- Thread starter
- #21
All toyota hoses including the PHH (not many use it but I heard Slee does), got all the part numbers from a previous thread and Wit’s End...
‘94 won’t pass emissions but NO CEL
- Thread starter 109madrid
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- #22
Replaced the pair valve and it runs much better and the motor is much quieter and even more smoother, RPM’s down to 850 now and CEL went away... but then code 25 came back a couple weeks later. The reed valve definitely needed to be replaced. So at this point, I got rid of the 25/26 code combo and vacuum leaks seem to be solved (PAIR valve S hose cracked, replaced with Tacoma rad hose) however it still will not pass emissions, it actually went way up! I used Red Heet, and Lucas Injector cleaner (should have used BG 44k, and will after I go though a tank or 2) and I’m at a loss. No vacuum leaks and the TPS is literally perfect, I just don’t get how HC’s went up. Last things left on the list are loose ground and ECU.
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- #24
So I’ve done some work and found out a few things (all parts replaced with OEM parts only, my local Toyota dealer offers 20% off to Mud members)…
plus my wife makes fun of me and threatens to sell it to the next neighbor who asks to buy it
- Checked the ground and found corrosion in the connection under the heat shrink and the lug was loose
- I also had a dead injector in cylinder #6, cleaned all injectors and got a replacement for the dead injector
- Checked main harness and it’s in great shape so I wrapped it in heat proofing wrap to keep it that way. Also checked it under dash at ECU.
- One of the VSV’s (the red one w/the filter on the back) diaphragms was punctured when I used a metal wire bread tie I to clean it because it was completely clogged (all VSV’s were completely clogged originally so only one ended up being useable even after cleaning, so those were all replaced and I may eventually replace the remaining original VSV although it tests fine)
- Throttle body R port completely clogged
- The EGR port was completely clogged and the EGR valve was completely stuck and would not hold vacuum (replaced w/new EGR valve)
- New fuel pump and Fuel pump bracket -I developed an intermittent no start and a fuel gauge that only registers a half tank even when it’s a completely full tank -cleaned float sensor and found a used replacement too but both float sensors do the same thing and it still only reads half a tank even with new parts
- Re-Checked all grounds and connections and everything is good
- New fuel pressure regulator -fu@k it, may as well have an entirely new fuel system at this point, right?
- Found that a burnt circuit opening relay was causing the no start/intermittent start (it finally would not start one day but would run when I jumped power to the fuel pump in the diagnostic box), starting issues had nothing to do with the fuel pump as I thought. I will add that I’ve had several relays die recently including my horn and tail lights as well (250k miles on the truck, 40k miles on the motor)
- Exhaust is rusty but deemed to have no leaks before cats by a reputable exhaust shop and was told to keep original cats by exhaust shop
- Idle still high (around 800 now/still) and still have code 25 so I but the bullet and removed the PAIR valve
- Put new OEM o2 sensors in place of PAIR
plus my wife makes fun of me and threatens to sell it to the next neighbor who asks to buy it
94 here. I went down these roads (scornful wife and bad emissions) so my sympathies. Just my worthless $0.02. My local official toyota, er, place originally assured me my O2 sensors "tested good" and they most assuredly were not. New OEM sensors aren't available and my *code 25* went immediately and forever away when I put in a NEW pair of NTK 24080 sensors.
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- #26
Same here, my o2’s tested fine too but were over 10 years old so I ended up buying some new ones and relocated them to the PAIR ports because the old ones were rusted in place… NTK are OEM for the 93-94 so I got the same as you; 24080 and a 24044. They did not change the lean condition but until it threw the code 25 a few days later again, it idled and ran near perfect. I just installed the o2 sensors within the past couple weeks and since the code reappeared after installing the o2’s, I’ve cleared the code a couple times now and as soon as I go from highway speeds to idling around town, the lean condition reappears but it will cruise the fwy at 80 and has much more pep after removing the PAIR/adding new o2’s
Joking aside, I would focus on code 25--running lean. Lean either means you have too much air or not enough fuel, beyond what can be compensated for by the ECU. Too much air could be a large vacuum leak, not enough fuel could be a plugged fuel filter, etc.
I would run a bunch of tests to pinpoint the issue. You can check for vacuum leaks using a smoke machine. Can check engine timing with a timing light, which I highly recommend. Checking fuel pressure would also be good to rule out a plugged fuel filter or some other issue with fuel delivery. You can check O2 sensors using a multimeter (an oscilloscope is best), though they are brand new so probably not the issue.
You could also post in the High Desert Cruisers group NM- High Desert Cruisers - https://forum.ih8mud.com/forums/nm-high-desert-cruisers.109/ and we may be able to help locally.
