Intermittent misfire after clutch replacement

[Plain Jane]

We had a new OEM clutch and flywheel recently installed and ever since we got the car back it's been throwing p0301 and p0304 codes off and on. Sometimes it's a solid light, sometimes flashes, sometimes the car behaves normally. The shop replaced spark plugs, wires and coil pack hoping to solve the issue but the light came right back. About to take it back for the third time and we're all at a loss. What could have happened, where should they look and how to go about fixing this? It must be related to the recent work but how?

Car has 85k kilometers

 

[econoboxrocks]

Something is probably loose. Check for vacuum leaks.

 

[Mercurios2011]

hello there , I am no expert mechanic but the only way could see cylinder one and four misfire after a clutch install , is if maybe by accident they moved the flywheel causing timing to break of TDC .
is a long shot , but sometimes working on tight spaces makes it very hard to move and may can cause to bump into things ,i really, really doubt thats the the case ,but you never know

 

[Handy Andy]

If you search our site, you may come across the CKP sensor thread - that topic was about several issues around Auto Manual and the CKP sensor position - so if it is not seated well, this can set a code because the CKP detect signal drifts off from where it thinks it should be.

When you look at the CKP sensor location - it's on the flywheels' housing. If the Flywheel is loose or out of round - there's a condition code being set here...

 

[Mercurios2011]

If you search our site, you may come across the CKP sensor thread - that topic was about several issues around Auto Manual and the CKP sensor position - so if it is not seated well, this can set a code because the CKP detect signal drifts off from where it thinks it should be.

When you look at the CKP sensor location - it's on the flywheels' housing. If the Flywheel is loose or out of round - there's a condition code being set here...

I swear dude , you are like a Ford manual sometimes , i would never know that or even think about it lol

 

[Handy Andy]

@Mercurios2011 - thank him, he gave you the biggest clue - after a clutch replacement - the OEM plate doesn't always need to be turned - but if it's bad, they have to replace it with an exact OEM one.

So not sure of the LUK clutch pack install had to make any changes to the flywheel you had used Originally - until this replacement.

Then too, if the whole transaxle and manual boxes had to be dropped to do this - the codes show it's highly likely it was not re-seated correctly.

This may also be giving you a sign that the clutch to wheel alignment might be a touch off. - There was supposed to be a insert tool that goes with this kit that aligns the pack to the plate - did they use the tool?

​

 

[Mercurios2011]

@Mercurios2011 - thank him, he gave you the biggest clue - after a clutch replacement - the OEM plate doesn't always need to be turned - but if it's bad, they have to replace it with an exact OEM one.

So not sure of the LUK clutch pack install had to make any changes to the flywheel you had used Originally - until this replacement.

Then too, if the whole transaxle and manual boxes had to be dropped to do this - the codes show it's highly likely it was not re-seated correctly.

This may also be giving you a sign that the clutch to wheel alignment might be a touch off. - There was supposed to be a insert tool that goes with this kit that aligns the pack to the plate - did they use the tool?

View attachment 9069​

Idk I never had mine replaced lol, I just learned something new when you mentioned there is a sensor in there, since the other guy replaced all the "usual" culprits.
But if it ever happens to me I know another area to look into

 

[Plain Jane]

@Mercurios2011 - thank him, he gave you the biggest clue - after a clutch replacement - the OEM plate doesn't always need to be turned - but if it's bad, they have to replace it with an exact OEM one.

So not sure of the LUK clutch pack install had to make any changes to the flywheel you had used Originally - until this replacement.

Then too, if the whole transaxle and manual boxes had to be dropped to do this - the codes show it's highly likely it was not re-seated correctly.

This may also be giving you a sign that the clutch to wheel alignment might be a touch off. - There was supposed to be a insert tool that goes with this kit that aligns the pack to the plate - did they use the tool?

View attachment 9069​

CKP sensor?

