Rough idle/hesitation/pinging?

[cp2295]

Heat is what causes 3.0 engines to ping, and the two contributing factors that cause that cause that heat are 197* thermostats in an older engine that wasn't really designed to run that hot (as evidenced by all the cracked cylinder heads you hear about on the Ranger forums), and spark timing from the factory that is too far advanced.

When I swapped a 180* thermostat into my engine it eliminated about 80% of my pinging (I also tried a 160* thermostat but it didn't do anything to further reduce pinging so I went with the 180*), and I bought a tuner and retarded my timing a couple of degrees, and that took care of the other 20%. I also blocked off the hot water feed to my intake manifold so that the intake charge doesn't heat up as much... whether that helped anything I don't know, but it certainly can't hurt.

Yes theoretically gas mileage is supposed to go down if you cool an engine down, but if anything my mileage seemed to go up a bit. As the poster stated a cooler engine will make more power, which theoretically should lower gas mileage, but a more powerful engine will allow the driver to use lighter throttle settings, so perhaps that's why mileage isn't affected all that much one way or the other.

Also, what's the hot water feed to the intake, is that those two vacuum lines on top that connect to some coolant hoses? And how do you retard the timing in these trucks? Sorry for all these questions haha

 

[stmitch]

What other cool little tricks can I do to increase engine performance like that ? Is an underdrive pulley a good idea and what about an electric fan? I've already done all I can to the suspension and stuff with replacing bearings and what not, but hasn't seemed to make a difference with fuel efficiency, made my truck smoother though. Any sort of aftermarket pulleys that reduces engine load?

And I've seen quite a bit that the 3.0 comes stock with a cold air intake, is this true? Will a k&n sort of deal help me at all?

Anyways different spark plugs to increase power? Anything my truck feels like a dog, it seems like it should have more power, my friends 2.9 has way more power, and on paper the 3.0 has more so I don't get it.. My truck should have more power!!

Underdrive pulleys and e-fans are great as long as they're set up properly. They can improve throttle response as well as fuel economy. I've had good results with both on the 3.0.

A cold air intake is any intake that takes in air from outside of the engine bay, instead of the heated air within the engine bay. That means the factory intake is a cold air intake. The open element intake kits sold by K&N are allowed to take in air that can be much warmer than ambient air. Using an open element filter means there is less restriction than the factory airbox, which can improve fuel economy. I noticed an MPG or two improvement over the stock airbox on mine.

What kind of truck is your friend's 2.9? The squarebody trucks were a good bit lighter from the factory than the newer trucks. If his is a regular cab, or 2WD, then that would contribute to even more weight savings compared to your truck. Whatever the configuration of his truck is, it is no doubt a lighter truck than your newer, extended cab, 4WD truck. That can have a big effect on how the engine "feels". I'm not saying there is nothing wrong with your truck, or that it can't be improved, but it's something to consider.

 

[RonD]

Heat is what causes 3.0 engines to ping, and the two contributing factors that cause that cause that heat are 197* thermostats in an older engine that wasn't really designed to run that hot (as evidenced by all the cracked cylinder heads you hear about on the Ranger forums), and spark timing from the factory that is too far advanced.

When I swapped a 180* thermostat into my engine it eliminated about 80% of my pinging (I also tried a 160* thermostat but it didn't do anything to further reduce pinging so I went with the 180*), and I bought a tuner and retarded my timing a couple of degrees, and that took care of the other 20%. I also blocked off the hot water feed to my intake manifold so that the intake charge doesn't heat up as much... whether that helped anything I don't know, but it certainly can't hurt.

Yes theoretically gas mileage is supposed to go down if you cool an engine down, but if anything my mileage seemed to go up a bit. As the poster stated a cooler engine will make more power, which theoretically should lower gas mileage, but a more powerful engine will allow the driver to use lighter throttle settings, so perhaps that's why mileage isn't affected all that much one way or the other.

Yes, heat is what starts the pinging, that is simply what pinging is, as said, but what causes the extra heat is the cause of the pinging not the heat itself.
By running engine a few degrees cooler you have fixed a symptom but not the cause, nothing wrong with that approach, it is simple and it will work.

