Injector problem?

06 Tundra DC 4wd limited 162,xxx miles. I’ve read several helpful ideas on here and looking for help with P300, P301, P304, P305. Running rough. I bought new plugs and coils and installed Denso coils and NGK iridium plugs. Still had same code error. So I swapped coil n plug from 1 cylinder to 3. And 4 to 6. 5 to 7. Still get same code error. 300, 301, 304, 305. I’m guessing injector problem? I added HEET to tank to dissipate any water. Any ideas? Fred

 

Heeeeeey Fred. Welcome to the forum, dust off your cap and add a feather for joining.

On no car ever have I seen a bad injector cause misfire codes on multiple cylinders, nor multiple injectors die at once. Solid detective work swapping plugs and coils to rule out electric though, that's something we'd have asked. I take it you checked out the other basic stuff first too, like air filter, looked for rodent damage, etc?

But what does an EFI engine need to fire correctly? Timed spark. Pressurized fuel. Metered Air (intake/exhaust).

Without the on-board computer being able to accurately sense (using its sensors) how much air and fuel is entering the engine/cylinder, or time the spark, it can't possibly avoid misfires.

You've focused on the electrical side, it sounds like. You've ruled out some more-common electrical/ignition/spark things. If you didn't buy your parts from fleaBay or scAmazon, which is notorious for fakes/counterfeits, there are some other things you may not have accounted for:

• Air ... If your car cannot detect the actual amount of air incoming, it can't possibly know how much fuel to squirt into the cylinder for proper fire. Get CRC MAF cleaner and clean your MAF, or use the factory service manual (FSM) to check its output is within spec, replace if not. Check your throttle body assembly/butterfly etc. to confirm no major buildup, clean if necessary. Check for cracked, loose, or missing vacuum hoses. If you live in rodent country, check the filter isn't chewed up and bits of it aren't stuck in places they shouldn't be.
• Fuel ... How many miles on this truck? Is it possible your fuel pump is going out and not supplying enough fuel pressure? That's classic for rough idle and misfire issues also, but I typically see cars throwing EVAP related codes first in that case.
• Other sensors ... Throttle position sensor could be giving faulty info about how open it is. O2 sensors could be misreporting how much spent/uncombusted fuel is on the exhaust side, making ECU put too much gas/air into the cylinder. I'd check around the front pulleys to see if your crank position sensor harness got nicked because it wasn't properly restrained during timing belt change. I'd look around for rodent damage, there's a valley under the intake they can easily slip into for a nice, cozy warm spot if you're in a winter climate.

What I wouldn't expect to find is your injectors went bad. Not without some kind of event, like varnished gas. Even if that's the case, it's nothing a bottle of SeaFoam put in with a lower, 1/4 tank of gas, and idled for 30 minutes, then on/off in 5 minute cycles wouldn't break up within an hour.

 

Long shot but bad gas was what a previous poster states his problem was with almost exact codes!

01 Tundra 4.7L Bank 1 misfire codes | Toyota Tundra Forum (tundras.com)

 

Air filter is good, cleaned MAF and throttle body. Still runs rough. What is best way to drain tank? Thanks, Fred

 

If it were me draining the tank? I'd siphon off at the fill neck. Granted, I have a siphon pump so it only takes 2 seconds for me to get a good stream and no gas in your mouth. I'd probably just set aside the gas and use it with the mower.

Read this. Just one recent example of fun stuff related to pumps. Scroll up from that pic to read more about the bizarre symptoms. Not saying this is your case, but ...

If you do end up installing a new pump, I'd go OEM. And I'd probably have a bottle of SeaFoam on hand. Put 4-5 gallons back in the truck and a full bottle of SeaFoam.

With that little bit of heavily Seafoam'd gas, installed, do some idle/off cycles (5-10 mins on/off) to clear out the injection system, then go on a 20-30 minute highway drive, and fill up with good gas.

SeaFoam is basically just highly refined petroleum. It won't damage seals, hoses, injectors, it's not harsh or abrasive, just don't be one of those guys that lets their truck suck it up through vacuum hoses.

 

Drained tank n purchased 91octane gas. Added sea foam. No help. Drove about 5 miles n barely gets up to 25 mph. I have a cheap obd2 scanner. What is a really good one for under $1,000. Thanks for your help.

 

Maybe it's in limp mode? Does it run normally if you use your cheap OBDII scanner to clear the codes out?

If you need live output to see what's going on, a lot of guys use a bluetooth module on the OBDII port with the Torque Pro app, I think? But most of the ones I've seen only work with Android phones/tablets, not iOS. I'm the wrong guy to ask. I get by fine with a simple code reader. But I also have an ISO of the Toyota diagnostic tool.

You can get a lot of pro-grade diagnostic tools in the 400-600 range that would hopefully let you confirm fuel pressure and other stuff. I've seen a number of guys with the Autel MaxiCOM (MaxiSYS?) units in their shops.

 

It might be worth unplugging the battery or removing the EFI fuse for 15-20 min to let the computer reset and then try driving. The suggestions above are right on point with my thinking.
Any pictures of the old plugs you replaced? I once had a misfire because of a leak in the sparkplug seal, and was able to see the oil on the plug. Might help with diagnosing the issue.

