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Discussion Starter · #1 ·
I own a 2008 tC with right at 160K miles. I bought it at 107K miles and it has been burning oil ever since I bought it. The way I understand the piston ring problem is that if you keep oil in it, then there shouldn’t be too much of an issue. The car has only had one previous owner, and, to my knowledge, they did not get the piston rings fixed.

I have noticed recently that I will momentarily smell gas while driving over 60 mph. This happens as well at 70 mph but with a stronger smell and a rough idle after coming to a stop. I turn it off and start it back up, and that usually stops the rough idle. I try to baby the engine but on the rare occasion that I accelerate hard, I will notice whitish smoke out of the tailpipe. Coolant isn’t mixing with the oil, and there are no p codes.

I am unsure if this has to do with the spark plugs since when I changed those, I didn’t gap them given the iridium tips. I recently changed the PCV valve to see if this helped the gas smell, and that hasn’t solved the issue. I am unsure if it is the ignition coils or something with the evap system or if it is ultimately the piston rings. I do not think that the cat is at the point to be changed.

Can anybody help me figure out the reason for the smell, rough idle, and smoke?
 

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2007 Scion TC 2.4L automatic
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Smell: cat's gone, exhaust leak, exhaust header gasket leak/loose bolts, loose exhaust bolts all along the pipe, rusted out/holes on exhaust, cat can be clogged. If severely clogged. A clogged cat can & will cause power loss, stumbling, erratic, surging, rough idling, dropping & up rpms & power/speed. If you see in the dark the cat red cherry hot or turning red. STOP the car & when cold remove the cat & replace. You can hollow out the cat. It will not make it sound like a clapped out glass packed sh*t box Honda. It will be oem/factory quiet.

Spark plugs: ALWAYS, ALWAYS, ALWAYS check the gaps on any spark plug. Don't listen to those damn idiots at the Autozone, O'Reillys, Napa, Carquest, Pepboys, Advanced Auto parts when they say spark plugs don't, never have to be checked for gap. That's bullsh*t. Buy an iridium spark plug gapping tool. Any real car/mechanic, DIYer, wrencher, small engine & large will always check spark plug gaps.

ignition coil: check the pigtail/wire connectors. These get brittle & break. Replace with new ones. While car is parked e barke on. Either at the connector or at the ignition coil pack itself. Remove the connector or coil pack & listen for rpm drops. If rpms don't drop/change that ignition coil is going bad/not good. Do that to each one & replace with new ones.

Throttle body: remove & clean throttle body. Carb cleaner or WD40. I used WD40 toith brush & paint brush. Remove the entire airbox.
USE MAF/MAP CLEANER ONLY! DON'T USE ANYTHING ELSE OR ANY TYPE OF BRUSHES/RAGS. JUST SPRAY & LET AIR DRY. clean the engine airbox, new engine air filter, replace all hoses to throttle body, PCV

engine idle: check the 10amp fuse. I cant remember what it is right now. But it's the engine idling 10amp mini fuse. Check & verify that the engine fuse box wires are not being pulled, twisted, pins pulled, twisted, kinked, bent, frayed, corrosion & no rust. Replace all or any relays fuses.

Check the age & condition of battery. Charging won't help if it's old. The acid is practically gone. Replace with a new one or borrow one that you know is still good.

check the age & condition of starter. Replace with new one if needed.

check the age & condition of alternator. Replace with anew one if needed.

Check & replace the engine serpentine belt. If covered in Crack, pittings, missing pieces, brittle, replace.

sscion tc are known for oil burners. Piston & piston ring failures.

check at engine oil for chocolate milk shake. If there you have radiator leakig & mixing with engine oil. Repair. If not milk shake mix then it's fine. Just dont be stupid & never check vehicle fluids.

Check age & condition of fuel pump. You have to remive rear seats & pull out to visually check & verify it's clean & not severely clogged. At start up you will hear the pump turn on/electical humming buzzing/pressure to fuel rail & injectors.

