First Thing to Fix? (weak power uphill)

[Sitcoms]

Hello all,

been here for a while but just got my 15 posts. Bought the 4r back around July/August, high mileage but the body and frame were relatively rust free and solid, and it ran well.

After a while, needed some repairs (CEL came on) and I've scanned it for some codes. The engine is very, very loud (high RPMs, especially when approaching 35mph) and has issues with maintaining/gaining speed going uphill (i.e. going 70 on the highway, come towards a hill and can put my foot down to the floor and only be going 50 up the hill). Here are the codes:

P0446 - Evap System, had the charcoal canister checked and they said it looked good, and have also tried replacing the gas cap to remedy it.

P0325 - Knock Sensor 1 Bank 1, haven't had the money to replace this yet and don't have the expertise to get to the area where these are. I know you should replace both if you're going in there, as it's a labor-intensive job.

Would either one of these possibly lead to the issue I'm describing, and which one would be the most important to fix ASAP? I'm leaning towards the knock sensors before engine damage occurs, but would need to save the money for it ASAP. Opinions?

 

[phattyduck]

The engine is very, very loud (high RPMs, especially when approaching 35mph) and has issues with maintaining/gaining speed going uphill (i.e. going 70 on the highway, come towards a hill and can put my foot down to the floor and only be going 50 up the hill).

Gonna need more information...

Assuming you have a V6 and auto? 2WD or 4WD? Year?

What do you mean by loud? Does it sound like a fan? Does it sound like an exhaust leak? Does it sound like BBs in a can? Squealing?

-Charlie

 

[Hepar]

Knock sensors recently came up in another thread. When you throw a code for them, your rig will retard the engine at high RPM's to avoid damage. Replace the wiring harness with the two sensors. They can often be the source of the code to begin with.

 

[sleepydad]

Hello all,

been here for a while but just got my 15 posts. Bought the 4r back around July/August, high mileage but the body and frame were relatively rust free and solid, and it ran well.

After a while, needed some repairs (CEL came on) and I've scanned it for some codes. The engine is very, very loud (high RPMs, especially when approaching 35mph) and has issues with maintaining/gaining speed going uphill (i.e. going 70 on the highway, come towards a hill and can put my foot down to the floor and only be going 50 up the hill). Here are the codes:

P0446 - Evap System, had the charcoal canister checked and they said it looked good, and have also tried replacing the gas cap to remedy it.

P0325 - Knock Sensor 1 Bank 1, haven't had the money to replace this yet and don't have the expertise to get to the area where these are. I know you should replace both if you're going in there, as it's a labor-intensive job.

Would either one of these possibly lead to the issue I'm describing, and which one would be the most important to fix ASAP? I'm leaning towards the knock sensors before engine damage occurs, but would need to save the money for it ASAP. Opinions?

If you have the knock sensor code and check engine light the ECU will retard timing advance and your going to notice a loss in power. It’s in limp mode when the knock sensors trip this code. It’s protecting the engine from damage. It’s probably just the wire harness going to the knock sensors and not the knock sensors themselves.

Not sure about the loud noises?

 

[96RedRunner]

[MENTION=168172]sleepydad[/MENTION], [MENTION=139000]phattyduck[/MENTION]
Speaking of knock sensors and harness what causes either or both to chit the bed?
Had 96Red 18 yr 370k mi, 01 211k mi have owned for 13k mi neither have had this issue.

 

[sleepydad]

[MENTION=168172]sleepydad[/MENTION], [MENTION=139000]phattyduck[/MENTION]
Speaking of knock sensors and harness what causes either or both to chit the bed?
Had 96Red 18 yr 370k mi, 01 211k mi have owned for 13k mi neither have had this issue.

IMO heat and time.

the wire harness gets sandwiched between the block and the lower intake manifold. after 20 years the wires just fall apart. when I replaced mine the wires just crumbled when I touched them.

still... they last for a dam long time. it is a pain to replace them but I bet I can do it in 3-4 hours. + 10 days waiting for parts.

