'95 SC Horrible Gas Mileage And Lacking Power

Cyboman

Registered User
I have a '95 5spd SC with less than 55k on it. When I say horrible gas mileage, I mean less than 10mpg! The gas gauge drops at an alarming rate. The car feels like it has a 4 banger with 100hp. Another thing I noticed is a lot of times the car will crank and sputter if I try to start it within a few minutes of turning it off. After a few minutes of this sputtering (I have to hold my foot on the gas or it will just shut off), it will just kick right on and idle high for a few seconds. This doesn't happen all the time, but almost always when it was colder out. The car always starts fine if I leave it for longer periods of time.

One thing to note is just before I got the car 2 years ago, the previous owner replaced the cam sensor. I've only driven the car a couple thousand miles since I have it. These symptoms certainly sound to me like the cam and crank sensors aren't synching properly.

I had a 35th 5spd SC directly before this one and got 24mpg driving 90mph on the highway, and that car had power, so I know this one is definitely lacking! I even had a '96 V8 Sport at the same time as my 35th that got far better gas mileage than this '95 SC.

I'm wondering if the cam sensor was not installed (timed) properly, or that the unit is faulty. There is not, or has been a check engine light on.

Can anyone tell me the proper timing procedure so that I can check it?

Thanks in advance!

Michael
 
If my memory serves, timing is not adjustable unless you have a way to manipulate the EEC-IV.

From what it sounds like you might have a VAC leak somewhere. I've seen a lot of VAC leaks on the SC Plenum and around that area.

I would also check the MAF and make sure it's clean.
 
There is no check engine light. The O2 sensors are probably the original ones.

The car stinks noxiously (unburned fuel) when it is started. That is not usually indicative of a vacuum leak. If it were a vacuum leak, it would have to amount to a sizable hole in order to destroy gas mileage and power that badly, and the sputtering would happen every time I tried to start it.

One other thing, I also hear faint detonation when accelerating, even gently. That is clearly a timing issue. Is there a way to test the cam sensor, or insure that it is installed correctly?

Michael
 
Found this on cam sensor install: http://www.sccoa.com/forums/showthr...cam-sensor-right&highlight=cam+sensor+install

Search for others if it isn't what you need. Also know that the 'adjustment' is to the stalk position, so if only the sensor was swapped, that may not have been messed with. Did the engine come apart for any reason?

As for the pinging....how old is that fuel? Do you know what octane it is? Have you treated it? How old are the cats? Did you see if they are running extremely hot? Did you run the codes? Have you checked the piugs lately? If not, I'd consider a tune-up with new air & fuel filters, plugs, wires and O2 sensors, but not until I knew the health of the cats for sure.
 
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One other thing, I also hear faint detonation when accelerating, even gently. That is clearly a timing issue.

Timing is based on calculated load. Load is calculated based on air passing through the MAF. Vacuum leaks allow air to bypass the MAF. With less air passing through the MAF, calculated load is lower than reality. With load appearing lower, spark advance goes up. With spark more advanced, the engine begins to ping.

Is there a way to test the cam sensor, or insure that it is installed correctly?

Just unplug it and tuck the connector out of the way of the belt. The car will run fine without it. It will, however, take several tries to start, because the computer is guessing which cylinder is up.

P.S. - I don't think the cam sensor has any control over spark timing once the engine starts. It does, however, maintain synchronization for fuel injector timing.

P.P.S - How do the catalytic converters look while running? Is one side getting very hot?
 
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Check the fuel pressure regulator. Pull the Vacuum line going to it and see if there is fuel in it.
 
There is no 'rotten egg' smell coming from the cats, and I don't feel any excessive heat coming from the floor boards. Other than that, I haven't looked at the cats after driving the car for a while, but I will tomorrow.

I can't actually believe that Ford put the fuel pressure regulator where they did. I can't get my hand up and under there in a position that allows me to even get two fingers on the hose, let alone twist it and lift it off. Even if I were to, I'm not sure I'd get it back on! I can't even see it! I do have a fuel pressure gauge. What would I be looking for, a high pressure or a low pressure? I'm guessing a high pressure. If I remember correctly, it should be about 45-55 psi?

I appreciate all of your suggestions. Tonight I'll look for my records and see if just the cam sensor was changed, or if it was the whole stalk.

Thank you all.

Michael
 
I can't actually believe that Ford put the fuel pressure regulator where they did. I can't get my hand up and under there in a position that allows me to even get two fingers on the hose, let alone twist it and lift it off. Even if I were to, I'm not sure I'd get it back on!l

It might help access if you remove the wipers and cowling at the base of the windshield. As suggested, check for raw fuel in the vacuum line at the regulator.
 
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You would see low pressure I would guess and the pressure would bleed off fast. If the regulator is ok it wll hold pressure for a while and also should only pump up to 40 psi when you turn the key on. You may be able to get to the other end of the reference line on the return plenum.
 
I haven't been able to check anything yet and probably won't be able to for a few days. I just calculated just about 75 miles of mixed driving to 5 gallons of gas. That gives me 15mpg, not as bad as I had originally thought, but still off considerably.

Michael
 
I'm in Ct, and gas stations here supposedly switched to summer blends in Feb. Why Feb. you ask? I was told by local politicians so they can charge us higher prices sooner, and that's exactly what they did! But I digress...

There was no change in performance with either blend. My 35th got 24mpg in both summer and winter.

Michael
 
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