This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
gregnash
Anal Retentive Analyst
- Thread starter
- #23
Alright scheduling some time with my dude on Thursday.
Connected Techstream on the way back to work from home and did a couple recordings.. Got a P0300 (P0301 was thrown on Sunday but hasn't returned) code as I was seeing misfires all over the place while idling, nothing while driving, no stumbling or stalling just stumbles a bit and rough idle.
FTs are #1 - 19.49S/21.82L , #2 - 19.49S/21.82L while idling. Doesn't move or jump around during idle but does once moving.
Once driving
FTs are #1 - 3.87S/19.49L, #2 - -0.04S/17.15L at 1588RPM
FTs are #1 - 11.68S/21.83L, #2 - 11.68S/21.83L at 1084RPM
FTs are #1 - -4.72S/17.15L, #2 - -4.72S/17.15L at 1837RPM
So what I am seeing is that below 1500RPM the FTs are kind of all over the place.
Other thing I am seeing is that the O2FT B1S2 is reading 99.15% so wondering if that sensor is shot and causing issues.
Also Cylinder #1 is consistently seeing misfire events, unfortunately with v12.24 of Techstream I don't have the ability to do a EWMA event lookup that would show me for sure which cylinder is having the misfire but this seems pretty consistent when at idle.
Connected Techstream on the way back to work from home and did a couple recordings.. Got a P0300 (P0301 was thrown on Sunday but hasn't returned) code as I was seeing misfires all over the place while idling, nothing while driving, no stumbling or stalling just stumbles a bit and rough idle.
FTs are #1 - 19.49S/21.82L , #2 - 19.49S/21.82L while idling. Doesn't move or jump around during idle but does once moving.
Once driving
FTs are #1 - 3.87S/19.49L, #2 - -0.04S/17.15L at 1588RPM
FTs are #1 - 11.68S/21.83L, #2 - 11.68S/21.83L at 1084RPM
FTs are #1 - -4.72S/17.15L, #2 - -4.72S/17.15L at 1837RPM
So what I am seeing is that below 1500RPM the FTs are kind of all over the place.
Other thing I am seeing is that the O2FT B1S2 is reading 99.15% so wondering if that sensor is shot and causing issues.
Also Cylinder #1 is consistently seeing misfire events, unfortunately with v12.24 of Techstream I don't have the ability to do a EWMA event lookup that would show me for sure which cylinder is having the misfire but this seems pretty consistent when at idle.
My money is on the intake gasket. Have the intake ever been taken off previously? Like to replace the starter?
"they" also replaced the gaskets on my intake, "they" did the job a year prior to the trouble starting, "they" were lying, incompetent bastids in my case
Have you checked how tight the intake nuts/bolts are? Just see if they've worked loose since that starter swap, and can be snugged up a little better.
ramangain
Clarksonian disciple
If you have consistent cyl#1 misfire events logged, start there. Drop in a new plug, coilpack, and cross your fingers.
2001LC
SILVER Star
Your ~20% LT fuel trims, indicate you're running very lean. The LT is what the ECM is doing to adjust fuel output to get zero baseline. ECM is working to achieve 14:1 (zero short term) mixture.
This may indicate vacuum leak both banks. May indicate fuel starvation. There's a other possibilities; But if vacuum leak already corrected, I'd check fuel pressure next.
"If this was a 06-07", I'd say fuel pressure to low at slower speeds of fuel pump. Our fuel pumps are multi speed in all 4.7L. But the newer smaller fuel pump used in the 06-07, are often faulty. They can't be test for fault. But signs is lean BK1 & BK2 at slow speeds, after running at high speeds (RPMs) on hot day.
Also look very close to see if wiring that runs down front of BK1 timing cover to cam sensor, than on down to crank sensor & oil sending unit are loose or routed wrong. They could be rubbing on drive belt.
Test MAF, make sure throttle body throat clean and working properly. Note: 98-99 had issue with throttle body, but usually throw a code if so.
No vacuum leaks, fuel pump pressure and fuel pressure regulator test okay, wires good & routed properly and others check out okay.
Next I'd do compression test, as I replace sparks and coil boots as needed.
Note: Looking at last work done on engine, always a good starting point!.
This may indicate vacuum leak both banks. May indicate fuel starvation. There's a other possibilities; But if vacuum leak already corrected, I'd check fuel pressure next.
"If this was a 06-07", I'd say fuel pressure to low at slower speeds of fuel pump. Our fuel pumps are multi speed in all 4.7L. But the newer smaller fuel pump used in the 06-07, are often faulty. They can't be test for fault. But signs is lean BK1 & BK2 at slow speeds, after running at high speeds (RPMs) on hot day.
Also look very close to see if wiring that runs down front of BK1 timing cover to cam sensor, than on down to crank sensor & oil sending unit are loose or routed wrong. They could be rubbing on drive belt.
Test MAF, make sure throttle body throat clean and working properly. Note: 98-99 had issue with throttle body, but usually throw a code if so.
