cmac2012

cmac2012
Renaissances Dude
Join Date: Dec 2004
Location: Redwood City, CA
Posts: 33,428 #1
Today, 06:16 PM


I’ve been getting the check engine light a lot, usually after about 20 miles on the freeway - ithe trouble code is always “rich fuel mix detected at O2 sensor.”

One of the main suggestions on the web is to get a new temp gauge sensor. I installed a new one last summer during my intake manifold gasket renewal, along with new jacks which were both in bad shape.

I had the fear of God put into me after about a week of doing a lot of driving with the engine complaining the whole time, really faltering off the line, I would floor it hard, and it would come to life. Off and on during this I would hear a funny knocking noise which would be gone the next day and then come back after extended driving.

At one point after a 40 mile drive back to my place it was really acting badly, as if some of the pistons were freezing up. I pulled over, got a Lyft home, came back the next day, and it ran much better. Then I noticed a new thing in my searching, which was that a rich mix can be a problem because the excess gas washes away some of the oil and you suffer poor lubrication. Only makes sense.

I had rebuilt the throttlebody injector unit a few years back, but didn’t renew the injectors . I bought some injectors from Napa and put those in 10 days ago. Also installed a new rubber, mounted fuel pressure valve. When I pulled the upper part out the area around the fuel pressure device seemed too soupy, a lot of unusual liquid down in there. The old injectors had a few signs of if she/ damage, long story. It seemed like there was less visible dripping from the injectors during idle than with the old ones. The air filter is almost new.

I discovered the flex tube taking heat up to the underside of the long oval pipe going into the air filter box, the automatic choke valve device, was no longer in place, beat all the hill, and I never could get the damn thing to see in place again anyway, so I stuck the shut off vent open full-time. I figured a bit of jerkiness warming up was much better than what I was getting with rich fuel mix the rest of the time.

Things improved after this, but after a few days, the damn light started coming on again, plus I am still getting missing off the line after warm-up. It runs great when I first started which is an indication of too rich a fuel mix perhaps, And that damned knocking noise would come back for a while. It’s freaking me out, man.

I found something on the web about fuel canister purge. They were saying that if there’s too much fuel vapor gonna be a rich fuel mix,with the check engine light coming on, etc. But the piece I found that is suggested to be renewed puzzles me, because I don’t remember seeing this on the intake manifold, which is where it supposed to be.

Also, this canister is under the hood, not too far from the passenger side, headlight housing. I’ve never really known what it does:





Here is the link for the part I am finding online; “fuel purge valve.”

http://tinyurl.com/2cpnvtb4

I really hope I don’t lose this engine. It runs pretty strong most of the time. Another 40 or 50K would be great. Then I’ll buy a crate engine or something

Derrick71

That picture looks like the receiver drier for the AC system. Don't purge anything from there.

The first thing I would do is pull the plugs and see if one or more look wet or fouled. That will let you know if your problem is with specific cylinders or a system that affects all of them equally.

cmac2012

Thanks, I’ll do that.