I have a '99 CV LX and when the outside temperature exceeds 85 degrees(F) then engine is a dog, no power especially over 100Degrees you could floor it and nothing happens. The car is completely stock. Under 80 degrees it performs just great!
I was considering putting a 180 thermostat in to lower the engine temp. Any ideas?? Anybody....

Allen

When it does that, check the fuel pressure.

It should be 30 lbs or so with the engine running.

40 Lbs with the vacuum line removed from the top of the regulator.

That definately makes sence, I will check that out right away!
How would I go about checking fuel pressure? I'm not sure how these fuel lines come apart.
I'm familiar with the old school carborators and stuff, but this electronic stuff??

Thanks

How long has it been doin that? Did you buy the car new?

I bought it from the dealer when she was 2 years old. It was like that sence i had her, I just kinda lived with it, but lately its been getting worse.
I did have the head gaskets replaced last year (leaking oil)and it was a little better... for awhile
Its still under warranty.

Get a pressure guage that will screw on a tire valve stem.

There is a pressure check port on the fuel rail that is just like a tire valve stem. It is on the right side toward the back of the engine. It has a valve cap on it.

Screw the hose for the pressure guage onto the valve stem, start the car, read the guage, remove the vacuum line from the fuel pressure regulator. It is on the other side of the engine, on the fuel rail.

Read the pressure. Put the vacuum line back on and turn off the car. It should still show pressure for some time.

The schraeder valve is down some in the valve stem. If your pressure guage does not open it, get a valve core remover and take it part way out. (Until the pin is about even with the top. Look at a tire valve stem to see how it should look.) Remember to tighten it back up after you are finished.

Be careful that the valve stem doesn't spray gas on you. Shield it with paper towel.

There's a temp compensation on both engine coolant temp and Intake Air Temp. Basically the computer runs less timing in an attempt to reduce the chance of detonation. This is normal with all gasoline engines. The effects are even more dramatic on supercharged/turbocharged engines.

Make sure the air into your filter is from the coolest source available. You do not want a conical filter drawing air from inside the engine bay. The stock airbox has a snorkel drawing fresh air from behind the driver headlight, which is good.

You could have a chip made for your car and go to 92 octane fuel and get some of the power back.

Ford started making fuel systems with no return line sometime. I do not know which year that was. If it doesn't have a return line, it may be all different from my 94.

Get a Haynes repair manual and check how it says to do it for your year car.

Thank you for the instructions, that will be no problem checking the fuel pressure now. Just need to stop and get a gauge. If its bad, back to Ford it goes!

Note: I did remove the snorkel and getting a chip would be difficult... (I'm married with child. The boss doesn't let me do much!)

Last time Ford had my girl they let me drive a HEMI truck!That was fun, but I was happy to get my CV back because I didn't need any tickets!

I'll let you know what I find out tomorrow

w/o the snorkel, the intake temps will be higher. You'd actually be better with it on the car. Or you could make your own larger one.

I made this out of a extra large drink cup. Worked great.

This uses the max space a round inlet can. I'm now running a Marauder airbox, which has a rectangular rubber inlet (even better).

Pic installed.

If you get a superchips programer you can select temps for the fans to turn on. You can go as low as 160 degrees. I called them and the tech says the stock setting is 190 degrees. Might try that. The superchip setting is 180 degrees, I checked that out too and that is what I am using.
If you have hot humid air power is just gone in any engine.

Also the fact that the ambient outside temp is very high will simply hamper your fuel efficiency
I live in Miami and today the "feels like" Temp was 105*F and my car's gas mileage actually falls below 10mpg w/the a/c on
Hot arrid air in the intake is not my friend
But when the temp falls below 75*f
It's a whole 'nother animal

Got a fuel pressure gauge, 42$!! Pressures checked out correct, but the outside temp was only 75 degrees, I will have to wait for a hot day and check again.
I am going to make a new snorkel to get cooler air in the intake.
Thank you for all your input.

Allen

Does the superchips programer reprogram the stock computer? And where do I get one? I need it for raising all the speed and rpm limiters!
I don't think I have to mess with the fan temps because I'm always running the Air Conditioning. (I have that auto temp control, very nice!) so the fans are always on.
And living in So. California the air doesn't get too humid.
Thanks for the info though.

JohnE , Where is the air temp sensor? I would like to check that out. You talked about it in thread #650971.

I wouldn't chase engine temp unless your temp gauge runs above half. (As in your thermostat.)


Here the Intake Air Temp sensor. On 2003+ this is built into the Mass Air Flow sensor. It's the proper place for it to be on a normally aspirated car.

I've always wanted to pipe one airconditioning vent right into the intake!! Ice cold air...um...
Has anybody ever thought of that? Tried it??

JohnE, your drink glass looks similar to my lamp shade intake. Mine has a little more bell mouth to it. Not much or it would never fit in that tiny hole for it to face forward.

