I bought a 94 f350 with a 351 a month or so ago, the things won't stop pinging when you give it over about 2/3 throttle. It starts as soon as you step into the throttle and stops as soon as you let off.

So far I have put 93 octane in it and it didn't help, the EGR valve is working, the timing is at 9 degress base, (the wires and harness going into the distributor look absolutely brand new so somebody had just worked on it) the EGR solenoid was bad replaced it today and that didn't help. The old solenoid was shorted read zero ohms. seafoamed it today, replaced the plugs, the old plugs looked normal, and I think they were the original plugs the truck only has 46k on it.


I also drove it with the spout wire off so the computer couldn't advance it and that didn't help.

I think the theromostat is stuck open (or possibly missing completely since it is an ex military truck, if it somehow found its way to iraq someone may have taken it out. I can see that the thermostat has been worked on because there is blue sealant visislbe) I planned on fixing that this weekend since it is supposed to be 65 degrees. I had read elsewhere that could contribute to it.

This is driving me slightly crazy, I am not driving the truck much since it isn't my daily driver, it acts just fine if I drive it real easy. Just get on the throttle and it pings like crazy.

 

first put the timing back to 10* btdc with spout connector removed. confirm and then put spout back into place.

I would then pull codes, Ford Fuel Injection has instructions on doing this using a paperclip and counting the CEL flashes. the truck needs a 195* tstat as well.
you might also have a bad cat converter also. also feel behind the upper intake down behind the heads, there is an exhaust check valve back there, if its shot could cause problems. I would also check your fuel pressure, it should be 35-39 psi at the valve.

 

I know that if th EGR is not working it will cause it to ping.Check the vacuum lines/EGR vacuum regulator solenoid,and the sensor on the EGR valve.

 

Got it fixed. it was the EGR position sensor.

 

I had the same problem with my 97 F250, 351. I have chked everything. I finally put in 93 oct. gas and it almost completely gone. You can still hear if very faintly if I get on it real hard.

 

have your cat converters checked, if they are clogging it will cause this also