mrohitredd

2002 LX Sedan -

Couple days ago, at temperatures below freezing... when i started the car... It sounded like a Machine Gun firing Smoke of the Exhaust ! A literal Machine Gun pattern smoke & sound from the engine. The CEL blinked for few minutes & then everything as normal. All good for 2 days & since morning the CEL is up. I got the codes checked & it says "P1456 - Evaporative Emission Control System Leak Detected". Looked around & realized it 'could' be a bad Gas Cap.


Does, changing a Gas Cap solve (if i'm lucky, from what i read) the issue ? The car runs smooth & feel nothing - no misfires or any vibrations like i felt 2 days ago.
How do i clear the codes after i replace the gas cap ?


Does this work ? its lot cheaper ($9) than what the OEM costs ($38)
http://shop.advanceautoparts.com/p/s...390#fragment-3

Mileage - 158000
Valve Gasket & Spark Plugs - ~5000 miles old.

ezone

The same reader you read the codes with will also erase the codes too.
Or disconnect the battery for several minutes to clear memory.

The blinking CEL was indicating misfire, and it set at least one code at that time. The code may not have been present by the time you had the codes read though (pending vs permanent code vs. cycles to purge code memory).
Probably aren't gonna find much of anything unless it gets more consistent and you can catch it in the act.

The EVAP code could be several things, a poorly sealing fuel cap is just one and it is pretty common.
(Or someone didn't get it tight enough at the last gas up.)

Replacing the cap would only solve the problem IF that actually is the problem.

Two easy gas cap checks:
Check the rubber gasket on the cap for cracking or hardening first (If the gasket is bad, then yes replace the cap).
Then check that the ratchet mechanism is still working right---make sure it gets the cap tight before it clicks

And..um... make sure the tether/strap/leash isn't caught under it...
Make sure the fill neck isn't bent from someone slamming the pump nozzle into the edge of it.




Clear the codes, drive it and see if it resets the same code again within a few days.
If it resets again THEN try a new one.

I can't comment on aftermarket caps, they seem to be hit or miss. Some work ok, some don't.

mrohitredd

Thanks for the reply...

I checked the gas cap & found couple breaks (confused if they were from the manufacturer itself or something new that came up with age). I tightened the cap, removed the Negative Terminal on the Battery & put it back... CEL is gone. Been 24 hours already... will check for couple more days & see if something changes...

With the Miss Fire - I'm not sure if a low temperature can cause that... Coz, all my spark plugs, gaskets are new... Have had this issue some 4 months ago & did all the replacements. The car was running like a charm all these months & the cold weather is really showing some effects on the car !

Anyways, i'll observer for few more days & update whats happening...

ezone

It's not supposed to. Keep an eye on it.

mrohitredd

so i went to pepboys, to get the compression test done... 100psi & looks ok...
they said that the Cylinder 1 Ignition coil is defective & needs to be replaced.

i did it 2 days ago.. now after about 40-50 hours... the misfire is back again

i dont see the CEL yet, but can feel the misfire... what can be done here ?
they swapped the ignition coils from one cylinder to another to check the defective one...

but now, what else could be it ?

ezone

If I did the test using my equipment and method, that would be a bad reading.


What were the compression test readings of all 4 cylinders?

Redneck_cdn

100psi seems a little low,

- more important are all cylinders the same as the test/tester may be off.

- If there was a CEL code present for the misfire, it would identify the cylinder that is seeing the fault. What CEL codes where retrieved ie: "P0301"

- waiting for the parts cannon to fire here any time )

mrohitredd

- If there was a CEL code present for the misfire, it would identify the cylinder that is seeing the fault. What CEL codes where retrieved ie: "P0301"

- waiting for the parts cannon to fire here any time >>>

Think it was P0301... Dont remember exactly though...

>>> 100psi seems a little low

how can i make this right ?

ezone

There are several possible reasons for low test result numbers. Including faulty test equipment, test methods, and actual engine problems.

If the compression tester works correctly when testing a different engine (or comparing to a known good tester) that would answer one of the questions.


Start with your test results from all 4 cylinders. If they are all fairly even, at least the valves might be considered OK in their ability to seal.

When I do a compression test on one of these engines using my own tester and my method, I expect to see 180 PSI or higher.