-------------------------------------------


I too have noticed a lot of difference in power on hot days. Most of it is when taking off after sitting a while. Like at a red light. For about the first 10 seconds it feels like you lost 80hp. Then it picks up some. Insulating the entire intake track helped a lot!

xRacer,
That sounds very similar to whats happining. How did you insulate the entire intake?

I did cut a piece of clear 2.5" Acrylic tubing to replace the snorkel, hopefully that helps.

Most important thing is to draw air from outside the engine compartment. Behind the headlight is fresh air. There is an air compressor under the airbox on HPP cars. Some w/o hpp have made induction from below. But that could risk drawing water into the engine, when driving through water...

Here's one from my archive of this site. Sorry I can't remember who made it. It's by far the best looking home-made solution. Marauder airbox is actually the best performing solution though.

allen

nice car! yep, high temps do drag the motor down a lot. i love driving my car in the early spring/late fall. it feels like a totally different car.

I guess from what I'm hearing(reading) is that these computer controlled engines are really sensitive to outside temperature, and there is not much you can do except for moving to a low atltitude cooler climate.

I wonder if I can disconnect or short out the temperature sensor to trick the computer into 'thinking' its cold....

It seems like your car is overly responding to high outside temps. You may want to check/replace the Intake temp sensor and/or the various engine temp sensors. The readings can be verified by a scan tool, you can directly read the resistance or voltage output with a multimeter and compare them to tables in the service manual, or they are cheap enough to replace on a hunch.

Sensors do not always short out. They can give in range but weird readings. I had a Intake air temp sensor go bad on my old POS lumina. It was giving a very cold temp reading but in range, and was making the car run super rich untill the O2 sensor warmed up and adjusted the mixture. I was not getting any codes etc. But my digital multimeter and the sensor output table solved the mystery.

Your IAT could be giving very high readings when it heats up causing it to lean out the mixture too much, but this is a guess.

If your temp gauge sensor is not working properly, you could think the motor is running cool but it's not. There is a second sensor that gives data to the PCM which is more accurate

Did you try changing your thermostat and flushing the cooling system? Is the cooling fan working properly? Good to check anyways.

The temp sensor appears to be a Thermistor and should read 30Kohms at 25C. Please correct me if I'm wrong. Resistance increases at temp drops, I'm going to disconect it or put a 40Kohm resistor (18C or 65F)in the sensors place and see what happens. I'll let you know...

I think most cars use thermistors instead of thermocouples.

The resistance spread is quite large, so it gives good resolution.

IIRC the PCM sends 5v to the sensor, then reads the voltage coming back.. a little V=IR calc, check the tables bingo got the temp.

Ok, drove it with the temp sensor disconnected. Works GREAT!! The car was very responsive! But...

The check engine light is on now. I reconnected the sensor but the engine light is still on. Anybody know how to clear it??

As soon as I can get the light cleared, I'm going to connect a 50K ohm resistor instead of the sensor. That will 'fix' the temperature in the 50 degree range.

Ok, never mind about the check engine light, I just disconnected the battery for about 5 minutes. Connected my 50K ohm resistor or 2 100K resistors in parellel (99 cents at Radio Shack) and tested, the check engine light doesn't come on anymore. Now I just need to test drive it.

This air temp sensor appears to effect the timing, and by tricking it into 'thinking' its 50 degrees, the timing is always going to be advance as far as it goes!! Just have to watch out for pinging, I have a 180 thermostat on order that should help.

The real test will be temps over 100...

You are running without an IAT sensor active..

thats just not a solution to anything...

there is a reason to vary fuel and timing based upon temperatures of the air in the intake... read about it...

the cel will come on soon enough or you will find the results of some real rich or lean conditions the other way...

the IAT is there for a reason...

What is the resistance setting of the IAT at ambient temp??

We calibrate temp sensors by Ice bath (O°C) then boiling water (100°C) if it does not read properly over the temp range replace the IAT. Loosing power in hot weather is not a normal situation, the car should be designed to run in hot weather Ford does arizona testing for those purposes.

I know there are reasons for the sensor, but I'll tell you she is a totally different car! The throttle responds like its supposed to! She pulls much harder and smoother under full throttle, shifts better, and as of right now I'm getting lightly better gas mileage, hard to tell right now with only 60-70 miles, but i'll let you guys know after a few weeks. I have that nifty digital dash!

I am presently driving with a 50Kohm resistor in place of the IAT which is telling the computer its 56 degrees F
outside.

A better solution might be to put a 10 or 20K resistor in series with the IAT just to 'lower' the temp and not eliminating the sensor altogether.

Please let me know if anybody else tries it.

Ok, I checked the resistance at 32F, 113F and 212F and the temp sensor checks out within 1Degree. Sensor is good. All I know is; I have a hole new car replacing it with the 50K resistor! Sleeping beauty just woke up!

Now I've only tested this with outside temp below 75F, the real test will be at 100F.
If someone tries this let me know.

I'm thinking 100k linear pot here, mounted in the dash, with a looonnggg harness out to the IAT plug.

