2.5 Pinging

[dancron]

At wit's end with this issue. My 98 ranger 2.5 pings at highway speeds and I can't seem to resolve the issue. So far I've replaced the entire EGR system, plugs, wires, MAF sensor and 180F stat with no results. Can anyone point me in a direction from here?

Thanks

 

[RonD]

Does higher octane fuel ping less or not at all?

What's the MPG like, lower, higher, or no noticeable change?

What's the engine temp like, does it go up higher at highway speeds or lower?

I assume no CEL(check engine light) now and no codes, any codes in the past?

The Bluetooth OBD2 plugins are not to expensive, they can display live data on smartphone or tablet while driving.
You could check that computer is opening EGR valve and also check Fuel Trims and O2 sensor voltage to see if it is getting Lean at higher demand, higher speed.
Also spark advance, computer may not be advancing spark enough for engine load.

Has fuel filter been changed in the last 5 years?
If not flow could be dropping a bit under high demand.

 

[dancron]

Higher octane fuel pings less, MPG is no noticeable change, Engine temp is pretty constant, No identifiable codes or CEL, and Fuel filter has been changed 2 months ago.

All parts were replaced with OEM motorcraft stuff too.

I like the blue tooth idea. I might have to invest in one.

It also does this strange thing when it sits at idle for awhile it will slowly ramp up from about 750 to 1000 rpm, then when I hit the gas and let off it goes back down. Hope this helps.

 

[97RangerXLT]

180 degree t Stat seems low...the 4.0 takes 192 degree...maybe car on build up over the last 18 years is causing the pinging. Lower engine temps at 180* might be adding to the issue, but double check the t stat value, it may be correct for the 2.5.

I would seafoam the upper intake and the fuel system. That should clean the carbon out and the injectors.

AJ



Sent from my Samsung Galaxy Note 4 while sitting in my underwear

 

[dancron]

It came with the 192 t-stat when I got the truck. I put the 180 in 2 weeks ago to see if it was pinging due to excessive heat. Turns out that wasn't the problem. It has been seafoamed recently but I was planning on giving it another shot

 

[RonD]

Could be higher compression from carbon build up, but 2.5l is 9.1:1 so have to build up quite a bit.

Does it ping when engine is cold?
O2 sensor is off-line for first 5minutes or so on cold start, computer is in Open Loop, running richer factory air/fuel mix

O2 sensor could be failing and reading less oxygen so computer sees Rich mix and is Leaning out the mixture too much.

If you unplug the O2 sensor computer would stay in Open loop and run richer air/fuel mix.

 

[dancron]

It runs great when cold. It could very well be the 02 sensor, it is the original one. I've had the truck for a couple years and it only recently started pinging so I was guessing it was sensor or EGR related.

 

[dancron]

Looks like the upstream O2 sensor has seen better days. I have a new OEM one coming tomorrow. Hopefully this is it! Also have the downstream one coming too but I couldnt get it out today.

 

[RonD]

Looks due.

Upstream O2 sensors usually cause Richer running toward 'end of life', MPG goes down a bit because of it.

But it is certainly possible it is the cause of lean mix, it has the final say in air/fuel mix, within reason, Computer does have a Lean and Rich limit based on MAF sensor air flow.

Downstream O2 checks if Cat is working, it can change Long Term Fuel Trims a bit, but main purpose is checking Cat.