91LS400LEX

UPDATE - Problem fixed... thanks for all of the replies. The shop cleaned the EGR system and all is well now... charged $49.00 + tax. Almost dont want to sell it now.

Oh well.

Had a code 71, thought I had fixed it, but the light comes on about every 100-150 miles at highway speeds. I had disconnected the battery about 10 seconds, but wondering if it either should be disconnected longer, reset some other way, or if I still have an issue? Thanks!

avalon42

iTrader: (1)

If you did any amount of searching on the issue, you would see that the previous direction I gave you to clear the code is correct.

The code 71 is because somewhere in your EGR system is malfunctioning, as I told you would possibly occur in your other thread.

91LS400LEX

Sorry, I have had a very bad (and I mean very bad) couple of days and I apparently overlooked that in your other thread. Your right, you mentioned this and the link there - my bad as usual.

I had went back and read it again on here.... http://www.lexls.com/tutorials/intro/codereading.html

When I capped those ports I had the hose to, I didnt disconnect the battery for more than 2 or 3 seconds, so maybe it didnt clear the code. I read your thread on the EGR and it seemed like too much for me to handle, because I didnt want to mess it up more. I only saw the one bolt your thread - I didnt even see the others to remove. Knowing my luck, I would have really screwed it up.

That easy part someone mentioned... about checking the filter... I did do that at least and it was clean, so I know that not the issue.

I also noticed there was a fairly loose hose going to the EGR, so that may have been the issue as well. I tightened it, then disconnected the battery for a minute and within 60 miles, the light has not came back on, but it took it 135 miles the last time before it came back on.

I may have the car sold anyway and the car will be sold as-is. If they light comes back on, they can deal with it. I am not putting tape over the light. They are getting it well under book value anyway - I am sure this will not cost much to fix. I MAY have the EGR cleaned somewhere if the price is reasonable. I am losing big $ on this car anyway.

As much as I love this car and as good as it is major mechanically, I cant wait to get rid of it, because it has caused me more headaches, high blood pressure and occasional rude remarks on many posts on the problems I have had - all of which were minor but nagging and confusing problems... all of which I have resolved. I have never owned any car like it... I just dont have the money or the brains to own a car of this stature.

91LS400LEX

Curses. The light came on again... this time after 40 miles.

Guess I will see if the repair shop can squeeze it in tomorrow and see if they will clean the EGR valve without charging me a fortune.

If so, it will be sold as-is I guess. That car is a fool to behave with me like this.

avalon42

iTrader: (1)

Like I said, check for an air leak in your EGR vacuum tubing. One of the stems on my VCV was slightly cracked because the air tube was moved a lot. I replaced it, and the light was reset and hasn't turned back on since. If not an air leak, then your EGR vac modulator has its internal diaphragm screwed up (the one that the filter is in) and you need a new one.

http://www.lexls.com/tutorials/emission/egrfilter.html

I have two extra EGR modulators that work great (tested on my own car without throwing a code), in case you need one to test or replace.

91LS400LEX

Thanks again. I went and read your other post on my other thread. I remember you saying you tested your EGR valve, but didnt see anything on how you go about testing the EGR valve. Also, how do I check for an air leak here? Just have to listen closely?

I also re-read and seen were you put to remove the EGR valve that you have to remove the VSV, EGR modulator as well. It really looks like something I could easily screw up. I am wondering if my shop will do it without charging me a fortune. If it turns out to be a bad EGR, how much do you want for one of yours?

I may also just tell the lady that wants to buy it that the CEL came back on and she can take it or leave it. Just let the new owner deal with it. Its so puzzling because its running better now than it ever has and its really disappointing that this didnt happen until I had the throttle body cleaned.

Makes me wonder why I even try.

avalon42

iTrader: (1)

Take a look at the link, read my post again, and look at the pictures at the same time. It will make sense.

As for testing the EGR, all you need to do is put an active air line to the top of it. If the engine shuts off, then it's good. If it does noting, then your EGR has failed or needs a cleaning. Usually when you clean your TB, you are loosening years of carbon buildup which then travels back to the intake through the EGR. It can get clogged in there, hence why you take it apart, clean it, then put it back together.

I don't have an EGR for sale. I have two working EGR modulators (look at the pic). Sometimes those fail. Only way to test it is by blowing through one of the air hoses (I don't remember which at the moment but will repost when I figure it out again). You can have it for free as long as you cover shipping.

91LS400LEX

Thanks. Well as soon as the weather breaks here (its been unusually cold), I will test it. I emailed the lady and told her the CEL was on and she could take it or leave it. I told her it was flashing a EGR code and it would not be that costly to repair. I even offered to knock off $50. I have like 16 people interested in buying this car. $2450 is a heck of a deal on a nice 1991 LS400 with a nice interior, nice body, everything working, and a powertrain that feels like it will last another 300K miles!

I called my shop today and like you said, he also said that sometimes when the throttle body is cleaned it gets some dirt in the EGR valve. It will be Wednesday before he can check it though. I did find a used on cheap if I need it though.

Oh yeah, I notice there is an EGR valve and an EGR modulator. You have the modulator... my bad.

If I need it, I will let you know. I appreciate it. Thanks again.

91LS400LEX

Car is going to the shop tomorrow to have the EGR valve cleaned. Hope it dont cost me a fortune.

91LS400LEX

Problem fixed... thanks for all of the replies. The shop cleaned the EGR system and all is well now... charged $49.00 + tax. Almost dont want to sell it now.

Oh well.