Small issues with new ride (catalytic converter)

Hello gentlemen, When I bought a Toyota Tacoma I had no idea how much technical information, manuals, how-to's, instruction videos and so forth was available online. I just needed a reliable vehicle for my business, that is, a small B&B in the mountains of Panama (the Republic). With my previous vehicle (a Lada Niva) I had great fun mud-busting through the jungle, but maintaining it felt like maintaining a yacht. For every hour driving it seemed I had two hours of maintenance. The original idea was to make some money doing 4x4 tours, but the demand was simply not there. So I sold her with some pain, and bought myself this: The car had been standing unused for perhaps 3 or 4 years, until some enterprising Hindustani found it and fixed whatever the main issue was. The thing is, Tacoma's were never sold in Panama. 4Runers, Hiluxes, RAVs, yes. So some parts are easy, some are not. But everything comes through the canal and can be obtained using Chinese and some patience. OR perhaps the seller got it at a bankruptcy sale. Anyway the price was fair and the car only had some cosmetic guano damage. So I put on some new tires and gave it a paintjob. The only persisting issue, the seller said, was ignition problems after driving for more than an hour. His mechanic had told him it was the mass-airflow sensor and he had ordered a new one, which he gave me a month later. However, that did not fix it. I will describe the problem in more detail. The engine is a standard RZ2 FE 2.4 litre 4 cylinder. After driving for more than an hour, I experience a sudden loss of power. After a few seconds it will pick up again, and come back again at intervals of +/- 5 minutes. It is especially troubling going uphill or waiting for a traffic light, in the later case the engine can stall completely. Naturally accelerating is challenging, pressing the throttle will result in quick bursts of acceleration followed by loss of power, causing you to hump back and forth in your seat like a first-time driver. First I tackled the usual stuff: changed spark plugs, wires, pcv valve, oil change, and flushed a lot of ignition cleaner through the gas tank. It made a difference but the problem is still there. By the way, this is what the spark plugs (all four of them) looked like: So I thought it might be the O2 sensor. I had a look underneath the car and found out this: The catalytic converter has been removed. In Panama they can't afford the luxury yet to care about emission standard, so I'm good from a legal standpoint, but I suppose not having a catalytic converter will mess up the O2 sensors? The check engine light is on but finding a mechanic to read the computer is a challenge here. So I am curious to hear the expert opinions here on the forum regarding the best course of action. One other minor issue is the parking brake handle coming loose. A small pin that normally holds it in place is missing and I don't see them for sale anywhere. Perhaps somebody here can show me what they look like so I can make something myself? Thank you for reading all this, I am glad to be in such good company

 

Anybody?

 

you need to find a way to get the check engine codes, I bet you have more than one. One is probably going to be emissions related since you don't have a catalytic converter and hopefully the others will help you solve the problem.

 

I wouldn't bother putting the cat back in but there is a thing you buy to plug into the o2 sensor that sends the engine the correct signals so it thinks the cat is there and the engine runs good without it.

im sure someone will post the link to it for you.

as to the e-break pin, post in the for sale/wanted section and ask if anyone has one they can sell you, its best to use the right part and not try to make something for it

here it is: http://urdusa.com/store/Electronics-Rear-Sensor-Simulator/c66_170/index.html

now that is the right way to do it and your truck will run best and get good gas mileage but ...

if you want a cheap simple fix and don't care about good gas mileage then this shows you how to "rig" it so it fools the computer into thinking the cat is working fine but the side effects will be an engine that may not run very smooth or get good gas mileage.

https://www.youtube.com/watch?v=qHD7T7EhuzI

 

Thanks for the advice & the link

I'd seen that youtube clip and I agree, it doesn't seem like the way to go. Besides, I don't have that kind of equipment nor the skills to start fiddling around with electronics.

Moreover I care about good mileage, gas is affordable here but not cheap (3.50 per gallon) even more so I like performance. So I'll go with the simulator and get it over with.

 

I would like to share some thoughts as I too have this problem. My truck is a 2002 regular cab with the 3RZ engine, standard trans and 4x4. The truck has 175000 miles on it and runs very well. It is throwing a code for the #2 O2 sensor. The sensor is brand new and therefor I am going with a bad catalytic converter as the diagnosis. There is no discernible flow restriction on the Cat.

