Horribly degraded performance

Means that it is trying to pull a crazy amount of fuel.

The temp should be staying gradual in movements. Clearly something is wrong with the reporting or the sensor itself.

What size injectors do you have in there?

After all you've tried, I suggest pulling the UCON to see if the OEM ecu alone works properly. Which may mean swapping the previous set of injectors in.

 

Thanks Torpsd! I’ll check on the injector size from URD (Stage 1 URD MkIII injectors). I stupidly threw my old ones away when I swapped everything out to the S/C, but I can grab some from Toyota or something unless someone has a bundle of stock ones they wouldn’t mind shipping out to me in exchange for getting them back when I’m done with a box of Maui caramacs or something

 

Ok, got a fuel pressure gauge in my cab now, typical is 44 PSI @The fuel rail before the regulator using the tap URD manufactures. Most I’ve ever seen was 46 PSI (WOT), least I’ve ever seen was 41 PSI.

never seen a short term swing of more than 2 PSI in any circumstance (even during the stalling.

Got this info back to Scott at URD as well, but am ordering a new damn set of injectors (stock size) to eliminate the ucon from this. Guessing I’ll go back to past performance where I experienced stalling in the same way, it was just so minimal that I didn’t think there was an actual problem the revamp wouldn’t help.

also have a boost gauge in my cab. Anyone have any pics of where they’re tapping in for boost? I have my gauge connected to the same line that feeds the blowoff valve.

had it initially connected to one side of the VSV, which measured a constant atmospheric pressure under all driving conditions, then the other side of the VSV which measured a constant -22 in hg under all driving conditions.

Now at the blowoff valve line I’m reading -22 at idle, and seeing immediate response when blipping the throttle. Also seeing the pressure return to -22 after extended throttle usage within a second or two. I believe this is normal indicating no issues.

 

have you tried pulling your efi fuse to reset learned values?

 

Would this be any different than disconnecting the battery for more than 10 minutes? If so, yes I’ve tried. It does help in a sense because the idle is so much higher that it’s less likely to enter the stalling state during transitions from virtually no load to heavy load on the engine. (Stop to go)

 

pulling the battery doesn't reset learned values. at least on the 3rd gen it doesn't. not sure about older models. i would try pulling the fuse for 5-10 minutes and see if it resets the learned values.

 

If this is true for second gens, and solves my issue, you my friend may have created a singularity. Maximum wtf levels vs maximum relief at the same time..

I’ll dig into it for second gens and try it out if thats the case.

thx for the responses!

 

give it a try and let us know what happens!

 

Ok..

found this thread: https://www.tacomaworld.com/threads/efi-reset-when-and-why.202559/

describing the same effects of disconnecting the battery and resetting the EFI fuse. Basically an ‘easier’ way to reset the ECU.

Will give it a shot anyway to see if there’s a magical difference

 

Any updates?

 

Combo of travel, rain and truck in the bodyshop for a while.

When I get back on island I’ll give it a whirl.

 

It took me FOREVER to find this post again..

so, like a dumbass wayyyyy back when I first installed the urd kit, I threw my oem injectors away…. Finally but the bullet and got a set of new ones after multiple attempts to find loaners without luck.

after I get a nod on my cam timing I can finally respond to this.

update, after pulling the ucon out and going the hptuners route with JustDSM at the helm, truck still pulling more fuel than it needs with fuel trims at -20 on both banks regardless of what JustDSM would try.

was using the 61lb Siemens injectors from urd.

replaced those with 650cc injectors from FIC during Black Friday. Still -20 fuel trims.

if I take the fuel regulator completely off the intake vacuum I still get -20 fuel trims.

so, checking timing because I don’t want to tear apart again and I’ve wanted to recalibrate for a while (not necessarily thinking timing could cause a constant -20 FT on both banks).

Reassembling with stock injectors, stock air box, and stock ECU flash to pull fuel trims then without the rotrex in the loop.

side note even at idle the rotrex pumps a crap ton of air out!!!

other parameters to note that have been constant since my last post here:

fuel pressure (measured at the end of the fuel rail before the FPR) is constant 47PSI
Boost gauge (measured from a vacuum tap) sits at -21inhg at idle consistently).

will update what stock injectors/tune/air box fuel trims are and anything else I learn from working with JustDSM or figuring out on my own. I’m running out of shit it could be and know I’m getting too much fuel through.

also compression is around 182 to 187 psi for each cylinder.

learning a lot through all this..

 

Neg 20 trim at idle? What do they do if you cruise up a hill?

 

This is a question for @Torspd
He is S/C with larger injectors

 

Haven’t been driving since ripping UConn out. Will see when things go back together in a stock form.

was just working on narrowing in tune with J’s help but my truck is being a right B.

 

Had a friend recently contact me about a super rich condition his truck was having. Had him do some wellness checks around the engine bay. It was pulling a lot of fuel and still running in the 12-11 range at idle. Ended up being a dirty MAF after a bad rainstorm. Once it was cleaned, it was all back to normal.

 

Haha tried that too, two different brand new OEM MAF sensors (one new for replacement, one new for sparing)..

interesting combo bad rainstorm to dirty maf. Totally believe weird crap happens, but that’s a strange one unless he got flooded with some crappy water..

Appreciate your words man.

Putting things back together tomorrow, hope to have some accurate stock air/fuel info then.

 

Have you replaced the air/fuel ratio sensors (upstream)?

They can be degraded slightly but not set the CEL off.

I just changed the one in my camry (no cel) and my fuel mileage increased by 2 mpg.

My taco had 190k on the o2 sensors. I'm about to change them to A/F ratio sensors. (There is some sort of difference, as far as i understand it)

 

Really wish I knew what I know now about EFI engines and how to troubleshoot better before jumping on the parts train. But yup OEM too.

 

You can override the resistor and check.