Got misfire on ALL driver side bank cylinders (1-3-5-7) (2 Viewers)

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Aug 27, 2018
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Hello friends,

Need your expertise to troubleshoot the sudden misfiles with all driver side cylinders (1-3-5-7). My car is 2004 LX470 with about 220K miles.

What happened:​

Couple weeks ago, while trying to pass on HWY-89 with floor gas, the LX suddenly vibrated and slowed down regardless how hard pushing the gas pedal. At the same time, CEL turned on (blinking maybe). Pulled over to scan the code, got P0300, P0301, P0303, P0305, & P0307 which basically saying all 4 cylinders at driver side got misfire. Before this happened, the LX have been travelling all the way from Phoenix past Flagstaff as normal. As you may know, I-17 has several big long uphill sections and the LX did it as it should be.

Car was still runnable but just couldn't go fast. Drove slowly (~25 mph) to safe place and rest to calm down. After about 1 hour of break, the LX seems back working again, and I could maintain 65 mph to reach my destination at Tuba City. The 2nd day, did some light offroad for about 100 miles without issue. However, when driving to next destination in the afternoon, started feeling the car is getting more and more difficult to maintain the speed like 45 mph, especially uphill. Eventually, right after I found a safe place to pull over on HWY-160 between Tuba City and Kayenta, the engine stopped on itself and couldn't be started immediately after that.

After hours of waiting for AAA to show up, the engine was able to get started, and AAA tow truck didn't want to get me back to Phoenix, and dropped the LX off at Tuba City. Tried to drive the LX for about 10 miles and found it still had no power to maintain the speed. Eventually, my buddy towed me to Flagstaff while the LX kept the engine idling to maintain the steering/braking/light. I knew it's not ideal but at midnight HWY-89 didn't have much traffic. Eventually got another AAA tow truck in Flagstaff to get back Phoenix.

Background History:​

After purchased this LX, realized it must had overheating as the heater Tees and radiator was replaced. Also white smokes from the exhaust. Eventually, coolant got into cylinders while parked overnight.

11/2021: Tried to get the shop to replace the head gaskets. However, shop said both heads were warped too badly to re-surface. Eventually, replaced both cylinder heads with rebuilt heads from eBay, including new head gaskets of course.

Since that, had driven for about 2000 miles without issue, and noticed slightly increase on MPG.

The following repair also has been done:
02/2022: Replaced the upstream O2 sensor with Denson one at driver side for code P0134, which was got before the heads replacement
05/2022: Repaired the small coolant leaking on Throttle Body by tapping it in and JB Weld it; Also repaired the cracked hose for "VSV for EVAP". See here for detail.

Troubleshooting so far:​

Tried to rule out the O2 sensor by changing it back to the old one, still misfires.
Just did the leak down test, it seemed all cylinders are in good range at about 15% except for the cylinder 7 is at 25%. However, the cheap kit from Amazon could only do it at 30 PSI.
Checked the timing marks on both cam wheels and crank wheel, and all aligned.
Found 1: The shop installed all the driver side (1-3-5-7) spark plugs super tight! Had to push hardly to loose them.
Found 2: The shop installed all the passenger side (2-4-6-8) spark plugs super loose! Removed them just with my weak fingers without leverage of any wrench.

Didn't do the compression test as I didn't know how to prevent the fuel from injection. Maybe disconnect the crank position sensor?
Before putting spark plugs back with the correct torque to test, anything else I should check?

All suggestion is welcome and appreciated!
 
Very often, misfires on the entire bank = timing is off or head gasket failure. Sounds like you’ve ruled out timing issue, so next step IMO is compression test, a better leak down test, and to test coolant for exhaust gases.

BUT, theoretically a bad ignition coil on one cylinder could send the others on the bank out of whack too. Not necessarily common but certainly plausible.

Didn't do the compression test as I didn't know how to prevent the fuel from injection.
Removing EFI fuse should work, I think?
 
Thanks for the reply!

Question 1: The way I checked the timing is to make sure the timing marks on both camshaft pulleys and the crank pulley aligned with the marker on the engine body. Is this sufficient to rule out timing issue?

Question 2: Since the rebuilt heads came with everything including valves and camshafts installed. Would it be possible that the valve clearance may also cause misfiles?

Will try to disconnect the EFI fuse (#21) and try the compression test. and then put everything back to see if any change by mixing/swapping the coils

Again, the LX has run over 2K miles without issue after replacing both heads, and it's all the sudden that cylinder 1-3-5-7 got missfires.

Another thing to mention that before replacing the heads, the coolant leakage was much worse that I had to suck the coolant out from cylinders before the engine could be started. Once started, it ran ok powerful without missfiring code.
However, this time, all cylinders and spark plugs are dry. There is also no white smoke or bubble in radiator. The engine ran very rough and thrown misfire codes.
 
just for giggles, when the rig is running spray carb cleaner or starting fluid around the intake manifold where it connects to the head. just little, short squirts
I went thru something recently and a previous mechanic used off brand intake gaskets and installed them wrong when doing a starter replacement, intake manifold gaskets failed.
 
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Sounds to me like bad ignition coil or coils. As @JunkCrzr89 pointed out, one bad coil can trip several codes. If you clear the codes and run it until you get the first indication of rough running you may be able to see only the bad cylinder before it trips all the rest. That’s what mine did last week.
 
You can use Techstream and monitor the cylinder which is causing higher Misfire, fix that and go from there.

There is a YouTube video on how to do techstream using in the Misfire
 
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Here's the video that shows the techstream misfire...

 
Removing EFI fuse should work, I think?
If I recall correctly I pulled the EFI fuse and the fuel pump fuse relay when I did mine.
Finally, completed the compression test with an Amazon kit. I can confirm that on LX470, removing either EFI fuse or EFI relay wouldn't work as it will disable the starter. Eventually I only pulled Fuel Pump Relay to complete the test.