All ford 3.0l ohv engines are prone to pinging, but not all 3.0l engines ping.
The Vulcan 3.0l engine runs 9.3:1 compression, all the other ranger "gasoline" engines are 9.0:1(2.8l was 8.7:1), this makes the 3.0l prone to pinging using 87 octane if any other component is not within spec.
Any carbon build up raises compression above 87 octane rating on the 3.0l, on the other 9.0:1 engines there is more tolerance for carbon build up.

Early 3.0ls had less pinging because of the Knock sensor, but Ford had to drop the Knock sensor in the mid-90 3.0ls to meet stricter emissions standards, knock sensors would retard the timing automatically when pinging started, but that also raised emissions.

The whole point of fuel injection is to get better MPG, and to do that you run the leanest mix possible.
A "perfect" air/fuel mix will melt pistons and valves because it is too lean, so you don't want mix to be too lean, lol, but to get the benefit of fuel injection you want it to be as lean as possible, just lean enough to get good MPG but not lean enough to heat cylinder to the point of pinging.
This is where the EGR system comes in to play, the exhaust gas actually cools the cylinders when mixed with the air/fuel at higher RPMs.
If you have pinging when accelerating or going uphill the EGR system is the most likely cause, that's when the computer uses the EGR system, when engine is under load.
Could be simple buildup in the EGR tubes or valve, so less flow=less cooling, could be the control module, the DPFE(usually a DPFE problem will turn on the CEL since it is emissions related).

If engine has been using oil with no visible leaks then you probably have some carbon buildup, this leans the air/fuel mix(carbon absorbs gasoline), and in the cylinders carbon buildup raises compression and holds in heat, so a double whammy.

The MAF sensor is the main provider of data used by the computer to set air/fuel mix, these do get dirty, the air plenum tube between MAF and intake can get cracked, connection can get corroded.
Any of this can cause a leaner mix.

The O2 sensors tells the computer if air/fuel mix is too rich or too lean, this is the secondary data the computer has to adjust the mix, but this is a fine tuning and has limited adjustment parameters.

If you have a '98-'00 there was a TSB for the coil and PCM related to pinging.
Google: Article No. 00-24-08

Interesting read overall in that TSB, lol

You can also try a cooler spark plug, although I think Ford already has a cooler plug speced.
And you have to watch out when switching brands of spark plugs, you may have a favorite brand which is fine but make sure the heat range is the same or cooler than 3.0l speced model, hotter model would increase possible pinging
Cooler spark plugs don't have less spark, cooler means the tip of the spark plug is kept cooler because it bleeds heat to the head faster than a hotter plug.
This can keep the tip of the spark plug from getting red hot and pre-igniting the air/fuel mix.
But too cool and spark plug won't self-clean(burn off carbon), so could foul and cause missing.

MPG
Well if engine was pinging like crazy and cooling it down via lower temp t-stat diminished the pinging then I would expect MPG to go up.
A poorly running engine will get less MPG

 

[cp2295]

Underdrive pulleys and e-fans are great as long as they're set up properly. They can improve throttle response as well as fuel economy. I've had good results with both on the 3.0.

A cold air intake is any intake that takes in air from outside of the engine bay, instead of the heated air within the engine bay. That means the factory intake is a cold air intake. The open element intake kits sold by K&N are allowed to take in air that can be much warmer than ambient air. Using an open element filter means there is less restriction than the factory airbox, which can improve fuel economy. I noticed an MPG or two improvement over the stock airbox on mine.

What kind of truck is your friend's 2.9? The squarebody trucks were a good bit lighter from the factory than the newer trucks. If his is a regular cab, or 2WD, then that would contribute to even more weight savings compared to your truck. Whatever the configuration of his truck is, it is no doubt a lighter truck than your newer, extended cab, 4WD truck. That can have a big effect on how the engine "feels". I'm not saying there is nothing wrong with your truck, or that it can't be improved, but it's something to consider.

Yeah he's got a super cab but it's 2wd.. Although it has a full ladder rack.. I bet it's because I got 3.73s and 31s, while he has small tires, but he has 3.08s.. I don't know! I'm gonna do the T stat switch and plugs and see if that helps, I've already changed the egr valve and dpfe sensor also

 

[McCormack]

By running engine a few degrees cooler you have fixed a symptom but not the cause, nothing wrong with that approach, it is simple and it will work.

