Modifying your intake? Think again!

I took my Tundra out for some off-roading in the desert. Near the end of the day it starting running like crap. Seemed like it wasn't getting fuel. The 4lo light was flashing, the TracOff light was on as well as the Check Engine light. I limped it home and much to my horror found that the ring clamp holding the air cleaner on had vibrated loose. I took it to the auto parts store and they said the codes were for the O2 sensors. I'll try and keep this short, but so far I have cleaned the throttle body, replaced the spark plugs, cleaned the PCV, cleaned all four O2 sensors (all of the things listed so far were black with soot), and changed the fuel filter and replaced the mass airflow sensor. None of those helped. I checked the air injection pumps and they run when I hot wire them, although I can't say for sure if they are running with the truck is running. They are getting 10.6 V supplied to them when I checked. On a hunch I gutted the catalytic converters and found in doing so that they were filled with dust and had began melting the guts of the front two. Yes, I know its illegal and I plan to replace them if I can ever get this thing running again. I put it all back together and now it seems to be running even worse after screwing with the cats.

Anyone got any ideas?

 

Damn...... If you're 4 lo and the Trac control light were flashing I wonder if you broke one of your ABS sensors? Maybe have a look under the wheels and check? Other than that it's all Japanese to me

 

Seems like you tried all the obvious stuff. Might be time for Service Mechanic $hop time. $$$

 

Welcome from CO

 

LOL, I'm sorry I found this to be hilarious.

But OP hope your truck gets fixed man!

 

Do a compression test.

 

Well, it’s his first post....

 

Seeing as I am having a pretty crappy day I appreciate the support

 

Welcome from CO. Yep.....mechanic time.

 

i cleaned them with throttle body cleaner and then let them soak in gas overnight. i don't know it to be a proven method, got it from YouTube. I disconnected the battery to clear the CEL before i did the test run after gutting the cats. At first it seemed to be running ok, although i was babying it. But then about 2 miles from the house it started running like it had 0 gas in the tank but none of the lights on the dash came back on.

 

Sounds like it’s in limp mode because a sensor is jacked up somewhere. As @040Tundra said check your ABS sensors. When they get messed up it seems our trucks will go into limp mode. It may just be a coincidence that you found the airbox hose clamp loose. While it’s not good it would take quite a bit of dust to ruin your engine completely. @dragos28

 

Sorry about your issue.
Welcome from CO though.

 

I am curious why didn't you replace the 4 O2 sensors? You replaced all the other items and yet the code was for the one thing you haven't replaced? I replaced all 4 of mine 500 bucks for all 4 OEM from online when I got the code for bank 2 sensor 2. If you now have to replace the cats with OEM parts that's going to be really expensive. They're 1500 per side for the assembly.

 

Whoa. How much time offroading did you do? Miles, hours, etc. How loose was the hose clamp to the air filter? Was there a gap at the connection?

It's possible, depending on how much dirt, if any, got in there that you "sanded the motor". Which as you can tell by those words, is extremely bad. Did you take any pictures?

Do what 15WHTRD suggests and have the compression tested.

 

I have always had luck using bung extensions on the o2 sensors when gutting cats... never had any issues on four vehicles in a row on that department. Just as a test dissconnect the battery, pull the rear o2 sensors out and zip tie them to the frame (or somewhere in fresh air). Go for a rip. If it doesn’t make a difference on the limp mode I’d bet it’s a pre cat o2 sensor. If a sensor is pooched cleaning won’t make a difference...

Also, on the motor end of it, you could try a compression test. A compression test device is only $30 at a parts store. This will prove if your piston rings/cylinder walls are worn or not. ~180psi is a pretty good compression pass in my experience.

My bet is on some type of sensor over a dusted motor tho. It wouldn’t run better for a few miles if it was dusted. It would just run worse and worse until ultimate death. Plus it makes sense it’s the o2 sensor/sensors. O2 sensors do not read anything until they reach a certain temperature (computer just runs blind for a while). As it was running good for a few miles then shit again I bet it this.

Good luck with the ghost chase. Never fun.

 

Because I couldn't get the O2 sensors for a couple of days, I started researching some methods for testing them. I found a video on YouTube (and once again I should say I have no way of knowing if that guy knows anything I don't just because he made a video) but the showed measuring the resistance of the heater coils in the O2 sensors in ohms, and then heating the sensor with a torch to see if it produces an electrical current when it gets to around 600 degrees. I performed those tests on each one of the sensors after cleaning them and they appeared to be good.

I pasted in a pic of the guts of one of the front cats. As you can see, once they started getting clogged and didn't get the proper airflow they overheated and melted. Once those melted areas cooled after shutting off the truck it sealed off those pores altogether.

I ordered the cats through O'Reilly. The total was less than $900 for both sides and they will be here today.

 

I suppose I haven't done the compression test because I am scared to face the truth... When I run to town later to pick up the cats I'll pick up a compression testing kit and post the results

 

Bummed for you man.

 

Dude. That sucks. Hate to see a Tundra down.

 

Wow those cats are crazy. ...

 

IN CONCLUSION: She lives

So after correcting all the things (including the new cats being installed) I got it running pretty close to normal- but something still wasn't right and when I got heavy on the gas it would go into limp mode. So, I finally gave up and took her to the dealership. She needed the new FOU update to the ECM anyway. If you have a FlexFuel, go get the update- it corrects the problem you have now and then (for me mostly in winter) with it taking 2 or 3 times to crank-up. Something about an Alcohol sensor or something.

So a couple months ago I installed a generic K&N air filter. I used a piece of 4 inch PVC to mount the filter on and act as a housing for the MAS. Fuel mileage went up a tad and all the world was fine. Until, that is, I got into the desert 600 miles from home. The bottom line is- that 4 inch PVC is slightly smaller in diameter than factory piece so although the engine is pumping the same volume of air, it causes air to rush through the MAS faster. This causes the MAS to tell the injectors to dump more fuel. The end result is not enough air to burn all this fuel. Not sure how it makes sense that my mileage actually went up slightly under these conditions, but whatever.

My advice is to not modify your intake, or if you do, make damn sure it is specifically engineered for your specific engine. These FlexFuels are extremely picky and anything being off can cause it to go into limp mode.

I never got around to checking the compression, but on this last test run she proved I don't need to. Apparently I sucked in enough sand to clog the cats, but not enough to kill a Tundra!

 

damn... sorry you had to go through that. now i just read you installed a generic K&N Filter

please read my experience. it wasnt as bad as yours but it was caused by the K&N
i'd highly suggest you stick to a regular OEM style air filter

http://www.tundratalk.net/forums/tu...sues/570858-major-dust-intake.html?highlight=

 

jesus, 900 for cats! would have just called @dirtydeeds and ditched them!

 

I talked to him about it and he said there were other options available, but none really better than cats. Cheaper, but not really better. For just the few extra $$$ I figured it was worth it so that I didn't have to worry about passing emission tests one day.

 

yep.. Tundra from the factory are tuned well to begin with. Us adding Mods make it worst and create issues. We are all guilty of it

 

Ugh! Black lung kills!

Any chance you can edit the title of this thread to something like a warning about modifying intakes? Wouldn't change people doing it (and many people on here have had no problems), but it'd maybe make this thread show up in a search by anyone researching and planning-- help them know to avoid using "at hand" or substitute parts in place of OEM. At the time it probably was an awesome McGyver idea to use that bit of PVC....

 

Did you check the air filter? Might be clogged even though the tube was off.

Never mind just saw the post. Thats good.