Hi,
I'm having a problem with my '88 F150, 5.0L EFI, AOD. The engine "pings" under load. This is most notable when the AOD shifts from 2nd to 3rd and from 3rd to 4th. Also, when trying to accelerate or pass at highway speeds. I've replaced the EGR valve, fuel injectors and muffler.(All were due to be replaced). Did normal transmission fluid/filter change(everything looked okay). Also replaced a rust contaminated fuel tank/pumps last summer. Fiddled with retarding/advancing the timing at the distributor, with no effect. I talked this over with several friends that have experience with Fords. All were stumped until it was discovered on checking the timing that the shop that installed a new water pump, and timing chain a few months back made a mistake. The timing mark on the pulley is about 180 degrees off(you have to point the timing light up from under the truck to see the mark). At this point everybody has an opinion. Now some people I've consulted say it isn't possible for the truck to run if this has happened. Others tell me this could be screwing up my cam timing, which would cause excess pressure which in turn would cause the "pinging". And other people tell me the mark being 180 off just means the pully was put back on upside down, but it's just an inconveinience and wouldn't cause my problem. One friend is convinced they put the chain on with the two gears "a few teeth off". Don't really want to take the truck back to the shop(don't trust them). Any input? Thanks.

 

I think yes they did make a mistake when the did the timing chain job. The mechanic, I'm sure, didn't miss a tooth when he installed the chain,but PROBABLY thought that , like a lot of GM,s , he had to turn the crankshaft one round so the cam turned a half round, bringing the cam dot to the top, and then stab the dist. with rotor pointing to number 1 on the cap. If thats what he did, and he put the plug wires around the cap like fire order says, the engine ain't gonna fire off, but should pop a bunch. When that happened, he realised that he put the dist in 180 degrees off (which actually the cam is 180 off), and just "rewired" the plug wires so that the order on the cap would begin with the #1 wire being on the terminal for #6 and following the order from there on out. Now the motor will run , just that it's "inconvenient" to have you're plug wires on different terminal then they should be. If what I explained is what happened,you placed the timing light on the wire that the cap "said" was #1, but actually leads to #6 cylinder (second left),and you will find that the wire from the #1 cylinder (front right) leads to the terminal on the cap that is right across from the the terminal that has the "1" imprint. The pinging comes from not being able to set the timing accurately, the mark don't show on the scale. Also, being the dist to cam relation is wrong, the computer thinks # 1 is # 6 due to the output from the hall effect type pickup coil.
Phil

 

Golly !...not even a single response besides mine....not even another suggestion on why ? Come on, someone else must have a different opinion...... I'm just curious to find out myself.
Phil

 

 

How about pulling number #1 spark plug out and having someone bump the starter over while someone puts there finger at the #1 sparkplug hole and bring #1 to TDC, you can get it close with the bump start then use a thin blade srcewdriver install it into the #1 sparkplug hole so it meets the top of the piston and turn the crankshaft back and forth until you come up with TDC real close, pull off the cap and see if it is at #1, if it is not, which I suspect it won't be, pull distributor and rotate to make #1 line up at the distributor cap to sparkplug wire, you should be able to time the truck engine correctly now. Also when you go to set the timing on this truck, make sure to pull out the spout connector near the distributor or it will not set base timing correctly. Hope this helps, Electric1