What the??? Barely getting 19 MPG!!!

[Pocket_Rocket]

Haven't been measuring fuel efficiency since my BP swap until last week, which I did just for fun. Well today was the day that I would fill up my tank to see how much fuel I used so I could make my calculations. And when I did, my eyes nearly popped out of my head : 18,82 MPG!!! I know it's cold, and my daily commute consists of four 5-minutes drives (go to school, come back home for lunch, school again, then home) so the car never gets up to operating temperature, plus since it's city driving with 30 and 15 MPH zones all the way I never get to go higher than 3rd gear. But I mean, come on!!! 19 MPG??? That's SUV territory! What could be causing this? Like I said before, I have an erratic idle, the engine misses slightly on high idle on really cold starts, and when the engine is hot, after maybe 10 minutes or more of hiway driving, it will stall at the first stop after taking the off ramp as soon as I put the clutch in without giving it gas. And then I've got all the trouble in the world to start it again, as the started seems to strain while turning the engine over. Waiting for like 10 seconds usually does the trick to start it again.I also have oil leaking OUT of the distributor (from inside the base, which means the cam angle sensor is constantly wet with oil) and my intake isn't perfect; the AFM isn't level, and I'll need to check to make sure there isn't a vacuum leak, since it's homemade (shortened Escort GT tube), also, my carbon canister is missing since I sent my car at the shop to have the MC replaced, and the lines are plugged with screws. And I'm not sure but I think my intake cam may be advanced by a degree or two; I had a hard time keeping it lined up with the mark while installing the timing belt during the swap; it would spring back clockwise just by a hair, not even a whole teeth, but I'm pretty sure I aligned it correctly. Maybe it moved while I was tightening the tensionner, IDK, but I guess I'll have to check it out. So any of you know which one of these problems might be the most responsible for my bad mileage? Or could it be something else?

[silver04rs]

bad O2 sensor.... heavy foot....

[Pocket_Rocket]

The O2 sensor is brand new since the swap, and like I said, I drive in 30 and 15 MPH zones, so I can't afford to have a heavy foot!!! Never took it over 3000 RPM on my last tank of gas...

[Pu241]

My guess is that you never get it warmed up so it running rich the whole time.

Just a suggestion; might want to block off some of your radiator, fill up the tank, and take it for a 60-100 mile drive and fill the tank again.
Watch your temp gage, but I don't think in these temps your going to over heat.
You could still have other issues that adversely affect your MPG, as you've mentioned, but I believe never getting properly warmed up is a major one.

[FestYboy]

alot of stop an go will eat gas quickly. with that said, you mentioned that you have a new o2 sensor: do you remember which brand you put in?

[bhazard]

Get it running right first.

[JPT]

My guess is that you never get it warmed up so it running rich the whole time.

I agree with this. My '81 Mustang does this in the Winter. The engine never even gets warm (seriously, down the highway, it has no heat) and gets less than 14 mpg. It runs ultra rich. In Summer, it easily gets 20+ mpg.

[Pocket_Rocket]

Thing is, it doesn't get that much better in the summer...

[FB71]

well then, the thing is most like running pig-rich all the time. What do the tips of the spark plugs look like? can you pull one, take a pic and post for me to see?

This sounds like you either have a biased ECT (Engine Coolant Temp sensor) or biased VAF.

[Pocket_Rocket]

I'll go check the plugs tomorrow. But I think it may be running rich cause the inside of the muffler tips has black soot, and on the bumper, over the muffler, and my new cat only has a year and a half of driving on it.

[ericsmith32]

And I thought my 25-26 was bad in my auto. Mine does need a whole new ignition but my problem is my commute. Similar to yours 1 mile city - 4 highway -1 city. Every vehicle I've had as gotten lousy mileage if I just drive it to work. We used in play around today alot of highway and so far 150 miles in a 1/4 tank.

[mr2gq]

Omg are you people serious with some of the suggestions you gave after he told you how it's running? Ummm like the other guy said get it running right. All the stuff you listed with give you horrible gas mileage. Oil going coming out the distrIbutor will make a missfire. The idle is a vac leak probably from having stuff pluged with a screw. If not could be a tps. And the having trouble turning over and you think it's off a tooth is probably why it does that. Cam timing has to be right or it will do that. All this will KILL you mileage. Fix all that and yours will probably back to where it should be

[Pocket_Rocket]

And by the way, any chance someone could make me a diagram of where the timing mark should be on the crank pulley? I want to check the ignition timing but the mark as been lost because of rust on the pulley. It's the stock festiva pulley, the '93 version. So could someone measure how many degrees the mark is relative to a reference point, like the crank pulley bolts for example?

[bhazard]

Just pull the #1 plug and turn the engine by hand til the piston is up top.

[Pocket_Rocket]

Ok, I got a little bit done this week. Took off the timing covers and checked cam timing. Right were it should be. But then, when the #1 cylinder was a TDC, I removed the distributor cap to check out the rotor's position, and it was almost past the #1 spark plug wire terminal, I.E. too much advance. The disty was almost turned all the way clockwise. So I adjusted it, based on photos of many people's BP engines for reference points. It took care of part of the problem; the idle is lower (around 1100 rpm) and the car runs smoother, has better throttle response, pulls great and linear with no hesitation and pretty much no more backfires on decelleration, and the irregular idle has backed down to just a 100 rpm variation. But but after a test drive, when warmed up, I hear a clicking sound, like a relay, coming from near the fusebox under decelleration, and as soon as I put the clutch in, it will stall if I don't give it gas. And then it's really hard to start. It does this every time I stop at an intersection now. It used to do that before with the advanced timing, but after a long drive only, would start again and do it maybe once or twice again, but that was it. Now, I can't "catch it" before it stalls because it dies as soon as I push the clutch; I have to keep my foot on the brake and the gas coming to a stop before pushing the clutch. So for now I have to set it back to advanced timing. Next step is replacing the distributor, lenghtening the VAF's wires ('cause right now it's sitting upside down so that the plug faces the front of the car because the wires were too short otherwise) and work on the intake tube so that the VAF is level, and check for vacuum leaks. If it doesn't help, I don't know what else to do!