1993 5.0L F150 XLT at about 83000 mi. runs great under throttle, gives good gas mi. (17mpg) and burns no oil. But it rattles or pings when asked for just a little torque in top gear (3sp+OD AT). Once it kicks down, it kicks....

Mid-octane gas makes no difference. Plugs, wires, etc., recent. What to check?

W.C. Epperson

 

Ping is caused by engine combustion temperatures heating up carbon ontop of the piston, igniting before they are suppose to. Make sure the timing is set at 10' degrees before TDC and also the EGR is clean inside, both are problems for Ford. Pull off EGR and inspect, I clean them with a propane torch and use a vacuum pump to pull them open, heat up the carbon and blow it out with air pressure, check timing, set at 10 BTDC, if it still pings retard timing by 5 degrees, so make it at 5 degrees BTDC, see if that does anything for you. Electric1

 

i have a 93 150 4x4 that is making me pull my hair out by the roots
i have the same problem of pinging when in a higher gear. first it was in #8 and it burned the valve and cracked the head. replaced the head thinking the crack was what took the valve out. a week later i am having the miss and pinging again. this time it was #2 that was burning the center electrode out. and once again a burned exhaust valve. with talking to people i have learned that a exaust leak can cause this problem for what reason i can not figure and they cant tell for sure but i have found that the cross over (from air pump to the back of both heads) had a hole rusted in it. i am waiting to get my head back from the machine shop and i will put it back together and see if it fixes it but keep that in mind when you got it torn apart it only cost me 10 dollars at the junk yard

 

I had the same problem many posts back. I replaced all the usual suspects too, and it never helped. Finally, somebody suggested disconnecting the battery for a while to let the computer reset itself with all the new components. Low and behold that worked. Who would have thought? Hey...it's something cheap and easy to do before you sink more $$ and pull out more hair. Good luck!

 

i finally found what i had been ripping the house down for. it was a bulletin from gopher engine rebuilders based in MN. and it says as follows



87-94 ford 302+351

please be aware of a problem concerning the spark plug wire routing on the above listed engines. the firing order of the 302 is 1-5-4-2-6-3-7-8 because 2 and 4 and 7 and 8 are next to each other in the firing order and in cylinder numbering it is necessary to separate the wires to the OUTSIDE locations of the factory wire loom.


on the 351 the problem cylinders are 1-3 5-6

this notice is in accordance with the ford bulletin #94-10-4, which explains this in more depth, it these procedures are not followed a drivability problem may occur and/or the engine will have extremely high combustion temperatures which can result in more serious internal engine damage such as: preignition, detontaion, scored cylinders, blown head gaskets, damaged valve seats, burnt valves and pounded out rod bearings..........

 

>talking to people i have learned that a exaust leak can
>cause this problem for what reason i can not figure and
>they cant tell for sure but i have found that the cross over
>(from air pump to the back of both heads) had a hole rusted
>in it.


The reason an exhaust leak can cause a problem is because air can actually enter the exhaust. The extra oxygen in the exhaust causes oxygen sensor to signal a lean condition, so EEC responds by richening the mixture. The oxygen sensor cannot provide correct feedback if there is excess oxygen introduced ahead of the sensor.

Yes, it would seem that the exhaust pressure would keep air from entering, but there are pulses in the exhaust stream from each cylinder firing, and air can be sucked in when there is low pressure in between pulses.

 

OK...I have a question. I have an extremely similar problem with my 1994 Ford F-250. A ping or valve knock at mild throttle inputs while in 5th gear going up a mild incline. I have a 460 and recently put on a Force II exhaust system (cat back single exhaust)?

I just purchased a K&N FIPK for it and cannot wait to put it on the truck (Waiting for the weather to clear)
:-staun

 

How can I get hold of that bulletin from both Ford and Gopher Engine Rebuilders?

I REALLY need it. Thanks for your time,

Mike

 

Basically on a 302 make sure that #7 and 8 plug wires never run parallel to each other....have them cross at good angles or keep them far away from each other. #2 and 4 are similar but not quite as close but you still want to have them seperated. What happens is that there can be induction crossfiring between the wires do to magnetic field buildup. I've seen this problem lots after people have just finished tuning up their engines and they made sure the new plug wires looked all pretty being evenly spaced and running nice and parallel to each other.

 

Ford's TSB # is 94-04-10
Not sure where you could look it up but it just says what I said but also gives pictures of how to route the wires.

 

the gopher bulletin is something i got from the company its self i typed it out word for word in a earlier posting hope that helps ya i have moved my wires apart from one another and replaced the cross over and i have not had on lick of trouble there after. good luck