Edge's warm idle rpm's?

[pbmitch]

Anyone know what the Edge's warm idle rpm's should be?

[818EDGE]

Im not sure, but our idles down to about 550 Rpm. It seems kind of low, but we haven't had any problems.

[rehtaf]

6-700 rpm for v8's. v6's should be same or very close. 550 is close enough. I set my ford low as it will idle smooth. Does the tach bounce any? Engine sputter or sound like its gonna quit running? Both ac and def turns the compressor on and will cause it to idle a bit lower from more load but still be a smooth idle. Computer may compensate but a 50 rpm drop with ac on or stopped in D(or both) is normal. Slight bouncing on a cold start is typical but should only last 1 min or less. Start it cold and listen from outside near pipes with air off for 30 secs. Then listen with ac maxed for another 30s. Is the sound from TP's smooth and constant? Do the same with tranny in D? In any case it should just be a simple data adjustment on the OBC. Newer cars my have settings for when the ac is on. I dunno. Bad gas can cause rough idle. Try to use gas stations with new tanks and sale high amounts of gas like the ones just off interstate ramps. Less chance of water in the gas. Put premium gas in every 5th tank. It has detergents to clean the injectors and remove any water. Check the gauges for normality. Don't sweet it... its under warranty! If it runs... drive it till it don't, screams bloody murder or a light comes on.

 

All the electronics just makes it harder to fix if you ask me. Code readers work but you need an explanation of the explanation. Might as well be Chinese. Almost ready to strip the f150 and put a carb on top. Much easier to trouble shoot and tweak. But I like to tinker... and fix it till its worse. LOL!

[007]

Idle is @ 550-600 rpm....yes, you will roll backwards on an incline with the trans in drive....this is something Ford needs to correct.....as to the premium gas....if you use a top tier gasoline (toptiergas.com) such as Shell, there is no need to use anything but the 87 octane the engine was developed to use....using higher octane gas just puts more profit into big oil's pockets, and takes more money out of yours needlessly.....

[07 MKX]

Idle is @ 550-600 rpm....yes, you will roll backwards on an incline with the trans in drive....this is something Ford needs to correct.....as to the premium gas....if you use a top tier gasoline (toptiergas.com) such as Shell, there is no need to use anything but the 87 octane the engine was developed to use....using higher octane gas just puts more profit into big oil's pockets, and takes more money out of yours needlessly.....

 

I've seen where their are major and I mean MAJOR oil pipelines buried underground. The refineries located along the gulf, refine the crude oil to petrol and start pumping it into those lines. They send kerosene and gasoline and other distillates one after another into that pipe. The end point of that petrol is the upper Midwest. If I remember correctly, they do not even place a plug or anything between different products that are pushed thru that line. The smaller refineries located along that oil line, start pulling it off, and adding octane boosters to the petrol, and then placing it into trucks for delivery to your local gas station. By Rights, everyone is actually getting the same petrol, it's just the different additives that get used.

 

Was it the beginning of 2000, that all local sellers of petrol, had to use a non-leakable tank (ie fiberglass)? Thus forcing a lot of small mom & pop stations out of business. Your edge now comes with a lifetime fuel filter. This is because of the reduced amount of contaminants from the holding tanks. I have a vehicle that for over 8 years, I will drive it past what the computer tells me is empty. And then I refill. I have not lost a fuel pump to excessive heat. And I believe I also reduce the chance of water buildup that way. Remember, a low fuel tank cause's sloshing and mixing of water and gas, and that will also help displace water buildup. Since the fuel system is pressurized, again; just a small chance of water mixing with your fuel. I hope this helps to dispel a lot of urban myth's.

[rehtaf]

there is no need to use anything but the 87 octane the engine was developed to use....using higher octane gas just puts more profit into big oil's pockets, and takes more money out of yours needlessly.....

Thats your fault. Thats why I own stock in Exxon and Chevron that pay me dividends which equals more than I pay a year for gas. Comes back to me every quarter. They just borrow it for a while. True the Edge and most engines are designed for 87 octane gas. Only engines with compression over 10 need higher octane. BTW, chip, reprogramming the OBC, etc. changes compression ratios. Higher octane simply makes the gas burn faster and hotter and push the piston down with more "umph". More mpg with high octane too.

 

Pull an injector out... you'll see the gunk.

 

it's just the different additives that get used.

YAY MKX!! Correct! It cleans the injectors and whole fuel system. My whole point!

 

Your edge now comes with a lifetime fuel filter.

I'll post some picks of JD gas movers fuel filters that use Texaco pump gas to show ya'll what they look like after 1 year if anyone want to see.

 

I will drive it past what the computer tells me is empty. And then I refill. I have not lost a fuel pump to excessive heat.

