i agree with you on this. after cancelling out fuel and spark... only next thing is mechaical.... before opening the engine i think its wise to carry out a compression test. this should also help in gathering more data and evidence towards resolving the issue accurately. ... but we lwarn everyday sha.
Re: Solving A Persistent Cylinder #1 Misfire by thebigkendo(m): 9:16pm On Jun 02, 2019
AutoMoTech:


great thought process here bro. and great job once again...
however like earlier stated. a compression test wld have told U alot. why? compression on cylinder one would most likely be lower that the rest.
dt done U kno U av a compression issue. however where wahala dey be say U will not be able to narrow down if the cylinder is leaking into the combustion chamber (via worn piston rings) or into the intake (if intake valves dont close properly) or into exhaust (exhaust valves not closing completely)
this is where a leak down tester comes into play.

men this business we need to invest in tools to make the work easier. but car owners no dey like pay at all...

would be really glad if we could share such quality knowledge here more often rather than this one dem "ogas" go about slandering eachother...

3 Likes

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