after i replaced my ignition module on my '91 f-250 5.0 manual transmission with thick film integrated ignition i have noticed that it pings when the engine is loaded. tomorrow i am going to change the timing on the distributor. i do not have a timing lite or any timing marks on my balacer, and have never checked timing before. which way (looking down) and how many degrees should i turn the disributor?

for what it is worth, the engine idles at about 1250 rpm. also when i take my foot off of the gas going down a hill the engine holds the vehicle back like the breaks are on. the check engine lite is on because i broke the air temperature sensor (located next to thermostat).

to set the timing do i loosen the bolt that holds the distributor to the block and turn the distributor?

 

Yes, you'll want to turn the distributor counterclockwise looking down on it. It shouldn't take much, but go about a degree or two at a time and then test drive it to see if it fixed the pinging. If not, turn it back another degree or so. Have you tried pulling the computer codes to see if anything besides the air temp sensor is throwing a code?

 

Don't forget to disconnect the spout connecter before you make any timing adjustments or the ECU will just adjust for it while you turn the distributer.

 

That air temperature sensor may be why it idles high, or the timing could cause it to idle high if incorrect. You need to replace that sensor (ACT) and then recheck the timing. The timing is suppose to be set with the engine to normal operating temperature and all the sensors working.

 

It shouldn't matter - the EEC has no other timing signal than what the distributor is sending out, so it doesn't know when you move the distributor. Plus, if it's done with the engine off then it won't matter anyway.