Another 2.5L Pinging engine
I have a 99 ford ranger 2.5L with 95k miles that pings, it doesn't matter if its cold or hot. I have dealt and researched this problem for over two years and have just about given up. She runs great since i replaced all these parts however the ping is always there. Have replaced just about every part related to the ping. Here is what i have replaced and done so far;

1. Spark plugs and wires
2. fuel pump and filter followed by checking pressure
3. checked timing
4. EGR system replaced that includes DFPE and pipe.
5. checked compression, 175-182
6. checked valves
7. both o2 sensors replaced
8. MAF, tried two different brands
9. TPS sensor
10. IAT sensor
11. Tried several cans of seafoam through the intake
12. Checked and rechecked All vacuum lines and hoses. Also checked pressure.
13. Air filter
14. PCM
15. Brought the truck to two different dealers, both shrugged their shoulders then raped me. They both basically said to run high mileage oil and high octane gas.


Here is what i haven't done along with why I haven't;

1. Fuel injectors= I haven't replaced the injectors because she runs and idles like brand new. Purrs like a kitten

2. Cleaned carbon deposits= It pings no matter if its cold or hot.

3. Ignition coils= Checked by dealer and falls out of the range of any TSB

 

I wonder if a stopped up pcv could cause it not to get enough air or vacum,,,,just for the heck of it change the pcv,,,not high priced ,,,easy to do,,,,and who knows when it was changed last

 

I bad pcv would cause all kinds of vacuum related problems. I have already checked the vacuum pressure.

 

I'm not very familiar with the 2.5 but does it have a knock sensor? Has that been checked or replaced yet?

And here's a bunch of questions:

1. What is your fuel pressure at idle, cruise and WOT?
2. Does it ping at idle? While cruising? At WOT?
3. Have you done a vacuum check for clogged catalytic converters? Although a clogged cat should show up on the upstream o2 sensor output.
4. What's your vacuum reading at idle and cruise?
5. Is your upstream o2 sensor cycling properly?
6. What are your short term and long term fuel trims?
7. If running high octane fuel is the pinging reduced or stopped entirely?
8. And there's probably a few more that I'll think of later.

Late Edit: WOT = Wide Open Throttle

 

Not necessarily.

 

1. WOT? Have no idea what that means but the pressure was 55 then shot up to 62.
2. Pings at cruising speed around 70 to 80. It can ping earlier such as going over a bridge or when the ac is on.
3. Haven't checked the cat because it runs like its brand new besides the pinging. Runs real good at highway speeds. Would a partially clogged cat cause pinging or other problems?
4. 14-15 at idle, goes up if i rev it up a little.
5. Not sure but both o2 sensors are brand new "motorcraft oem". Had the same problem with the old ones
6. Have no clue but its great on gas, nothing has changed since i bought it
7. reduced, have slight pings instead of constant pings

 

Oops. I should have clarified, WOT = Wide Open Throttle.

On the 2.5 I believe fuel pressure should be 60-65 psi all the time. If you got WOT and hold it there while on the highway, fuel pressure should not dip below 60 psi.

I'm not 100% sure on a partially clogged cat but I would assume so as it's putting extra burden on the engine. It's easy enough to check for using a vacuum gauge, but, if your upstream o2 sensor is cycling properly and the downstream o2 sensor also looks good then your cats are probably fine.

A vacuum reading of 14-15 seems low unless you are above 4000'-6000' in altitude. If you are at or near sea level your vacuum should be around 19-22. And the reading should be almost rock steady.

Your fuel trims will tell you a lot about how your engine is running. I'd suggest getting some sort of monitor such as Torque Pro (for android devices) or forscan (free software from forscan.org) to help you monitor them as well as a lot of other engine parameters.

And something else I just thought of is the thermostat temp. If it's running hotter than normal, that might cause it as well.

By the way, what spark plugs did you use? Just curious as I've had trouble with Bosch in the past in some of the vehicles I've owned.

Hopefully others will chime in soon.

 

This s jut a WAG, but since -as shultzaberger mentioned- the vacuum reading is so low and since this is a rubber band engine, I wonder if it's been changed?
Late valve timing will cause a low vacuum reading.

 

are you still using the factory oem air intake from air filter to TB?
When I first got my 2.5, I found a so called cold airtake which was made of shiny metal. Looked cool but caused my engine to ping like a MF...\
It also had an open cone air filter made from cotton and used oil. Kind of like K&N but a different brand.
The thing used the stock MAF and the stock air temp sensor but still caused my engine to ping ping ping.
If you are still using the factory rubber air intake, maybe it's got a leak?
Are you using a paper air filter?
I just thought I would throw that out there because I have no idea why my metal cold air intake would cause a ping.

 

After all these years just found out the problem was from a bad fan clutch. Even though it seemed to work and the temps stayed within the "normal range" it was still causing the head to heat up which caused pinging. This heat up built up fast even in cold months

 

Good work! Thanks for updating the thread. It's always nice to get closure on these.