Misfire guidance needed - 2005 1GR-FE Misfire

Man, this truck is a love hate...... I love a Toyota and I love not having a car note..... and generally these things are bulletproof. I use it for Fire/EMS response and my daily commuter so it's not totally uncommon for it to be idling for 20-60 with the strobes flashing....... but this truck the last few years...... it's just not doing what Toyotas are supposed to do: just fricking work and under no circumstances - fall apart!! . What can I say, I am a Toyota and VW fan for a reason.

Right then, here's the 30 second skinny:

-243K Miles
-P0300, P0303 and P0304 (started up out of the blue after an oil change with Rislone additive)
- Currently 10K miles ago, I replaced the head gaskets after I heard gurgling at shutdown with multiple P0300 and P0301 misfire codes. (It's a 2005 Taco..... known headache on the 1RG-FE motors)
- 10K miles ago: new cam sensors, MAF sensor, timing set and oil solenoids.
- This week, I changed Plugs, coils, and fuel injectors over the last few days after work. (Bosch, Denso)
- Cleaned throttle body and MAF sensor (CRC brand)
- All ignitors gapped to .40 (Bosch 8810 iridium)
- I almost always fuel with 88 octane 100% gas at the RaceTrack here in town, (none of that ethanol BS!)
- Air filter cleaned (K&N last 2 years)
- Intake ports cleaned (while I was changing the injectors yesterday, those intakes were pretty foul looking.)
- Battery disconnected and reconnected after 30 min (just to trying to reset the computer.)
- Injector/carb cleaner used in gas once a month (I generally fuel up 8 times a month).
- 80% highway, I generally run in 5th doing about 70-75 mph on interstate on my commute for about 45 min twice a day.
- I don't tun it hard.... I treat my rides like I treat my wife and kids.
- other than this lunacy, it rides well, Ive worked all f the bugs out and got it back to awesome status...... but about 3 times a year some nonsense like this presents itself!!!
- Arrrrrraaaaaggggghhhh!!!!!

I'll be checking compression this week and bleed down as well.

Any further guidance would be appreciated from my fellow brother and sister Tacoma owners/mechanics..... especially for any of y'all who have had to deal with this on the 2005/2006 1GR-FE motors. Really though, I just don't want to get rid of a paid for Tacoma.

Thanks in advance!!

Nuch

 

Sorry its late and I'm wearing my back up glasses I thought I read 305. Disregard.

 

Bishop.... LOL. It's cool..... might have been one of my edits after I posted and reread. So, a borescope of the valves. Dude, I'm gonna drive this thing into the Mississippi if I have like -25 psi from the other 4 or 5 cylinders this week. How much you think a crate motor rebuild goes for?? Cheaper than the repair of the installed one??

 

Going to have to do the hard work and check the plugs, then coils, then compression then do a cylinder leakage. The thing that sort of worries me is the P0300 code.

 

Yea, but I replaced the plugs, checked gap to .040, installed, replaced Denso coils. Looks like we have 2/2 in the thread so far (plus me) looking at the compression checks next!! :/

I'm just glad these 1GR-FE are easy to wrench on.... like a 90s Chevy or a Subaru....... pure ease....... but if you're like me, we just hate spending $$ on what should be top-top mechanics

 

They arent terrible to work on. Highly agreed. Just annoying as they should not be as much maintenance as they are. For sure do a compression test, if not, cylinder leakage and you will find your answer in no time.

If both those tests pass stellar then you have another issue and then we can go from there.

 

OK, I've finally got some numbers:

Cylinders 1-6 all between 150-155 PSI, they all bleed down a little bit but nothing worth getting all uppity about.

I pulled number 4, and held a paper up to look for any coolant in the cylinder. It's not getting any fuel, just only blowing hot air. I wonder though, if a coil is not attached to a plug, will that cylinder's injector spray fuel into the cylinder. The good news: there was no coolant blowing out go the igniter port either. Only reason I ask is that it's clear the number 4 infighter plug has been firing just fine. P0304 is recent (a few days before this post) and it ran well for over a year since the head gasket replacement.

I'm starting to lean towards electrical at the point.

Nuch

 

P0300 was an anomaly..... came and went. Hasn't resurfaced in several days. Leak down was 15-20 PSI on all cylinders..... puts me at 10-15 % about. I'm an airplane guy by trade and we have some tight compression/leakdown limits..... I understand we are a bit looser though where light vehicles are concerned. Like about 25-30% is when it time to be concerned?? Is that accurate?

Nuch

 

Yeah 30% leakage is well within tolerable range.

I don't understand your last message. Your verbiage is not automotive and I don't know the aero industry lingo so you gotta translate it over for me.

 

-P0300 only displayed once in the last doze or so OBDII reports
-When 100 PSI applied to each cylinder with, the most bleed down was 20PSI. Still had 80PSI so I think that was a good cylinder in auto. Lycoming and Continental engines are a little different in tolerances for compression, leakage, et cetera.
- Light vehicles meaning cars and light trucks on the road with Chevy and Ford motors vs a Bonanza with a Continental motor.

At the end of the day, you validated that 30% leak down is good so I'm well in limits. Just trying to see of all of our Tacoma lovers have seen anything that might point it into the electrical issue category or have Just missed something in the checks to get #4 to start firing again.

- Nuch

 

What methods do you have of testing for spark and fuel in #4 cylinder?

How many miles do you have in the rebuild and what sort of condition were the injectors/ coils in when you did the engine?

You could do a dynamic compression test on 4 and any other cylinder to be 1000% sure that it is not an actual mechanical misfire.

 

-243K Miles.
-No method for testing spark, I only have a dry igniter. I will be getting a pulse tester from a mech at work so I can test my injector harnesses on Thursday.
-Head Gaskets replace 16 months ago for #1 and #2 misfire combined with leaking coolant (no brainer head gasket failure).
-About 30K since the gasket replacement.
-Injectors are 4 days old.
-Igniters are 7 days old.
-Compression check was 150-155 PSI on all cylinders.
-Bleed down was 15-20 PSI on all cylinders.

- Nuch

 

Sounds like an electrical issue if everything is fresh and engine mechanicals check out okay.

By pulse testing are you referring to the noid lights? If so those things are junk and pass on that. You may have to break out the heavy artillery and get a graphing labscope if you want to spend the money on it. If not, you may have to take it to a shop that has access to such capabilities.

 

Yeah..... Noids......... I know they're not the greatest thing since canned beer and many of us are not the biggest fans, but I'm about to wit's end now, bro..... As far as the M1299 artillety (oh yeah..... good stuff right there), I can't take the scopes from work, nor can I use work equip for personal gains..... it's cool though, its a great job!!! But........ rules. Yeah, Jeff and I were talking at work today about that and he was at a dealership for like 20 years before coming to the aviation GSE side of wrenching. We're both looking toward the electrical side of issues, but dude..... I don't smash wires, I don't break wires, and these wires in cars tend to hold up real well. I just worry that willet spends because working 6 days a week, time is limited an I'll want to outsource that to a pro.

- Nuch