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There were a few on eBay that ranged from $11 to $75, and one said "Genuine OEM" at $75. MSRP is $110 at my local dealership. If it's just a $35 difference between "OEM" and from the dealership, I should probably just buy it from the dealership right?
I still haven't been able to break loose the current one from my fuel rail without fear of snapping the rail itself. I am going to separate them using the other banjo bolt and hopefully I can break it loose with more force.
Last edited by Obscurations; 06-07-24 at 12:27 PM.
Okay little update as to what's going on. I went to a local auto salvage yard and pulled a fuel rail from the same make, model, and year that was there due to a rear end crash. I also got a few spare fuel injectors since I had broken one pulling off my fuel rail earlier in the day. (Yes I put new O-rings on them and I have not seen or smelt any fuel leaks yet)
That fuel rail appeared to have fixed the problem mostly. On the first test drive the car only threw a cylinder 6 misfire after about 3 minutes of driving, but no Bank 1 Too Lean!!! But then I kept driving the car, and after about 30-40 minutes of road driving time, the bank 1 lean codes came back, (I know it was 30-40 minutes of driving because my dad checked the codes at 3 minutes, just cylinder 6, I checked it at 10 and 20 minutes, and it only showed 6 confirmed and pending, and then I checked at 40 minutes and it was back on). But I can assume that the fuel rail damper on the fuel rail that was replaced was an issue because the DENSO one on the new (wrecked car) rail did have a screw in it compared to my old one, and now the p0171 code took 30-40 minutes instead of instantly after first acceleration.
So I can confirm, it is multiple things working together that are causing issues.
As for the Cylinder 6 misfire. I was planning on taking out the coil, spark plug, and fuel injector out one by one in that order and swapping them with cylinder 4, which is also on the front row. I did the coil pack and immediately, cylinder 4 misfire. (I had a spare coil pack in my garage and swapped it out with that but that one was also bad).
So I am going back to the auto salvage place tomorrow and getting like 3 or 4 coil packs since they are ~$12 each there so I can have extras and hopefully most, if not all of them will work. Once I have the coil pack replaced and working, then I'll worry about the bank 1 too lean coming back.
Last edited by Obscurations; 06-09-24 at 07:40 PM.
Reason: price is higher :(
Keep in mind that we have a port injection and not in-cylinder injection. So fuel problem typically would not be localized to a cylinder.
Have you checked compression/leak-down in 6? If not, please do so. Even though you are not spending a lot on money on parts, but try to avoid throwing parts. Logically eliminate issues.
Keep in mind that we have a port injection and not in-cylinder injection. So fuel problem typically would not be localized to a cylinder.
Have you checked compression/leak-down in 6? If not, please do so. Even though you are not spending a lot on money on parts, but try to avoid throwing parts. Logically eliminate issues.
Confirming spark is a good idea.
Salim
So I'm reading a few articles about compression tests but I'm not sure what the symptoms that it shows means for how it could relate to p0171 or cylinder misfires. The symptoms of the issues revealed in a compression test are not even close to what is happening with my car. Although I am not a mechanic so I have no idea what's going on here. Can someone explain how this might be related to my issues?
Also back when I did a smoke machine vacuum leak test a few months ago, I had some smoke leaking out of the cylinder 2 coil hole up until I tighten down the coil pack to be snug. Does that mean that cylinder 2 spark plug doesn't have a good seal or something? I haven't gotten a code for cylinder 2 at all back when I had the p0171 before the fuel rail replacement.
My reference to #6 was some how I thought there are misfire on 6 ... but that should trigger a different code.
Access to plugs is through the valve cover and there is a tube with seals that prevents oil from entering the tube. You can have a vacuum leak from there. If you are not getting oil filled up in the tubes [your coils come out dry], I would put that issue aside.
I went to the salvage yard and from the same car, I got a DENSO (yes it said DENSO on it) coil pack and put that in my car, and it works. Before I put it in, I was reliably getting code p0304 and p0303 (cylinder 4 and 3 misfire) and the multiple cylinder misfire codes. So far after about 20 minutes of driving, the check engine light has yet to come back on and I do not hear or feel any engine misfires! There is one small problem though.
The MAF sensor readings appear to be quite high, Some said idle should be about 3.0 g/s and I don't know what punching the gas should feel like, but I don't think it should be in the high 60's of g/s.
I took 2 screen recordings of live data from my Blue Driver scanner. One of about 7 minutes of me driving on the highway and country roads back to my house after the car being warmed up from 13 minutes of driving. One of my car in idle in park, and halfway through the video, at 2500 rpms held for about 8-10 seconds. (And yes, I did use some MAF cleaner on it and I know that the red bulb in it is not covered in dust or anything and is fully exposed)
Here is the second video of the car idle and at 2500 rpms.
If the problem does not come back and this is the end to this thread, I will come back in a day or 2 after confirming the car is fixed and summarize all I did for anyone who gets this problem in the future because I know I would want that for any other thread.
Last edited by Obscurations; 06-10-24 at 05:41 PM.
Reason: text after videos
If the problem does not come back and this is the end to this thread, I will come back in a day or 2 after confirming the car is fixed and summarize all I did for anyone who gets this problem in the future because I know I would want that for any other thread.
It has been a bit longer than a few days but after roughly 3 hours of driving total, the issue is gone!
When I started this issue I double checked that the MAF was fine, I cleaned it off and swapped it out for my dad's 2006 Toyota Highlander MAF (which is the exact same part), and neither car got better or worse engine issues. I used a smoke machine from amazon and checked for vacuum leaks, which there were none. (I would recommend checking vacuum leaks first for anyone who has this issue, you can also use stuff like carburetor cleaner or something flammable and spray suspected trouble spots and watch for if the rpms go higher for a moment).
