My 93 has alway's knocked under a load. I checked into the EGR valve to find it doesn't have one. I run high octane gas (91-93 Octane), I've replaced the plugs and plug wires with high quality wires and made sure the plugs are gapped correctly. What the heck..?

 

You didn't say what engine you have. I have a 93 with the 4.0L 4X4 auto. It pinged or knocked ever since I got it under heavy acceleration or pulling a trailer. ( I have severly overloade it, like pulling a heavy tandem axle trailer with over 2000 pounds of payload on trailer) It had 72,000 miles on it when I got it, and at 165,000 miles the mass airflow sensor went bad, and had to have it replaced. Since then, it hasn't ever pinged or knocked since. I had cleaned the mass air sensor every spring and fall with ford brand cleaner, but it finally went bad. Just my 2 cents worth.

 

Welcome to FTE bigmike.

I assume your using hi-test fuel to help cut down on the knocking, right?????

Actually premium fuel isn't recommended for this engine, as over time, it can cause excesive combustion chamber deposits, which will exacerbate the knocking problem under load.

With the vintage of this engine, a vacuum leak should be on your suspect list too.

Good suspect spots for vacuum leaks are, loose fitting, split, cracked, or missing vacuum lines & they could be located anywhere from the cabin AC/Heater control, to the PCV valve, to the brake booster, to the fuel evap canister, to intake manafold gasket leaks, from loosened fastners, which the 4.0L is famed for.

So a visual inspection of those lines & maybe a propane sniffer probe around the intake manafold, might be in order.
If you find a leak there, try retorquing the intake manafold fastners, pehaps if the gasket isn't sucked in it'll work.

On the carbon deposits, if you suspect the engine has this problem, you could try running most of your present tank of gas out, then filling up with a tank of Chevron or Chevron Texaco gas, with a bottle or Chevron Techron Plus, at the specified per gallon treat rate, then run most of that tank out, with some spirited highway driving, wih 3 mile runs at, or above 3K rpm, to loosen & remove the carbon from the combustion chamber.

I have to do this on a regular basis, to keep my 99 4.0L quiet, as it suffers from CCDI & it's very sensitive to ANY combustion chamber deposit build-up!!!!

If your 93 has a MAF sensor & you suspect the MAF sensor may be part of the problem, try disconnecting it & give her a run & see if the ping subsides. If so, suspect the MAF may be dirty, so remove it & carefully clean it with "throttle body" spray cleaner & look up stream to find out why it's dirty. Look carefully for a poorly fitting air filter, or improperly buttoned up air box.

If you have a MAP sensor instead of the MAF, try disconnecting it & do a test drive & see how it goes. If better without the MAP, then suspect it & replace it, as it can't be serviced.

Just some thoughts for consideration.
Let us know how it goes.

 

Do you have one of the vintage 4.0's? Cuz if ya do, the answer is here in this faltering forum for your review......

Do a search in THIS forum and look for...

*carbon build up
*vac leak (the lose bolt boogie)
*MAF sensor dirty, ESP if you have the kiddie/puberty driver and victim/childfest rated air filter that contamintaes it with oil. Namely, KY or the like.

 

Sounds like the same year and motor. Thanks for your reply I will get the Mass airflow sensor sometime this week. Thanks again.

 

Thanks for the info. I will check into all of that this week. I will let you know what turns out and thanks again!!!!!

 

I think your saying that if a kid drives it or it has a K&N filter. I drive it and it does not have a k & n. Thanks for the advice.

 

The air filter mentioned is associated with disbursing an oil film on the MAF sensor that results in issues, like engine knock. As such, and if you like that filter, you might want to plan on cleaning that MAF sensor on some scheduled basis.

 

Thanks Cowboy.

 

I have done most of what you said in your reply to my problem. It is like someone breathed new life into my truck. It hasn't pinged since I cleaned the sensor and ran some Sea Foam brand cleaner through my throttle body. It looked like my driveway was on fire for about 5 min. but after the smoke cleared and I ran it @ 3500 RPM for 2 min. in addition to what I did in the driveway and it runs great. Oh yea I also changed the oil and plugs after putting in the carbon cleaner. Me and my truck thank you!

 

Good feedback & to hear your ride seems to be better bigmike.

Yup the Seafoam sure will smoke things up for a while, sometimes scares the heck out of folks. They think they've blown a gasket or blown the engine. lol

After the decarb, is it running ok on regular now????