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I have a 1995 Ford F150 pickup with a 5.8L (351 Windsor) motor that had a bad pinging noise and loss of power when either accelerating or when it was under load (and especially so when accelerating under load). The thing is, it would only do so when warm. It idled and worked fine when the engine was "cold."

I had to change the timing cover gasket, so I took the opportunity to do not just do that, but change the distributor cap, rotor, put new wires, and new plugs (Motorcraft). Everything was original and after 23 years, it's probably time for some new kit due to deterioration.

Long story short, the engine runs great, idles smooth and flawless except after it gets hot when the pinging and loss of power returns.

My next thing to check is the EGR valve. However, I wan't to look at any other possible "systems" to check out. What would be causing this and where else should I look?

Update

After running the diagnostic procedures provided by Moab, the codes the codes I pulled were 1-1-1 or All Systems OK. So unfortunately, I still have the problem and no diagnostic info to go after.

  • See this page on how to retrieve codes.....fordtruckzone.com/threads/… – Moab Apr 18 '18 at 19:51
  • @Moab - thanks. I ran the diagnostics and came back with a 1-1-1. See the update. – Allan Apr 20 '18 at 0:27
  • As you may already know, there are so many things that can cause this. How well has the cooling system been maintained? Have you tapped near the knock sensors to see if there's a noticeable timing adjustment? Or checked for vacuum leaks around the manifold gaskets and other locations? Tried carbon deposit cleaning additives? Any other information you can give us or relevant symptoms before and during your problem? Unfortunately, without an ecm response, you'll have to check out all possible causes... – Mustangguy809 Apr 20 '18 at 6:01
  • Did you set the base timing correctly after the t-cover gasket replacement? – Moab Apr 20 '18 at 13:56
  • The cooling was just replaced because of the leak on the timing cover gasket but what I noticed was the cooling started going brown. I would flush it, it would be "green" for a few months then go brown. The leak was on the timing cover gasket "inside" near one of the studs that started to rust badly (should have taken a picture). I haven't tapped the knock sensor - I'll try that. My weekend plans were to check out the EGR valve and pipe to see if it needs a cleaning or needs to be replaced. I don't do additives (never have), but I think I'll try to drip some water to do a carbon cleaning – Allan Apr 20 '18 at 16:01
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Pinging under load/acceleration is usually a sign of incorrect ignition timing and/or wrong grade of fuel being used.

Check ignition timing and try a higher octane fuel as an example from 87 octane to 91 octane and buy fuel from a reputable fuel station so you don't get questionable fuel, you may have to add an octane booster to stop the pinging which is very harmful to the motor.

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    I'm going to check timing this weekend, but as far as octane goes... This engine was designed to run on 87 octane. Increasing the octane to stop a symptom is hiding the symptom, not fixing the problem, IMO. – Allan Apr 20 '18 at 16:42
  • What was the quality of the fuel you bought? In my older vehicles, I've bought 87 octane fuel that was junk, some of the "discounted" service stations buy left overs from fuel tanks and is really bad stuff. Also, you might want to read up on octane, here's a couple of articles; eesi.org/papers/view/fact-sheet-a-brief-history-of-octane and aaa.com/autorepair/articles/…. – Draw3D Apr 20 '18 at 17:28
  • I buy from either Shell, Mobil, or Costco. The one thing I won't do is put no-name gas in any of my vehicles. – Allan Apr 20 '18 at 22:20
  • +1 for higher octane rating. Also, being an older engine, you could have some serious carbon deposits inside the cylinder causing premature ignition. If that is the case, taking the heads off to clean out the insides would help a lot. – jp2code Jul 19 '18 at 19:05
  • @Allan, I definitely agree that upping the octane is fixing the symptom, not the problem. However, running for a couple weeks on 92 octane would at least help you determine if the problem was incorrect ignition timing, as Draw3D suggests. After you know for sure, you could hopefully fix the problem, and switch back to 87 octane. – Sam Jul 19 '18 at 19:13

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