Car question? Update!

[Pepsi90919]

Originally posted by: BlackOmen

Originally posted by: yellowfiero
cold weather.

Ditto. Now that we're facing some cold days your car is going to spend much more time warming up. The state that your car warms up in is called "closed loop". In this state your air/fuel mixture is going to be richer and you will get poorer fuel economy while in this state. Now, I believe a friend of mine, who has gone from 26mpg to 16mpg on the highway, is not reaching the open loop state. He likes to crank the heat and is running a colder thermostat. Even in my four cylinder Chevy I havn't been getting the same fuel economy. Early last week I stopped cranked the heat (blower sees a high position of 2 now) and now I appear to be getting better fuel economy then. When I would crank the heater on 4, my engine water temp gauge would start to drop below its normal position. My friend turned the heat down as well and placed some cardboard in front of the radiatior and just got 24mpg on a 350 mile trip.

If you're milage got worse as the temp has really started plunging, then maybe you're not getting out of the closed loop state or you are reentering this state. Turning the heat down allows the motor to retain it's heat, at the expense of your comfort of course

YMMV.

you have it backwards, open loop is ignoring certain sensors until they warm up, closed is using all sensors.

 

[Pepsi90919]

btw SCAN THE CODES. that's why the check engine light is on.

 

[Thegonagle]

Originally posted by: BlackOmen

Originally posted by: yellowfiero
cold weather.

Ditto. Now that we're facing some cold days your car is going to spend much more time warming up. The state that your car warms up in is called "closed loop". In this state your air/fuel mixture is going to be richer and you will get poorer fuel economy while in this state. Now, I believe a friend of mine, who has gone from 26mpg to 16mpg on the highway, is not reaching the open loop state. He likes to crank the heat and is running a colder thermostat. Even in my four cylinder Chevy I havn't been getting the same fuel economy. Early last week I stopped cranked the heat (blower sees a high position of 2 now) and now I appear to be getting better fuel economy then. When I would crank the heater on 4, my engine water temp gauge would start to drop below its normal position. My friend turned the heat down as well and placed some cardboard in front of the radiatior and just got 24mpg on a 350 mile trip.

If you're milage got worse as the temp has really started plunging, then maybe you're not getting out of the closed loop state or you are reentering this state. Turning the heat down allows the motor to retain it's heat, at the expense of your comfort of course

YMMV.

All you smarties here, and nobody has mentioned that the FIRST thing one should do when mileage drops suddenly is replace the thermostat!

(It should be all of $6-16 for the part, including a new gasket, depending on whether you get Motorcraft, other brand, or generic.)

BlackOmen came closest, so his post gets to be quoted by me.

 

[coolVariable]

Well like i said I live in 85° warm weather so I don't think any cold is the problem ... (rather the opposite).
I think it's the O2 sensor(s) and I will bring my car to a shop on Wednesday.

I will tell them to look at the O2 sensor and replace the spark plugs if necessary.
Oil seems still fine on me, so I will tell them to skip that.

BTW Anybody know at how much I will be looking $$$-wise?

 

[BlackOmen]

Originally posted by: Garfang

Originally posted by: BlackOmen

Originally posted by: yellowfiero
cold weather.

Ditto. Now that we're facing some cold days your car is going to spend much more time warming up. The state that your car warms up in is called "closed loop". In this state your air/fuel mixture is going to be richer and you will get poorer fuel economy while in this state. Now, I believe a friend of mine, who has gone from 26mpg to 16mpg on the highway, is not reaching the open loop state. He likes to crank the heat and is running a colder thermostat. Even in my four cylinder Chevy I havn't been getting the same fuel economy. Early last week I stopped cranked the heat (blower sees a high position of 2 now) and now I appear to be getting better fuel economy then. When I would crank the heater on 4, my engine water temp gauge would start to drop below its normal position. My friend turned the heat down as well and placed some cardboard in front of the radiatior and just got 24mpg on a 350 mile trip.

If you're milage got worse as the temp has really started plunging, then maybe you're not getting out of the closed loop state or you are reentering this state. Turning the heat down allows the motor to retain it's heat, at the expense of your comfort of course

YMMV.

All you smarties here, and nobody has mentioned that the FIRST thing one should do when mileage drops suddenly is replace the thermostat!

(It should be all of $6-16 for the part, including a new gasket, depending on whether you get Motorcraft, other brand, or generic.)

BlackOmen came closest, so his post gets to be quoted by me.

WOOHOOOOO!!!!! So when can I pick up my cash prize?

I never knew that the tstat could be to blame if fuel economy drops right away, although now that you mention it, it does make a lot of sense.

With my backyard mechanic skills, I've usually attributed fuel economy issues to ignition problems. Most of the time a friend will be complaining about bad milage and when I bring out the timing light, they're running something like 0* timing BTDC, or their ignition components have 80k miles on them. My friends mustang, with a recent tune up, forced me to rethink this and blame the weather.

But since the original poster mentions that he is in 85* weather (I'm jealous), I agree that the thermostat needs checked and/or replaced.

 

[Zenmervolt]

Originally posted by: Garfang
All you smarties here, and nobody has mentioned that the FIRST thing one should do when mileage drops suddenly is replace the thermostat!

(It should be all of $6-16 for the part, including a new gasket, depending on whether you get Motorcraft, other brand, or generic.)

BlackOmen came closest, so his post gets to be quoted by me.

