Power Problem - Help!

[TONEDOG513]

Gentlemen,

'07 V8 Limited 225k - Owner 14 years now.

Problem: No power

Conditions: 85 degrees and over, a/c on, average drive 7 miles, 5x a day.

I know the summer is rough on this truck with the a/c running and sometimes even the fan fully engaged.

But I know this vehicle well and this is different.

This is a depress accelerator down steadily, continuing to depress until way passed normal waiting for acceleration to happen, wondering if rpm's are ever gonna get up, usually "she never needs more than 3k to go anywhere i need, highways ramps ect.. however this passes 3k, 4k rpm and still not impressed. (No fan roar during this btw)

At first I thought air is hot coming in, mas airflow, heat soak ect.. ect...

But then today a hot 94 degree day, drove to the office after and hour of around town work, nice and toasty, parked for 3.5hrs, go to leave, jump in, start to pull out of the parking lot, i need to make a sharp right, and go up and overpass immediately, then around the on ramp and onto the highway that requires a good long hard straight push to get up to speed.

I make the right out of the lot with what felt like normal power, until the 1st shift and "bog city" I hung in there over and onto the ramp (thinking wtf was that) go around and launch her from almost a stop, she kept the rpms climbing with a lot of throttle applied, but no where near normal.

No codes thrown

At the time;

Trans temp 138.1
Coolant 194.0
Volts at ecm 13.2
Cat 1,368
Intake 95
Almost full tank Mobil 93

Pretty cool compared to what she runs at in a 95 degree day normally, just got outta the lot stats.

After my trip, 30mins, I check the temp of all 4 rims by feeling, incase maybe had a stuck caliper, all warm but no one different than the other.

So who wants to take a guess?

1. Throttle, maf, intake, ect..
2. Tranny, 2nd gear, old, slip...
3. Fuel delivery....
4. Sensors....

Where to even start...

Thanks in advance..

Tonedog

 

[rdruss]

So rpm goes up but mph does not as would be expected?
If that's what you are saying it sounds like trans to me.

 

[TONEDOG513]

I'd add that I feel like I detected previously some slight surging or better engagement/lock/power after 2800 rpm...

Could maybe it be a worn torque converter?

Is that a thing with these...

 

[Syr4RinNC]

Sounds similar to when my transmission went

 

[CameronHannah]

To me it sounds like a transmission issue, but I am definitely no mechanic. Just sounds like an issue I had with a previous vehicle. I’ll ask a couple buddies of mine and see what they say.


Sent from my iPhone using Tapatalk

 

[Captsolo]

Start by changing the plugs. I have three F 225 Yamaha 4 strokes and when an engine "bogged" I changed the plugs and fix the issue - and got 59000 RPMs (before 5000 rpms). Had this issue several times with Yamahas. Changing plus solved the issue.

4runner 2005 SR5 144,000 miles - runs like a champ/new. original owner

Use iridium plugs

After plugs I'd look for fuel issue - filter block - fuel pump failing (always buy OEM), vacuum leak?

Find a top mechanic to diagnose with good testing equipment.

 

[DRUG DEALER]

cat? catalytic converter? that temp is extremely high if thats the case.

 

[TONEDOG513]

Plugs changed with dealer denso iridium last year, could still give em a check.

Catalytic is a good one, could be. I'll have to look up how to check em. I do notice they run at idle around 900ish but as soon as I start to drive they shoot up to 1400/1500, then if I stop and hang they will cool pretty fast down and then will go up fast the minute I'm on the throttle. Does this indicate a problem? What is normal at lets say 55mph cruising?

I have some more i fo on the problem to share.

For the last 2 days I have not had the issue because I have not used the a/c in a specific way (I'll get to it) then today I decided to duplicate my initial problem and I was able to exactly.

Here is what I found.

If I start engine with a/c off and use on highways only I'm good to go. If I start up (not 1st of the day) with a/c on it happens.

Leaving work i started with a/c, pulled up to the apron of the lot to make my right turn and go up the inclined over pass, I let a bunch of cars pass, i make the turn and get on it, it totally bogged. It couldn't get the rpm's up fast enough, like between idle and 1900rpm after 2k it felt better.

