Hey Guys,



This may be a lot, but if someone could provide me some expertise that would be GREATLY appreciated



I know there is a million threads for this out there. And I have pretty much read them all. Hopefully someone on here can be of some assistance. I have certainly done my homework, but to no avail in actually fixing my issue.


I have a 1999 Mazda B2500 (Ford Ranger 2.5 Lima) 2WD 5speed Manual 94,800 miles.



I have been having engine pinging problems for several months now, and I cannot for the life of me figure it out. It only does it under certain throttle positions, and mainly up hills and right as I get back on the gas after a shift.

I should also mention it really only does it in 4th and 5th gears, and very rarely in 3rd, and does not happen while cruising, only while accelerating or up a hill.

When I floor it, the pinging stops, but then as I back the throttle off the pinging returns, until I feather the throttle, it goes away again. SO WEIRD.

When I unplug the battery it seems to solve it for a slight period and then the pinging returns.

This problem is boggling my mind because the truck idles perfect, runs great and makes good power, runs and shifts totally fine and purrs like a kitten.

Never had a CEL, truck does not die at stop signs/lights, no shakes or noticeable misfires.



Here is a list of things I have already done/checked based off the other forums I have read:



1. Cleaned MAF

2. Tested MAF by unplugging and driving around (truck pinged more and noticeably drove worse)

3. Replaced Spark plugs and wires, Autolite double platinum, gapped to 0.044

4. Running 89 octane gas

5. Sea Foam through the intake and in the gas tank

6. Chevron Techron through the tank multiple times

7. Checked EGR Pipe, no leaks

8. EGR Solenoid checked by taking off cap and plugging the port

9. DPFE Sensor replaced

10. Fan Clutch checked

11. IAT Sensor replaced

12. Fuel Pump was replaced around 80k miles, right before I bought the truck

13. Replaced IAC, unplugged to check for vacuum leaks, engine almost stalled

14. Replaced Fuel Filter

15. Replaced up and downstream O2 sensors as well as the Catalytic converter (this was a separate issue, I didn't replace to try and fix pinging)

16. Engine Air filter replaced

17. Coolant temp sensor and sender both replaced

18. Checked for intake manifold gasket leaks



Any help is appreciated or tips or words of wisdom. This truck is super clean and I really don't wanna blow the motor or cause other issues by just leaving this.



PLEASE HELP!!! Thank you!



Ben

 

You don't say if the 89 octane helps???

Unplug the 3 wire connector on either coil pack, so run the engine on just 4 spark plugs to see if all 4 are working as they should, no misfires, should drive fine
The Lima engines ran just fine from 1974 thru 1988 on just 4 spark plugs, slightly less power, dual plugs adds a few more horses

If all is well then swap it around and test the other coil pack the same way

What the temp gauge show?
Is it running hotter than "usual"

 

Thanks for the reply!

The 89 does seem to help a bit, but lately it doesn't seem to be helping as much. The pinging has definitely improved from the numerous things I have done with the truck, but still present.
I just put half a tank of Sunoco 91 in to mix just to see if that helps.

Temp gauge reads totally normal, right below halfway point. My code reader shows 180 degrees coolant temp consistently. I should also mention the truck has a brand new thermostat and coolant flush.
That's really interesting about unplugging one half of the plugs, never heard of that but it does make sense. I can try that later today. Would that throw a CEL? Or anything to look for?

Should also mention that under wide open throttle my scanner reads the throttle position to be 78%, with some very slight pinging. Could there be some slack in the throttle cable leading to a lean air fuel mix or maybe a bad TPS sensor? Car idles fine which makes me lean more towards cable slack if that is a possibility.

Any thoughts? Thanks for the help
Ben

 

I should also mention, I put 5 gallons of 91 in the tank along with the rest being 89, and that seemed to smooth it out a bit and it barely pings at all.

Any thoughts? Thanks so much
Ben

 

Throttle sensor should read 16 to 19% with throttle closed, 90 to 92% at wide open
Test with key on engine OFF
But TPS issue wouldn't cause pinging
If under 90% wide open Google: Ranger throttle cable mod
Simple fix for stretched throttle cable

Yes it will set a code with 1 coil pack unplugged, code will self clear once its plugged back in

If computer sees 90%+ from TPS it will ignore O2 sensor and just dump in fuel, lol, because at that time driver want best power not best MPG

If EGR system is working OK, then you may have past carbon build in the cylinders, this causes higher compression which causes lower Octane fuels to self-ignite(ping)
Going to higher octane and having less pinging kind of points to that
There are ways to clean out cylinder carbon, but have to be very very careful when doing it

Is there pinging just after Cold Start, before engine temp gets above say 1/3 on the temp gauge?
If its compression related it might still ping cold, and EGR is not used at all until engine coolant is above 150degF

 

Okay, I thought I had read somewhere that a bad TPS could cause pinging because it tricks the computer into running too lean. Could be wrong though. I've read so many forums in the last few months LOL.

