I have a 1994 Explorer XLT w/ 110K on it and it pings under load (going up a hill or when I have to get on it), especially when its warm. I haven't really noticed any problems when its cold yet. I cannot seem to find the problem. Things I have tried:

1. Replaced spark plugs w/ Autolite Platinums (of course properly gapped)
2. Pulled MAF sensor and cleaned it w/ brake cleaner first then some electronics cleaner
3. Replaced air filter (it was kinda dirty and was due for replacement anyway)
4. Warm water through the vacuum tree at a slow rate to try and burn off any deposits
5. Re-torqued the upper intake manifold
6. Attempted to pull codes with a code reader and the only codes I could get were 412 and 538 during the engine running test

If you have some ideas, please let me know. I do not want to take it to the shop if I don't have to. I would really like to fix it myself. Thanks in advance.

 

if i remember correct, using high octane (premium) fuel will elimate this.

 

Using premium or plus grade gas does help, however it does not eliminate the problem. And with gas prices the way they are I'd really like to not have to pay for premium. Besides, I think that by using a higher grade of gas I'm just bandaiding a problem that needs to be fixed.

 

Had that pinging problem in my 93 Aerostar 4.0 (120000 miles). Ford people could not fix it. I changed out sensors, plugs etc. Rebooted computer no luck. Finally I put in some new plug wires rebooted the computer and drove it up & down some steep hills. No pinging. Three years and I finally fixed it last June. The Ford people put it on the computer a number of times and the plug wire & all looked good.I went with new Motorcraft wires.

1993 Aerostar AWD
1992 F 150 XLT ext cab
1989 Bronco II XLT
1974 Maverick
1964 Avanti

 

I replaced the plug wires sometime last year (if I remember correctly) with new ones from NAPA. From what I can see they're okay. But I think I will look into new wires anyway. How do you reboot the computer? The only way I know of is to pull the negative battery lead off for 10 minutes or so.

 

That is correct, disconnect the battery. After reconnection drive it hard up some hills after the engine is warmed up. It worked for me. I have found some wire sets to work better than others depending upon who made them and the vehicle installed in. Good luck.

 

I had the same pinging problem and this URL really helped.

http://www.glue.umd.edu/~singletn/web/pages/ping.html

Notice any oil loss? Mine was getting into the #5 cylinder, fouling the plug.

 

Yes that is a good website. That is where I learned about the MAF sensor. No, I don't really have any oil loss. The #5 plug looks good.

I haven't claimed victory yet, but I did want to pass on an update to the problems I've been having. Through the various things I've tried (see initial post for this thread), the pinging is starting to go away. In addition to the list I have done two more things which have really helped. First, I cleaned and regapped all of my spark plugs. Though they were fairly new (about 2000 miles on them), I decided to do this to check for any oil or fouling-specifically on the #5 plug. No problems found there. The second thing has made the most difference though, I changed the thermostat and flushed the coolant system. It had only been about a year and half since my last flush. But I never had replaced the thermostat before (I've owned the truck for only about 3 years).

The thing that led me to the thermostat was that I noticed the temperature gauge never reached above the 'N' in NORMAL, even after driving several miles. The other indication was that if I drove the truck about a 1/2 a mile the upper intake manifold got reallllly hot. I'm not sure if this will help anyone else, but this is what is helping my truck. If anyone else out there has any other suggestions please don't hesitate to post them.

 

FORD released a tsb stating that after doing all other 'ping'diagnostics,to check the keyway on the crankshaft pulley,on some explorer's the keyway came out causing the crank pulley to slightly rotate..remember the crank trigger is on the pulley and this slight rotation could cause an out of time condition

 

LG-Do you happen to know the TSB# or have a copy of it? This sounds very promising. Thanks.

 

Was the EGR and the lines checked? An improperly working EGR or plugged EGR lines can be a cause of pinging.

 

No, I haven't done any checking on the EGR valve or lines to it. When I pulled codes from the computer, I received nothing to indicate an EGR problem. Matter of fact, I really didn't receive any codes except for a brake switch problem that I had, and I replaced that. The truck is still pinging under the same conditions as I described in the initial posting. I haven't had much time to work on it the last few weeks though. I should be able to look closer at it again starting next week. The keyway on the crankshaft pulley seems like it is definitely worth looking into. If anyone has more info. on this I would greatly appreciate them posting it.

 

I have a 94 Mazda B4000 and it did the ping thing that they all seem to do. Cleaned and changed the MAF, checked the manifold bolts, etc, etc. Finally got a new cat, as mine was shot at 130,000. Then I proceded to drive the snot out of my truck and blow out all the garbage that built up because of the clogged cat. No ping since.

 

Had the same problem on my 92 explorer. Finally after 1 year a code came up as the Mass Air Flow Sensor. Changed it and no problem since and I'm back on regular gas! I also had the same problem on my 1997 F-250 and I was just able to clean the two small wires in the sensor to solve the problem. Maybe try to clean it first.

 

Hey dinograd. Ever fix it? Mine's doing the same thing

John