Cylinder misfires after head gasket replacement

[Jdcarlson]

Hi,
I've been going through the process of fixing my 2012 fiesta se after it overheated earlier this summer. I replaced the head gasket because it was shot, and in the process also replaced the timing belt and a couple of tubes in the coolant system. After getting everything put back together I plugged in an obd2 scanner and turned the engine over to see what codes it came back with. The scanner returned the codes p0017, p0300, and p0304.
I tried swapping spark plugs around and coil wires and the codes stayed the same. I've also run a compression test on each cylinder and it came back like this: (all units are lbs/in^2)
1- 110/124/123/124/124
2- 125/126/126/127/128
3- 116/120/122/120/116
4- 130/129/130/130/131

I am also going to run a cylinder leak down test tonight after work. I am wondering what else I can do to trouble shoot what my problem may be?

 

[LionsTooth]

Did you plane the head? p007 is bad crank or cam position senor....crank and cam are probably not aligned. p0300 p0304 is a random misfire...plug wire not seated, plug wire bad or water leak or little/no compression? That's why I asked if you planed the head...a cylinder could leak water, if the head got warped in the overheating, causing a misfire.

 

[Jdcarlson]

After the head was off I took it to a machine shop to be inspected for cracks or warping and we did end up having it planed, there were no cracks. I haven't been able to tell if any coolant is being burnt, it hasn't been run long enough to be sure.

 

[LionsTooth]

After the head was off I took it to a machine shop to be inspected for cracks or warping and we did end up having it planed, there were no cracks. I haven't been able to tell if any coolant is being burnt, it hasn't been run long enough to be sure.

You didn't say how it runs. Does it run smooth, but pitches codes? More details needed.

 

[Jdcarlson]

Yeah the engine ran smooth from what I could tell, there was some white smoke the first few times running it yesterday from the exhaust but that could have been from leftover coolant in the block from when the head gasket originally failed. Ran the engine for about 20 minutes today and there was no smoke at all

 

[LionsTooth]

Yeah the engine ran smooth from what I could tell, there was some white smoke the first few times running it yesterday from the exhaust but that could have been from leftover coolant in the block from when the head gasket originally failed. Ran the engine for about 20 minutes today and there was no smoke at all

Yeah the smoke/steam is always disconcerting! Since it's running fine, try disconnecting the battery for like 30 minutes. See if that clears the codes. Does your ODBII reader clear codes? If so clear them and see if they come back. Could just be from the first start-up, and they may be fine.

 

[Handy Andy]

Could be that the cam timing to crank is a little off, one tooth or two can easily set the codes you see.

The Cylinder compression test seems to be ok not the best but within 10lbs of each cylinder as the oil pressure builds.

Just 3 seems to be weak to the others by comparison - lowest of any others and it's in the center of the pack too, again possibly because of the CAM to Crank timing teeth off a little can also affect this pressure thru valve advance too.

 

[scotman]

Did he perform a misfire monitor recalibration? If it is running smoothly and throwing the misfire MILS, that's why.

 

[Handy Andy]

misfire monitor recalibration

How can someone initiate that?

 

[scotman]

Sorry for the slow reply
I fell asleep. Monday bad. He needs to get an enhanced scan tool with system calibration and testing capability.
I think this was required for the purposes of confirming that the cam gears are properly aligned. Being an interference design, that is a critical factor.
Just like the smile on a beautiful woman. Missing one tooth can have a profound effect.

 

[Handy Andy]

Just like a the smile on a beautiful woman. Missing one tooth can have a profound effect.

Ah, yes...There's Mona Lisa - then there is - whatever that Girl had whatever in between her teeth...

​

 

[Jdcarlson]

Hey just an update, I went ahead and took the covers off and adjusted the timing belt and camshafts. I made sure when I was tightening the cam pulleys down that both the camshafts and pulleys were in time with each other (at what would be TDC) and that the crankshaft was at TDC. I did notice that the timing belt had a little play in it (less than what would take a tooth to jump) when the tensioner was applied but didn't think much of it. When the engine was all back together I turned it over and checked the codes and it still had the p0017, p0300, and p0304 errors but this time it also had a p0016 error as well. Not really sure what's going on here as the engine still ran smooth and sounded like it did before it overheated, some insight would help
Edit: I should add that all of the spark plugs, coil wires, and coil pack have been tested and they seem to work well, but that seems to indicate that it's not anything to do with those

 

[scotman]

Did you use the special service tools available to hold the cams in the proper position when you put the head back on? I gotta ask because you dont "adjust" the timing belt and gears. You assemble them in their correct positions!
The obd code P0016 is a camshft position sensor correlation code. Is the scan tool you are using an enhanced version that can perform the calibration and system tests?