Too much heat for a given combustion chamber design is the root cause of pinging. Reduce the heat via a lower compression ratio, or removal of excess carbon accumulation, or retarding of it's ignition timing, or lowering the engine's temperature (or a combination of any of the above) and you've fixed the cause of the pinging.

The whole point of fuel injection is to get better MPG, and to do that you run the leanest mix possible.

The whole point of fuel injection was for emissions purposes. Better MPH is an unintended benefit.

A "perfect" air/fuel mix will melt pistons and valves because it is too lean....

Maybe in a highly stressed racing engine, but the only thing an overly lean condition will do in a passenger car or truck engine is make it run rough.

This is where the EGR system comes in to play, the exhaust gas actually cools the cylinders when mixed with the air/fuel at higher RPMs.

EGR's were invented to reduce NOx emissions, not cool cylinders for pinging purposes. And EGR's don't kick in at higher RPMs, they kick in at light throttle settings when not much power is required, and engines in general ping the most under heavier throttle settings, so the EGR system has little effect on pinging one way or the other.

If engine has been using oil with no visible leaks then you probably have some carbon buildup, this leans the air/fuel mix(carbon absorbs gasoline), and in the cylinders carbon buildup raises compression and holds in heat, so a double whammy.

If you're burning so much oil that it's causing carbon to build up, then pinging is the least of your worries.

And in regard to normal carbon build-up causing pinging, today's gasolines are clean burning so the build up of carbon is in most cases light and not enough to raise compression ratios by any significant amount, but it is however enough to insulate combustion chambers, which retards the transference of heat to the pistons and heads, and too much heat is the cause of pinging for a given combustion chamber design.

You can also try a cooler spark plug, although I think Ford already has a cooler plug speced.

Colder than stock spark plugs for the 3.0 engine are hard to come by. I found some made by Accel, and they only reduced pinging a little in my 3.0.

 

[RonD]

Robbing an engine of power will decrease pinging, but is that the best way to do it?

Over lean will melt pistons and valves in any gas engine, even a lawn mower engine.

Point of fuel injection is performance then MPG, emissions is 3rd in line in benefits, it's a consumer market after all, lol.
This is why production cars in the mid 1950's offered "bendix" mechanical fuel injection, very few were sold, lol, early corvettes also had that option, it has been offered on and off ever since, none were emission related.
A Bosch direct injection engine won a grand prix race in 1954
Bosch bought the Bendix design in the 1960s, and developed electronic fuel injection, again for performance and MPG, no emissions reason, gas in Europe(and Japan) has always been alot more expensive than in North America.
Soaring world-wide fuel prices(along with the Oil companies cover up of the 200MPG carburetor, LMAO), and the now available/reliable electronic fuel injection was the reason for the North American switch, competition against Japanese and European cars that had been using fuel injection for many years was the reason Ford and GM came on board.
American car makers tried a "feedback" carburetor for a few years for emission reasons, best you can say about those is that they never caught on fire,

EGR system was added to cool the cylinders which reduces NOx, semantics
But yes it was for emission reasons, when you want to lower the HCs(lean it out) and advance the timing to meet emission standards you end up with pinging and high NOx.
High cylinder temp = pinging and high NOx
EGR lowers cylinder temp so prevents pinging and lowers NOx
Lowering engine temp and retarding the timing will do the same thing, but lowers power as well.
i.e. lower temp t-stat and knock sensors

 

[cp2295]

I shouldn't be having much carbon build up anyways because I just rebuilt the motor and got new pistons and rings .030 over.. So I'm not burning oil and it's all clean in there.

 

[RonD]

Wouldn't expect a rebuilt engine to ping like that, assume EGR was clean at that time.

Could be MAF sensor needs cleaning or there is a vacuum leak, regular or ported could do it.

 

[cp2295]

Yeah switching the Tstat really helped.. Gave it nice power too, I'm still going to get a smoke test done on the vacuum system.. Seems necessary haha

 

[cp2295]

Is it necessary to switch the coolant temp sensor with the Tstat? My idle seems a little weird, seems like it's idling higher so maybe I need a different sensor that's rated at this temp?