Now the previous 2 days with no ac I was watching out for any shifting funniness and nothing, she pulls hard in every gear and shifts nice. Of coarse she's not the same as when she has 30k on her!

She's rated over 7k tow with the big hitch, imagine i made that turn with ac on and a 5k trailer! LOL I would been in serious trouble!

How does one check fuel pump, system ect..?

I run the 93 octane every tank for years, because I like the power and have had some rattling from detonation at high rpms for about 8 years, I wonder is she being retarded (timing) under the load of ac, hot, incline, 225k, cause of a major ping/rattle?

Oh god this is drive me nuts. My mind is rolling with ideas now!! I could keep typing forever, let me stop.

Best
T

 

[ElectroBoy]

Plugs changed with dealer denso iridium last year, could still give em a check.

Catalytic is a good one, could be. I'll have to look up how to check em. I do notice they run at idle around 900ish but as soon as I start to drive they shoot up to 1400/1500, then if I stop and hang they will cool pretty fast down and then will go up fast the minute I'm on the throttle. Does this indicate a problem? What is normal at lets say 55mph cruising?

I have some more i fo on the problem to share.

For the last 2 days I have not had the issue because I have not used the a/c in a specific way (I'll get to it) then today I decided to duplicate my initial problem and I was able to exactly.

Here is what I found.

If I start engine with a/c off and use on highways only I'm good to go. If I start up (not 1st of the day) with a/c on it happens.

Leaving work i started with a/c, pulled up to the apron of the lot to make my right turn and go up the inclined over pass, I let a bunch of cars pass, i make the turn and get on it, it totally bogged. It couldn't get the rpm's up fast enough, like between idle and 1900rpm after 2k it felt better.

Now the previous 2 days with no ac I was watching out for any shifting funniness and nothing, she pulls hard in every gear and shifts nice. Of coarse she's not the same as when she has 30k on her!

She's rated over 7k tow with the big hitch, imagine i made that turn with ac on and a 5k trailer! LOL I would been in serious trouble!

How does one check fuel pump, system ect..?

I run the 93 octane every tank for years, because I like the power and have had some rattling from detonation at high rpms for about 8 years, I wonder is she being retarded (timing) under the load of ac, hot, incline, 225k, cause of a major ping/rattle?

Oh god this is drive me nuts. My mind is rolling with ideas now!! I could keep typing forever, let me stop.

Best
T

So, this happens only when the A/C is On?
If you’re driving with A/C Off all is well?
If you then turn A/C On it bogs down?

 

[TONEDOG513]

@ Electroboy

Yes with ac on.
Kind of slow to accelerate without (just thought it was old age)
In general there has always been a huge loss in power with a/c on.
But the bog is different, it could get me in an accident entering a highway for example.
Maybe its happening without also but just that the ac being on makes it more obvious.

 

[TONEDOG513]

I'm searching and searching everywhere to find an average catalytic temp for 4runner....

Tough to find.

Anybody can check it would be great.

Best
T

 

[ElectroBoy]

@ Electroboy

Yes with ac on.
Kind of slow to accelerate without (just thought it was old age)
In general there has always been a huge loss in power with a/c on.
But the bog is different, it could get me in an accident entering a highway for example.
Maybe its happening without also but just that the ac being on makes it more obvious.

Could the A/C compressor itself be the problem? Maybe the bearings are shot and seized up. This could put a huge load on the engine.

 

[spdrcr29]

Could the A/C compressor itself be the problem? Maybe the bearings are shot and seized up. This could put a huge load on the engine.

Was just thinking the same thing after reading all your posts. If the issue only happens when the A/C is turned on, i would look for something with the compressor possibly causing it...

 

[rdruss]

A/C compressor bearings seized you would burn up the serp belt wouldn't you, or the compressor clutch would kick in (?) and you wouldn't notice except no A/C?

 

[Keros]

Reading through the replys, I'd love to speculate:

I don't think any of the front pulleys on the accessories could be the problem, as someone mentioned the serpentine belt would probably get eaten long before it produce the kind of power loss we're talking about. And the bearing, if rotating at all, would SCREAM BLOODY MURDER while being rotated.

The emissions related elements are generally very sensitive to throwing codes. Almost anything even a smidgen out of normal and it'll throw a code. So clogged cat, that sort of thing, I'd assume would produce a code?

