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Hey guys, long time reader first time poster. I am experiencing an interesting winter ping problem with my '93 Ranger 4.0. I have definitely covered all the basics, thanks to FTE. I have checked/replaced/cleaned MAF, EGR,new Ford Platinum plugs, wires, thermostat, idle control etc. This truck does NOT ping in the summer, even under load with the A/C on, but come winter under hard accelereation it pings badly and loses power. Especially on the highway in overdrive it is totally bagged. Since it gets real cold (-40 ) where I live, I was wondering if it could be injector rings or the intake gasket shrinking in the cold.
Sorry I didn't mention that in my post, but I have checked for vaccuum leaks and retorqued the manifold. I pretty much covered everything that I have seen posted on this forum.
Could someone please expand on the IAT issue, I am not familiar with this. What is it? How do I check it? Where is it? What does it do?
IAT is the intake air temp sensor. It should be located up high on the upper intake.
A warm engine will run leaner than a cold one. Should your's be indicating warm intake air during cold engine operation, it may be possible that your air/fuel mixture is lean. Lean mixtures burn hotter than rich ones and this can result in engine knock.
To test, I'd begin by checking for codes. It may also be required that you perform the pinpoint test on that sensor/system. BTW, have you altered the air cleaner or the heat riser setup? If not, I would suggest making sure that the heat riser is operating properly.
Last edited by CowboyBilly9Mile; Dec 2, 2004 at 12:13 PM.
No I haven't made any intake mods at all. I spoke to a former Ford mechanic who was confused that the issue is only during cold weather he said ping is usually a warm weather issue. He suggested decarboning (done).He said if nothing else works ther is an Octane sensor that has a plug in it, located on the driver's side, and by removing the plug the timing is retarded 2 degrees. He said this should stop the ping and not hurt performance too much. I hate to try that until I have used up all the great ideas you guys have given me.
Well I tried it all and nothing worked. In the spring I will change the lower intake gasket and then there is nothing left to do. Even took it to the shop to check for codes, and there were none.
Did you run pinpoint diagnostics on the IAT system? Have you checked the heat riser to make sure it's open when the engine is warm? Normally this would raise issues in warm weather, but maybe it's not opening until the ambient temp is warmer than needed (bad sensor, and computer won't catch that one).
Last edited by CowboyBilly9Mile; Jan 30, 2005 at 05:45 PM.