Low Fuel Pressure

still under warranty, get it back to the Toyota dealer those CEL Codes are stored in the ECU let them handle it

 

Wow, that looks like quite the tool. If a local buddy does not have similar capability w his scan tool, then maybe it's time for me to purchase a model like yours. Then again, I might not be able to figure out how to use it......I'm not smart, but I can lift heavy things.

I do have the new part, I would like to upload it but my phone does not appear to have transferred it to my computer yet. I'll have to post that in later on. The new new part does not have that little round circle on it, the "hash mark" as it's been described, but it has two parallel lines, sort of like an equal sign. The numbers on the base are 0972 06U27 while the old part shows 0971 04T16. I'm going to go install now, but will also be dropping down the back end of the transmission so I can install the upgraded transmission detent pin and cap, so no test driving it til later on.

As far as calling Corporate, might anyone feed me a working number for this sort of thing? I'll give that a shot if I can come up with the right number.

 

I think you are about to solve your issue..!! Good luck my friend..!!

 

Okay, so let's try a photo. The new CPS on the left, showing the equal sign, and the original one on the right with the circle hash marks. From reading numerous other threads of woe and frustration, the early production Gen 3 had a PN ending in 89, and there was no marking on the base of the CPS. Mine has a build date of 6/16, so I suppose it was far enough in the production run to get the newest upgraded CPS. It appears there is yet another iteration, as the one I bought has a new/different marking on the base, despite having the same PN. Price was about $115.
I did go drive my truck, and as expected it drives fine, but things always drive fine until they don't drive fine, then you're stuck. I suppose if it doesn't occur again in like a decade or 2, then I suppose I can say this is a fix. But I still don't see why a CPS failure would trigger low fuel pressure/lean banks one and two, and not trigger a CPS fault code. Hopefully I'll get more input on that.

Regarding the mongo way-cool OBD2 scanner that can tell me fuel pressures, I've been looking into options. What about the Bluetooth deal you plug in your diagnostic port and get an APP and pull things up on your iPhone, or even on an Apple Airbook Pro? I'm a dinosaur but I suppose I could try that if it does all the neato stuff the recommended scanner is able to do. Anyone with a wealth of experience on this subject? I've looked at threads, but they seem to deteriorate into non-reassurring/off-topic stuff and do not come to a consensus opinion.

 

Yeah, the bluetooth things are even better with the right software/APP... and cheaper... I'll probably get one of those, too. (I've had the SGII for over 10 years.)

 

The CPS may have just triggered a false fuel pressure code.

 

Yes, I see this as possible, I had been considering (wild guess) that ECU detected bad CPS signal and shut down fuel pumps. I would still have expected a CPS code in the mix though.

I understand I should correct my terminology though. Having dug into even more threads of similar woe, it's called a CKP. I'm catching up fast.

In the meantime, I have a ton to learn about the bluetooth deal to connect to my laptop and iPhone, costs, availability, etc etc. More reading.

 

Check the fuel pump module connectors for corrosion. It’s on the inside of the frame rail under the drivers door.

 

I will do this. Thank you.

 

No signs of any contact issues or corrosion, etc with the fuel pump module connectors, they're squeaky clean and intact, no loose wires or connectors pushed back out of the sockets, etc. Thanks for the suggestion, thepinktaco.

 

I was in your boat. Mine had the circular "hash" on it and was BAD as it could get without totally failing - I replaced with the "98" sensor and haven't had an issue since. Rough idling (felt like it was about to stall every time I stopped - esp. when the AC compressor kicked in and the whole truck shook), weird MAF readings, etc., and the only way I was able to pinpoint this could be an issue was by using my OBD2. I just bought a Carista that works over Bluetooth then use the OBD Fusion App for my iPhone and with an additional $9.99 package you get access to ALL of the custom Toyota "PIDs" so you can track anything the ECU reads. If you have an android can do a similar setup but using an app called Torque.

Edit: And my production date was 8/16 for a Baja-made '17 offroad 4x4. No doubt these were still shipping with some level of issues with that sensor long after...

 

Interesting, as the circular "hash" was the upgraded part. Neither of us should have had an issue based on that. Thanks for adding in your build date. The original-original part # ended in 89, the upgraded ended in the 98 IIRC. Hopefully neither of us have a problem again, but I'm going to scavenge some heat shield type material next time I go to the salvage yard and wrap around the rubber boot on the CKP and zip tie it into place on the theory it's heat related from Cat proximity.

I am looking into Bluetooth type (Carista, Scangauge, etc) OBD2 devices that I can link to my iPhone. It will be a steep learning curve for me I'm sure, but it seems to be the way to go on this Truck.

 

Might be onto something there..!!

 

I bought a wifi obd2 dongle from Amazon and I also use obd fusion. Helped me figure out I had a bad a/f ratio sensor. Really easy to use app.

 

Interesting - what readings were you comparing to determine the sensor was bad? (Sorry I know somewhat of topic but I’m always eager to learn more about the OBD readings)

 

Yeppers... love that thing!

 

There's a recall on this...
https://static.nhtsa.gov/odi/rcl/2017/RCLRPT-17V356-5979.PDF

 

Yes indeed, there is. But my Tacoma was well outside of the production date range of this safety recall. Likely it should be broadened. End date of included vehicles was Nov 2015, while my build date is June 2016.

 

Updates of course, but not smiley-face news. The Truck did it again.....loss of power, bucking as if running out of gas. Interestingly, within 100 yards of the exact same place as before, on the identical trip, same speeds, gear, etc. This time I get codes (Confirmed) P0087 fuel rail pressure low, and codes (pending, for whatever that implys) P1078 "no DTC definition, see service manual," P0174 Bank 2 too lean, P0191 Fuel rail pressure Sensor A circuit range/performance, and P0171 Bank 1 too lean. This time the CEL popped on a few minutes after this without me shutting off the engine and turning it back on. After about 15-20 minutes of shut down time, it ran fine again and I drove it home.

So I suppose it's safe to say that the issue is not the CKP, and it likely forces me to purchase the Scantool as previously mentioned so I am able to monitor fuel pressures. I'm wondering if anyone has any input on other considerations of what is going wrong on my truck.

 

mine was running lean pre-CKP just not (yet) lean enough to throw codes, but I'd say if you HAVE codes now take it to the dealer. They can't deny something is wrong when they have the proof in the ECU and it likely captured freeze-frame data with those codes that they could see with their scanning tool (Techstream)