Misfire Problem - Could use some help

[thegipper]

One other thought. My step dad's 06 Tundra was throwing a random code (something to do with the idle actuator or something like that). We diagnosed it using the FSM and everything came back fine. When the code would show up, his truck would go into limp mode.

The only thing that we eventually ended up doing was cleaning all of the grounds because they all looked pretty bad. Since we have done that, the code has never showed up again (about 8 months ago).

Poor grounds can cause some crazy stuff and are often overlooked.

 

[mtbtim]

Is he loosing any coolant?

When my HG started to go on my original engine I pulled the plugs and they all looked the same to me, including cylinder #3 which is where I had my misfire. I even used two different bore scopes to inspect the cylinders/pistons and I couldn't tell any difference.

Dye test was worthless, didn't change color at all.

Finally, the leak down test was how I 100% knew I had a HG failure on cylinder #3. The second I started to pressurize the cylinder, bubbles started coming out of the radiator. I was loosing coolant though. Not a ton but enough where after a few weeks it was down about an inch in the reservoir.

Hopefully its something else/simple.

Greg has mentioned nothing about losing coolant. If he did, I would have suspected a possible HG leak immediately. But, I'm going to ask him just to be sure.

 

[thegipper]

The amount of coolant I was loosing was not like "omg, where the hell is my coolant". It was a super tiny loss over a couple weeks. Not enough to notice unless you are looking for it. Just have him double check it (bring truck up to operating temp) and see where his level is in the reservoir.

My cylinder #3 compression test numbers were pretty damn similar to the other cylinders I checked (only checked the passenger bank). Leak down test is by far the best test to know for certain. If the leak is super tiny, it won't really show up on a standard compression test.

If he isn't loosing any coolant, you probably don't need to do a leak down test but you can certainly do it for peace of mind.

I don't know for certain if an 02 sensor can cause a misfire but I believe I've read that a bad one (won't always throw a code either) can cause either too much or too little fuel. But, if the code is always for just one cylinder, that makes me think its not an 02 sensor. You would think that you would have misfires on other cylinders too. But then again, I don't know what the hell I'm talking about in this area soooo.... lol

 

[det107]

..... was swapping ECU's. I went to a local yard and grabbed one and swapped it in...

Wondering if the old ECU is still laying around? Perhaps go inside to "take a look" to see any burned circuits.

I got a reman from a San Frisco outfit & it was VERY pricey-

 

[thegipper]

I actually did open it up to see if anything obvious stood out. Unfortunately, it all looked fine.

 

[LittleCaesar]

Greg has mentioned nothing about losing coolant. If he did, I would have suspected a possible HG leak immediately. But, I'm going to ask him just to be sure.

Usually with a leaking HG you only see it on initial start up. White smoke, etc., then it can go away as the engine warms up.

Using a leak down tester, as [MENTION=138943]thegipper[/MENTION] can attest, leaves no stone unturned so to speak.

Just for clarification he had the 301 before changing out the injectors, wires, plugs correct? Are they OEM?

And yes, a lazy O2 sensor can throw a code, rare, but happens.

 

[mtbtim]

Usually with a leaking HG you only see it on initial start up. White smoke, etc., then it can go away as the engine warms up.

Using a leak down tester, as [MENTION=138943]thegipper[/MENTION] can attest, leaves no stone unturned so to speak.

Just for clarification he had the 301 before changing out the injectors, wires, plugs correct? Are they OEM?

And yes, a lazy O2 sensor can throw a code, rare, but happens.

Yes, he had the P0301 code before he replaced the plugs and wires and the injectors we replaced the other day. The plugs and wires looked OEM to me.

I reckon I'll add the O2 sensor to the list of possible causes.

 

[DaMonkey]

Funny... I wanted to pull my injectors and went to go see if you have a video for that. You posted it 2 days ago for your friend Greg's 0301, and I figured that was for this thread?

Did the injector swap cure his code? I didn't see an update in the video.

