QuestionI have a couple of questions. First, I have driven and owned a few of the 3vze engine Toyotas and I have noticed that some have substantially stronger engines than others. Is there something I don't know? Or are they just worn. Most of the trucks are between 100K and 150K miles.
The second question is about me truck. It is a 1994 with 160,000 miles. I failed emissions and I get trouble code 71 (egr). I followed the directions in my Chilton's manual for testing with a vacuum gauge, and it seems to be fine. I have also removed it and checked for clogging. I even blew through it to make sure the valve opens and closes. It does take a bit of blowing to make it work though. I am not sure how hard I should have to blow. Oddly enough, I passed the NOX and HC parts of the test and only failed the CO. I was double the allowed amount.
In an effort to fix the problem I have replaced the cat and the o2 sensor. I may not have needed to do this, but I suspected one of these might be the culprit. I have not taken it back for testing yet because I am still wondering about the EGR.
About 6 months ago the check engine light came on, and I think I got the error for the ignitor not sending a signal for 6 consecutive starts. I think it's 6. Anyways, two years ago I passed with flying colors...probably in part to the stuff that was running through my tank. I wish I could find more of that! And two years prior to that I barely passed the CO portion.
Also when I have just started the engine, sometimes it seems to be unsure of the idle speed it would like to settle on. It goes between about 1.5k and 1.8 k every few seconds.
The only engine modification that has been done is the previous owner installed a K&N style air filter on that replaced the stock air filter box. I like stock better though, it's much quieter.
Any help is greatly appreciated.
AnswerMost of the EGR failures are caused by the EGR modulator valve attached to the EGR valve on a bracket, if air can pass through from the bottom port replace it and clear the code.
High CO is not caused by a malfunctioning EGR system, it's caused by an engine that is running a too rich of an air/fuel mixture, it's getting too much fuel and not enough air, it's possible the cat and 02 sensor could have fixed the high CO reading, take it to a smog test station and have them do a pre-test, this will give you all the readings before doing the real test, if all the readings are good then go ahead and have them run the actual test and it will pass.