Very often, misfires on the entire bank = timing is off or head gasket failure. Sounds like you’ve ruled out timing issue, so next step IMO is compression test, a better leak down test, and to test coolant for exhaust gases.

I got around 130 PSI on all cylinders except for cylinder 6 which got 118 PSI. The number seems low. However there is no difference between driver side bank cylinders and passenger size bank cylinders. So I believe the head gasket failure is unlikely the cause, as the compression at the msfiring cylinders are slightly better than the other cylinders. Plus, last time when the head gasket did failed and the coolant leaked into cylinders badly, the engine did run very well without any misfire at all.

Will order the exhaust gas test kit to make sure coolant is good. However, watched the coolant in the radiator when engine is running, and didn't see any bubble.

BUT, theoretically a bad ignition coil on one cylinder could send the others on the bank out of whack too. Not necessarily common but certainly plausible
Sounds to me like bad ignition coil or coils. As @JunkCrzr89 pointed out, one bad coil can trip several codes
So I have put everything back and mixed the order of plugs and coils. Fired up and the initial test was better and the engine runs more smoothly. However still getting misfire code on cylinder #1 and #5. Will road test when it's cooler and see what may happen.

damage to the wiring harness that runs to that side's ignition coils?
This may be possible and will double check the wire.
You can use Techstream and monitor the cylinder which is causing higher Misfire, fix that and go from there.
Here's the video that shows the techstream misfire
Excellent finding! I tried techstream but didn't realized someone had put a guide video on it. Thanks for the link of the video...

Next Step:​

  1. Road test to see how bad the engine could be after re-installed the spark plugs in the correct 13 ft-lbf torque.
  2. Follow the video to use the techstream to monitor the misfire.
  3. Order exhaust gas test kit for coolant test
  4. Order a new coil to rule out or confirm all coils are good
Any other suggestions?

Thanks everyone again for helping the troubleshooting. I'm pretty confident the issue will be resolved.
 
Sounds like you’re narrowing down the possible causes pretty quickly 👍🏽
 
did you try the spray test?
 
Btw if you go to Autozone for the exhaust gas test kit. Autozone will give you the fluid for free as well.

There are not a lot of things that are absolutely free but getting the exhaust fluid for free is a good perk for the inflated part prices the part store take.
 
The compression test showed 130 PSI on all and 118 on one?

Isn't that extremely low? When I did a compression test on mine all cylinders were at 190+

Actually, from the factory service manual -
This measurement must be done as quickly as possible.
Compression pressure:
1,324 kPa (13.5 kgf/cm2, 192 psi) or more
Minimum pressure:
981 kPa (10.0 kgf/cm2, 142 psi)
Difference between each cylinder:
98 kPa (1.0 kgf/cm2, 14 psi) or less
 
Btw if you go to Autozone for the exhaust gas test kit. Autozone will give you the fluid for free as well.

There are not a lot of things that are absolutely free but getting the exhaust fluid for free is a good perk for the inflated part prices the part store take.
Good to know. Will try...
 
Isn't that extremely low? When I did a compression test on mine all cylinders were at 190+
Yes, it's low. I don't know how accurate the test kit is which is cheap one from Amazon. However, at least it shows no difference between good cylinders and bad cylinders. So I think it's unlikely that the low compression is the cause.
 
I agree, the compression is way too low. Did you try a wet compression test to see if numbers go up vs dry compression test? If numbers go up with wet test could indicate piston ring or cylinder damage. Also a proper leak down test with at least 90-100 psi shop air. Might require two people, one to just hold the crank from turning off top dead center. Listen for air at tailpipe, intake, crank case, and bubbles in the coolant. Did you have the block deck checked when replacing the heads? If the heads are warped bad then the block most likely needs to be decked. One other thought is did the head bolts get replaced? It is hard to see bolt stretch if you don’t know what to look for or if you don’t have a new bolt to compare the old one to.
 
I agree, the compression is way too low. Did you try a wet compression test to see if numbers go up vs dry compression test? If numbers go up with wet test could indicate piston ring or cylinder damage. Also a proper leak down test with at least 90-100 psi shop air. Might require two people, one to just hold the crank from turning off top dead center. Listen for air at tailpipe, intake, crank case, and bubbles in the coolant. Did you have the block deck checked when replacing the heads? If the heads are warped bad then the block most likely needs to be decked. One other thought is did the head bolts get replaced? It is hard to see bolt stretch if you don’t know what to look for or if you don’t have a new bolt to compare the old one to.
Since the engine has a good bank (passenger side) and a bad bank (driver side), my principle of troubleshooting at this moment is more at comparing between the banks to see if any difference which made one bank bad. Based on that, I saw no difference on compression and leak down under the same test method and equipment at home. However, I do agree the DIY test method/equipment can't match what the shop has. So the next step is to have the shop to do it if I couldn't figure out.

As far as the head replacement, the dealer claimed my heads were too warped to re-surfacing. So the rebuilt heads were purchased from a rebuild shop (Odessa Cylinder Head) in FL from eBay. While assuming the rebuild shop and the dealer are "professional" and should follow the procedures, my confidence is not really high at all.

It was an expensive decision for head gaskets and then the heads replacement instead of engine swapping. I will try my best to isolate/fix the issue by myself first...
 
just for giggles, when the rig is running spray carb cleaner or starting fluid around the intake manifold where it connects to the head. just little, short squirts
I went thru something recently and a previous mechanic used off brand intake gaskets and installed them wrong when doing a starter replacement, intake manifold gaskets failed.
Not quite sure if I understand this test. What should I look at once sprayed?
 

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