I use ultraguage bluetooth to connect to my truck and my iphone.

 

timing?

 

Service manual points to injectors as a probable cause on misfires, and rough idle. Check your injector o rings too.

 

Update 2006 tundra 4.7l 162,000 miles. Had a local shop test my engine. He said it threw a rod! I’m going to search and see if this a common problem. I certainly appreciate all your response! Fred

 

I'd get a 2nd opinion on that one.

 

^^^ Do a compression test on that cylinder. No gauge, then remove the spark plug or injector and and feel or listen if air is being pushed out. Hear something banging around in there? If not, use a long long screwdriver or rod pressed against the head over the bad cylinder and put your ear on the screwdriver's handle or opposite end of rod and listen for abnormal noise. Similar to a Dr using his stethoscope. There's another way but I'm not telling ya because I don't know how experience you are turning a wrench, but if you know what your doing, you already know.

Don't get your clothing, hair, fingers or some body part caught up in things that turn; the belt, fan or pulleys!

 

Not only that, but know that no compression on a cylinder DOES NOT necessarily mean blown engine. It could mean stuck valve, for example.

In fact, this one member replaced his entire f'n engine thinking it was a rod or similar, no compression on one cylinder. Led to a whole world of nightmares swapping the new engine in, I still don't know if he got it running right on the new engine.

When he got into the original engine, expecting at least something bent/broke/thrashed ... everything was fine. Stuck valve.

@Bergie4449 here's the thread. It's long. Read it. https://www.tundras.com/threads/new-member-old-truck-dead-cylinder.96468/

 

Just going off what his mechanic said (broken piston rod), and ways for the dude to confirm that for himself if he has next to nothing for tools. One would assume his mechanic tested for that, or is a rip off wanting more money for a repair job. I agree, he's mechanically lost from the get go, and needs to stay with washing and waxing cars only...like most coming here with how to fix questions. I should have remained silent before he kills himself poking around the engine. Your right about his getting a mechanics second opinion. His getting a cheap compression gauge to do a compression test and following with a leak down test, if he could get compression, would cost next to nothing off Amazon, and would save the cost for second opinion. But he doesn't have a clue about how to do it and might cause more damage.

I'm learning quick about people asking questions about how to fix something on this forum. Most don't know the difference between a phillips and flat head screwdriver, or don't know transmissions use different type fluids. The type of people (sisters) you tell to go get a snow jack before your changing their tire in winter, or to change the tire's air out to summer or winter air before the season gets here, otherwise you won't come and get them when the car gets a flat. Ever get hobbyist type mechanics on here that get stuck on something or looking for any tips on how to do it easier. Those are easy.

Your a pretty kool dude Fred.

 

I think it may be the latter.

I've thrown a rod once in my life downshifting too aggressively at high speed to slow down STAT. I was 16 or 17, too long ago to remember which, I just know it was my 4th or 5th car at that point, and my dad was pissed as hell, but I scored a '70 Impala with new crate motor for $1500 after that, it had 2drs too many, but loved it fit 8 friends comfortably. The car I thrashed was a late-80s Pontiac Lemans "egg" hatchback.

Anyway, the car was basically undriveable after that. It'd start. It'd run. But I'll be damned if it wasn't making a helluva lot of racket while running, like a marble in a coffee can. You could audibly tell something was wrong, as is normal for rod probs. I would expect @Bergie4449 would know if this was the case by sound alone, since limp mode is something that can be caused by a number of things and limp mode + no compression on one cylinder is not a diagnosis for thrown rod.

My car didn't sound dissimilar from this, only with an extra clang or two in there:

https://www.youtube.com/watch?v=wmtBqNnnvrs

This is another fun video where some guys intentionally get a vehicle to throw a rod, same rhythmic marble-in-a-can sound:

https://www.youtube.com/watch?v=erQIvSiLZSI

 

Years ago I had an Audi 100 (Aluminum block). My wife comes home one night, says "the car was making a noise on my way home from work...I added 5 qts of oil when I got home, but it's still doing it". Later that night she goes to the mall, and calls me to come pick her up "something went bang, then the car stopped".

When I go to get her I see that it tossed a rod through the side of the block by the engine mount, exiting through the hood! The engine AND transaxle (front wheel drive) dropped to the ground and dragged ~ 100 feet until the car stopped.

Well, these things happen...but the dichotomy between her assessment and the reality of it still gives me a chuckle.

 

Yes my engine sounds like the video, bolts in a metal can. Looks like a reman engine $4k!

 

Well damn, that's a pretty significant symptom to miss in your original post, Fred.

Being the skeptical hombre I am with anyone touching my vehicles, I'd still go for a 2nd opinion at a dealership or something, but I realize that's not an option for everyone, and if this is your typical mechanic, it'd probably piss them off.

But then again, USAA tows me anywhere up to like 15-20 miles for free, and I have at least 3 dealerships within 25 miles. I think that's the only benefit of living where my work has landed me.