Hello all...

I have an 88 F-150 w/ 302 EFI 102,000 miles

Here is my problem: When I first start the truck, it idles very high for about 1 minute, then it cycles up and down about 3 times, then the idle goes down to normal. Sometimes when I start it warm, it idles way too high and cycles up and down at an almost dangerous level until it evens out.

I spoke to a mechanic about a knocking/pinging that I got when I hit a gradual incline in high gear. He suggested that I rotate the distributor slightly to adjust the timing. I have been doing this but I can't seem to get it exactly right. Could it be possible that the timing chain is stretched a bit and I'll never get it exactly perfect until I replace that? Any techniques for rotating the distributor to get the timing as close as possible?

The truck overall lacks power. I've changed the distributor, plugs, and wires. I've run EFI cleaner also.

Any hints on what I should do? I'm no mechanic (obviously) but I'm not afraid to get my hands dirty. I have access to a shop with basically anything I might need.

Any help would be appreciated.

Thanks in advance!

-RCF Pittsburgh, PA

 

I would go ahead and change the timing chain and gears, couldn't hurt.

I would also test your TPS, I have heard other users complain about the High idle and it turn out to be a bad tps. That can also account for some power loss, because the computer will use different timing/ fuel settings for different TPS signals.

When you moved the dizzy, did you mark its original location? if not you will need to pull the #1 spark plug and turn engine over to TDC. When you feel air rushing out of the hole, your on the combustion stroke. Look at the timing marks on the damper behind the crank pulley. Look on the passenger side of the damper. Rotate the engine 'till the 10 degree mark is lined up with the outside of the scale bolted to the block. ( one side looks like a saw, the other side has only one prong, use that one) Remove dizzy and reinstall it with the rotor pointing to #1 cyl location on the cap (mark this location on the dizzy base to make it easier.) tightnen it down. Now you have a rough estimate of 10 degrees BTDC. Use a timing light to fine tune.

If you wish to advance the timing, while you have the timing lite out, turn the dizzy clock wise a very little bit. set timing to no more than 14 degrees BTDC or you will have detonation. At 14 degrees, you will need to run premium to avoid detonation. 11 or 12 degress, you may be able to get away with running 87 or 89 octane.

 

in order to set the timming you MUST first locate the (spout) connector in the wiring harnnes and unplug it, then crank it up set your timming , lock down the distr. turn off the engine, plug in the spout connector. you can not set the timming any other way the comp. will not allow it. along with TPS, you need to check your IAC (idle air control), your fuel pressure on the rail. test your prssure regulator, a (lean) fuel condition, as well as ignition timming will cause valve rattle(PING),(SPARK KNOCK). Good luck DW

 

Thank you for the info guys...

I'm going to work on it this weekend and I'm going to try and get my hands on a timing light.

Actually I messed with it a little bit last night and it's running quite a bit smoother with more power. I would like to get the timing exactly right though. I need to also invest in some testers...

Thanks again, I really appreciate it.

 

yup, you cant set the timing by hear like the older motors, the comp will try to compensate for it, and it will all come out wrong. DW