Important Update!!

[leonbentz]

Well, I guess, some of you may know my story by now. About fighting a fuel milage issue. I took my car to a shop, after several failed attempts to fix my fuel consumption issues.

I dropped my car off at a Good Year Auto shop, close to where I work and went over to Applebee's for a few brews and dinner. After I returned, the fellow was nice enough to let me in on the project and show me what's been going on. At first, he told me my ECT Sensor was shot and it turned out, he was testing the fan control switch, in the thermastat housing. I pointed out that the ECT was infact in the rear of the throttle body and he was working on the Coolant Fan control switch. Hmmm.... I kinda had a few doubts, but I just walked away and went to the bar.

So, when I returned to the shop, him and I looked things over and he found that my ECM was just fine......and infact, all of my electronics were just fine. After a while, he decided to check the fuel pressure with a guage. WOW!! 60 PSI?? There's no wonder I'm getting lousy milage!! The fuel pressure through the Throttle Body should be between 16 - 23 PSI. He ran a line, from the fuel return connector to a bucket, and the car ran like a clock. The fuel was able to freely run out the return then.

Sure enough, the return line was completely plugged up. I could not blow through it. So......after finding out that blowing through it would not work, I went and got my air compressor. I hooked the return line to the air nozzle and triggared it open and it seemed like it was still plugged. I noticed that the regulator on the air compressor was set at 60 PSI, so I cranked it to 125 PSI and blew through the return line again!! At this time, a stream of gas shot out the filler and onto my truck. LMAO!! So I figured that it should be unplugged now. I hooked everything back up and went for a drive. SO far, the car runs great. I went into town and topped off the tank. I should know in the morning, how it does at start up. Hopefully, I'll have more good news to bring.

This message goes out to DoctorBill. While you're cleaning out your Throttle Body, you may want to check your fuel return line and make sure it's completely clear, because if the fuel is not flowing freely through the FPR and back to the fuel tank, then it could fuck with your gas milage in a bad way. LOL So, to those other folks out there, who are getting lousy milage, you may want to check that out as well.

Good Luck. I hope this input will help some or all of you. I'll keep you all updated as to how this effects my gas milage.

Leon

[carpenter_jai]

Thank you!

A few questions. Did you ever run it empty? Can you account for the blockage in the line? And, where is this puppy?

I will be checking mine out for sure!

Jai

[leonbentz]

**A few questions. Did you ever run it empty?

It ran close a few times, but it never actually ran empty.


**Can you account for the blockage in the line?

No, not unless I find it on the hood of my pickup truck. lol I just disconnected the line from the throttle body and blew the line out with compressed air.


**And, where is this puppy?

If you remove your air cleaner, you'll see it on the front, right side of the throttle body, near where the the fuel inlet hooks up.

**I will be checking mine out for sure!

Cool. I hope this may fix whatever trouble you're having. Good Luck. Worse case senario, you may have to pull the gas tank and make sure ALL of your lines are clear.

[RossT]

Good post, I would have never thought of that!

[leonbentz]

Yea, I worked on unplugging it tonight and I just found a kink in the hose, back by the fuel tank. So, there really wasn't a clog at all. The more pressure I put into the line, the harder it would kink. So I just crawled under the car and shortened the rubber hose. It seemed like it was a bit too long and that made it easier to kink up. Oh well.....it happens. I hope this post will help a lot of you folks out there. I spent 86 bucks at a shop, to find out that. They ran a fuel pressure test on it and it was pumpin 60 PSI!! Holy shit!! It's supposed to be, between 16 and 23 pounds.
When your fuel pressure is that high, then your FPR is no longer functionable and that's because the excess fuel pressure, just keeps it wide open. I took it out for a 31.6 mile drive and the needle on the fuel guage barely moved. It looks like a BIG improvement.

[DOCTORBILL]

"...After a while, he decided to check the fuel pressure with a guage.
WOW!! 60 PSI?? There's no wonder I'm getting lousy milage!!
The fuel pressure through the Throttle Body should be between 16 - 23 PSI.
He ran a line, from the fuel return connector to a bucket, and the car
ran like a clock. The fuel was able to freely run out the return then.

Holy firestarter, Batman! You are lucky no hole formed in your
fuel line or you might have been riding a FIRE CHARIOT home!

OK - first time I've seen what the fuel pressure should be.

Amazing that the Fuel Pump can put out 60 PSI...! Should have been
pulling quite a few amperes.

Please look at the photo below that I just made and tell me which
port is Fuel In From the Pump - A or B ?
Obviously the other one is Fuel Out Back to the Tank.



I have the TB top half about ready to put back on.

Now your post (almost missed it BTW....) puts a new bug in my
ear.

"Sure enough, the return line was completely plugged up. I could
not blow through it."

Can you blow air thru the fuel line back into the tank!?