Haven't had a chance to try disconnecting the plugs yet, I will let you know how that goes when I do.

I know carbon build up is a problem on these engines, and I did run a few cans of fuel injector cleaner, one sea foam treatment through the intake, and did sea foam in the crank case before my last oil change. Should I possibly do more sea foam through the intake or brake booster line maybe? Maybe one isnt enough? It smoked out my whole neighborhood the first time I did it LOL. What would be a better way to clean out cylinder carbon?

As for pinging when cold, it does not seem to ping when cold at all no (But there is also no highway close enough to my house to try it out before the engine fully warms up), but when the engine fully warms up it will start to ping, and if I climb a long hill the pinging will get progressively louder I assume as the cylinders heat up. I thought maybe it would be the EGR valve? I have a brand new one waiting to go but I read that would probably throw a CEL, and I was worried about snapping that EGR pipe because it is a bit rusted. What do you think about that? When I replaced the DPFE sensor the pinging got a lot better, but I was also doing other things like the sea foam and fuel treatments at the same time.

Note, I should also mention this truck sat for a long time. Bought it off an 86 year old guy, only had about 9k miles put on it from 2007 to 2021. It did a lot of sitting. The truck is in great shape though, but I know sitting doesn't help any vehicle LOL. No ticks or weird noises at all at idle.

What do you recommend next? Thanks for all your help.
Ben

 

No, air/fuel mix is decided by RPM and fine tuned by MAF sensor(air weight), Air Temp and O2s, O2s have the final say

TPS is there so driver gets instant throttle response, MAF sensor is to slow to react to increased air flow so engine would stumble when first accelerating if computer didn't get a "heads up"
It also slows when foot is off the gas pedal so computer can turn injectors off while slowing down, which is one of the bigger fuel savings vs a carb

The sitting and only being driven now and then pretty much says "CARBON BUILD UP", lol
I would run it low on fuel and then add say 5gal of 91 and a can of seafoam then do some highway speed driving to try and clean out some of the carbon build up

But yes the seafoam in the intake is faster and better, just BE CAREFUL

 

Very interesting. I will try some more sea foam in the tank combined with 93, that's what I've got around here.
Yeah the one time I did sea foam through the intake all I could think about was hydrolocking it LOL. It wasn't my first sea foam experience, but its terrifying everytime.

Do you recommend doing multiple cycles of a full can of sea foam/5gal of 93? I figure it will probably take more than 1 run through.

Thanks,
Ben

 

Hey Ron,

Update on this. I have ran a few gallons of Shell 93 and a full can of Seafoam through the tank 3 times.

I will say, the 93 gas has essentially made my pinging disappear.

Do you think maybe I should just run 93 from now on? I will also probably try to do another Seafoam treatment through the intake, as I am starting to be convinced that the issue is carbon build up as well.

I'd like to know your thoughts on this. Thanks!
Ben

 

Hey Ron,

Update on this. I have ran a few gallons of Shell 93 and a full can of Seafoam through the tank 3 times.

I will say, the 93 gas has essentially made my pinging disappear.

Do you think maybe I should just run 93 from now on? I will also probably try to do another Seafoam treatment through the intake, as I am starting to be convinced that the issue is carbon build up as well.

I'd like to know your thoughts on this. Thanks!
Ben
​​​​​​​

 

Yes, I think you are right, its carbon build up, try Seafoam another time then lessen to 91 or 89 octane

The 2.5l should not ping on 87 octane well not much, lol, as long as EGR is working and carbon in cylinders is not to bad
Try to do a few freeway runs, higher speeds and RPMs, but be safe, that helps clean out the cylinders from day to day lower speeds and RPMs

 

Got it. Yeah I have been trying to do the ol' Italian tune up when I go out and drive. Luckily I drive a 15 mile stretch of highway to work each day, so I've been using that to get it up in the RPM range.

Probably done that about 10-15 times foot to the floor up to around 5k RPMs. I'd like to go back to 87 if I can at some point, obviously much cheaper and you're right, I shouldn't have to run 93. However it is nice to go up hills without sounding like my engine is filled with pebbles LOL. I might try to do another Seafoam through the intake, even though it was terrifying the first time, I'll just go slow!

Thanks for all your help, if you have any other ideas please let me know. I will keep you posted!

Ben

 

Hey Ron,

So, I ran 3 cans of Seafoam through the gas tank with Shell 93, and then a can through the intake (scary, but it turned out okay). I went on about a 2.5 hour freeway drive today, and still running the truck on 93, I noticed it is still pinging, BUT, the pinging is MINIMAL.

It pings only a little bit when I am feathering the throttle, and then stops when I give it more gas. Again though, the truck is on 93 still.