FWIW... I just pulled my old man's injectors out (non Toyota) to send to witch hunter. They are backed up like 2 weeks, so I found a new guy and he turned them around day after he received them with a thorough report. Very very nice guy and he was only $17 per injector: Description of our fuel injector cleaning & flow testing process.

 

[mtbtim]

Funny... I wanted to pull my injectors and went to go see if you have a video for that. You posted it 2 days ago for your friend Greg's 0301, and I figured that was for this thread?

Did the injector swap cure his code? I didn't see an update in the video.

FWIW... I just pulled my old man's injectors out (non Toyota) to send to witch hunter. They are backed up like 2 weeks, so I found a new guy and he turned them around day after he received them with a thorough report. Very very nice guy and he was only $17 per injector: Description of our fuel injector cleaning & flow testing process.

It did not fix the misfire. I'm going to try some more things when I get Greg back over my place and hopefully we can figure it out.

 

[DaMonkey]

It did not fix the misfire. I'm going to try some more things when I get Greg back over my place and hopefully we can figure it out.

You mean it did not fix the misfire 'code'... FTFY... I think Greg or you had mentioned that there was not any kind of drivability issues or rough idle? Just the annoying CEL?

Is there any information available what these ECUs measure for symptoms to trigger the 0301 code? 'How' does it determine misfire in #1?

Just curious... did you have before and after flow numbers from the injectors? How many miles? Also, why not swap the regulator while you had it out?

Sorry to hear it did not fix it. Injector video was a good one though. Quite a stache you have rollin'...

 

[mtbtim]

You mean it did not fix the misfire 'code'... FTFY... I think Greg or you had mentioned that there was not any kind of drivability issues or rough idle? Just the annoying CEL?

Is there any information available what these ECUs measure for symptoms to trigger the 0301 code? 'How' does it determine misfire in #1?

Just curious... did you have before and after flow numbers from the injectors? How many miles? Also, why not swap the regulator while you had it out?

Sorry to hear it did not fix it. Injector video was a good one though. Quite a stache you have rollin'...

Yeah, after driving 20 miles, the P0301 CEL code popped back up. His engine idles and runs smooth. Greg did say he had better throttle response and the engine felt like it had more power after the injectors were swapped out.

Yes, there's information on how the ECU measures for a misfire in they FSM but I don't have my FSM with me right now. I'm stuck at work for another day. If I'm remembering correctly, it uses the crank position sensor and knock sensor and other feedback I'm not remembering to determine a misfire.

I bought the injectors for Greg in advance while I was visiting a friend in Los Angeles so we don't have any before and after flow numbers. I think Greg's engine has somewhere in the neighborhood of 150k miles. We didn't swap out the fuel pressure regulator because it wasn't something we were suspecting was bad. But, maybe we should have. I wonder what they cost.

Already got rid of stache. I grow one but never keep them for long.

 

[LittleCaesar]

Never heard of a FPR causing a misfire, or at least one that was cylinder specific. If you pull off the vacuum hose and fuel comes out, or you can strongly smell gas, then you have a problem. Otherwise assume it is fine.

My $$$ is still on the A/F sensor if it is original or is a non OEM/Denso replacement.

If you don’t have one Tim, invest in a fuel pressure tester that includes the banjo bolt. Less than $60 usually.

 

[mtbtim]

Never heard of a FPR causing a misfire, or at least one that was cylinder specific. If you pull off the vacuum hose and fuel comes out, or you can strongly smell gas, then you have a problem. Otherwise assume it is fine.

My $$$ is still on the A/F sensor if it is original or is a non OEM/Denso replacement.

If you don’t have one Tim, invest in a fuel pressure tester that includes the banjo bolt. Less than $60 usually.

I'm going to get Greg back over my place this Sunday to replace his upstream A/F sensor.

I don't have a fuel pressure tester. Do you have a link to one you like? Where do you hook it up to? I know there's the banjo bolts I disconnected on the fuel rails.

 

[thegipper]

I'm going to get Greg back over my place this Sunday to replace his upstream A/F sensor.

I don't have a fuel pressure tester. Do you have a link to one you like? Where do you hook it up to? I know there's the banjo bolts I disconnected on the fuel rails.

