My old 5.0L was like that. Would run like a rapped ape one day and feel like it was running on 7-cylinders another. Can't speak for my 4.6L as of yet though. 
does any of your cars feel good some days,
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Its the weather, the IAT sensor will back off the fuel when its warm outside and dump more when its colder. Another factor is the ECT sencor, when the coolant is cold, the computer increases timming to get it up to temp, on hot days it will back off the timming. The person who mentioned the resistor mod is right on the money.
I did this mod in my previous Ford with potentiometers that would vary the reading of the sensor. Worked like a charm.
I did this mod in my previous Ford with potentiometers that would vary the reading of the sensor. Worked like a charm.
stripped302
New Member
I'm gonna run this tank down,cause opening day is sat.pray for nice weather,so its going to get a good dose of racing fuel added to the 94 usually run,so maybe that will help
StratGT
Founding Member
SRMobile said:
Thank you, I know the resistor mod works cause I do it all the time. When I don't use it, I can run 87 octane and 13.5 degrees of timing with no knocking. So I know timing is being pulled from somewhere. I put the resistor back in, get full timing and she starts pinging. A good SCT tune can probablly alter this too.
As for gas, forget it cause it won't help you unless your car is knocking or pinging. Once the sensor becomes heat-soaked, your car will pull timing anyways. IT never adds timing, only refers your timing back to normal.
i took the car out again today to test things out a bit. car seemed ok. i laid 
a little rubber. got on it. this leads me to believe it was prob. a heat soaked issue, but not completly. i was driving the car yesterday for a while before getting on it so it may have become heat soaked. however ive driven it in 90 degree weather after an hour and got on it and it has felt good. so i really dont know. its not that bad of a problem, but it just seems less peppy somtimes. oh well time to mod!
a little rubber. got on it. this leads me to believe it was prob. a heat soaked issue, but not completly. i was driving the car yesterday for a while before getting on it so it may have become heat soaked. however ive driven it in 90 degree weather after an hour and got on it and it has felt good. so i really dont know. its not that bad of a problem, but it just seems less peppy somtimes. oh well time to mod!
gtstangrunner
Member
I think it may just be the quality of the air that day. Since cars run mostly off air anyway the density and quality of the air will play a major role in how the air is compressed and combusted in the chambers. Mine does it too. Its funny how we know the feeling of our cars so well.
That was good!!StratGT said:
First of all, what are you tapping into IAT (Intake Air Temp) and/or ECT (Engine Coolant Temp) ? I’m assuming from your other post your only doing IAT. That’s fine, but there’s allot more benefits of doing a combo AND you need a variable resistor such as a potentiometer to tweak/adjust to optimize results.
I have a fully built circuit from my last vehicle that I will test this summer, flip the switch and you are at optimum power as it disconnects from the sensor itself and the PCM relies strictly on the potentiometers resistance. This is of course used for short bursts at a time.
IAT will only dump fuel, thus your pinging, ECT will advance timing a combination of more fuel and timing = better results.
There is however a minor draw back, the ECT sensor also controls the fan so when you feed it the false cooler temps, the fan turns off regardless. So turning this on at a streetlight
You have to use it sparingly. The other draw back is that these computers "learn" to compensate for faulty sensors, so you need to reset your computer every now and then.StratGT said:
Gas has nothing to do with it; our cars are equipped with emissions systems. Computer programming is done in the following order: emissions, gas mileage, power. By fooling the sensors your change the priority to power.
REF: http://www.zx2racing.com/pages_mods/pots2.htm
Yes this example is from an Escort, but this mod works with all Fords. You need to verify the wire colors for the IAT sensor and ECT sensor to do this correctly from the PCM as this is the prefered method.
Yes this example is from an Escort, but this mod works with all Fords. You need to verify the wire colors for the IAT sensor and ECT sensor to do this correctly from the PCM as this is the prefered method.
StratGT
Founding Member
SRMobile said:First of all, what are you tapping into IAT (Intake Air Temp) and/or ECT (Engine Coolant Temp) ? I’m assuming from your other post your only doing IAT. That’s fine, but there’s allot more benefits of doing a combo AND you need a variable resistor such as a potentiometer to tweak/adjust to optimize results.
I have a fully built circuit from my last vehicle that I will test this summer, flip the switch and you are at optimum power as it disconnects from the sensor itself and the PCM relies strictly on the potentiometers resistance. This is of course used for short bursts at a time.
IAT will only dump fuel, thus your pinging, ECT will advance timing a combination of more fuel and timing = better results.
There is however a minor draw back, the ECT sensor also controls the fan so when you feed it the false cooler temps, the fan turns off regardless. So turning this on at a streetlight
Gas has nothing to do with it; our cars are equipped with emissions systems. Computer programming is done in the following order: emissions, gas mileage, power. By fooling the sensors your change the priority to power.
That's true about the resistor, I mostly keep the resistor in my ashtray and use it when needed for, as you mentioned, short bursts like at the track.
As for gas: I was referring to the comment of using a higher octane gas to recapture that sluggish performance. Higher octane gasoline will not help in this situation.
I have noticed the inconsistency of my car's performance. Some days it is really strong, other days I actually look down to see if the parking brake is on.
I have always figured it was due to weather BUT during the summer here it is un-godly hot and some days my car will be great and some days it will be horrible no matter that the temps are well over 100*
So I can't really attribute it to temps. Maybe humidity?
I have always figured it was due to weather BUT during the summer here it is un-godly hot and some days my car will be great and some days it will be horrible no matter that the temps are well over 100*
So I can't really attribute it to temps. Maybe humidity?
02LaserRed2V
New Member
On those "bad" days, I can't help wondering how much slower my car would be, if not for the 4.10s...
stripped302
New Member
well i just finished my NX install so maybe that will help with my prob
can not wait till tomorrow for opening day
can not wait till tomorrow for opening day
Gunfighter
Founding Member
I've felt this in several cars that I've owned. I'm very weather concious, as I work at an airport, and it always happened on days that were either humid, or hot and humid. A lot of people don't realize that central MD gets 95 degree, 100% humidity waaay too frequently.
Last winter, with no mods, I spun through first gear in my automatic at 20 degrees with less than 40% humidity. This summer, before I started modding, I couldn't even get it to peel at all.
Air density plays a huge part, but humidity also has its place there too. Until I'm running a hydrogen car, I figure water won't help me make any HP.
I was unaware of the "resistor" mods though. Good to know!
Last winter, with no mods, I spun through first gear in my automatic at 20 degrees with less than 40% humidity. This summer, before I started modding, I couldn't even get it to peel at all.
Air density plays a huge part, but humidity also has its place there too. Until I'm running a hydrogen car, I figure water won't help me make any HP.
I was unaware of the "resistor" mods though. Good to know!
AmBo
Active Member
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