I was thinking of trying a low temp thermostat (180 or 160degree) to see if it stops the spark knock on my '97 4.6L. This should force the computer to run a richer fuel mixture, which is what I think it needs. A cooler engine would be less likely to ping,also. Has anyone tried this?

 

Have not tried this, but I do remember it being brought up a long time back in a post called "Attn 98 Pingers Club." To the best of my knowledge it did nothing to correct the problem with the pinging, and could possibly present other problems. From everything I've read, there is basically no reason at all to use a cooler thermostat. Useing a cooler spark plug was also brought up without much success. All of the above are really only 'bandaids' to cover up a bigger problem. I've had problems with pinging in the past but only in the colder temperatures during the winter. This time of year I don't have any problems whatsoever in the heat. If your truck is pinging this time of year, start out by clearing the computer by disconnecting the negative battery terminal, and turn the headlights on for ten minutes to clear the computer completely. After ten minutes, reconnect the negative battery terminal, let the engine idle for about 5 minutes, and then drive just a hair more aggresively than normal for the first few days especially at whatever point you were noticing the pinging. I've had success with this in the past. If that doesn't take care of it clean your MAF sensor, and check your spark plugs. If that still doesn't help, search for the post I mentioned "Attn 98 Pingers Club" (the thread was originally started by me) and you will see a whole list in order of relevance that could possibly be the source of your problem... Personally I'd research the possible negative effects of useing a cooler thermostat before trying that though. It's been mentioned in the past and shot down pretty hard by a lotta people that know a lot more about what there doing than I do!

 

I am not the last word in engine tuning, but in my opinion you do NOT want to put in a 160 thermostat. There was a time for this on some older motors. That 4.6 of yours makes most efficient power and fuel economy when coolant is 200 to 210 degrees. Even the Lightnings aren't running a stat that cold.

Let's start with the easiest remedy. Fill up with 91 - 93 octane premium fuel (NO GASAHOL PLEASE) and see what happens. I can tell you I had this problem on my wife's 99 Explorer. I had to run premium fuel to avoid detonation. This was in its pre-chip days. Now I run premium fuel for the Superchip and have had no trouble.

Try that and see what happens. Perhaps 89 octane would do the trick, but for at least this first tank, you will be mixing with old 87, I suspect. Run several tanks of premium from the same station, and see what happens.

 

a lower t-stat will also screw with the computer, not a good thing to do.

 

Running rich will also kill the converters alot faster, plus it'll smell bad too.

 

Useing higher octane gas will take care of the issue for the time being, but again it's just a 'bandaid' to cover up the real problem... I did this for a year or so with the 89 octane, then eventually the problem came back. Useing a higher octane gas will in the long run cause more carbon deposits inside your motor which will just cause the problem to get worse... If your going to go this route, get a chip and go ahead and get the added advantages of a superchip. (Personally, I think the problem is atleast partially computer related anyways.) If you just want to cover up the problem, you can take out that octane shorting bar that alows your timing to advance and you shouldn't ever hear any pinging again.

 

I have tried all of that stuff, and it has not helped. It has been to the dealer at leat 4 times, each time they say they cannot find anything wrong. The last time, the guy told me to run regular (87 octane)! The motor wouldn't last 3 months pinging as bad as it does on regular. I am going to get a chip custom programmed to elimitate the spark knock. Mike Troyer from Performance Products told me a superchip would not help, but I have read posts here that claim a customchip worked. I am going to contact Reinhart Automotive Services in FL to see if they can program a chip for me. I will post a message if this works. Thanks

 

Definatly go with dennis at Reinhart...tell him Seabass sent ya....he's a good guy.

Seabass

 

I don't know how bad it is pinging, but it sounds like it may be a MAF sensor problem. If your fuel pressure is in spec. try to barrow a sensor from a friend (making sure his truck doesn't have the same problem) and install it. Be sure to disconnect the battery for a few minutes to reset the Keep Alive Memmory. Drive it, if the pinging is gone, go buy a new sensor.

 

El Carbon strikes again! Have the dealer clean it out with a flush. My brother had his 98 4.6 done and it runs flawlessly now.