I used to think the same thing. Think about it. Gas turns to water how? Needs air right? So mostly air and little gas in a vented tank what happens? To Minimize water, keep it full! Fuel pumps are lubricated and cooled by the gas. Why chance it? Fuel injected engines don't like running out of gas. Bad for 'em.

 

Dunno about the fiber tanks. Maybe new stations have em but they're still transported in same trucks and rail cars.

 

What are the tell tell signs of bad gas? Whats the symptoms? Anyone?

[akirby]

BTW, chip, reprogramming the OBC, etc. changes compression ratios. Higher octane simply makes the gas burn faster and hotter and push the piston down with more "umph". More mpg with high octane too.

 

This proves you know absolutely nothing about engines. You can't change the compression ratio of an engine with software. You have to change the pistons or the heads so you have more or less air when the piston is at the top of the compression stroke. There is one experimental engine that has a variable compression ratio but it physically moves the entire head and I don't think it's production yet anyway.

 

As for your theory on higher octane, you're dead wrong there, too. Higher octane gasoline actually burns SLOWER and has LESS energy than lower octane. The higher octane is required in higher compression engines to prevent the air/fuel mixture from detonating before the spark plug ignites (knocking).

 

What tuners typically do is advance the timing, which yields more power and better fuel economy. But if you advance it too far you get knocking. Premium allows the engine to run with advanced timing without knocking.

[rehtaf]

I got a nibble!

You have to change the pistons or the heads so you have more or less air when the piston is at the top of the compression stroke.

When I'm wrong I admit it. In this case both of us are not wrong... but only half right! Temp, air/fuel mix and pressure can change compression. Then we have spark advance or retard, controlled by the OBC nowadays, can change compression and even adjust to prevent knock. A spark or high pressure is needed for combustion so when this spark happens, before or after TDC, will also determine the compression. Then there is also the cam and rod length which determines the stroke, pressure and also the compression. It can change as the engine gets older due to wear. Every engine, even the exact same design, will have different compression. Yes the compression ratio cant be change by software but compression and compression ratio are not the same thing. The ratio is calculated from measurements that vary on each engine of same type and design that "should " be the same. Its theoretical. Only in a perfect world would it be the same for every one that comes off the line. The actual compression is the measured real world value and even changes with barometric pressure.

 

The VCR engine by SAAB is the one I recall but VCR was developed way before that. Dunno who, when or why.

 

For octane burn I was half wrong and again so are you. High octane has the SAME or sometimes MORE energy than lower octane fuel. Detonation resistance is what the octane measurement determines. High octane DOES burn slower but burns more efficiently. The fast burn of lower octane may burn out before the piston completes the stoke and power loss is the result. Also prevents knock as you described very well. Octane matters most under heavy load.

 

If you notice tach bounce or erratic movements while idling, knock, hesitation or similar try a higher octane fuel. It should run very smooth and constant with no sputter.

 

Saying I know nothing is kinda...well...just rude! No worries though. How about... we both know a little, don't design engines for a living and still have much to learn. I know enough to rebuild one. Having no parts left over, turning over and starting...well....thats another story.

 

The only true way to fail is to stop trying!

[akirby]

Ok, let's start with octane. You're still wrong, although I did make a typo. Instead of saying higher octane burns more slowly I should have said it's slower to ignite. Knocking occurs when the air/fuel mixture spontaneously combusts before the spark plug fires. The higher the compression ratio, the more likely this is to occur. Advancing the timing also makes this more likely to occur because you're delaying the spark. Retarding the timing, OTOH, fires the spark earlier which prevents knocking but results in less power and lower fuel economy. Octane doesn't affect how the fuel burns once it's ignited. If that were the case then running higher octane would always result in better power but that doesn't happen. You only get more power if you advance the timing - which may require higher octane to prevent knocking - but it's the timing that's providing the extra power, not the fuel.

 

As for compression ratio - it's a simple volume comparison. The cylinder holds X amount of air and fuel when the piston is bottomed out and it holds Y when it's at TDC. The compression ratio is X/Y. There is not enough variance in modern engine components to make any type of significant change to the compression ratio, even with wear. Temperature, humidity and fuel may change the characteristics of the air/fuel mixture but that's not the same as changing the compression ratio.

[rehtaf]

Just to be clear I said "Put premium gas in every 5th tank". Ford dealership owner told me this when picking up our Edge. Also said change oil and rotate tires ever 5k miles. Normal driving or non-towing Edge w/ 8.5:1 CR(or 8:1? Dont recall exact) will run fine on regular 87 octane. It matters more as load is increased and/or high rpm's. I don't think I'm wrong. Nor is Akirby. Just opinionated.

