I NEED HELP.....

[Shogirl95]

I know that I have not posted too often here but I need some help from some folks who know what they are talking about. If you guys don't know already I have a 1995 ATX SHO. I have had the dreaded check engine light for about the last year or so. I have had my codes read and I have fixed every problem they have thrown at me. I have changed both O2's, all of my plugs and plug wires, my water pump, my alternator...three times, and most recently my Fuel pressure regulator. My car runs fine except my gas mileage is really bad. I only get about 200-220 Miles to the tank. I don't know what else to do. My car is stock so there is no reason the gas mileage should be this bad. My boyfriend (knows cars pretty well) says that the only thing that he can think of is the fuel pump or the fuel injectors. I was just wondering if anyone else has had this problem, and if you can give me any advice on the situation. PLEASE HELP ME. I would love to spend the money putting performance parts on my car instead.

My car is at about 95600 miles. (if that makes a difference)

Thank you.
Shogirl95

 

[SHOck]

Common gas mileage killers:

Bad plug wires
Bad plugs
Bad coils
(Getting enough spark energy for good flame action?)
Leaking injectors
(running way too rich? - tends to **** cats)
Timing belt off by a tooth or three
Loose crank pulley
(bad timing between crank and cam = not good)
Bad fuel pump/regulator
(fuel starvation also kills mileage)
Bad thermostat
(cold engine mode kills gas mileage)
Really leaky rings
(causes much smoke)

Um, can't think of much else right now as I'm very tired. Wanted to get you a start, since everyone else around here seems to be asleep wink

David

 

[SHOck]

Oh, yeah, you've got an ATX-

Is the converter locking up at highway speeds? Not sure what the speed is, but you want it to lock or you'll burn more fuel. Now, if you are complaining about getting 200 miles to the tank in the city, just go away! I get 10 miles per gallon there...

 

[projectSHO89]

Add to David's list:

ECT
Cats
Lead Foot
Dragging brakes

BTW, how is performance? Does it seem to good or is it lagging?

Steve

 

[Mr Anonymous]

When you've driven the car for a while, where on the temp gauge does the needle usually settle?

 

[Shogirl95]

First of all thank you for the help. The car runs just fine. I have had no problems with starts or anything. There is no smoke from the exhaust or anything. My boyfriend says that it has to be fuel related because he can smell gas when I shut the car off. Not really strong but it is there. I think I will try to change my injectors and see if that helps.

Thank you again for the input.

Oh and SHOck, I usually drive a lot of highway miles. Even when I took a trip to my moms house which is a 200 mile hike, I only got 250 or so. Last year before this problem, I could get almost 400 in the same trip.

Shogirl95

 

[Off Road SHO]

SHOGirl,

See if you can find out what the actual temperature is of the thermostat housing after the engine is at normal operating temperature. The inside guage might be in the "NORMAL" but you need to make sure that your engine really is warm enough to have the computer shut off the "enrichening" mode of the injectors. An infrared thermometer works great for this. Just point the laser spot at the thermostat housing and read the true temperature of the water.

The computer is told what the engine temp is by the ECT sensor. The ECT sensor is a two wire sensor that is screwed into the thermostat housing, just to the right of the main outlet tube.

The inside gauge is fed by the one wire temp sending unit that is to the left of the outlet.

If you need a pic, I can take one later this afternoon and send it to you.

Tom

<small>[ July 23, 2003, 11:19 AM: Message edited by: Off Road SHO ]</small>

 

[91 SHOplus]

Shogirl95:
First of all thank you for the help. The car runs just fine. I have had no problems with starts or anything. There is no smoke from the exhaust or anything. My boyfriend says that it has to be fuel related because he can smell gas when I shut the car off. Not really strong but it is there. I think I will try to change my injectors and see if that helps.

Thank you again for the input.
Shogirl95

SHOgirl95, when you said your BF smelled gas fumes I remembered something I read on shotimes.com. I've pasted it below.

Thanks to a very smart SHOTimes member and lots of perseverance, I cured my 92 SHO's gas fume problem. I want to pass on what I learned because this subject isn't covered well in the FAQ.

The problem was a gas fume odor coming from under the hood on the driver's side after stopping the car and turning off the engine on warm days (65-degrees-plus). As I learned from the smart SHOTimes member, the cause of the problem usually is the gas-fume purge valve not opening and shutting properly.

