Tapping noise from lifter and misfire on cylinder five

Tiny
TRICIA JOE GRIZZARD
  • MEMBER
  • 2002 DODGE RAM
  • 4.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 189,000 MILES
My truck was making a tapping noise from the lifter then it stopped. Now I have a misfire on cylinder 5 what would cause that? Why would the tapping noise stop and misfire start?
Sunday, October 20th, 2019 AT 5:25 AM

1 Reply

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

The lifter may have been collapsed from dirt or debris in the oil not allowing it to pump up.

Then it did get the oil and it may be the opposite. It may be fully pumped up not allowing the valve to close.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Also, there was a valve issue with this motor as well.

I would start by doing a compression test to see if there is compression in the cylinder.

https://www.2carpros.com/articles/how-to-test-engine-compression

Roy

DIAGNOSIS AND TESTING - HYDRAULIC LASH ADJUSTER
A tappet-like noise may be produced from several items. Check the following items.
1. Engine oil level too high or too low. This may cause aerated oil to enter the adjusters and cause them to be spongy.
2. Insufficient running time after rebuilding cylinder head. Low speed running up to 1 hour may be required.
3. Turn engine off and let set for a few minutes before restarting. Repeat this several times after engine has reached normal operating temperature.
4. Low oil pressure.
5. The oil restrictor in cylinder head gasket or the oil passage to the cylinder head is plugged with debris.
6. Air ingested into oil due to broken or cracked oil pump pick up.
7. Worn valve guides.
8. Rocker arm ears contacting valve spring retainer.
9. Rocker arm loose, adjuster stuck or at maximum extension and still leaves lash in the system.
10. Oil leak or excessive cam bore wear in cylinder head.
11. Faulty lash adjuster.
a. Check lash adjusters for sponginess while installed in cylinder head and cam on camshaft at base circle. Depress part of rocker arm over adjuster. Normal adjusters should feel very firm. Spongy adjusters can be bottomed out easily.
b. Remove suspected lash adjusters, and replace.
c. Before installation, make sure adjusters are at least partially full of oil. This can be verified by little or no plunger travel when lash adjuster is depressed.
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Sunday, October 20th, 2019 AT 5:53 AM

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