No vacuum leaks, fuel pump pressure and fuel pressure regulator test okay, wires good & routed properly and others check out okay.
Next I'd do compression test, as I replace sparks and coil boots as needed.
Note: Looking at last work done on engine, always a good starting point!.
gregnash
Anal Retentive Analyst
- Thread starter
- #31
Ok Thanks for input.
Unfortunately last night as I was attempting to replace plugs, found that #4 plug was so in there that I just couldn't fight it out (awkward positioning and late) so I called it quits (had already replaced #1, 3 & 5 but couldn't reach #7 with tools I have currently). As I was re-installing the #4 coil pack I snapped the bolt in the valve cover. Praying that my local toyota dealership has them in stock and that it comes out easily with an EZ-Out as it sheared off flush with the top of valve cover. After that, wasn't going to tempt murphy with the rest of them.
Oh and most recent stuff done was done by another member here, and member of our club, that is a Toyota Master Tech. Trust that when he did TB/WP that he routed wires properly. The intake manifold when I had starter replaced a year ago was done by someone else and so not 100% on that but they are a local, well-known and highly rated shop. Since I will be doing other stuff I will likely hit those intake nuts to ensure nothing has walked out.
Again, based on what I am seeing with plugs thus far, they are DEFINITELY factory. So they have 208k on them.
Unfortunately last night as I was attempting to replace plugs, found that #4 plug was so in there that I just couldn't fight it out (awkward positioning and late) so I called it quits (had already replaced #1, 3 & 5 but couldn't reach #7 with tools I have currently). As I was re-installing the #4 coil pack I snapped the bolt in the valve cover. Praying that my local toyota dealership has them in stock and that it comes out easily with an EZ-Out as it sheared off flush with the top of valve cover. After that, wasn't going to tempt murphy with the rest of them.
Oh and most recent stuff done was done by another member here, and member of our club, that is a Toyota Master Tech. Trust that when he did TB/WP that he routed wires properly. The intake manifold when I had starter replaced a year ago was done by someone else and so not 100% on that but they are a local, well-known and highly rated shop. Since I will be doing other stuff I will likely hit those intake nuts to ensure nothing has walked out.
Again, based on what I am seeing with plugs thus far, they are DEFINITELY factory. So they have 208k on them.
JunkCrzr89
Competent Ignoramoose
That sucks about the coil bolt. Soak the #4 plug in PB blaster overnight - should come out next day. Might require some finesse to not strip the threads in the head by loosening the plug, then tightening it, and repeating a few times. PB blaster and leaving the ugga-duggas in your pocket will be very helpful.
gregnash
Anal Retentive Analyst
- Thread starter
- #33
Yeah... the #1 fought me kind of like that, did the process of just going back and forth with tightening/loosening and it eventually came out. Just odd position with short ratchet, so now have something bigger to work at it. NO UGGA-DUGGAS for sure! I will pull the other coils and soak them with some PB too just for good measure. The #7 is the one that concerns me because their ain't much room and I don't want to live life an 1/8th turn. So pull that coil pack too and soak the plug with PB in hopes she doesn't give me grief.
ramangain
Clarksonian disciple
With the stuff you've replaced, did th3 issue go away?
gregnash
Anal Retentive Analyst
- Thread starter
- #35
Nope not yet. Still combating it but getting other stuff popping up to on occasion which has got me wondering whattheactualfuck is happening. Had a random P0301 pop up over the weekend. Finally got techstream running and noticed all kinds of misfires that finally resulted in Techstream catching a P0300 but no definitive cylinder. Did notice that cylinder #1 seems to be main culprit and have two new Denso coil packs coming. Spark plugs are factory (with 208k on them) so those are in the process of being replaced when I snapped the bolt last night.
Did notice in the recorded techstream event that Fuel Trims seem a bit high which main indicate that fuel filter or fuel pump are causing issues. The damn P0171 is just such a random, vague code.
They are all random vague codes, and that's why we don't throw parts at it. The code is no more than a crumb trail. The code only points to a fault in a system. That's it. The part throwing the code may or may not be the one at fault in the system, but it's the one that caught it. That's all it is.
As our LC/LX are getting older we r going to start seeing a lot more of these codes. I have an old Toyota T100 with 393k miles on it that was giving me the same symptoms. And although that is a v6 5vz-fe engine I had to troubleshoot it the same way. I would suspect it your fuel pressure problem if the other steps did not fix your problem. What fixed my problem was replacing the fuel pump.
The Pita part is getting the fuel pressure on these trucks. But I would first look at that before throwing any other part at this. Also even before that change the fuel filter. This is not going to help but with your milage it's a good item that needs replacing.
Btw another major problem that was happening with these symptoms was the T100 would not start after initially being started. So at cold start it would start right up, but hot engine start it would not. Not sure of this is one of your symptoms but you may want to check this as well.
Silver lining at least on the LC you don't have to drop the tank to replace the fuel pump.
T100 Troubleshooting link.