Sometimes, the electronically-activated valve stays open or shut all the time. This valve, by the way, is right behind the radiator on the driver's side. A hose runs from the throttle-body to the top of the valve, and another hose goes from the bottom of the valve to a charcoal canister that collects the gas fumes (the canister is located ahead of the left front wheel in the fender well). The solution when the valve isn't opening/shutting properly is to go to an auto store and purchase a two-inch-long male-to-male coupler with an outside diameter of one-quarter inch (cost about $1). Cut the two hoses mentioned earlier where they join the purge valve and simply splice together the two ends using the coupler. What you've done is bypass completely the purge valve. This results in the canister always being purged of gas fumes (rather than the valve controlling the operation). One negative result, I'm told, is that the recirculated fumes may add a tad bit to one's pollution readings. Possibly. I'll let you know at inspection time.

Unfortunately, after performing the above operation successfully, I still smelled gas fumes. I tracked the odor to the charcoal gas fume canister under the fender, which was so saturated that it couldn't be purged. The fix was to buy a new canister (about $40) from my local Ford dealer. Installation takes about 30 minutes, two small open-end wrenches and a stiff neck. No more fumes! Now this isn't the only cause of SHO gas fumes, of course, but I've been told that many SHO owners have experienced the same problem (due to the faulty purge valve and saturated canister). I hope this helps anyone who has this problem.

<small>[ July 23, 2003, 11:21 AM: Message edited by: 91 SHOplus ]</small>

 

[Shogirl95]

I'll check the engine temp this afternoon hopefully. Ill also take a look at the purge canister. I appreciate your help guys. If anyone has any other ideas please post them up.

As far as the raw gas smell goes, I can smell it when we get out of the car after driving. Its clearly coming from the exhaust. It isnt increadibly strong but you can tell that it is there.

Thanks for the help guys
Mike "The Boyfriend"

 

[Shogirl95]

Sorry for the double post. doh

<small>[ July 23, 2003, 01:45 PM: Message edited by: Shogirl95 ]</small>

 

[Slo-Sho]

What codes are you still getting?

 

[LOUDSHO92]

Somehting that was causing me problems like bad gas milage and a gas smeel was the egr tube. You didnt say if you had any codes for the EGR but if theres a hole in the tube it will throw your O2 sensors off. Also have you tried fuel injector cleaner?

 

[fred79]

are you reading your own codes or taking it to a mechanic? some times a dealers code reder can pull more information than is reported by the CEL code distrobution process or a after market reaader like a mechanic would have.
I also thought that it could be a MAF incorrectly reading the air coming into the engine and running rich, a vacuum leak can also cause this so check all the fernco couplings on the intake. and also aroung the throttle body.
is your idle high at all or is it staying normal.
this is the only problem with computer controlled engines they are difficult to diagnose problems. are you noticing any other problems like going through brakes fast(sticking pad), or noises like a wheel bearing going bad. these could affect teh gas milage with out posting a code. is your tranny slipping at all feeling like reduce power or torque and some times jumpiness or hesitation from a stop? you can check the fuel by checking the fuel pressure

 

[Mr Anonymous]

Shogirl95:
My boyfriend says that it has to be fuel related because he can smell gas when I shut the car off. Not really strong but it is there. I think I will try to change my injectors and see if that helps.

It is probably fuel related in that your fuel mixture is too rich -- it is probably NOT a fuel delivery problem (i.e. injectors, fuel pump, pressure, etc.).

Shogirl95:
I'll check the engine temp this afternoon hopefully. Ill also take a look at the purge canister. I appreciate your help guys. If anyone has any other ideas please post them up.

When the engine is cold, the computer runs the car in 'open-loop' mode, which includes a full-rich mixture, until the car reaches operating temperature. Once the car reaches temp, it runs in closed-loop mode where the mixture, timing, spark curve, etc. are all dynamically adjusted by the computer.

One common factor that can cause the car to stay in open-loop mode even after the car is fully warmed up is a thermostat that gets stuck open. This is a very common cause of SHO fuel-economy problems in an otherwise well-running car. If your temp. gauge on the dash isn't getting into the 'NORMAL' range (IOW it's staying at or below the blue hash mark), the first thing I'd do is replace the t-stat. The ECT (Engine Coolant Temperature) sensor could also be contributing to the problem if it is reporting an erroneously low temp to the computer. If you find the temp reading abnormally low on the gauge (or with a temp probe) and decide to replace the t-stat, you might want to consider replacing that sensor while you're replacing the t-stat since they're next to each other (Wells SU201 at AutoZone for about $15).

Keep us posted!