 

[Handy Andy]

Wow.

Ok, sounds like when you went back in, you found a new problem.

The "wiggle" - Which cam is causing this wiggle (freeplay) Intake or Exhaust - the belt and tensioner having play in it - worries me, that may be your drift causing the error in the timing.

To make sure - redo your compression test and see if CYL 3 has risen back up closer to the numbers of the other cylinders?

If no change, you may have to investigate which cam, and its valve assembly (advance chamber) - something with freeplay or wiggle - that at 3,000 RPM can do some serious damage.

Firing order is 1 - 3 - 4 - 2

 

[Handy Andy]

Here is my main fear...

You checked, planes and reassembled the cylinder head.

One problems with that.

If you had warpage, you needed to remember where that warpage was the most deformed.

If it was around Cylinder 3 - remember too, the motor was run in this lopping, lobbing condition and then cooled off, under stress - this may "temper" the warp in the cam and the shaft it belonged to.

Got a runout gauge? Put that on the cam to make sure it "plumb" not lobbing...

Here's why it also worries me...

Each tooth of the cam, and each groove of the belt - needs to seat together to have the best long life. You know that...

IF the cam lobe - now lobs (off center due to the warp) the cams' aspects to each other or distance from tooth to tooth as well as groove to groove - if the belt is loose in one degree angle of turn - what happens on the opposite side - it is a longer offset - overstressing the belt in the 180 degree position from that degree 0 (Start of rotation) this is the tolerance problem - there is enough warp to make one cam and all it's belt - slightly loose to the other.

One 180 degree turn and then that cam is placing a larger stretch stress on the belt. The belt to tensioner should have no slack now, but the belt - to - cam - to - cam is now slightly different distance - then rotate back to that original loose position another 180 - you now back to 0 - and the tension is relieved - one cam will wobble and will stretch the belt in such a way to shorten it's life.

Remember in turn the cam is also lobbing on the bearings in the head.(Cylinder 3 comes to mind)

I've owned vehicles with warped heads due to overheating - the warp of the head is one thing, many don't check the cams to see if they warped too - you might get a couple of thousand miles out of the motor after it - but the wearing of the bearings on those cams - the engine will fail soon enough.

 

[Jdcarlson]

Yeah I bought a set of tools meant for timing the engine components, and made sure they were in place before setting the tensioner on the timing belt. The scanning tool I am using is only able to read and delete the obd codes, I think it can run some tests on the emissions system but it dosent have any calibration features. I tried retiming the engine again today and made sure to check everything multiple times, and still had the same codes. The idea with the cams being warped makes sense to me, assuming I did time everything correctly. I also did check and after rotating the crank once the wiggle in the timing belt was gone so I think that was just a symptom of the belt not being rotated at all.
I am going on a trip for a week and a half starting tomorrow so I may not update much but I have some family who said they are willing to run tests to better understand whats going on. Thanks for all the help so far

 

[Handy Andy]

Good luck with this project!

Keep us posted!

One of the hardest things to do, is bring everything back to where the system says, "nothing ever happened" - that would make the codes disappear.
.

 

[Handy Andy]

I just reminded myself of something...

This is the start of a mountain - hope it isn't going to wind up be a lost cause for this motor...
https://enginetech.com/cylinder-head-spacer-shims/

Blueprinting - this deals with the "Warp" of that head and if the warp was excessive - it may explain much of the conditions you're encountering.

Did you manage to get a number of the material they have to grind off to square the head?

It makes the clearance to the top of the head even closer on a stock motor with a re-machined head. The valve clearance gets even tighter. Changes the length of the belt the tensioner has to take up - along with other things...

The distance to the top of the piston, or the volume of the chamber, is less. And the overall "lengths" the piston uses may stay the same, but the volume for compression doesn't - if you didn't use a shim, this can also affect the timing belt - and it's discrepancy. Which those cams and pulley - affects the cam to crank aspects and how they may drift over the firing order sequence as the engine tends to see the different power levels delivered in the cylinder combustion "ratios" being different - could make the crank "shake" from the effects of the valve timing advance and retard - wonder if the valves can still strike even though it's planed.

I would like to know if there is a way to "convert" this "interference capable motor" to something more into a long lifetime motor by using a spacer in the block to cylinder head - a spacer - to increase the clearance so the motor doesn't self destruct and still provide good power - just not a TON of it - for longer life.