Another 3.0 FFV Pinging Question

[GrumpierGrunt]

1999 Ford Ranger 3.0 Flex Fuel Automatic Transmission 2WD Single Cab 121,000 Miles.

My Ranger has had really bad pinging issues when under load and terrible acceleration. Going up hills was treacherous.

I was driving around earlier this Summer and got a CEL for P00153 related to my O2 sensors. I am not a mechanic (famous last words) but attempted to remove the O2 sensors myself after getting the loaner tool from Autozone and three replacement Bosch sensors. I started with the passenger side and didn't get further then cutting the wire before I decided to bring it to the shop. $150 for removal and replacement of all three sensors was totally worth it since they were most likely the original sensors.

Prior to taking it to a shop, I drove around with the cut wire and didn't immediately get a CEL. I probably drove it around three or four miles before the CEL popped on. On my way to the shop, I noted that the pinging and acceleration was gone. The truck was taking on hills like a champ, I was able to accelerate easily on hills without pinging from the engine. I even reached 75 Miles Per.

Once I got the oxygen sensors replaced, the truck ran a lot better with less pinging and better acceleration. However, it felt better with the cut O2 sensor wire. Is this because with the cut wire the computer was dumping more fuel? My diagnostic tool shows negative long term fuel trims at idle (around 4.7) but on heavy acceleration it leans out even more, usually negative 11.7 plus on both long term fuel trims.

I plan on replacing the following items as part of a valve cover gasket replacement/tune-up project and want to know if there is anything else I should replace since all of this stuff is original to the truck. I already did a new MAF (it was a cheapy), wires and plugs (not cheap), ignition coil (cheapy), and IAC (also cheapy). Also, advice on this issue/general life advice is appreciated.

Throttle Position Sensor
EGR Valve
Fuel Injectors
Fuel Filter
DPFE

Thanks,
Chris

 

[dvdswan]

Do you have that methanol fuel in your area? Generally, it comes out in the summer months and it will cause pinging issues. I don't know the truth to this (summer only status, could be year around in some areas) but it will make your engine ping.

 

[GrumpierGrunt]

Hi, I am not too sure. I live in a metro area and only noticed the pinging had returned when I left this city this past weekend. And I cant remember if the pinging happened on the way out of town before I fueled up for the return trip.

I can put in a new tank of gas at a different station and see what happens.

 

[RonD]

The 3.0l Vulcan engine runs Compression Ratio(CR) of 9.3:1
9.4:1 is usually the limit for Regular gasoline(87 octane) and pinging
This makes the 3.0l prone to pinging in general
The 3.0l did have Knock Sensor for some years, don't think 1999 was one of them

Overtime an engine will get a bit of carbon build up in the cylinders which is a double whammy for pinging
The carbon layer holds in a bit more heat, and the layer increases CR by making the compression space in the head smaller
As a test I would try running 91 octane gas for next two tanks, see if pinging stops, that would confirm the build up, then run regular gas and a can of Seafoam in the tank two times to try and clean it out

EGR system helps reduce pinging as a by-product of its primary function
EGR system is there to reduce the NOX(toxic gas) emissions by slowing the burn rate of richer fuel mixes, which increases with the higher cylinder temps during acceleration and higher engine loads, i.e. cruising at highway speeds
Lowering the higher temp spikes by adding exhaust gases also reduces the chance of pinging on acceleration
You should get a code if EGR system is not able to add enough exhaust gases to the richer air/fuel mix
Which you didn't mention so I doubt that's the issue

Older O2 sensors tend to show False Lean condition as they run out of the Oxygen detection chemicals, so computer runs the engine Richer than it needs to, which, of course, costs you $$$ in extra fuel use
This is why you should always change O2s after 100k miles or 12 years, which ever comes first, that way they are "free" because the money they cost is more than made up for in fuel saving over the next 100k miles or 12 years
But.................while this False Lean and lower MPG is going on your cylinders are getting more and more carbon build up, see above, so the Rich mix over the years causes the pinging you have now
While a Lean mix can/will cause pinging, a Rich mix can/will cause pinging as well, just in a different way over time

Yes, without O2 sensor feedback the computer runs a way Richer mix and less aggressive spark timing to prevent engine damage
So less, or no, pinging without O2 sensor hooked up is not really a sign of anything specific, like a bad O2 sensor, just means there is a problem if you have pinging with working O2s

 

[GrumpierGrunt]

@RonD

Hi Ron, thanks for the thorough response. It really cleared some questions up for me.

I never thought of running seafoam, I was always a little intimidated by it. I have run E85 and higher octanes on it at different points in the past, and it did run better. When I go to seafoam it, should I do the half and half (half through the brake booster line and the other half in the fuel tank) or should I just drop it all in the tank?

Thanks again

 

[RonD]

All in the tank, it goes thru the injectors(cleaning them) and into the cylinders to hopefully loosen up any carbon build up

The brake booster thing can be a dangerous thing if you slip and put in too much fluid, you can break a piston or bend a connecting rod if too much liquid gets into one cylinder of a running engine, "hydro-lock"

You can use a spray bottle and remove intake's air plenum(big tube) then hold open throttle a bit on running engine and spray in the Seafoam, or other cleaner, much much safer than pouring a liquid in
Engine should be fully warmed up for this method
REV engine periodically when doing this to clear out any carbon that's loosened up

 

[GrumpierGrunt]

@RonD Might try this over the weekend, how much regular gas should I have in the tank if I’m going to dump a can of sea foam in it?

 

[RonD]

Instructions are on the can.

Generally to clean the whole engine, use 2ounces per gallon of gas
Seafoam comes in 16oz cans
Rangers use 17gal or 20gallon gas tanks

So at 1/2 a tank on gauge put in a whole 16oz can

For just fuel system cleaning, i.e. injectors, 1oz/gallon is fine, so dump one can into a full tank

 

[GrumpierGrunt]

Might as well do the whole can on a half a tank

All the smoke might help clear out the mosquitos too!

 

[cbxer55]

I did the through the brake booster thing years ago. I put one of those small valves used in fish tanks in the line from the can of Sea Foam to the booster. Started the engine, then slowly cracked open the valve. Waited til the can was empty, shut the engine off. Let it sit for an hour, started it up, smoked out the neighborhood. Still pinged when done. So I just run 91 or 93 in mine. Doesn't ping, runs great. Never changed the o2 sensors in mine, 23 years old, 178,500 miles. Still gets 18 mpg or better on the highway. In town sucks, but it did when it only had 10,000 miles on it as well. I don't have mine for mileage concerns. It's my daily drive beater. I drive it like I stole it all the time. Drive it hard, put it away wet. It's like the Eveready bunny, it just keeps going and going.

With 4.10 gears in the axle, a hard shifting shift kit in the trans and low profile tires, no muffler, CAI and tuning chip, it's a blast to drive.