The clutch and flywheel are both legitimate Ford OEM parts. The mechanic explained how they line up onto dowel pins for alignment and if it was misaligned in any way, the codes would be always on and not intermittent. We took the car to another shop to get looked at. They confirm the cylinder 1 and 4 misfire, and noted the compression in all four cylinders is low (110 being highest recorded, 150-160 being what they consider normal) with cylinder 2 being the lowest. They ordered a new coil and are trying that on today, but I have my doubts it'll change much. Could the timing be off somehow? Low compression and misfire...

 

[Mercurios2011]

All I can think off ,make sure all grounds are clean and tight, do get the battery tested ,bad crank sensor ? Weak fuel pump, I will get some opinions at work tomorrow and see what the guys suggest 🤷🏻‍♂️

 

[Handy Andy]

The CKP sensor is on the bell housing of where the engine meets the clutch - and its "magnet" on the opposite side on the flywheel they would turn to smooth out and prep the surface. IF they didn't clean off all the shavings - they can get caught in the magnet and change the way the CKP sensor can see that field- Since it's a Hall effect device - the simple change in a shaving or two across the magnetized surface can affect how much signal the CKP can detect, let alone WHERE in aspect the CKP thinks the TDC of the flywheel is in relation to it - sooner than it was or later than it was or a "bump" which then makes it confused.

So if "lost timing" is an issue, they need to run more stringent diagnostic on it to find if there is a need to replace a sensor.

That may need them to spend a day or two with the vehicle to test drive it and see if this mis-fire can be detected in live data and then the data might show some more detail than a simple code scanner looking for DTC's can.

Not trying to make this a convoluted mess, but with simple factors of being a clutch swap and a re-trurn to prep the flywheel, the timing loss can be a simple need to reset the system to relearn the TDC so the Cam sensors and Crank sensors can line up right.

To have to tear down the motor to replace or re-fix the timing belt - might as well replace it and the water pump - this can solve a few things but still does not clear up the mis-fire because it can be something deeper - being the CKP sensor off to TDC and it just has to relearn.

Got pulled away for a moment...

To help you - the comment about the compression being low is valid and would also show this as a timing problem

But the biggest clue would be from the plugs themselves and how they look.

The car was doing great until this clutch issue, then all when whacko - this may mean the engine was "fine until it got out of line with time" and may have created a cascaded event where the clutch failed, and the engine lugging and changes to driving habits made the system try to adapt to something new and cannot or after all these years of undisturbed sleep and proper operation - you now have awakened a slumbering giant and it's eating away at the fun the vehicle once was.

To further the help:

The firing order is 1 - 3 - 4 - 2 - so that means ...

You have a reciprocating engine - 4 cylinders of 4-stroke action - so that means the engine has to turn 2 complete revolutions for complete the 4-stroke up down process. 360 x 2 = 720 degrees timing calculation for all those cylinders to complete the intake, compression, power and exhaust strokes.

Out of that 720 - you divide by the number of cylinders to determine the degree of next power stroke - or simply divide by 4...

I get 180 degrees. Top and Bottom of the flywheel location of the magnet.

The Firing order is the clue - 1 and 4 are at TDC where the CKP sensor is at the "magnet" on the flywheel.

You're having mis-fire on 1 and 4 - which tells me the TDC is off, so that may mean Cam and CKP are not "synced" - you had to have them turn the flywheel for clutch install - which is the only thing that has changed (we hope) in all the aspects of the motor.

So to me, this may mean just a "recalc" a forced relearn process and should be ok - but if the CKP got DAMAGED during the service - then the CKP sensor should be replaced as a default. Cheap Insurance and needed for diagnostics.

 

[Plain Jane]

Update: car's fixed. They had to do a relearn after disconnecting the crank sensor. Says it's running well now. Will pick it up next week. Thanks for the advice guys

 

[econoboxrocks]

Update: car's fixed. They had to do a relearn after disconnecting the crank sensor. Says it's running well now. Will pick it up next week. Thanks for the advice guys

Good to know. It's a relief when it's something simple like that.