08 Hihy 3.3l, misfires on cyl 2 & 4. Cold start mostly

kornshadow097

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May 4, 2022
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5
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Make
Toyota
Model
Highlander hybrid limited
Year
2008
Miles
300000
Engine
3.3l
So after battling for several months. My 08 hihy is still misfiring when cold. On cyl 2 and 4. It did on cyl 6 as well before the headgasket was changed by an unreliable mechanic before I moved out of state.

I tested compression. All passed. I changed injectors on all 3 cyl, changed spark plugs, changed coils, replaced the bank 2 AFR sensor and even swapped components around with no changes.

I changed the oil and cleaned the maf sensor.

Fixed vacuum leaks and my mpg went up.

It all started when I had a blown headgasket and burned water, it would shake at start up n misifire mostly only when cold. Some mechanic replaced the gasket and I got a valve job and the heads checked and they passed. it worked fine for a few days then started misfiring on the same cylinders.

Runs smooth with minor misfires when hot, but cold especially at start up it adds up several and the check engine turns on after I turn off the engine and restart it later.

I bought a fpr and partsgeek was wrong about it being on the fuel rail... Cuz a diagram a friend showed me showed my exact part is by the pump in the tank..
N Id think if it was the fpr it would make several random cyl misifire not just the same 2 everytime..

Only possible culprits I can think of are:
FPR
ECM
wiring harness somewhere (fuel or ign)
CPS (crank and/or Cam position sensors)
Bank 2 sensor 2 AFR sensor

I'm out of ideas and am running out of money to toss at this problem.... I'd like educated guesses...
 

grcauto

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You should do a fuel pressure test if you want to know.
What do the trims do at cold start? Sounds like it still misfires after it's warmed up?
 

kornshadow097

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You should do a fuel pressure test if you want to know.
What do the trims do at cold start? Sounds like it still misfires after it's warmed up?
Yea I wanted to do a fuel pressure test but it's so messy to do in this car... It just never stops spewing out. Even with a battery disconnected. I lost an entire gallon last time I changed injectors, Everything is steel lines and banjo bolts.

Is there a less messy way to test for pressure on this type Of car?

I did a realtime datalog and got this for fuel trim:

had a - 19% on LTFT at idle with other rpm showing
- 11%. But I doubt it's enough to cause misfires unless an injector is being stuck open too long or not sealing properly when it's off.

Misfire datalog after 1 test run 5 miles til warm.
Cyl 1: 1
Cyl 2: 94
Cyl 3: 0
Cyl 4: 174
Cyl 5: 1
Cyl 6: 33

Just a quick restart after sitting 10min, misfires raised up.
Test run 2:
Cyl 1:1
Cyl 2: 205
Cyl 3: 0
Cyl 4: 200
Cyl 5: 1
Cyl 6: 33

It may misfire when warmed up but it's extremely slow and mostly only when the hybrid let's the engine turn off and it shakes to life (not always shaky. It's smooth after a maf cleaning). Misfires 80% are at cold start.
 
Last edited:

grcauto

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If you just want to guess and throw parts at it I can't help you.
 

nickb2

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I'm out of ideas and am running out of money to toss at this problem.... I'd like educated guesses...
I second what grc wrote.

Cuz if I read right, you want a educated guess. I will take time, I will see how this thread progresses.

Something is eluding you.

Focus on the steak.

So I am going for a shot in the dark, and take your writing to prove.

1 3 and 5, dead, why. ?


If it was a mass air flow problem, you would see it on all cylinders,.

Once you have eliminated the impossible, only one thing remains.

1 3 5 are on same bank.

So I am just going by logic, if 1 3 5 quite all at once, billr will second if he wishes, compression, if comp good on that bank, look edlswhere, and yup, stop throwing parts at the truck. Start wiggle test etc.

But I hugely suggest something that is real.

If this truck is still running on only one side, the engineer thought of this, so this is not a ecu problem, if AFTER 2 comp tests, guage is not the problem, that side if engine is shot. time to visual;ly inspect, and stop throwing parts.

I know the algorithm of this hybrid, no way it shuts down comp to near zero.

My educated guess, engine shot on bank one, extremely surprised it run, the the hybrid side may help, but thuis is not good, start looking for a knew engine.

so yeah. after taking time, my sherlock homes mind say, if repeated comp reading a close to zero, engine is screwed and needs investigation.

plz confirm if this was a educated guess?
 

nickb2

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So in case you find me condescending, (I assur you I am not trying) read my moniker, at risk of repeating mysylf. something very easy is eluding, no way bank 1 shows close to zero comp without something evident. Hybrid or not, comp readings dont lie. That bank is shot.
 

nickb2

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nickb2

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When things don’t go the way you expected, it’s time to figure out what went wrong, why it did what it did, and how to do it better next time. That starts with eliminating all the impossibilities, and narrowing down the remaining possibilities, in an effort to hunt down the truth.
;):bat:
 

billr

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Is the OP still with us? If so, speak up. I don't want to try getting this thread "out of the weeds" if the OP doesn't care anymore.
 

kornshadow097

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I second what grc wrote.