Now maybe fouled plugs won't throw a code... but I had a coil pack that was full of water and it just didn't run great, but moved the truck along pretty well still. But interestingly did not throw a code. But for bad plugs to cause that sort of power loss? That'd be odd. Does it soot really badly out the tailpipe after being hard on the throttle?

I'm very much leaning towards a transmission issue, as others have mentioned. Seems the ECU knows alot more about what the trans is doing and problems it may have than the check engine light codes display. I think a selenoid has to completely fail for a CEL to turn on. All my transmission problems never produced a check engine light, and they were pretty bad at various points; except for when a solenoid completely failed and put the truck into limp mode... obviously because the truck couldn't get past 3rd gear.

Because the A750 (the V8 trans) is so similar to all the A-series transmissions, which have a lineage going back to the mid 80's, many transmission shops have a lot of experience with them. It might be worth a few phone calls to shops and see what they tell you.

At the end of the logic train, I really can't think of something engine related that would cause that sort of massive power loss that doesn't throw an engine code. Maybe fuel pump? But wouldn't that cause lean errors? All rotating assembly items are good otherwise it would have exploded by now. MAF? Maybe? They're surprisingly cheap for a Toyota MAF, so maybe worth a try... but again, that's emissions related so I'd expect a CEL code if there was a problem.

I love a good speculation and look forward to seeing your problem resolved (hopefully inexpensively as well). Best luck!

 

[ElectroBoy]

[MENTION=55794]TONEDOG513[/MENTION], All good ideas here, but the common trigger is AC on. Even a properly operating AC compressor presents a huge load to an engine. That’s why there’s an idle up function that increases idle speed when the AC kicks on while sitting at a traffic light. And there’s some sort of acceleration sensing AC cutout, to temporarily drop the AC compressor load when under heavy acceleration. Probably controlled by the MB ECU and depending upon the input of several sensors. Like throttle position sensor, speed sensor, MAF sensor, etc., maybe an AC control relay.

It’s good to check on all your common tune up items but you might wind up going to someone who has special AC system knowledge with Toyotas.

 

[randy88fj62]

You said "rattling and detonation" issues for years when running regular octane. You are masking the problem by running 93? My 08 V8 never has an issue with low octane.

This tells me you should check the gap on your spark plugs. If they are too far apart your truck is struggling to get a good burn.

Another person mentioned vacuum leak but I doubt that as you would have stalling issues as well.

Fuel and spark. Sounds to me like your spark may be the issue.

 

[TONEDOG513]

Gentlemen thank you

In order I guess
[MENTION=34192]Keros[/MENTION]

The a/c is cold, cycles on and off, and little uptick in idle and back down during engage/disengage, belt and pulleys are quiet. All supporting the compressor being ok.

Checked the plugs they look good. They are still young.

That is an interesting story about the coil pack, mine are original and the wires as well. Maybe something to think about. No soot at all from the tailpipe, only water vapor.

About the throwing codes, never realized it was that sensitive. i almost wish it would.

Well about the tranny, I hope it isn't, I always feel weird calling tranny shops, I never know if the info is biased or not, i guess it wouldn't hurt, I wish there was a place I could go to and run a diagnostic on it. It does shift manually through each gear nice, tons of pull, it does shift and pulls hard through all gears and locks up the OD nicely. I do admit, she doesn't have the same get up and go off the line like she once had, and is a little slow keeping up shifting, if i race around short neighborhood blocks making fast left, rights, stops signs, but i don't really drive like that anyway.

I took it down tonight to a safe spot to launch it a couple times, in auto and manual modes, no a/c. it feels like it is boggy in the 1st gear from idle to about 2000/2500rpm and then is better and kind of kicks into a power band, problem with being in auto is that the shift to 2nd comes relatively fast, now when manually in 1st same thing boggy (like not enough air or exhaust) and at 3k - 5k is a beast all torqued up on steroids! It seems like if she came off the showroom @ 260hp, 12 years later of general wear she is @ 210hp hypothetically and the extra 50hp make the difference in that 1st gear from idle until the motor is making enough power to overcome, then add an a/c on, fan clutch partially engaged, 167 degree air in through the intake and now she's at a point of critical mass and just all the pieces together yield this scenario.

