OK folks, this is weird and I can not figure it out at all and can find NO common denominator that will point me to the right thing. A few months ago we had the intake manifold gasket replaced because of a water leak and lack of time to do the work myself. After that repair we had AC but no heat. After a lot of playing around in the dash and checking vacuum lines I finally got heat back later, no real clue how but it started to work. Then a little more then month ago I left our wagon at our office parking lot overnight. (Probably not the best move). Everything was in tact the next day and was relieved. A couple days later I filled the gas tank and found I only got 7 to 8 MPG. I made an assumption that some one stole gas and drove it another tank only to find 8 MPG. Well The next tank I took it back to the shop to see what was wrong. After this one we lost AC and heat. The compressor does not kick in. I was told that the carb needed rebuilding and given a cost. Reluctantly I said go ahead (I may have been better off replacing it with an AutoZone one but too late now). Well it took it up to a whopping 9 MPG. When I went to start the car after getting to my office I found that it started great. What a relief that was. I drove 50 feet and it was dead as a door nail. After a couple hours playing parking lot mechanic I found that they CUT the metal fuel line to make a part for the carb they lost and they hose clamped a fuel line on both ends. It turned out that the line folded closed and thus NO gas was getting to the engine. Fixed that and had a conversation with the repair shop about cutting the line.. Overall it ran improved but not what it was When we got it back the AC was hit and miss again and the heat was out again. I did take it back soon after and they fixed the AC. A couple weeks later it is out again and I noticed that a relay was removed from the side of the firewall. AFTER he did the carb and the mileage was so low he suggested the catalytic converter may need replacing. I figured OK, we have 119K miles so I bought one and installed it. It was nearly closed up. I could only see one pinpoint of light through it. Well it sounded much better and seemed to run smoother and the mileage went to 10.5 MPG. Tonight I found one vacuum line open on the top of a part number 25525518 that rests on the driver side valve cover that indicated one line to the MAN and the other to DELAY. I plugged it (the third line) for now to see if it helps because I can not find an open line anywhere. I also noticed that there is a 4 vacuum line junction that is in front of the carb that one of the 4 lines gets sucked closed as soon as I start the car it goes to a similar part on the passenger side valve cover. The other three lines are fine and hold shape. I fear that the problem is STILL the carburetor. OK, here we go. I have lost ENOUGH hair and the remainder is quickly departing as I pay a $400 gas bill due to 10 MPG. Anyone have any thoughts as to what I may be missing? I have almost gotten to where I am ready to have it looked over by the dealer! Problem is the one that rebuilt the carb, did the valve cover and other work used to work for Buick before opening his own shop. Thanks! Kevin
Kevin, Those 307's use electronic spark timing. See if you can check and see if the timing is advancing properly with engine speed. If not that really could cut into your mileage.
After the work and the way it was running it seems that the timing needed to be farther advanced and it was not until then I realized that the timing advance was not a vacuum. How would it be checked with this type of distributor to see if it is advancing properly? With a vacuum you can generally see that it works. I will say even after advancing it some I found no change and figured that may have to do with the way it advances with out a vacuum line. I have never gotten one knock or ping out of it no mater how hard I hit the gas. I have always thought that was a little odd. It would be NICE to get this thing running the way I know it can. A 307 is not HUGE but it is enough to make up to 75 ish when needed. I used to have a 72 torino wagon (school bus yellow) that was all pre electronic stuff. It makes life much easier....... Thanks, Kevin
Kevin, Is there a check engine light on? Is there fuel getting into the crankcase? (bad fuel pump?) Check the charcoal cannister purge valve. You can check the timing with a light the same way you would check centrifugal advance. The electronic spark timing distributor uses a 6 pin module. It is possible for that part of the module(advance) to fail. Do you hear the mixture control solenoid in the carb clicking while the engine is running. Have you changed the oxygen sensor lately? Just a few ideas. Good luck.
Well check those things. No check engine anymore. We did the Oxy sensor when we did the Cat Converter. When I changed the oil last weekend I did not see any sign of gas in teh crank case. Thanks, Kevin
Have you done a basic tune-up? I know that sounds like a ridiculous question, but you never knowo No: I've missed some pretty obvious things before. Just think to yourself, you'll be getting 18mpg soon:Brow: I surprised myself when I drove to Flint this summer - 23mpg!!!
My wife's 90 Estate Wagon is a daily driver subject to all seasons etc. I bought it four years ago with a blown engine and I put in a 307 out of a 84 Custom Cruiser. I ditched the electronics for a normal quadrajet and a vacuum distributor. I've never looked back! Side note: It's a towing package car with a 3:23 posi!
yeap! Did the tune up stuff and everything else I can thing of so far. Still searching around. I was getting about 17 to 22 depending on the driving. Kevin
OK, the real test will be to see what happens with the milage but here is the last findings, I gave up but after I found the vacuum line to the CCV flat I figured we were close. It turns out that the fuel was getting sucked out of the carb from it. I figured they would have to re-adjust everything again so I would let them fix it all instead of me. SO, probably never needed the carb rebuild but.......... Computer Out No Signals in system ECM Fuse Service Engine Soon Light & Housing Burned up CCV Sucking fuel and dumping into back side of engine TPS out of specs. (AC still gone but hey, it is under 83 out now so I will worry about that one later. Thanks for all the help! Now I can afford to drive the family Kevin
I too have found the vacum response valve with it's open port. As you can see by the emission's diagram it does not get a line going to it. According to my Chilton's manual, that port is used for testing. The problem I'm having is mine is pulling vacum all the time. Take a look at my other thread. So far everyone of the valve's that I've seen has been open. Can anyone shed some light on this. Is there supposed to be a cap on this thing. Thank's. Cal
Cap it and see what happenso No: I can't imagine it's doing any good being open and sucking vacuumuzzled: Talk about a major vacuum leak.:shock:
Boy Smartin,,you're everywhere I go. You following me.:laugh: :beer Actually I'm glad to see someone trying to help as many as he can.:TU: As far as capping it goes, I did. But I can't really tell for sure if there was a differance. I'm going to uncap it and see how it run's. What I'm really trying to find out, since I've seen so many uncapped, ARE THESE THING'S CAPPED FROM THE FACTORY OR NOT. I would not want to put a cap on it if it's not supposed to be there. o No: Thank's for any input. Cal
Re: Re: 307 Y one more brain storm That line is supposed to be open, and yes it pulls vacuum. From the factory it has a foam filter attached to it, but they rot and fall off. Leave it alone, that's the way it is supposed to be.
Re: Re: Re: 307 Y one more brain storm Thank's for finally setting the record straight.:TU: Please don't take this wrong, I'm greatfull for your input and I beleive what you are telling me,,, but, how is that you are so sure. Did you have a new one, or worked on them before. Just curious. Thank's again, Cal :beer
Re: Re: Re: Re: 307 Y one more brain storm Just from being around 307 motors. On my emissions sticker showing vacuum hose routing, I believe it shows this(not sure) If it does, I'll see if I can take a picture
Cal, I took a picture of my emissions sticker. The valve is labelled "VRV". You can see that it has an open port that goes nowhere. In the next post, I'll show a closeup of my valve. When I first got my car in 1991, there was a small filter attached to the port. It fell off, so I made another one out of foam-rubber, and stuck it on there. Hope this is what you are talking about.
