Is your truck fuel injected? On mine I can hear the fuel sysyem tick at low speeds but not at high speeds. Also, what kind of oil are you using? I also notice that mine will make a ping/clacking noise if I use anything heavier that 5W30. This is just my .02 worth. Hope this helps.

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'96 F-150 302
Hedman Hedders, Catco Cat., Gibson Super Truck, K&N F.I.P.K.

 

The truck is fuel injected. I am using 10W30 Valvoline Synthetic with a Motorcraft filter. The pinging that I am hearing is high RPM light throttle. It is a preignition sound, detonation ping.

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2001 Ford F150 Supercab 4.6L
Airlift Rear Suspention with onboard compressor

 

FastDEW , I'll bet that your Engine Timing is advancing a few degrees , i have a 91 chevy c1500 with a 350 ( I know ... not exactly a ford ) , and it pinged just like you say , i had the tiiming checked and that was the problem , it was advancing 6 degrees, Have that Timing checked .

 

I have a 94 F150 with the 5.0L V8. The truck has 75K miles on it and is all stock except for a K&N filter and a flowmaster muffler. The truck runs great and has good power. The problem is that it has a bad case of pinging. It does not ping under heavy throttle. It only pings under higher RPM light throttle. Say if you were climbing a long mountain grade and dropped out of OD, when you try to keep your foot at the position to maintain speed at that higher RPM it will ping really BAD. If you let off or squeeze the gas on it will go away. The ping is so bad it sound like something is going to blow up. I tried different gas, octanes, and changed the spark plugs. I can't figure out why it is pinging only under light throttle at higher RPMS. Again it does not ping at heavy throttle, regardless of RPM. There is no codes or engine lights and the truck runs very well other than this.

This is driving me crazy, I would greatly appreciate advise on this.

Thanks!!

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2001 Ford F150 Supercab 4.6L
Airlift Rear Suspention with onboard compressor

[This message has been edited by FastDEW (edited 05-03-2001).]

 

Your timing is too advanced. Factory setting is 10 degrees. Buy a timing light or take it to a mechanic. Checking/Adjusting it is usually part of a regular tune-up. Climbing a long mountain-grade is about worst case scenario so put in the gas you want to run, and advance the timing as far as you can w/o detonation under the worst case scenario, then retard it 2 degrees to accomodate a poor tank of gas. That is how you would derive the optimum timing. Point is 10 degrees makes the truck much less responsive at part throttle. I run 18 degrees and 93 octane gas. Haven't towed heavy loads with it yet in hot weather to see if this is too much. I'll know shortly, its getting warmer in Texas.

 

I adjusted the timing. It was too far advanced, now it is set to stock. I have not driven the truck yet, so I do not know how it will act.

Question though? I did not check the timing because I thought that timing would only effect heavy throttle applications. When I was climbing the grades the ping would go away if I gave it more gas. I do not understand that? Could someone explain why that is, if you know?

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2001 Ford F150 Supercab 4.6L
Airlift Rear Suspention with onboard compressor

 

I can't really .... but Thats exactly what my chevy did , if you gave it alot of gas it would just about quit.

 

I adjusted the timing on the truck. It isa little better, maybe, but it still pings realy bad. I also noticed a large decrease in performance. Could the EGR be sticking or something? I am trying to figure this out. Thanks for all your help.

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2001 Ford F150 Supercab 4.6L
Airlift Rear Suspention with onboard compressor

 

Thanks Jerry!

I am going to try this after work. I hope it works.

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2001 Ford F150 Supercab 4.6L
Airlift Rear Suspention with onboard compressor

 

email me if it doesn't and I'll help you brainstorm some more.. can't promise i'll be back quickly to check the thread. That should definetly do it though. To pierce the wire you may need a needle (like a sewing needle).. its that or backprobe the connector but I haven't successfully done that. Enjoy!

 

I don't know your email address?

I checked the TPS voltage. It is .97 at idle and 4.64 at WOT. I made no adjustments because this seems correct to me. I am starting to think maybe there is something going on in the EGR system. Maybe a stuck EGR or plugged?

 

I know what it is then: TPS, Throttle Position Sensor. Its out of adjustment. I had an 89' that did this. Did EVERYTHING to no avail. Timing, plugs, wires, cap, rotor, octane. Turns out the silly TPS was out of adjustment. Adjust it so its < 1 volt at idle with key on engine off. MAJOR pain on the truck since you can not loosen the adjustment screws w/o removing the upper intake. Remove it, flip it over, loosen the adjustment screws, make sure the harness is connected (you may have to disconnect to flip it but reconnect it to test/adjust it). Pierce the Green wire with your positive probe, ground the black lead of your probe, check to make sure its <1voltDC. That is it. Truck will drive WAY better, trust me. Its like gaining 20HP! Plus no pinging!!

 

I checked the timing with the SPOUT out. I am going to work on the EGR a bit to see what happens.

Thanks!

 

Egr is a good thought. I had the same problem. My buddy who works on ford trucks for a living helped me with mine. My original problem was a miss at light throttle. He made a restrictor plate for the egr because i was way too lean. It was fine till they changed to the summer fuel mixtures. It started pinging real bad. First he told me to do this. He gave me a can of motorcraft carb cleaner. He told me to block off the radiator with cardboard and get the engine very hot. Then using the air intake hoses as a funnel,set to fast idle,use half the can to flood the engine.Let it set for 15 min. Then use the rest of the can to flush (very slowly). It will smoke, and idle rough for a while. This is what they call a carbon bust at the dealer. Carbon buildup can cause spark knock because it gets hot and lights off the gas before the spark does. the secondary flame front collides and causes a audible ping.Also carbon can increase compression due to decreased cylinder volume, and the increase in pressure makes the gas more likely to light off due to engine heat. Slight spark knock will cause no problems, but prolonged high speed knock can destroy pistons. Now to what i know about the EGR. Egr recirculation puts an inert gas into the combustion chamber that actually displaced the oxygen. This causes the heat level of the combustion chamber to lower. Also the inert gas causes the flash point of the mixture to be higher and less likely to detonate early. If you arent getting enough egr flow then it could be clogged egr. I had too much egr flow that was causing a miss at light throttle. He made me a restrictor plate to put between the egr and the manifold, it worked great but when they changed over to the summer fuels i started getting knock.I had to either make the hole bigger in the plate or take it off. I took it off and now I dont have a miss or knock.Ill put the plate back on in the fall. He also told me i could retard the timing 2 or 3 degrees if nothing else worked. Sorry so long. Hope this helps.

 

IF it is not EGR, check the routing of the number 7 and 8 plug wires.. they should be as seperate as possible. OR if you have HO firing orderr, the same for the 5 and 6. Just a thought..