The Pita part is getting the fuel pressure on these trucks. But I would first look at that before throwing any other part at this. Also even before that change the fuel filter. This is not going to help but with your milage it's a good item that needs replacing.
Btw another major problem that was happening with these symptoms was the T100 would not start after initially being started. So at cold start it would start right up, but hot engine start it would not. Not sure of this is one of your symptoms but you may want to check this as well.
Silver lining at least on the LC you don't have to drop the tank to replace the fuel pump.
T100 Troubleshooting link.
Last edited:
gregnash
Anal Retentive Analyst
- Thread starter
- #38
Yeah definitely not throwing parts at it. Stuff that I would consider "normal maintenance" is getting handled, like the plugs. Every... single... one... has given me grief coming out, finally had to get out my 24" ratcheting breaker bar to get them out better/easier. Still working them slowly though. Problem is that it is large enough that I cannot get to the last two cylinders #7 & #8, so gotta figure that out.
Had one coilpack last night that had cracks along the body of the coil so I replaced since I had the two Densos that I purchased. Put new one on Cylinder #1 to see if that resolved that code, and not dice thus far. Replaced the cracked on #6 for good measure. Going to the buddies place after work tonight to do some more troubleshooting. This morning on the way to work she threw a P0300, P0301, P0305, P0307 but no P0171. Think she was throwing codes just because I had been spraying around the intake to see if I possibly missed a vacuum leak last night. CEL started blinking as I left the house but light didnt stay on, and when I tried to read codes nothing was there... Wasn't until a few lights later that it did same thing again and light stayed on that time which is how I got the codes. Funny thing is that in all of this, when I am monitoring through Techstream, cylinder #6 is the ONLY ONE that doesn't have misfires.
We will see what we can come up with. Unfortunately my EZ Out didn't work last night for getting the sheared bolt out. Gonna talk with him to see what can be done, really hoping that I don't have to remove the valve cover to get it out, I know he said he has a good set of lefthand bits so maybe his stuff will be more successful.
I did drive her to work this morning and while she did the normal stumbling/rough idle at the first couple lights, by the time I got to work she was running rather smooth. So who knows. Maybe something like the Crank Position Sensor, Camshaft Position Sensor, Fuel Pump, Fuel Filter or something else is causing issues. The two things that have me really questioning what is going on is the Fuel Trims and the one O2 Sensor that is constantly at 99.15% (Bank1Sensor2)
Just to confirm that I am not going crazy... Drivers side of the engine is Odd Number for cylinders (1, 3, 5, 7) and Passenger side is Even Number (2, 4, 6, 8) correct? Which would make Bank 1 passenger side and Bank 2 side, correct?
Had one coilpack last night that had cracks along the body of the coil so I replaced since I had the two Densos that I purchased. Put new one on Cylinder #1 to see if that resolved that code, and not dice thus far. Replaced the cracked on #6 for good measure. Going to the buddies place after work tonight to do some more troubleshooting. This morning on the way to work she threw a P0300, P0301, P0305, P0307 but no P0171. Think she was throwing codes just because I had been spraying around the intake to see if I possibly missed a vacuum leak last night. CEL started blinking as I left the house but light didnt stay on, and when I tried to read codes nothing was there... Wasn't until a few lights later that it did same thing again and light stayed on that time which is how I got the codes. Funny thing is that in all of this, when I am monitoring through Techstream, cylinder #6 is the ONLY ONE that doesn't have misfires.
We will see what we can come up with. Unfortunately my EZ Out didn't work last night for getting the sheared bolt out. Gonna talk with him to see what can be done, really hoping that I don't have to remove the valve cover to get it out, I know he said he has a good set of lefthand bits so maybe his stuff will be more successful.
I did drive her to work this morning and while she did the normal stumbling/rough idle at the first couple lights, by the time I got to work she was running rather smooth. So who knows. Maybe something like the Crank Position Sensor, Camshaft Position Sensor, Fuel Pump, Fuel Filter or something else is causing issues. The two things that have me really questioning what is going on is the Fuel Trims and the one O2 Sensor that is constantly at 99.15% (Bank1Sensor2)
Just to confirm that I am not going crazy... Drivers side of the engine is Odd Number for cylinders (1, 3, 5, 7) and Passenger side is Even Number (2, 4, 6, 8) correct? Which would make Bank 1 passenger side and Bank 2 side, correct?
Last edited:
FWIW my P0171 was the fuel pump. I tried replacing all of the cheaper items, including the filter, before the pump finally failed while on the road. Might be worth at least testing the pump, especially if it's original.
gregnash
Anal Retentive Analyst
- Thread starter
- #40
Oh yeah that will be tested. From what some of the guys have been saying on here (and in other threads), the higher end Fuel Trim ratios seem to be indicative of the fuel pump having issues keeping up with the system. Especially with 208k on the truck I am thinking that it could be a good "maintenance" item while I am working through all this. Believe my buddy has a Fuel pressure tester, but will see tonight for sure.