"....a stream of gas shot out the filler and onto my truck. "

I don't follow! What do you mean filler? The screw cap where you
fill the gas tank? Lord!

"So I figured that it should be unplugged now..."

If I understand you, whatever was plugging the line is now inside your
gas tank....yes?!

In any case, this is most instructive.

Of all the bullshit things that can happen...! How can something get
FROM the throttle body into the fuel return line and be big
enough to plug the damned line!?

Fuel at that point should be quite clean! Has something broken
off inside your Throttle Body? Part of the FPR Diaphragm maybe?
That port at the inside bottom of the FPR is quite large. The TB Top
I got from the Pull-n-Save had a large piece of plastic inside it when
I took the FPR top off and removed the diaphragm.
A piece of tan plastic like something broken off of another 'thing' was
under the diaphragm. Could it have broken off of the Injector?

If the Fuel Pump pumps through the fuel filter (and it has a
screen on it to boot!), then where could this crap come from!?
And why just lately?

Aliens. I knew it.....

My God! That is amazing - unless I have misunderstood what you
have said. Quite possible.

In any case, you can bet I will pursue this line of examination.

DoctorBill

[leonbentz]

It wasn't actually plugged. A hose was kinked, and kinked harder, the more air pressure I put on it

[leonbentz]

Fuel In, is A

Fuel Return is B

[DOCTORBILL]

I edited this.....you answered my question before I could get back.
Confusing!?

A kinked hose...Why didn't you just say that right in the first posting?

I think I fingered this whole thing out by examining my ruined and fully
opened up TB Top Half and the Chilton Manual diagram on page
4-30.

The Fuel goes from the Fuel Pump thru the Fuel Filter into the TB and
directly to the Fuel Injector. That means "A" is the input port.
YES?

It then passes thru or past the Injector (some gets injected into the TB)
and goes to the bottom half of the FPR and into the chamber and
if the pressure is high enough - lifts the diaphragm and then
can go down the little hole and back to the tank thru Port B.
That big rectangular hole on one side of the FPR chamber bottom half
is just a "pit" for some reason...(?)

What is the purpose of the top half of the FPR - that portion is connected
directly to the intake manifold - a partial vacuum!?



As Mr. Spock (on Star Trek) - my hero - would say..."Fascinating!

DoctorBill

[leonbentz]

Well, good news!! I went out this mornig to start my car and I was amazed. I didn't even touch the gas. I turned the key and it came to life. No more Metro Misquito Fogger. I can even drive it, while it's cold. The gas milage is a lot better. and it's running better at start up.

Check and make sure, the small portion of rubber hose, for you return line is in good shape and not kinked. It's right behind the rear drivers side wheel, at the front left corner of the gas tank. Under the car, you'll see the series of metal lines running together along the uni-body frame and the return line is closest to the center of the car. By the front corner of the gas tank, all these metal lines are spliced together with short rubber hoses and they must be free of kinks or clogs or nothing will work right.

[unbe]

Thanks to Leon and Doc for another great post.

[geozukigti]

Awesome Leon! I never even thought of that. Perhaps a rock came up and hit it, or you ran over a big speed bump too fast one day, and it nailed the line. Makes sense on the poor mileage though

[DOCTORBILL]

OK - so the test would be to try blowing air back thru the Fuel Return
Hose - right?

I have yet to put my Throttle Boddy Top Half back on and this
would be a good time to test the Fuel Return Hose.

If I cannot mouth blow air thru it, I must assume it is plugged or
kinked. There is no valve back there is there which would need high
pressure to push the gas thru...?

I don't want to use a compressed gas hose as you did. I might break
something!

DoctorBill

[leonbentz]

Well, clearing my fuel return line has given me another 11 miles to the gallon.
I took a trip this weekend and I got 37.1 miles to the gallon. I even gave this booger a cold test. I got in it and drove it, within a few seconds after a cold start. Pretty cool. I never could do that before. So...I think I made some good improvements over the last week. It still seems I should do a little better but this is good.

[leonbentz]

To answer your question Doctorbill: You should be able to freely blow through the return line with your mouth. There are no valves or anything on this line that would keep you from doing so. The place you would likely have any problems with the return line, is right behind the left rear wheel, where the metal line on the car and gas tank are spliced together with a short rubber hose. I tend to believe that this little area is a problem spot for Metros that are delivering less than acceptable fuel milage, because the way the two metal lines come together to be spliced with a rubber section, The two metal pieces come together at about 90 degrees from each other and yet the rubber hose splice is just a straight piece clamped on with a curve in it. Over time, this will likely creat a kink or fold in the line. What I did, was I took a little off one end and bent the two metal ends to match each other better and respliced them with the same piece. It took a lot out of the curve of the rubber splice. Good luck. I hope this helps.