Do you think I should do some more Seafoam through the intake? I've done it 2 times now total (a few months apart) and over the last few months I've been fighting this issue the pinging has definitely improved by a lot.
The truck used to ping louder as I would press the pedal harder, LOL.
If not, should I try to go down in octane and see if it gets worse again? Or other things to check for? Or maybe just keep running 93? (Wouldn't love this option LOL).

Also, is it possible either my MAF or ignition coil(s) are slow/going? Would it be wise to change those? I've been holding off because they're a bit pricy.
But if you think it might be worth it to switch them since the truck is like 24 years old, let me know!

Maybe I should just leave it be and "live with it?" If you can't tell I'm not too keen on that option. But, I'm sure there's lots of pinging Rangers out there where the owner just lives with it LOL.

I'm still mostly convinced it's carbon build up, and feel like maybe a few more Seafoam treatments would help, then I would go down in octane to see what happens.

Let me know what you think! Thanks!
Ben

 

I can't remember if you have changed the upstream O2 sensor, but these go lean after 100k miles or 12 years, so shouldn't cause pinging, they cause lower MPG from Rich running

Most common form of Pinging is when air/fuel mix in a cylinder has 2 differently timed ignition points, the noise is from the explosive wave fronts meeting, this is why Diesels sound the way they do, they use compression ignition so its more common to have multiple ignition points, and they are built specifically to handle that, in a diesel its not called pinging or knocking, its called engine running, lol

Anyway to test if spark delay may be causing the issue do this test

The 1995 to 2001 2.3l and 2.5l will run fine with only 4 spark plugs working, so you can unplug the 3 wire connector on one coil pack, move it back so it can't arc to coil
Do it after engine is warmed up and more likely to ping
Then go for a drive, should run smooth but slightly less power
Then repeat with other coil pack

You are seeing if there is a spark delay in one of the coil packs or a few spark plugs or wires
If no pinging then you most likely do have delayed spark in two or more cylinders with both coil pack firing

If you still have pinging then it is not delayed spark

And if runs poorly on either coil pack replace that coil pack

I assume all 8 spark plugs are the same brand and number

MAF sensors often cause Lean codes(under reports air's weight), which means the computer is running the engine Richer than it should, not leaner
Rich codes means computer is running engine Leaner

You can get an under $20 Bluetooth OBD2 reader and watch the fuel trims to see if there is a "false" Rich being seen by computer
STFT(short term fuel trims) change fast and come in as -10% to +10% in normal operation, after warm up
the "-" numbers means leaner, "+" is Richer
STFT 0 is what computer has calculated as the open time for each fuel injector
+5% would mean, after feedback from O2 sensor, that the computer is opening injectors 5% longer than it originally calculated, so adding more fuel
-5% would mean computer is closing injectors 5% sooner, so adding less fuel

-15% to +15% usually won't set codes, above that, either way, will, +20% will set Lean code, -20% sets Rich code, so its the opposite of what most people think the codes mean

 

Hey Ron, thanks for the reply.

Yes, I have changed the upstream O2 sensor within the last few months, and all 8 of the plugs are Autolite Double Platinum plugs according to what the local auto parts store said I would need.

As for the coil packs, I am looking for the truck to still ping, and then replace that/both of the coil packs if it pings with one disconnected?
Also, should I drive on the highway with one disconnected? That is really the only place I can get it to ping anymore.
But I figure if one coil pack is the problem then driving on normal streets will probably make it ping when that is the only coil pack connected.

I have actually looked at the fuel trims using a scanner I have. I have seen Short term FT go as low as -15% for a split second, but generally it is between + or - 5%.
I will say however that generally it is always in the "-" fuel trim, and I rarely see it go positive.

I will try the coil pack method after work today, just wanted to get a better gauge of what I should do and if the highway is safe to drive on with one pack disconnected.
Also, should I put 87 back in the truck? I feel like running 93 might mask some pinging if one of the coil packs is causing it to ping.

Any thoughts? Thanks as always for the help!

Ben

 

The 2.3l Lima engine(2.5l as well) ran just fine on 4 spark plugs from 1974 thru 1988
So you can drive it any where and at any speed with one coil pack unplugged
It will set a code for the unplugged coil pack, but no harm, and code will clear on its own once coil pack is plugged back in

What you are testing for is, first, if all 4 spark plugs on the working coil pack are OK, with dual plugs you would never know if one spark plug was bad
So engine should run smooth, no misfires, with either coil pack unplugged

Second, you are testing if there is a delayed spark from one coil pack, the spark timing is not Matched, which could be higher or lower OHMs in the coil pack, or an issue with computer
If this is the case then there would be NO pinging at all at highway speeds with only one coil pack, OR pinging with one coil pack(delayed) but not the other coil pack(no delay)