Some cars like LT-1's respond to re-locating the IAT to a "cooler" location. So your car is running richer due to fooling it into thinking it's 50°F outside. Some inline "chips" feed false readings into the PCM like JET modules and possibly do similar things.

You could sell this on EBAY for $29.99 as a Turbo boost kit

If you ever go to a real cold place you may have some trouble as it will not compensate enough due to lack of temp imput.

You could be running lean for some other reasons, bad O2 sensors etc, Since the IAT checks out ok, maybe look for another source of a lean condition??

If this continues to work out and after my warrenty is gone I will put a 10 or 20K resistor in series with the IAT just to 'lower' the temp and not eliminate the sensor altogether.

So... this is what those aftermarket chips do? I just saved myself 300-400 bucks with a $1 resistor from Radio Shack!??

Nah. They do all sorts of terrific things with the fuel mapping, the shift programming, etc. You've simply discovered a fake-out for the factory system that is,in one sense, effective, but in reality is not optimal because it causes the system to run outside it's proper parameters and is detrimental over the long run.

Drop $500 with A.D.T.R., Innovative Interceptors, or Dennis Reinhart for the Marauder airbox, MAF, and chip for a real happiness episode!

I've had my '98 CV since '99 w/ 14k miles and it has always done this - I've never had this on any of my 5.0 Ford engines and it really is annoying. I guess the good thing is that it is nearly impossible to overheat the thing but...

Bret, maybe that what the chip makers want you to believe... it's a conspiracy...

Well, if the result is a little richer A/F mixture, means cooler head temps and a higher advance curve (as long as it dosen't ping) I would say that is more 'optimal' than 'stock'. It's probably 'optimized' for california smog emmisions!

(Of course I will not drive this now on the street anymore because it might not be smog legal anymore, I'll have to drive my '74 wagon - thats still smog legal!)

But your correct, doing what you suggested would be a better way to go... If you had $500!

Well, I had $500, but it went for a crown and a root canal.

Well I highly recomend this mod for all you poor (or married) CV drivers!

Drove it today and the outside temp got to 82F And drove like a dream! The pinging even stopped, it use to ping when I romped on it!

I tried the 180 t-stat. But it didn't quite run the same as the 195 t-stat. Can't quite place my finger on it, just not as smooth and maybe less power. I did some research and found this web site:

http://www.meziere.com/adobe/28.pdf - Note Recommended Operating Temperatures
http://www.meziere.com/adobe/29.pdf - Recommended Operating Temperatures Cont.

http://www.menziere.com

I think this explains the problem with the 180t-stat. I'm going back to the 195 (stock)t-stat and putting a 20K resistor in series with the air temp sensor (10-20 degrees Celcius cooler than it really is), this is where she runs best. Very smooth, quick response and strong acceleration!

I wonder if the 180t-stat tradition comes from the 60-70's engines when the octane 105???

Let me know if anybody finds anything else out or tries this.

Wasn't octane rated different in the 60's. I have a little chart that I got from amoco that tells me now the take two different ways of rating octane (research octane,less strignet, and motor octane more strignet) add them together and divide by 2. R+N/2. The chart tells me that todays 92 octane is the same as the 60's octane of 97-98.
Anyone else read this info. Maybe that is how my wifes tarus with the duratec engine can run at 9.5 to 1 compression of 89 octane.

The outside temp went over 100 degrees F* today. The car performed great with the resistor mod in place. Almost no noticable loss of power!

Sounds like a success! How's your gas milage? I might be asking you for complete instructions on this mod

Since the resistor is in series you could wire a small switch across the resistor. That way you can easily add the resistor on hot days and remove it on cooler ones. Here in the frozen north, winter temps typically hit -30 to -40 and in summer reach 90 to 100.

Bill
95 CV LX

The great thing about the sensor (Thermistor) is it's not linear.
At 50*C the resistance is 11K and by adding 20K its 25*C.
At 20*C its 37K +20K would = 10*C, at 0*C its 95k + 20k = -4*C, again at -20*C its 271k + 20k = 21.5*C.
As you can see, at the sub zero degree temperatures the difference is nill.
50 = 25
20 = 10
0 =-4
-20=-21.5
(The chart i'm reading is all in *C and i'm too lazy to convert to *F, sorry)

95cv, I'm sorry about that weather; It's gotta be a killer on your car! I'm very spoiled in here in Souther California!!

As far as gas milage, not sure, I might have lost around 1 mile/gal. around town (at 80*F).

Getting an average of 16.8 MPG city/highway driving, with mod described above. Still runs great!

It's been hot and humid here in Sacto. and the power has dropped because of it. Very noticeable but normal. Dog days of summer.

I know this is an old thread, but I found this hoser on e-bay selling my idea: (I guess it's not a new idea!)

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7954360068&category=33597

20HP gain?? To tell you the truth, I did feel a significant difference though.

I guess $2.75 is not a bad deal, it only costs $0.25 or less for the resistor!

But it would cost more than a quarter to repair the potential effects of the false reading.

yeah , I think that ebay think is a joke, Ive done it either way in the 1/4, it dont mean crap to the times.