After neither of those did anything, we replaced the oxygen sensors on Bank 1 Sensor 1, and Bank 1 Sensor 2. Bank 1 Sensor 2 had a change in the graph so I'm assuming that part was having issues but I have no idea or not.
Then I replaced the fuel pump and that improved on the car misfires roughly 10% so that also did something, might have been the fuel filter attached to the fuel pump idk.
After that didn't work, we replaced the entire fuel rail with a auto salvaged fuel rail from the same year make and model. (It has to be a 1999, because the 2003 one that I checked out and pulled before the 99 did not fit). The assumed problem was the fuel pressure damper that was missing the screw in the middle. After replacing that the misfires were 80% gone and the issue was still there, BUT, it fixed the p0171 (Bank 1 too lean) code. Now we were only getting cylinder 6 misfire. After doing some testing (swapping individual parts on different cylinders), we figured out that we also had a bad coil pack. After replacing that, the engine was 100% fixed as of 6/11/2024. (I will post here if it comes back after some driving because apparently that happens some times with small vacuum leaks idk).
Before all of the fixes I mentioned, The codes we had was P0171, P0303, P0305, P0306.
p0305 and p0303 are cylinder 5 and 3 misfires and they are both on Bank 1, so I assume the fuel pressure damper is causing those issues along side p0171 (bank 1 too lean), as for p0306, (cylinder 6 misfire), The bad coil pack cause that code as far as I know, and it had nothing to do with the bank 1 too lean code.
So all in all we replaced:
-MAF Sensor (cleaned and swapped with known working)
-Oxygen Sensors (graphs of voltage changed so assumed not working old ones)
-Fuel Pump (slightly improved car's performance and gas mileage so assuming weak/blocked)
-Fuel Rail (Mostly because we could not get the Fuel Pressure Damper off of our old one no matter how much WD-40 we put on the threads and because it was cheaper this way)
-Coil Pack (Also part of the problem but not known until p0171 was fixed)
Word of caution for readers/members... if you are having similar problem, follow the approach and not just swap out identical items on your vehicle. Each vehicle's problems are unique.
Did you buy the car like this or just let the maintenance get out of hànd?
I try to stay on top of issues with my car because it's so hard to diagnose multiple issues at once 🤓
We bought the car for $400 from my dad's co-worker when it had a blown cat and a few other issues and it was working for a few years like that except for a knock sensor replacement about 2 years ago. Then this issue started and we could not figure it out at all for a few months, and right about then is roughly when I suspect the fuel pump and coil pack when bad. So it just stacked on top of each other before we could figure it out and it delayed the fix for a long time.
Hey all, I'm back with some bad news... My best guess is that it's the MAF that's not 100% functioning but idk... Freeze Frame of it.
Originally Posted by Obscurations
The MAF sensor readings appear to be quite high, Some said idle should be about 3.0 g/s and I don't know what punching the gas should feel like, but I don't think it should be in the high 60's of g/s.
My guess is that this ^ is an issue that appeared after ~5 hours of driving time. Check engine light came on while I was parking so I immediately checked the codes and these 2 popped up.
Unless anyone has a better idea, I'm going to buy a OEM / Denso MAF sensor and see if that does anything different.
At least you seem to be making progress! I would hold off on buying any parts until you do some diagnostic work. Doesn’t your father own an RX with the exact same MAF? Try swapping them and see if that has any effect before buying a new one. Is the first time you have gotten the code for bank 2, P0172? That might be a clue to your problem? It’s possible you get the fuel rail on bank 1 sealed up tight and now it’s raised the fuel pressure in both rails and that has caused the injector seals in bank 2 to leak? Or something like that, I am just throwing that out there to generate some ideas about what could create the current scenario?
At least you seem to be making progress! I would hold off on buying any parts until you do some diagnostic work. Doesn’t your father own an RX with the exact same MAF? Try swapping them and see if that has any effect before buying a new one. Is the first time you have gotten the code for bank 2, P0172? That might be a clue to your problem? It’s possible you get the fuel rail on bank 1 sealed up tight and now it’s raised the fuel pressure in both rails and that has caused the injector seals in bank 2 to leak? Or something like that, I am just throwing that out there to generate some ideas about what could create the current scenario?
My dad has a 2006 Toyota Highlander that has the same MAF sensor that I have been swapping back and forth between the cars, he has his own engine problems but whenever we swap the MAF sensors, they have the same readings on live data when the car is warmed up, and his car doesn't "seem" to have any issues with it when swapping, but it's hard to tell cause he has other issues with his car. We have swapped the 2 multiple times but I am worried that both of them might be (going?) bad because of how high it sits on live data when idling compared to what everyone is saying it should be.
Also no, p0172 would come up every so often before I fixed it, but it would take a while to reappear after clearing codes as far as I recall. Maybe not but I do remember seeing it before the fuel rail fix.
I checked the codes this morning and only p0172 stayed, the temporary codes are gone.
Last I checked, there was no fuel coming from the injectors or rail and I couldn't smell anything, so I don't think I have a leak. I haven't disconnected the battery since the fix at all, do you think by letting it do a full reset (disconnecting the battery for a few minutes and reconnecting) after having the issue fixed it might do something?
Last edited by Obscurations; 06-29-24 at 04:37 PM.
Unplugginf the battery shouldmt be any different than just resetting the codes with your obd2 scanner. Actually, unplugging the battery can return the ecu to base settings. And itll cause it to run crappy the first couple times you drive it, and itll need to relearn the drivers characteristics. I wouldnt unhook the battery. But try resetting the codes and them keeo the scannwr plugged in, see what codes return first, and how soon they return. You can also check your fuel trims and see if they are still way off? Or either bank is getting the fuel ratio?
06-07-24, 12:24 PM
