CrazySC300

iTrader: (16)

Did you clean your clogged egr ports? Because apparently, that's what my problem was.

splacke

When I replaced the EGR valve, I took a wire brush to the EGR port on the "Y" pipe. It was removed to replace the valve cover gaskets. Did I miss something there?

nlc

Instead of buyin an replacing a bunch of parts n it still doesnt work, wouldnt it be easier to jus delete the egr...mine has had the same code for like 3 months. After seeing wat u guys are going thru i think its time for me to go check the egr delete diy thread.

teddyporte

I bought my 95 sc300 and cut the mufflers off, the day after my cel light came on. I ran a code and got code 71. I assumed this was for the delete so i haven't worried about it. Should I have it further looked into?

KahnBB6

iTrader: (5)

This depends on whether or not you want your EGR system functioning for any required smog testing. You probably have a Federal Emissions (49-State) SC300 but you could have a California Emissions (50-State) which has a 3rd O2 sensor (4-wire, heated type) underneath the car which is located on the side of the factory 2nd catalytic convertor. If that sensor is removed or disconnected or missing or if it detects that the 2nd cat is operating out of range then it will not report the signal values the ECU wants to see and so the ECU will throw a CEL code 71 (EGR system malfunction or insufficient EGR flow in one or more of the passages).

All 1996+ OBD2 SC300's also have the 3rd O2 sensor on the secondary cat or further up on the factory exhaust pipe on later models.

Note that this 3rd O2 sensor does not have any bearing on the engine's running condition and air/fuel ratio. It just monitors the efficiency range of the 2nd catalytic convertor.

I believe that 49-State Federal 1995 SC300's still use 2-wire non-heated front O2 sensors on the exhaust header. 1995 50-State CA Emission SC300's have 4-wire heated front O2 sensors in that location. It wasn't until the 1996 model year that all SC300's in both emission markets uniformly used two front 4-wire heated O2 sensors... in addition to the 3rd 4-wire type under the car.

Being a 1995 model year even if you do have a 49-State Federal Emissions model (ie: no factory 3rd O2 sensor under the middle of the car) then it is possible that having removed the cat might change something related to... back-pressure, perhaps? This *might* cause one or both of the front O2 sensors to be thrown off. Not sure on that.

Also, it's possible that the main functional part of your EGR system coincidentally developed a carbon clogged passage condition (it happens after 25+ years and there is a DIY cleaning procedure for cleaning the SC300/2JZ-GE EGR system out if you need it) or it is possible that your EGR VSV has failed to function any longer and needs a replacement. Or it is possible that the EGR valve diaphragm has failed (rare) or the valve has become clogged (more common). Or it could be that the EGR Vacuum Modulator's internal diaphragm has failed (it's the plastic flying saucer shaped thing right next to the EGR valve's metal saucer). Or you could have a broken or leaking vacuum hose in that part of the system.

That's the gist of what's probably happening with your EGR system. At minimum removing the 2nd cat underneath the car probably triggered an abnormal condition either from a factory 3rd O2 sensor being disabled/absent or from the 2nd cat's absence somehow throwing off the readings at the two active front O2 sensors on the exhaust manifold just before the 1st factory cat.