If you hop on the throttle from a dead stop, ur waiting to get outta that low rpm band and into the next band, then slow rapidly to a stop and get on it again it does the same thing, you can recreate it every time. The time it takes to get the mass rolling is the bog add 50hp and your happier/time to roll is reduced, add 100hp and the effect is minimized again etc. etc.

The question is where did the hypothetical 50hp go? I’d say a couple hp from all over, compression loss, carbon buildup, clutches, converters, injectors less efficient, diffs, everything really up until the power touches the ground.

How do you fix that? Tear the motor down and rebuild it, tear the tranny down and rebuild it, rebuild the diffs, replace the exhaust, replace drive shafts, all rubber components, pulleys, breaks, etc. Maybe throw a supercharger on it! The bog would be gone, but that tranny probably last a week! Lol.

Maybe one could speculate there is a failing component like the coil packs or the catalytic that could yield enough of a gain if repaired to allow for the truck to be peppier in that low rpm range and overcome the issue.

Wow did I just talk myself out of believing there is any problem at all! Lol

You guys with over 200k must be feeling the effects of hp loss due to wear or maybe with all the mods like big tires and stuff the perception of what once was and should be is lost in the mods that are known for some loss, like the big tires.
[MENTION=200736]ElectroBoy[/MENTION]

What a well thought out idea! I make the turn, the a/c is on, I give it some “go” and the compressor which should disengage to afford me the power for my maneuver doesn’t do it! Yummy. This is a great idea, I wonder what controls that, maybe I get lucky and a simple relay of some sort detects the throttle position that could be tested easily.

 

[TONEDOG513]

Sorry I missed one comment
[MENTION=403609]randy88fj62[/MENTION]

Yes years. It started around 30k out of nowhere really. At this point I was a consultant for the Toyota dealership where I purchased the vehicle new. It still had a warranty and I was in a very good position to get some really good eyes on troubleshooting the issue. I did just that, i had to be there at least once or twice a week for the whole day and the truck would go in to be looked at. Nothing really came of it, if you look up my previous threads from around 2010 you will see me talking about it on this forum.

During that time the iridium’s were supposed to stay in 90k or some ridiculous time imo, so I had them changed every 50k that means they have been changed approx. 4 times already, once by myself and the gap is good. Even though it does say on the box not to gap the irids..

But what you’re saying I think still holds weight, what if spark is a problem, and instead of plug, we said wire, or coil? Still spark and still a great thing to look into...

I can't tell you how it has bothered me since 30k - 225k that i hear that crap!

As for the vacuum leak, I like that idea too, I will look up a place that maybe could smoke test it for any leaks.

As for the fuel you mention, That too may need a check, I did have some weird problem with a knock in the mornings when 1st putting it in drive or reverse and holding the brake, sound like a rod knock/motor knock. i took it in for that to the dealer and they said nothing found, i kept taking it in and they never found anything but they did make up a that they detected in so a "super" tech would come down from Toyota to look at it. He came down and said fuel pump and related components were causing that knock, a fuel knock, so the fuel pump and related components were replaced. Although i felt like it still did happen once in a while during winter, i never really pursued it. I might have made a post in this forum about that knock also.

Weird stuff right! Funny too how fast you go from 13 miles on it from the dealer and now 225k miles, so much has happened in my life in that time and with all the stuff i complain about this truck it is still taking me to work, fishing off-road, long trips without ever being towed 1 time.

Go figure!

I might just go crazy and change the wires, coils, maf, smoke it, check the relays and see what happens.

 

[Keros]

Holy crap, this has been going on since 30k on the clock? I'd have gone nuts.

Yeah, I'd say something is wrong that can be corrected: I had my truck dyno'd at ~260000km and it put down 206awhp on the rollers. Doing some redneck mathematics from some forum post I found somewhere about the relationship between driveline losses vs wheel weight, I calculated I've lost negligible horsepower over the stock 270hp.

Perhaps an oil, coolant, and transmission fluid analysis might tell you something about the condition of various parts. Mostly about the combustion habits going on from the oil, and overall health from the transmission fluid. Coolant just for good measure.

It's wildly disappointing Toyota let this go on for so long while it was still in warranty