 

[96RedRunner]

IMO heat and time.
still... they last for a dam long time. it is a pain to replace them but I bet I can do it in 3-4 hours. + 10 days waiting for parts.

Guess I got lucky on 96Red won't have to worry on it though since it got totaled.
Wait n see on 01, thought of it when doing VC gaskets, roll the dice.
Your good 3-4 hrs, no beer breaks Lol.

 

[Hepar]

[MENTION=168172]sleepydad[/MENTION], [MENTION=139000]phattyduck[/MENTION]
Speaking of knock sensors and harness what causes either or both to chit the bed?
Had 96Red 18 yr 370k mi, 01 211k mi have owned for 13k mi neither have had this issue.

I think when I supercharged mine, that it shortened their lives. Especially since I was running on the lean side for the first few months with it. As well as I was on the gas more in that time due to the novelty of more power.

 

[gamefreakgc]

I think when I supercharged mine, that it shortened their lives. Especially since I was running on the lean side for the first few months with it. As well as I was on the gas more in that time due to the novelty of more power.

It really does seem like it's a matter or luck or not. My engine was supercharged for 221k miles and never touched the knock sensors, go figure.

I do know that the valley in the engine beneath the intake manifold is notorious for ninja coolant leaks. In fact, when my engine blew (unrelated) I took off the manifold and sure enough, pink crust everywhere. I think this might have to do with why they fail.

For the OP, when the ECU pulls timing because of the CEL, it also pulls power. with little to no timing advance the engine has to rev up very high to have enough power to move the vehicle like it did before. You might want to check into if your fan clutch is going bad though.

 

[96RedRunner]

For the OP, when the ECU pulls timing because of the CEL, it also pulls power. with little to no timing advance the engine has to rev up very high to have enough power to move the vehicle like it did before. You might want to check into if your fan clutch is going bad though.

Sounds like your in limp mode because of knock CEL. Not a good idea to run it but to the garage as the book says.

@gamefreakgc, yours and 96Red were older than [MENTION=56396]Hepar[/MENTION] 01 don't know what [MENTION=168172]sleepydad[/MENTION] MY is talking about or what MY OP is having problems with, wonder if Toyota swapped from petro based to Soy based insulation in later years

 

[maclean216]

Do the harness and both knock sensors. Only use Toyota oem parts. Mine went out at 250,000. Only use Toyota parts for this.
It isn't that difficult of a job just time consuming

 

[Sitcoms]

First of all thanks to everyone who replied. Sorry for the delay, had some crazy stuff going on as of late. Gave me the info I needed, now to just come up with the money for it. It makes perfect sense that it would be in limp mode - High RPMs, lack of power to protect the engine.
[MENTION=139000]phattyduck[/MENTION], I am running a 2001 v6 4wd.
[MENTION=115347]gamefreakgc[/MENTION] I think that might be another thing I have going on. There was a 2ish month period where I was just CHEWING through coolant. Will have to see if that's an issue too.

the 'Loud noise' seems like the fans are running very loudly, in similar situations to loss of power, and occasionally at idle (high RPM)

 

[phattyduck]

There was a 2ish month period where I was just CHEWING through coolant.

!!!! Unless you found a leak and fixed it, that would explain the misfiring and low power... (head gasket) Let's hope that's not the issue.

-Charlie

 

[WWRD99]

Agreed on the Knock sensors...the loud fan noise???...can you turn the engine fan with the engine not running?? I have had a few of those clutch fans stick on where they sound like a Semi truck going from a stop...it should spin free when cold and a little tight when hot...not running of course...I have got 2 new clutch fans for my runners lately and one runs the fan hard from first start for about a minute or a few hard throttle hits and the other shuts off almost right away...I'm going to change the one that shuts off right away because it comes on sooner when it's hot out...maybe that's your fan noise issue??? Clutch is locked up to soon.