As I understand it, there are three options (besides just ignoring the CEL or putting a piece of tape over the light). The first option is a signal generator that simply makes a signal to the CEU. It is completely isolated and has no connection to the exhaust. It merely generates a signal that the CEU will like. To my way of thinking, this is the least desirable of the three as the signal is complete fantasy and gives the CEU nothing that's based in reality. I would expect that on an engine with any wear, you'd want the CEU to at least have an idea of what's going on. I think that this option is most likely to give poor HP/fuel economy.

The second option is the introduction of a resistor and a capacitor into the signal from the #2 O2 sensor. As I understand it, this will dampen the volatility of the signals sent to the CEU. From what I've read, the CEU looks for high signal, low signal and signal change frequency. The resistor and the cap simply take the high and low edge off the graph and reduce the frequency of change to a a level acceptable to the computer. That said, the CEU will also see the broadest part of the range and will be able to make some consideration and accommodation as it adjusts the air/fuel ratio. While it's true that the #1 sensor is the primary sensor for the fuel/air, the CEU does, apparently, consider the signal from the #2 in some small ways. The video in the previous post addresses this a bit. This is not a signal generator, it is a signal conditioner.

The third option is the black box from Underdog Racing Development. URD is not talking about what's in their box, but I'm guessing that there is some logic in there as well as the resistance and capacitance adjustments. After all, they charge $110 for that little box so it should be be more than just a handful of Radio Shack parts and a couple of connectors.

As I consider my options, I've ruled out number 1, the signal generator. I like options 2 and 2 as they are "conditioning" the signal from the sensor and therefore have at least one foot in reality. In a truck with as many miles as mine has, I'd like to continue to consider what's actually happening in the combustion process.

So for me, I think I'll try the approach in the video (resistor and cap for $5.00) first and see what happens. If it works, great! If not, I'll simply remove it and drop the big bucks for the URD magic box.

I hope this makes sense and is helpful.

 

BTW Benfatto, As for reading codes on your truck, you can purchase an OBDII reader, sending unit on Amazon for about $20.00. Torque Pro software which you would run on a laptop, tablet or smartphone costs about $5.00, downloads directly from the internet and works as well as any big Buck Scanguage.

Hope this helps.

 

I've gutted my cats, haven't had any engine codes/problem smogging/O2 sensor issues.

 

I wonder how much the fact that you have a supercharger affects your sensors? I had a 97 Previa with a supercharger and it was a strange beast! Great car, but not your average mechanical project!

 

Well that was before the super charger. I recently as of two days ago got magnaflow high flow cats and a flowmaster super 44 muffler installed and the throttle response is 100x better. Not to mention the low beefy tone now. Cats are just restriction of airflow in my opinion. Every time I've "gutted" cats I've seen improvement. The magnaflow high flow cats make me a little more at ease with smog though haha

 

Thanks!

You mean this one

Professional U480 CAN OBD2 OBD II Car Diagnostic Scanner Engine Code Reader Tool

http://www.amazon.com/Professional-...m=1996:toyota:tacoma&keywords=computer+reader ?

(Just want to make sure it works.)

The way I see it regarding the sensors, is that I put a simulator on my second (rear) o2 sensor. The first one will still give a proper, real signal when something is not in order with the fuel mixture. The second is only there to measure the effects of the catalytic convertor.

 

have you changed the fuel filter? your symptoms sound fuel related to me.

 

Not yet. I should, if only to exclude that possibility.

 

On second thought, I doubt it is fuel related.The symptoms only manifest itself after an hour of driving, and the engine stalling when idling is also not consistent with a bad fuel filter.

 

that is exactly consistent with a clogged fuel filter, not saying that's your problem but it is how one acts.

the fuel starts flowing then the sediments that settled in the filter while it wasn't running start blocking up the still flowing parts of the filter until you don't get enough gas and the engine starts you lose fuel pressure so the engine struggles at times where the injectors aren't fully open such as idle or when stopping at lights. there could also be sediments in the lines adding to the blockage as you drive but falling out and settling in the lines when the fuel pump is not running.

that said, the same symptoms could result from a clogged filter on the fuel pump itself or a weak fuel filter not putting out good pressures.

as you already said, it doesn't hurt to be sure and even if its not bad its still good to replace them from time to time so replace the filter and see what happens.

 

How do you "gut" the converters and does the decrease in back pressure cause any problems?