I found a vacuum leak after building one of these:
Some good info in this post: Code 25 Lean - and VAF testing. - https://forum.ih8mud.com/threads/code-25-lean-and-vaf-testing.691652/#post-8279578
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- #29
Thanks for the pointers and ridicule lol, and I was chasing code 25 lol, so pretty much the entire fuel system is new/double checked at this point (plus something totally clogged up the entire vacuum system), and unless something is in the fuel line I think I’m good there, hence why I’m thinking it may be a valve issue because everything fuel related is new minus the fuel lines. I haven’t checked the fuel pressure since installing the new fuel pump and new OEM fuel filters and will check the fuel pressure again jik. I recently put new crush washers on the fuel tank banjo because I had previously reused the old ones so it shouldn’t be losing fuel pressure unless a line went bad. I also haven’t done a compression or leak down test since buying it over 5 years ago, but I do like the smoke machine idea -would you just plug that baby into the evap line like in the video? I was simply trying to check vacuum by killing the motor through the EGR prior to replacing it. Also, pumping in baby oil smoke won’t do something stupid like mess something sensitive up like a VAF right? BTW, I used that link awhile back when checking my VAF and everything was within spec, there are a few links on the VAF and was also shown by a local shop how to adjust the VAF if need be to richen up the mixture with the idle screw under the metal plug on the VAF. I also replaced the rubber intake hose recently as well along with the OEM clamps, I used turbo type clamps for a better seal.
Yeah I disconnected the brake booster hose and put it in there and the smoke traveled through all the hoses and came out the air intake inside the passenger fender. It won't hurt anything as far as I know (professional shops use mineral oil like this), but the smoke made my garage stink bad for a week or two so I'm going to try it outside next time...
I also saw this on Amazon: Amazon product ASIN B06XHRBKTM.
Just as an FYI to other mud members who read this. O2 sensors are a wear item, their switching response starts to slow with thousands of miles of use, and as they get dirty. Even though they may still test okay, they should still be replaced periodicity as part of a good maintenance program. Some car manufactures use to recommend O2 sensors be replaced in as few as 30,000 miles, others recommended 60,000 miles, but that all depended on the type (single wire, 2 wire, or 4 wire) of O2 sensor that was installed.
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- #33
So I put the smoke machine together, thank you for the direction… I hooked it up to the booster hose and smoke began pouring out of the vacuum modulator a few minutes later. I just wanted to check whether the vehicle should be on or off during testing though because I thought it vents through the modulator with the motor off? Just want to confirm what the procedure is to smoke test our 80’s…
I think smoke coming out the EGR is normal, it did on mine and I just ignored that. You cannot have the engine running. Are you using a few psi or so from a compressor to help flow the smoke?
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- #35
Yes, I have it hooked to my compressor so it is definitely pushing the smoke through but the smoke is leaking from the blue modulator next to the EGR and not the EGR itself.
Pretty sure that is normal, do you see any other leaks? Has the smoke made it all the way to the air intake in the passenger fender well? The leaks may be small, using a bright flashlight with low ambient light helps. You could also put smoke up the tail pipe to check for exhaust leaks. If leaks are near the O2 sensor, can mess up the O2 readings.
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Here is the page in the FSM for high HC emissions:
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And here are the steps in the FSM for troubleshooting high idle (in order of likelihood):
- Accelerator pedal link
- ECT sensor circuit
- IAC valve
- Intake Air Temp Sensor Circuit
- Throttle Position Sensor Circuit
- A/C Signal Circuit
- PNP Switch Circuit
- Injectors
- EMC
- Thread starter
- #39
So the update after the smoke test leads me to believe that I don’t have any obvious vacuum leaks; the smoke eventually poured out of my snorkel but the smoke did also leak out of the filter area of my vacuum modulator too. I finally got a timing light and I am in the process of testing my vacuum modulator (got a bunch of snow last night so that’s on hold for the moment) but after the smoke test I was checking the vacuum line routing/connections and I did notice that when I disconnect the vacuum lines from the bi-metal switching valve and reverse those 2 connections of the vacuum lines to the valve, there is no reaction from the engine at all. I will add that when I got the vehicle, all of the sensors were crushed on the driver side of the engine so I am going to smoke test again and look under the intake at the bi-metal valve for leaks this time or check to see if the valve is clogged. I believe the knock sensors and the temp sensor got crushed when the PO installed the new engine, because when I bought it, it didn’t run, but after replacing those crushed sensors, it ran and PASSED EMISSIONS tests 2x prior to my current situation of not passing. That valve was the only thing that I didn’t clean when I had the intake off to replace the vacuum lines and clean the injectors and I will add that most of my vacuum ports and throttle body ports were completely clogged.
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- #40
Double checked for leaks today with more smoke tests and I even smoke-tested the EVAP system and I have ZERO leaks whatsoever. I used a flashlight this time and validated that my gas tank is airtight so the only smoke I saw was from the top of my vacuum modulator and leaving out of my snorkel on the intake side and smoke leaving from my gas filler on the evap side when I removed the gas cap. I will add that I have the VC-120 charcoal canister (and the bottom cover of the canister popped off so I put it back on), would this matter any because the charcoal canister is the only non-OEM part on the vehicle? Everything on the list is testing fine and I am in the process of checking the timing and it looks like it’s at 4-5* instead of dead on 3* so I will adjust the timing to dial it in at 3* and see if that affects emissions and/or idle speed.