2.8 Pinging...

[rangerin]

Okies, my 2.8 pings a little. It's not bad, but something I'd like to get worked out. I only notice the pinging when getting up on the highway quickly (@ about 45mph) or having to really speed up a big hill. Once I am done accelerating hard, it goes away. I originally got this truck for free. When I first got it, literally nothing worked. I've rebuilt the carb, but other than adjusting it, I've left the carb alone otherwise. Should mention that the previous owner did a lot modding (ie. hacking). The computer does not control fuel/air anymore.

Quick info:

2 Barrel Holley Carb using #73 jets for both primary and secondary
4.5 power valve
Steady vacuum at 22 inches
Fairly new plugs (about 8k on them)
Can't remember the timing, but it's around 12 (can double check later)

 

[RonD]

Pinging/knocking is when the fuel/air mix ignites just prior to the spark plug firing, the "noise" you hear are 2 explosion wavefronts meeting inside the cylinder.
This causes extra heat in the cylinder and if continued sever pinging can melt valves and pistons.

Does it have an EGR system?
EGR system prevents pinging under load.

Could be the timing is too advanced, base timing with vacuum advance disconnected or SPOUT jumped should be 10deg.
12deg can give better performance but could also cause pinging under load, one of the trade offs.
Ford TFI ignition system info here:
http://www.therangerstation.com/tech_library/TFI_Diagnostic.html

Could also be some carbon build up in the cylinders and/or on the back of the intake valves.
Carbon in the cylinders retains heat and increases compression, either can cause pinging under load.
Carbon on the intake valve absorbs fuel, leaning the mix, leaner mix causes pinging.

 

[John Smith]

Hi there all..

I/ve been here b4...a re-curve of your diz should solve ur problem...

 

[kimcrwbr1]

How many wires are coming off the distributor. If there are more than three it is running on base timing you will need to put the duraspark distributor and ignition to bring that engine to life. You want exactly 10 degrees base on the 2.8 I have tried every possible combo 10 degrees base timing and run the idle air needles rich you will get the best performance and fuel economy.