I couldn't find a kit that had a banjo bolt adapter (searched Amazon) that fit Toyota fuel rails.

I think you can buy any decent fuel pressure gauge and use this adapter.

I don't remember which brand one that I bought but it's nothing special. Most fuel pressure gauges have a 7/16-20 threaded schrader fitting. The banjo adapter that I linked threads onto the 7/16-20 threaded schrader fitting on the gauge, and the other end has the metric M12x1.25 that Toyota uses on their fuel rails.

Most domestics have the 7/16-20 schrader fitting right on the fuel rails so no adapter is needed.

 

[LittleCaesar]

Ask and you shall receive. Usually can be found on Fleabay for $45:
https://www.summitracing.com/parts/anm-cp7838

Be aware that you will have to buy the crush spacers for the banjo bolt to hook up to the fuel rail. They usually sell them in packs of ten at the dealer.

Good luck; I am not one to fire the parts cannon without hard data but go for it. Change the rear one also if $$$ permits.

 

[DaMonkey]

Never heard of a FPR causing a misfire, or at least one that was cylinder specific. If you pull off the vacuum hose and fuel comes out, or you can strongly smell gas, then you have a problem. Otherwise assume it is fine.

My $$$ is still on the A/F sensor if it is original or is a non OEM/Denso replacement.

If you don’t have one Tim, invest in a fuel pressure tester that includes the banjo bolt. Less than $60 usually.

Agree that regulator would be unrelated to single cyl miss. I'm not sure if your question was in response to my question about regulator. I only axsked about it because Tim is diligent about replacing wear items (like the crush washers in his video), but not the regulator. I've kind of thought of regulator as something worth swapping at that point, but maybe a reason not to.

 

[thegipper]

Ask and you shall receive. Usually can be found on Fleabay for $45:http://https://actron.com/content/professional-fuel-pressure-tester-kit

Be aware that you will have to buy the crush spacers for the banjo bolt to hook up to the fuel rail. They usually sell them in packs of ten at the dealer.

Good luck; I am not one to fire the parts cannon without hard data but go for it. Change the rear one also if $$$ permits.

Your link didn't work for me but I believe this is the same kit. I found it on Amazon and according to the "questions/answers" it does come with the correct banjo adapter.

https://www.amazon.com/gp/product/B0009XQUKC/ref=ask_ql_qh_dp_hza

 

[LittleCaesar]

Your link didn't work for me but I believe this is the same kit. I found it on Amazon and according to the "questions/answers" it does come with the correct banjo adapter.

https://www.amazon.com/gp/product/B0009XQUKC/ref=ask_ql_qh_dp_hza

Thanks Mike. I fixed my link. This pressure tester works well for anyone, especially those automobiles that used a fuel filter in their system. On the direct injection and such today, not so much.

 

[LittleCaesar]

Agree that regulator would be unrelated to single cyl miss. I'm not sure if your question was in response to my question about regulator. I only axsked about it because Tim is diligent about replacing wear items (like the crush washers in his video), but not the regulator. I've kind of thought of regulator as something worth swapping at that point, but maybe a reason not to.

Just going off experience more than anything here, if the FPR was failing or bad, Tim should be able to pull off the vacuum hose and fuel would either spill out or at least the smell of it would be noticeable. Here though, is where a pressure tester would put to rest any questions.

 

[mtbtim]

Ask and you shall receive. Usually can be found on Fleabay for $45:
https://www.summitracing.com/parts/anm-cp7838

Be aware that you will have to buy the crush spacers for the banjo bolt to hook up to the fuel rail. They usually sell them in packs of ten at the dealer.

Good luck; I am not one to fire the parts cannon without hard data but go for it. Change the rear one also if $$$ permits.

Yeah, I'm pretty much throwing parts at it but I've replaced both the upstream and downstream sensors on my rigs without any known issues to fix. With the miles he has on his rig, the sensors are probably a little lazy I'm suspecting.

I'm going to check out that pressure tester. Thanks!