 

[RonD]

The ECT sensor shouldn't need to be changed and not sure what you could change it to.
here are the spec for the Ford ECT sensor:
http://oldfuelinjection.com/?p=28

Since computer sees lower voltage from the ECT sensor as engine warms up, you may be able to add a resistor in the circuit so computer sees correct voltage for 200degs.
There was an ECT Mod that some used to increase power, they would "highjack" the ECT sensor voltage, when they wanted more power they would adjust a variable resistor mounted in the dash, which would increase voltage on the ECT circuit, so computer would run engine rich and advance the timing thinking engine was cold, even though it was warmed up

Yes, higher idle would be the computer "thinking" the engine is not warmed up all the way, based on ECT sensor data.
But it could also be a vacuum leak.
With engine warmed up(such as it is, lol) and idling, unplug the IAC valve, RPMs should drop, low idle should be about 500rpm.
If RPMs drop that means computer is setting the high idle, so could be ECT data doing this.
If RPMs don't drop that means IAC valve may be stuck open a bit or you have a vacuum leak

 

[stmitch]

Point of fuel injection is performance then MPG, emissions is 3rd in line in benefits, it's a consumer market after all, lol.

Maybe originally, but that order of priorities has now changed. Meeting emissions standards is now priority number one for any engine manufacturer. You can't sell an engine that doesn't meet emissions standards, and when you can't sell your engine, it doesn't matter how much power/mpg you can squeeze out. I'd also argue that one of the primary reasons fuel injection was implemented is reliability/predictability compared to a carb setup.

EGR system was added to cool the cylinders which reduces NOx, semantics
But yes it was for emission reasons, when you want to lower the HCs(lean it out) and advance the timing to meet emission standards you end up with pinging and high NOx.
High cylinder temp = pinging and high NOx
EGR lowers cylinder temp so prevents pinging and lowers NOx
Lowering engine temp and retarding the timing will do the same thing, but lowers power as well.

Both you and McCormack are kind of right here. The EGR can cool the cylinders, which results in less NOx, but the EGR also reciculates a portion of the exhaust to be recombusted, so it reduces NOx in that regard as well.

 

[cp2295]

The ECT sensor shouldn't need to be changed and not sure what you could change it to.
here are the spec for the Ford ECT sensor:
http://oldfuelinjection.com/?p=28

Since computer sees lower voltage from the ECT sensor as engine warms up, you may be able to add a resistor in the circuit so computer sees correct voltage for 200degs.
There was an ECT Mod that some used to increase power, they would "highjack" the ECT sensor voltage, when they wanted more power they would adjust a variable resistor mounted in the dash, which would increase voltage on the ECT circuit, so computer would run engine rich and advance the timing thinking engine was cold, even though it was warmed up

Yes, higher idle would be the computer "thinking" the engine is not warmed up all the way, based on ECT sensor data.
But it could also be a vacuum leak.
With engine warmed up(such as it is, lol) and idling, unplug the IAC valve, RPMs should drop, low idle should be about 500rpm.
If RPMs drop that means computer is setting the high idle, so could be ECT data doing this.
If RPMs don't drop that means IAC valve may be stuck open a bit or you have a vacuum leak

So if the rpms do drop then there's no chance of vacuum leak?

 

[cp2295]

When I unplug the Iac valve nothing seems to happen but when I plug it back in the rpms shoot up by about 400-500.. Not sure what that means

 

[RonD]

It means computer and IAC are working.

When you unplug the IAC the computer would see some change in idle, it would go down, it might be slight but computer is using the Crank position sensor, so more accurate than your senses, lol.
It would then try to open the IAC valve a bit to get idle back up, but IAC is not connected.
So when you plug IAC back in it would get that voltage signal from the computer and open up, so idle would go up.

Yes, I would look for a vacuum leak, and check the throttle plate to make sure it isn't sticking a little so not closing all the way.

The IAC is not a sensor it is an electric valve, computer opens and closes it each time you start the engine, just to test it.
When engine is started hot or cold idle should go up to 1,500+ RPMs then come back down to cold idle, 1,000 rpms, or warm idle, 750 rpms, that's the computer testing the IAC Valve.