If the thermostat goes, you can tell in 2 seconds by watching the coolant temp guage. Since he didn't say that the car was overheating (or underheating( it makes no sense to recommend that he change the thermostat. If the temp guage is fluctuating in weird ways, then yes, look at the thermostat. However, he made no mention of strange temp readings. Since it wasn't a symptom I saw no reason to further confuse him with unlikely possabilities.

But since the original poster mentions that he is in 85* weather (I'm jealous), I agree that the thermostat needs checked and/or replaced.

NO. In 85 degree weather even with a low-temp thermostat there is _no way_ that he'd be stuck in cold-start mode. If he was in 10-20 degree weather, it might, might be a remote possability, but only if there was the accompanying odd behavior of the temperature guage. As long as he's getting a stable temperature reading once the car is warm (or as long as the needle isn't dropping into a very cold portion of the guage), his thermostat is fine. For comparison, the guage on my car varies between 1/2 to 3/4 (at 1/2 the thermostat closes, at 3/4 it opens), and that's only noticeable in town. On the freeway it hovers right around the 2/3 mark. Unless his temp guage is falling all the way to the bottom, he's not getting back into the cold-start mode.

I will tell them to look at the O2 sensor and replace the spark plugs if necessary.
Oil seems still fine on me, so I will tell them to skip that.

BTW Anybody know at how much I will be looking $$$-wise?

Good idea. Dollar-wise an O2 sensor should run about $60, but it can vary by a good deal depending on the car. Lucky for you the O2 sensors for American cars tend to fall on the happy end of that spectrum. If the plugs need changed, it's maybe $2/plug if you use the expensive plugs. I'm guessing that it will be about $100 with labor, best to ask the shop for an estimate though.

ZV

 

[coolVariable]

Thanks guys!
You were very helpful and I will let you know as soon as I've gotten it fixed!

 

[coolVariable]

UPDATE:
I took the car to Midas today (it's just down the street) and they hooked it up to the computer ($88 :Q)
They found out it wasn't the O2 sensor (sadly) but:
- the coil pack (the secondary one??) ($189 )
- the ignition module ($402 :Q)

:Q :Q :Q :Q :Q :Q :Q :Q :Q :Q :Q :Q


But since the mileage was so way off and the check engine sign didn't go off I had them repair it.
Sucks to spend so much money on repairs.

 

[Pepsi90919]

i'm going to take a wild st@b in the dark and say it's a GM car, mid 80's to mid-90's.

 

[coolVariable]

And ... you missed:
93 Ford Mustang with 73k Miles on it!

 

[Vette73]

Originally posted by: coolVariable
And ... you missed:
93 Ford Mustang with 73k Miles on it!

I wish you would have NOT had that done. $600 for a coil pack and a module. Is it a 4cyl or V8?? And if V8 what is the Vin#

National Chains are mostly NOT THE PLACE TO GO. Pre. Tune, etc... in general are not ethicial.

Find a good independent shop and stick with them.

 

[coolVariable]

I don't know a good shop around here ...
It's a 4 cylinder.
Well, they told me the parts would be most of it (work is supposed to be only ~$50).


Damn I hate being ripped off. :|

 

[Vette73]

Originally posted by: coolVariable
I don't know a good shop around here ...
It's a 4 cylinder.
Well, they told me the parts would be most of it (work is supposed to be only ~$50).


Damn I hate being ripped off. :|

Part should have been, anywhere from $200-300 range and another $50-120 for labor. This is of course NOT including the Diagnoses.

Like I said before, FIND a good independent shop and stick there.

 

[Vic]

Dude, Midas is terrible. I wouldn't take a car there for ANY reason.
Several years ago, the master cylinder in my mother's old car was failing. My mother knows absolutely nothing about cars. I tested it out and the symptoms were pretty obvious. At a stop, the brake pedal would slowly sink to the floor and you could actually hear a slight hiss from the master cylinder. A quick pump and the brake pedal would go back up to the top, then slowly sink again.
Midas had a good special on master cylinder replacement at the time for less that $100 so I sent her there. The mechanic there talked her into doing everything on the brake system BUT the master cylinder for a total bill of over $500. New pads, rotors turned, wheel cylinders rebuilt, etc. For those of you who know about cars, you know that this is the worst possible thing that they could have done. Basically, the master cylinder had a failing seal and they toughened up the entire brake system BUT that seal.
So, naturally, the very next day (she didn't tell me what happened at Midas) the brakes failed entirely and she totaled the car into the back of another. Luckily, no one was hurt. Needless to say, she got a decent settlement from Midas and the mechanic was fired, but I strongly advise anyone and everyone never to have any work done there.

 

[Evadman]

backup coil packs. that's a new one. Too bad yoru vehicle was nto a GM. I have 4 of their coils (that fit most snap in coil packs) And why did they charge you to put it on a scantool? Pep-boys does that for free I believe.

I am sorry to say, but it looks like you have been screwed by Midas.

 

[Vette73]

Originally posted by: coolVariable
For some time now my car has been guzzling gas like there is no tomorrow.
Thinking that the air filter was due for renewal, I just went out and bought a new one. But now I#ve seen that the old one is still fine (looks still white with only very little gray residue).
What else could account for the low miles/gallon?




UPDATE:
I took the car to Midas today (it's just down the street) and they hooked it up to the computer ($88 :Q)
They found out it wasn't the O2 sensor (sadly) but:
- the coil pack (the secondary one??) ($189 )
- the ignition module ($402 :Q)

:Q :Q :Q :Q :Q :Q :Q :Q :Q :Q :Q :Q

Have you gotton the car back yet?

Did it fix it 100%?

And if not ask for the old parts