5.7 fouling plugs? (1 Viewer)

[nwcoast]

I have a buddy with a 2010 tundra with the 5.7 and 120,000 miles and he’s keeps getting a misfire on cylinder 6 and the spark plug on that cylinder keeps fouling after a hundred miles or so.
He replaced the coil pack and no improvement, then replaced the injector, no improvement.
If you drive it with the scangauge it shows misfires on cylinder 6 but everything feels fine with the truck. Then if you get on it and rev the engine the Injector shuts down the cylinder and it runs terrible.
We’ve been trying to figure it out for a month or two and haven’t made much progress. Our local mechanic could t figure it out, he hasn’t worked on any 5.7 engines.
I have the same engine in my 200 series and it’s been great, which seems to be the general consensus on the 5.7.
I thought I’d see if any cruiser guys have dealt with this issue or have any good theories about what’s going on.

 

[hdj105]

Have you done a compression test on that, or more cylinders?

 

[Cruisin911]

Compression and leak down. Go from there.

 

[Sandroad]

Check the late model (5.7) Tundra forums.

 

[nwcoast]

He hasn’t done a compression or leak down I don’t think. That would be your guys first guess?

 

[TonyP]

This guy traced it back to an ECU

07 Misfire on cylinder 8

I haven't heard of a 5.7 ECU taking a dump but it's a possibility, apparently.

 

[nwcoast]

I actually forwarded that thread to my buddy last night. We have been thinking an ECU would be a last resort. All the mechanics we’ve talked to say it’s never the Ecu. But yeah that thread was pretty interesting.
It didn’t sound unreasonably expensive either.
I found another thread about a tundra guy who was fouling plugs and it ended up being his aftermarket exhaust system. His theory was backpressure?
My buddies tundra does have aftermarket exhaust, but I’m not sure if Ecu is more likely the culprit.

 

[TonyP]

I had an aftermarket exhaust on my 5.7 single cab regular bed Tundra with no issues. Sounded awesome too... Man I miss that truck.

 

[nwcoast]

Yeah he put a pretty nice exhaust on his. It’s not to loud, just a pleasant throaty sound.
He bought his brand new and has taken immaculate care of it and has it all dialed in with suspension etc..

 

[nwcoast]

I got an update on this finally. Buddy has had a bunch of mechanics check it out. Finally took it to a Toyota dealer and they say it’s a blown head gasket. The head service tech at Toyota said he has never seen it happen on a 5.7. They are going to get a Toyota engineer down from Portland to check it out because it’s so unusual.

 

[Cruisin911]

Blown head gasket? Leaking around the seal for the spark plug? Usually a blown head gasket causes coolant mixing with the oil. Did he see any indication of this? Or did it solely manifest itself as a misfire?

 

[nwcoast]

Yeah he started seeing coolant consumption. He’s pretty bummed

 

[Weedhopper]

Sounds like my old Nissan. Did he ever overheat the engine? Sometimes it takes months before a problem shows up after overheating. Ask me how I .....

Hope it works out.

 

[Docboy]

I got an update on this finally. Buddy has had a bunch of mechanics check it out. Finally took it to a Toyota dealer and they say it’s a blown head gasket. The head service tech at Toyota said he has never seen it happen on a 5.7. They are going to get a Toyota engineer down from Portland to check it out because it’s so unusual.

Ouch, sorry to hear. Very unusual for the 5.7V8 to have engine issues.

I've heard reports of blown head gaskets on certain 4th Gen 4Runners with the V6 engine, but not with the V8 on the 200. Coolant consumption along with "milky coolant" a common sign for such a failure. Not a cheap fix unfortunately.

 

[Hokie99]

What ever happened here? Did he ever overheat before the issues? What did he do to resolve after the engineer came down?

I have a weird situation going on with my 5.7 currently, never over heated, low on coolant in reservoir, missing number 2 cylinder not the coil or fuel injector. They are thinking a very slight issue with head gasket at this point....

 

[bloc]

What ever happened here? Did he ever overheat before the issues? What did he do to resolve after the engineer came down?

I have a weird situation going on with my 5.7 currently, never over heated, low on coolant in reservoir, missing number 2 cylinder not the coil or fuel injector. They are thinking a very slight issue with head gasket at this point....

This thread is old enough it would probably help to ping the OP

@nwcoast any feedback?

 

[TeCKis300]

Thing I love about the cruiser is it uses a mainstream engine found in several models. If I ever had a motor problem, just buy a used low mileage motor from a donor. Complete motors can easily be found for ~$3k. Then swap all the 200-series ancillary items in, and good to go.

 

[Moby]

Perfect excuse to build a stroker paired with Darton sleeves and a blower to really take advantage of his exhaust.

 

[RyanArcane]

The 5.7 used in the Cruisers have different SQCs, usually known to be MR imaged for cracks after cast settling. But the problem of having issues starting sometime after having after market exhaust components is quite common, definitely starts with o2 sensor reading deviations. But I have read a couple of successful replacement with Tundra 5.7s in the 200 forum and a certain classified who replaced the whole engine with a used one.

 

[RyanArcane]

What ever happened here? Did he ever overheat before the issues? What did he do to resolve after the engineer came down?

I have a weird situation going on with my 5.7 currently, never over heated, low on coolant in reservoir, missing number 2 cylinder not the coil or fuel injector. They are thinking a very slight issue with head gasket at this point....

Hi did you figure this out, if you dont mind sharing what had happened. Was it related to the radiator leak and overheating issue. Would be great to know.