splangeland

Hey guys, I have a 1994 4runner with the 3.0. Recently I noticed a noise that sounded like a miss. Sometimes it is rhythmic, sometimes it isn't. I had my dad listen to it and he said he thought it might be a sticky valve. So for ˟˟˟˟s 'n gigs I fueled up and added some gumout to the tank and marvel mystery oil the oil, with no results. I checked wires and cap, they both seem to be ok. I then went to the ol' paperclip in the OBD slot trick. It came back with two codes, 52- knock sensor signal, and 71- EGR system. Any ideas whats going on here?

abecedarian

If I had to guess, it looks like the ECU isn't getting a signal from the knock sensor and the EGR system isn't working properly.

Plenty of information on YT about these. Search.

4x44runner

Before you spend the money on KS reset your computer!! my KS was 160$ from local autoparts!!! remove POS battery connector for 1-5mins and ground it for 30 seconds. And run it for a few miles and do the jumper again. as for EGR idk i removed mine.

splangeland

Ok, what are the advantages/disadvantages of removing EGR?

scope103

The engine will run a little hotter internally without the EGR. You'll be poisoning all of us with your NOx emissions without the EGR.

The advantage of removing the EGR is, well, I don't know of any advantages.

(Incidentally, just removing the EGR won't make your code go away. That requires even more horsing around than just fixing it.)

splangeland

Alright I think ill just leave it on then

MudHippy

1. You can put a 10k ohm resistor in the EGR gas temp sensor connector. That will clear the code PERMANENTLY.

2. One of the advantages to removing the EGR valve is to prevent it from caking your intake with crud. Which, over time, can/will lead to significant intake air flow restriction(loss of power). And all that filth can be a pretty big hassle to remove once it's in there(try cleaning the inside of your plenum chamber sometime...not fun).

3. Fundamentally, the EGR system is designed to be a "fire extinguisher". Its function being to "extinguish" some of the "fire" happening in the combustion chamber(s). Thereby lowering the effective burning temperature of the fuel, which results in fewer oxides of nitrogen(NOx) being emitted through the exhaust. And, consequentially, it also lowers the amount of power extracted from the fuel during the combustion process. Simply put...Less fire = Less heat = Less power = Less NOx emissions.

splangeland

Ok, thanks that's a big help. I don't know that I wanna put much money into since I'm afraid it wont last too much longer. It wont idle when its cold and the transmission keeps getting stuck in different gears. As much as I love it, it may be on the way to the scrap yard in the not so distant
future.