 

Knocking occurs when the air/fuel mixture spontaneously combusts before the spark plug fires.

Should never happen on newer low compression computer controlled engines like the Edge carries. Very bad for gas engines. A common death for a racing engine. Normal for diesels.

 

Engines w/ CR's above 9.5:1 will almost always generate more HP and MPG with octane higher than 87. Most sports cars say "premium only" on the gauge if recommended even if 9:1. Also, octane levels vary greatly from US levels in other countries. Regular unleaded is octane rated in much of Eroupe at 95 and 80 in Russia.(from wiki link)

 

Temperature, humidity and fuel may change the characteristics of the air/fuel mixture but that's not the same as changing the compression ratio. Even with wear.

The ratio never changes without changing internal parts. Numbers for the design/spec sheets, not actual, only ballpark and assumed to be true. Its not measured for every engine of a line. The compression is not the same as the ratio and varies from the ever changing world in which we live. (maybe called piston compression?? Wiki calls it absolute compression) Temp etc. can change this as you said. Don't forget the air pressure/altitude that LOWERS the octane needed the higher up you go. So a trip from the beach to 7000 ft. can change how the engine runs and the fuel it needs to run the same as at sea level. Engine wear more or less is metal loss from friction. A worn cam, groves from and on pistons, bent rods, etc. can change everything! Imagine oil getting past the piston.

 

A quick Google and you'll find opinions vary on this topic from page to page. No confirmed scientific data thats agreed to be conclusive by a majority that I've found. Like "There are some high octane gasolines in the marketplace with fast flame speeds and some with slow flame speeds. It depends on how they are put together." on one site. On http://en.wikipedia.org/wiki/Octane_rating "This section needs additional references or sources to facilitate its verification." Even contradicts itself if I'm not mistaken. Lists E-85 @ 105 octane. Didn't know that.

 

When late-model Corvette is run hard on hot days, as shown in our tests on the SuperFlow Auto-Dyn with the ZR-1 and later with a Z06, engine computers will often enable spark retard. This is because the car’s engine controls are calibrated for aggressive spark advance to get best performance in cool weather, then “save” the engine with spark retard when mild detonation is sensed during high-load/hot-weather operation. Because of the retard, their performance is reduced slightly and coolant temperature is slightly higher.

 

On cool days there’s no problem, but in warm weather, the engine will get a little detonation, the knock sensing will retard spark and performance will drop slightly. A small amount of unleaded race gas mixed with premium pump gas (start at 1:5, then work up) is the best way to eliminate this problem, short of engine modifications, changes in calibration or moving to a cooler area.

Aviation and racing fuels

May explain some hot weather quirks some are having.

 

Some gas treatments in stores are no more that Isopropyl Alcohol. Bought from a drug/grocerie stores and used in a`10% (1:10 is max) mix with pump gas will add 2-3 octane, clean the system and be cheaper!

 

Boring read but interesting...

Mixing high and low octane concept?

 

Heard of this for diesel but not gas...

Make your own better Hi-Per fuel?

 

Sorry to get off topic PB! Your's running/idling ok?

[akirby]

Just to be clear I said "Put premium gas in every 5th tank". Ford dealership owner told me this when picking up our Edge. Also said change oil and rotate tires ever 5k miles. Normal driving or non-towing Edge w/ 8.5:1 CR(or 8:1? Dont recall exact) will run fine on regular 87 octane. It matters more as load is increased and/or high rpm's. I don't think I'm wrong. Nor is Akirby. Just opinionated.

Should never happen on newer low compression computer controlled engines like the Edge carries.

 

There is NO benefit to running premium every 5th tank. You're just throwing money down the drain. That's a leftover from the days when Premium contained a lot more detergent than non Premium which is no longer the case.

 

While it's true almost all modern engines have knock sensors and will retard the timing to prevent knock, at a certain point the timing cannot be retarded any further and knock can occur - typically because of bad gas or internal engine problems.

 

Engines w/ CR's above 9.5:1 will almost always generate more HP and MPG with octane higher than 87.

 

This is ONLY true IF the engine management computer is designed to ADVANCE the timing to take advantage of the increased octane. An engine designed to run on 87 octane which is NOT programmed to advance the timing will NOT get more power or mpg with higher octane. It's not the octane that's generating the power - it's the timing advance. The octane ALLOWS the timing to be advanced without creating knock.

 

You're confusing cause and effect here. If you keep the timing the same then changing the octane won't increase power or fuel economy. If you advance the timing without increasing the octane you'll get knocking.

[BOBM]

Normal driving or non-towing Edge w/ 8.5:1 CR(or 8:1? Dont recall exact) will run fine on regular 87 octane.

 

Ford lists Edge compression ratio at 10.3:1