2007 Kia Grand Carnival 3.8 VQ Auto Misfire P0300 and P0302

1362 Views 54 Replies 6 Participants Last post by bopbo, 8 d ago

axtigin36

Discussion Starter · 2 mo ago

Hi all,
Hoping someone can help.
I'm having issues with my car, its only been with me for a month. Its got less than 200,000kms on it.
Recently while driving, the car started misfiring and trouble codes P0300 and P0302 came up.

I tried checking it myself by replacing the spark plugs and moving the injectors and coils around.
The P0300 and P0302 code stayed on after swapping coils, injectors and plugs around.
I replaced the fuel pump and no change.
Brought it to a mechanic nearby who blamed the leaking valve covers and replaced it.
After replacement, misfire stayed and codes are still the same.
We have plans this Easter but looks like we wont be going.
Thinking about bringing it to Kia due to Easter coming up, they are fully booked until mid April.
Any suggestions or ideas would help.

Thanks in advance.

41 - 55 of 55 Posts

bopbo

· #41 · 21 d ago

Regarding engine removal, I have done both, subframe lowering and out through the bonnet opening. To drop the subframe you need a proper hoist to get the car up high enough and a stand to put the subframe onto. I didn't and it was a struggle to get the car high enough. Taking the motor out through the engine bay was much faster and easier, I didn't remove the trans but that probably easier with the engine removed.
When I replaced the ECU I replaced the ECU, and had a locksmith clone the ECU chip to a new key that suits the existing key. I have had no problems. You could change ALL the locks if you wanted but it seemed far too much work.

axtigin36

Discussion Starter · #42 · 21 d ago

bopbo said:
Regarding engine removal, I have done both, subframe lowering and out through the bonnet opening. To drop the subframe you need a proper hoist to get the car up high enough and a stand to put the subframe onto. I didn't and it was a struggle to get the car high enough. Taking the motor out through the engine bay was much faster and easier, I didn't remove the trans but that probably easier with the engine removed.
When I replaced the ECU I replaced the ECU, and had a locksmith clone the ECU chip to a new key that suits the existing key. I have had no problems. You could change ALL the locks if you wanted but it seemed far too much work.

Thanks for the heads-up.
Thats much appreciated.

I will probably try to lift the trans and engine at the same time, hopefully it goes well. Driving down to Melb on thursday night. How long did the engine swap take you?

I might just grab an ECU, JUST IN CASE.

Thanks!

bopbo

· #43 · 20 d ago

The engine swap took a day and bit in my drive way and a block and tackle hung from the carport.
Not sure both will fit through the hole at the same time, but probably easier

axtigin36

Discussion Starter · #44 · 12 d ago

So update, removing the engine was very painful, tried separating it in the engine bay but the TC wont stay behind (removed the 6 retaining bolts). Unsure why so had to remove the engine and trans at the same time. Still trying to figure out why the TC is stuck with the engine. Removing the engine and trans took almost 8 hours, half was wondering why the TC wont separate. Will be going at it around lunch time again. Any tips on what im missing?

bopbo

· #45 · 12 d ago

Not really able to offer an assistance, removing the 6 bolts and a gentle pry screw driver was all i needed to separate the TC from the drive plate.

axtigin36

Discussion Starter · #46 · 12 d ago

Got it off, thanks for all the inputs, final stages of installation. Waiting for driveshaft seals because it was already weeping.

Upon further inspection of the old parts, both upper cats has started breaking off thus blocking the bottom cat. Not sure why, could be because it had faulty O2 Sensors when I bought it. Timing chain started rattling.
Hopefully, everything checks out fine once I finish tomorrow.

Rob22315

· #47 · 10 d ago

Timing chain rattle is a known issue for these engines. OEM considers a few seconds of rattle on startup to be acceptable. Excessive rattle is usually (but not always) caused by a failure of the ratchet mechanism in the self-adjusting tensioner. Oil pressure causes the tensioner to provide the proper tension with the ratchet holding the tensioner in the approximate correct position. The ratchet mechanism failing is a known issue with the Lambda engine.

axtigin36

Discussion Starter · #48 · 10 d ago

Rob22315 said:
Timing chain rattle is a known issue for these engines. OEM considers a few seconds of rattle on startup to be acceptable. Excessive rattle is usually (but not always) caused by a failure of the ratchet mechanism in the self-adjusting tensioner. Oil pressure causes the tensioner to provide the proper tension with the ratchet holding the tensioner in the approximate correct position. The ratchet mechanism failing is a known issue with the Lambda engine.

Thats good to know. The old engine was rattling under high rpm so. So i guess it was really something else.

axtigin36

Discussion Starter · #49 · 10 d ago

Update:

Had the new used engine and installed and tested.
Everything seems to run fine on idle and low load. A lot better and quieter than my old engine. Still have issues though, the moment that i put my foot down or the cruise control needs more power it comes up with P0302 and P0306 and P0300. Not a good sign at all. New spark plugs. It bogs down when under high load. Could this be coils?

ron1004

· #50 · 10 d ago

Those are misfire codes - does it feel like its misfiring?

Could be fouled CAT's.

If the old engine was burning oil it would destroy the CAT's.

leo42.2875

· #51 · 10 d ago

Did you not start out with the P0302 ?

axtigin36

Discussion Starter · #52 · 10 d ago

ron1004 said:
Those are misfire codes - does it feel like its misfiring?

Could be fouled CAT's.

If the old engine was burning oil it would destroy the CAT's.

I forgot to mention, ive already replaced the 2 manifold/cats because the old ones disintegrated.

axtigin36

Discussion Starter · #53 · 10 d ago

leo42.2875 said:
Did you not start out with the P0302 ?

Yes, I did. Replaced the engine now its a lot better. The old one started rattling and the misfire was just continuous P0302 and wouldnt even idle evenly.

Rob22315

· #54 · 9 d ago

axtigin36 said:
Thats good to know. The old engine was rattling under high rpm so. So i guess it was really something else.

Your timing chains and tensioners all needed replacement on that old engine. Ongoing rattling means that whole set of mechanisms is shot. No wonder the new one is quieter.

bopbo

· #55 · 8 d ago

As to the miss fire, I would be looking into the exhaust being clogged with the remnants of the failed cats

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