Cuz if I read right, you want a educated guess. I will take time, I will see how this thread progresses.

Something is eluding you.

Focus on the steak.

So I am going for a shot in the dark, and take your writing to prove.

1 3 and 5, dead, why. ?

>> I said cyl 1,3 and 5 are fine... Not sure why u are saying they're "dead"... They have almost 0 misfires combined.. Misfires on non-issue cylinders can happen if there are large issues in others. Seen it before lots of times.

If it was a mass air flow problem, you would see it on all cylinders,.

>>I know. But I already had it taken apart. So crossing maintenence off the list.

Once you have eliminated the impossible, only one thing remains.

1 3 5 are on same bank.

>> bank 2 is what has issues before and after the headgasket job.. Not bank 1.

So I am just going by logic, if 1 3 5 quite all at once, billr will second if he wishes, compression, if comp good on that bank, look edlswhere, and yup, stop throwing parts at the truck. Start wiggle test etc.

>> I'm not "throwing parts at the truck"... The idiot mechanic STOLE all the parts I just replaced. He got caught and "returned" the parts.... With junk yard parts cuz he had likely sold my brand new oem parts. Since he is mobile and literally closed his shop 3 weeks after taking my car in.. It was hard to get him to take accountability or answer calls. But after being threatened with legal action he suddenly became more available.

But I hugely suggest something that is real.

If this truck is still running on only one side, the engineer thought of this, so this is not a ecu problem, if AFTER 2 comp tests, guage is not the problem, that side if engine is shot. time to visual;ly inspect, and stop throwing parts.

>> THE head was redone. Completely for the gasket job. Unless that specialty shop also screwed up inspection, pressure testing and/or the valve job, then it's not that. Comp test shows 125-130psi on all problem cylinders (bank2). Which rules out gasket, rings. But the block could be damaged, I'd of thought the mechanic looked before putting it together since he is a certified dealership mechanic of 30+ years... And was referred by a long time friend who I worked with when I was a mechanic.

I know the algorithm of this hybrid, no way it shuts down comp to near zero.

>>? What are you talking about? Do u think my misfire datalog I posted, is compression results??

My educated guess, engine shot on bank one, extremely surprised it run, the the hybrid side may help, but thuis is not good, start looking for a knew engine.

so yeah. after taking time, my sherlock homes mind say, if repeated comp reading a close to zero, engine is screwed and needs investigation.

>>ur "Sherlock homes mind" needs to re read what I wrote... I said all cylinders passed compression...

plz confirm if this was a educated guess?

>> do you know anything about Ecu issues in 08 hihy suv's? I've read a lot from forums that the Ecu goes bad and things stop working well... Hybrid drive range decreases due to Ecu battery cooling controls going out of sync or config.misfires, bad fuel controls and more.

If I had a good eeprom burner or fancy computer to reflash for free I totally would.
 
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kornshadow097

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When things don’t go the way you expected, it’s time to figure out what went wrong, why it did what it did, and how to do it better next time. That starts with eliminating all the impossibilities, and narrowing down the remaining possibilities, in an effort to hunt down the truth.
;):bat:
Yea. That's why I listed it all. Maybe someone could catch something I didn't. I was a mechanic for 14yrs. But I've rarely worked on suv's, especially Toyotas suv's or hybrids. (not that hybrid really makes a difference with repair that's non hybrid related). So I hoped someone who knows more about the 3.3L highlander engine would maybe know of common causes for misfires. I mean I've heard things as silly as a gas cap causing all sorts of havok.

I bring it up because the last time I filed up I know it was empty since I drove a ton... Yet I went to add fuel in and it sprayed out... After adding 2gallons in a 14+ (IIRC) gallon tank... Have no idea why... Never heard of such an issue....
 

kornshadow097

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Is the OP still with us? If so, speak up. I don't want to try getting this thread "out of the weeds" if the OP doesn't care anymore.
I have a lot going on. I'm planning a 400mile trip with a borrowed car this week. I also have this problem posted on 3 forums so forgive me for not checking in often enough.
 

billr

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OK, I understand, no need for forgiveness about the delayed reply. I just did not want to invest time if you were gone for good, I type too slowly!

What are all the codes that are being set? Are there any other symptoms that 2-4-6 are all misfiring (like plug fouling or O2 sensor readings)?

What are the actual compression readings? Note that compression can be great, even if the exhaust valves are completely inoperative.

Which brings me to my biggest question right now: how much do you mistrust the "unreliable mechanic"??? Maybe the wise thing to do is pull the head and make sure the job is repeated and done right. At least, pull the valve cover and check valve timing on that bank.

This engine has VVT, correct? That opens up a whole new bunch of possibilities for the valve timing to be off, I'm thinking live-data may be good for catching/reporting problems there, but you would probably need to log all the data for careful analysis, not just a quick look-see at a few parameters.
 
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