I have a 93 F150 with a 302 and is automatic. As im gaining speed when pulling a boat and sometimes under regular driving conditions I hear a pinging sound comming from the back of the motor. Seams like right in the middle of the firewall. It only pings about 3 to 4 times. Could this be from the cheap grade of gas im using or is there something wrong? Done a compleat tune up about 5 months ago and even changed the O2 senser. Also just changed the air pump check valve that is behind the motor cause it was compleatly broken. I also have a loud blowing noise as im taking off and goes away when it goes into third gear. Does that sound like the transmission? Also have a vaccum leak that causes the air to quite blowing from the vents and blow out the defrost. I have checked a few vaccum lines and the check valve with no luck. Could this all be one big problem? Thanks for any info anyone may have!

 

I would say "CHEAP GAS".

Pinging is a problem with all the engines not getting enough octane. I got rid of my filling both my tanks with the highest grade possible & running it.

 

Hi,
If you have a vacuum leak, really try to find it, because it can cause you all kinds of symptoms.
Also check the base timing on your engine, and use a better grade of gasoline.

 

I think modern engines have knock sensors. You will hear a ping because of the cheap gas and then the computer changes the ignition timing so that it goes away. You hear the first few. Normal.

Blowing sound? Need more info.

 

Thanks for the info. I will try switching to a better grade of gas to see if that will help the ping. As far as the blowing goes when im taking off its a loud blower moter type sound. As I gain speed it gets louder and louder, but when the transmission switches to third gear it goes away as the rpms fall back down. It does not do it all the time either, and the times it doesn't do it I seem to have more power and can get up to speed alot faster. Hope this helps better describe my prob. Thanks!

 

A blowing sound. I heard something like that once. It was the engine fan. If your fan clutch is stuck the fan runs hard and sound like an airplane. That could use lots of horsepower. Hope thats it.

 

My brothers truck makes the same loud "blower" sound. It started when a shop replaced the fan. He had them replace it again and the new one does the same thing. It's weird but when you gain some highway speed it gets quiet.

 

Thanks for the great info. I changed the fan clutch a few months ago. It didnt make the noise till a little later. I went to O'Reilly and the only one thay had was super duty. Do you think that its bad or is it soposed to be like that? Thanks

 

Might have to get an OEM fan.

 

Not sure about the clutch. I have heard a few engines where the fan seems very loud. Your fan might not make noise all of time because the clutch is temperature activated.

I think the fan clutch is a piece of junk. Electric fans must be better but I have never had one.

 

Thanks guys. Yesterday I put the orignal fan clutch back on, and it quite manking the noise. And seems to have more power taking off. I replaced it because I thought the old one was a little loose, but with the new one on it didnt run any cooler. So this one is going back to O'reilly and getting my money back. Thanks again!