Check & remove fuel rail & injectors for junk cloghing the injectors. Just clean with clean gasoline or carb cleaner & a very soft baby tooth brush/extra soft tooth brush.

replace your gas fuel cap with an OEM/factory one from the local Toyota dealership.

i have a post on my TC.
 

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Discussion Starter · #5 ·
Is there a check engine light on? How often does white smoke come out the tailpipe?
There aren’t any codes at the moment, and I only notice smoke during hard acceleration. I re-torqued the spark plugs and that may have improved a bit. But, right now, I believe the smell has something to do with the exhaust
 

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Discussion Starter · #6 ·
Smell: cat's gone, exhaust leak, exhaust header gasket leak/loose bolts, loose exhaust bolts all along the pipe, rusted out/holes on exhaust, cat can be clogged. If severely clogged. A clogged cat can & will cause power loss, stumbling, erratic, surging, rough idling, dropping & up rpms & power/speed. If you see in the dark the cat red cherry hot or turning red. STOP the car & when cold remove the cat & replace. You can hollow out the cat. It will not make it sound like a clapped out glass packed sh*t box Honda. It will be oem/factory quiet.

Spark plugs: ALWAYS, ALWAYS, ALWAYS check the gaps on any spark plug. Don't listen to those damn idiots at the Autozone, O'Reillys, Napa, Carquest, Pepboys, Advanced Auto parts when they say spark plugs don't, never have to be checked for gap. That's bullsh*t. Buy an iridium spark plug gapping tool. Any real car/mechanic, DIYer, wrencher, small engine & large will always check spark plug gaps.

ignition coil: check the pigtail/wire connectors. These get brittle & break. Replace with new ones. While car is parked e barke on. Either at the connector or at the ignition coil pack itself. Remove the connector or coil pack & listen for rpm drops. If rpms don't drop/change that ignition coil is going bad/not good. Do that to each one & replace with new ones.

Throttle body: remove & clean throttle body. Carb cleaner or WD40. I used WD40 toith brush & paint brush. Remove the entire airbox.
USE MAF/MAP CLEANER ONLY! DON'T USE ANYTHING ELSE OR ANY TYPE OF BRUSHES/RAGS. JUST SPRAY & LET AIR DRY. clean the engine airbox, new engine air filter, replace all hoses to throttle body, PCV

engine idle: check the 10amp fuse. I cant remember what it is right now. But it's the engine idling 10amp mini fuse. Check & verify that the engine fuse box wires are not being pulled, twisted, pins pulled, twisted, kinked, bent, frayed, corrosion & no rust. Replace all or any relays fuses.

Check the age & condition of battery. Charging won't help if it's old. The acid is practically gone. Replace with a new one or borrow one that you know is still good.

check the age & condition of starter. Replace with new one if needed.

check the age & condition of alternator. Replace with anew one if needed.

Check & replace the engine serpentine belt. If covered in Crack, pittings, missing pieces, brittle, replace.

sscion tc are known for oil burners. Piston & piston ring failures.

check at engine oil for chocolate milk shake. If there you have radiator leakig & mixing with engine oil. Repair. If not milk shake mix then it's fine. Just dont be stupid & never check vehicle fluids.

Check age & condition of fuel pump. You have to remive rear seats & pull out to visually check & verify it's clean & not severely clogged. At start up you will hear the pump turn on/electical humming buzzing/pressure to fuel rail & injectors.

Check & remove fuel rail & injectors for junk cloghing the injectors. Just clean with clean gasoline or carb cleaner & a very soft baby tooth brush/extra soft tooth brush.

replace your gas fuel cap with an OEM/factory one from the local Toyota dealership.

i have a post on my TC.
That’s a good list of things to check. I’m not too mechanically inclined, but I relatively lately had the battery and alternator replaced. The spark plugs were purchased from a Toyota dealership’s parts department and not just Autozone or something. The oil doesn’t look milky, so I should be good with the coolant matter. I’ll look into the other stuff you mentioned.
 
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