Help: 2004 Sienna P300, P305, P306 codes, strong fuel smell, Heavy Smoke in Exhaust

3696 Views 7 Replies 3 Participants Last post by bluezucsky, Dec 23, 2014

bluezucsky

Discussion Starter · Dec 21, 2014

I recently purchased a Sienna LE, 158,000 miles, which had not been sitting for over 6 months. When changing the front plugs (didn't do back ones yet) I noticed number 6 plug had black gluey stuff on it. Got the van started, however, there is so much smoke and unbearable fuel smell in the exhaust that I cannot run it for more than 30 seconds. The smoke and smell begins as soon as I start my car. Found these codes: P300, P305, P306. I opened plug 6 and noticed the tip of the new plug soaked in oil. No coloration. Tested spark on the plug (after pulling it out) and it appeared to be fine - coils seem to be fine.

Is it a coincidence that error is showing on opposite cylinders 5 and 6. I am planning to remove fuel injector connectors for number 5 and 6 to see if engine can run for a few minutes. Is it a bad idea? I was thinking about get compression checked on cylinder 6 first. Amount and smell of smoke is really puzzling.

Please help. If my engine is bad, I do not want to spend any more money on it and just will sell it.

Thanks

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jc

· #2 · Dec 21, 2014

Re: Help: 2004 Sienna P300, P305, P306 codes, strong fuel smell, Heavy Smoke in Exhau

This could be many things. You need to check all the vacuum hoses to make sure they are ok. Maybe the fuel pump is bad. Is the battery ok?

I would try to charge the battery overnight first and then fire up the van to see if that makes a difference. Search youtube for tips.

Regards, JC.

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bluezucsky

Discussion Starter · #3 · Dec 21, 2014

Re: Help: 2004 Sienna P300, P305, P306 codes, strong fuel smell, Heavy Smoke in Exhau

Thanks JC. Battery is at 100%. I opened the front valve cover and found it full of the dreaded sludge. Does the back side of the engine need cleaning as well? What else do I need to clean? How can I get to internal passages within engine (I don't have skills/tools to go any further than valve covers inside the engine)?

Is it worth cleaning the sludge or just get rid of the van?

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jc

· #4 · Dec 22, 2014

Re: Help: 2004 Sienna P300, P305, P306 codes, strong fuel smell, Heavy Smoke in Exhau

bluezucsky said:
Thanks JC. Battery is at 100%. I opened the front valve cover and found it full of the dreaded sludge. Does the back side of the engine need cleaning as well? What else do I need to clean? How can I get to internal passages within engine (I don't have skills/tools to go any further than valve covers inside the engine)?

Is it worth cleaning the sludge or just get rid of the van?

Do you have a picture of under the valve cover?

I hope you didn't pay much for the van. Both sides will need to be cleaned. Depending on what you want to do, you might be having major repair issues with the van.

If it were me I would do the following. First change the PCV valve. Next I would change the oil and filter soon. I would use Pennzoil Yellow bottle 5w-30 and add a can of seafoam to the oil. Not sure if the van is driveable. I would run the van if you can with he new oil for 10-15 minutes. Stop the van and have a look at the dipstick. Seeing the condition of the new oil. I would also want to remove the oil pan to see what the condition on the bottom of the engine is like. The oil pickup might be covered in sludge. I would want that cleaned as well.

If van is driveable then you might be able to clean the sludge with some products like Seafoam or Rislone or Marvel Mystery Oil added to the oil using a short oil change interval.

I read of some people running kerosene in their engines (instead of motor oil) to clean it. I don't know if this is a wise approach in your Sienna. How much time and money are you willing to spend to see if you can correct it? If the sludge looks like black crusty stuff everywhere under the valve cover, then I think that you would want to forget it and sell the van.

Regards, JC.

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bluezucsky

Discussion Starter · #5 · Dec 22, 2014

Re: Help: 2004 Sienna P300, P305, P306 codes, strong fuel smell, Heavy Smoke in Exhau

JC, Thanks for taking time for your response. I paid under $2k for it as the body and interior were in good shape. I am attaching pictures before I began cleanup.See what you think. I have circled an area to the left (next to the timing belt side), there is a channel under it completely blocked. Do you know where does it go (oil pump?). I have emptied out one full cup of hard sludge (we post pictures later for that). A local workshop was offering to put replacement used engine for $1300 (parts and labor). I am so disappointed to see the sludge problem that I feel it may not be worth it.

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thanwu

· #6 · Dec 22, 2014

Re: Help: 2004 Sienna P300, P305, P306 codes, strong fuel smell, Heavy Smoke in Exhau

The previous owner must have not changed oil according to schedule or not changed at all for a while. I just can not imagine I got a vehicle with engine like that. Good luck to you!

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jc

· #7 · Dec 23, 2014

Re: Help: 2004 Sienna P300, P305, P306 codes, strong fuel smell, Heavy Smoke in Exhau

That is some very bad sludge. I guess you can try to manually clean it up, but you'd need to remove the intake to be able to access the rear valve cover and remove it. You'd also need to remove the cowl.

I'm not sure about the replacement engine option. Have these guys ever replaced the engine in a Sienna?

Regards, JC.

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bluezucsky

Discussion Starter · #8 · Dec 23, 2014

Re: Help: 2004 Sienna P300, P305, P306 codes, strong fuel smell, Heavy Smoke in Exhau

I removed cowl a couple of days ago when attempting to look at the rear plugs. Three bolts in the back scared me so I gave up. Between today and tomorrow I am planning to get to the oil pan and EGR and do a best effort to clean them up, then after closing these I would make another attempt to open the back bolts. Do I need to pull VVT solenoids as well for clean up?

The only thing that keeps me going is the fact that the van started even after standing for 6 months and with 6 months old gas (luckily tank was full). I am hoping with your clean up procedure, I can get cylinders 5, 6 to fire up. Don't have compression gauge, but I suspect may be same sludge has prevented compression built in these cylinders.

As far used engine is concerned, the mechanic has changed Sienna engines before. I didn't explore this option because with my current cost on the van, I can sell it back as-is with hopefully no loss. However, spending more money on engine replacement will increase sunk cost and will leave fewer options to quit.

Thanks again for your continued very help advice.

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