All about Timing - Correcting and Adjusting your 258's Spark Advance.

[@stephenburke9909]

Awesome video my friend. I'll be driving the Eagle down in the next few months and we'll have to test my car. I just want to see the results on the ol dot matrix printed paper for nostalgic reasons :) What an awesome piece of equipment to have laying around hehe

[@rplace8737]

I love the car. That's a lot of steps to set timing on an engine. With the bulletin, though, the process was more inline with what one would expect for engines of that vintage. I suppose that smaller "modern" engines required timing to be set in or near the power band of the engine. In the "olden" days, we just plugged the ignition advance vacuum hose and set the timing at idle. Great channel, by the way....I am subbed!

[@CelGenStudios]

In my '92 Tracker you warmed it up, jumpered two pins and then set the timing from there. No vacuum advance.

[@olik136]

that is way more complicated than I would have thought. My 60s Volvo has no vacuum stuff at all- all you do is turn the distributor until the engine runs best (which is very easy to hear) and that is it. You can check the markings with a light gun- but it won't get you any closer.

[@ReaperRestorations]

i'm having the same issue on my '85 and another issue with the sol-vac unit not responding to loads on the charging system, AC, etc. its like it's not receiving the tach signal. it doesn't bump the rpms up no matter what adjustments i make. i've followed the procedures in the manual, but for the timing there seems to be several versions of how to set it properly

[@CelGenStudios]

Verify that the diode module (black box usually next to the wiper motor and combines the AC, defroster, headlight and computer signals to a single wire for the solenoid wire without backfeeding) isn't damaged.

[@ReaperRestorations]

@@CelGenStudios interesting. would that also affect the tach feed to the computer (or vice versa)? i got an Eagle tach gauge cluster off ebay but when i hook up the tach it doesn't work. could be a faulty unit, or could confirm that i have no signal (which would make sense). ill be checking that box to see what the deal is

[@CelGenStudios]

In '82 the distributor reluctor goes straight to the Duraspark and then out again as the TACH signal for the computer, the optional tachometer and the negative post on the ignition coil. Starting in 1983 they added a knock sensor and upgraded the computer to handle it, but now the reluctor goes straight to the computer, the computer can then directly retard spark timing by itself and then goes to the Duraspark module which then gives you the TACH signal for the optional tachometer and the negative post on the ignition coil. In both cases the TACH signal will be a dark green wire. If the computer detects an erratic or low RPM (and it can only do so using the distributor reluctor) it will use the SOL-VAC to try and kick up the idle using the Idle Speed Relay. It, the AC, the defrosters and the headlights all pass through mentioned set of diodes to prevent backfeeding but any one of those being turned on should get you battery voltage exiting the diode module.

[@ReaperRestorations]

@@CelGenStudios is there any way to get a pdf of the TSM service bulletin? i bought the manual, but i dont think it included it.

[@CelGenStudios]

@@ReaperRestorations Look in the video description for an archive.org link. That will take you directly to the bulletin.

[@compu85]

So did it drive better??

[@CelGenStudios]

Yes and no. Yes in that I could accelerate and get up to highway speeds far faster than previously and it was considerably more responsive taking off at a light or stop sign, HOWEVER it became considerably harder to maintain a stable curb idle on a hot soaked engine. Occasionally it would simply stumble and stall. I didn't mention this in the video as there's some instructions that through the Internet are inconsistently described and I have not fully tested enough to be confident talking about in a video, so follow the suggestion below with caution. Two things that you need to factor into timing adjustments, prior to adjusting your idles: -On an average day/week/month/year of driving the car, How many thousands of feet are you above sea level? Your timing will change by half a degree for every 1000 feet. Eventually for AMC/Jeeps you exceed 5000 feet and there is a physical jumper and alternate timing spec you need to pay attention to. Modern vehicles can compensate for altitude using the MAP/MAF Sensor. -Do you use Ethanol blended (Regular) gas? Ethanol blends like to more readily vapor lock and less readily ignite (at lower cylinder compression) than gas did 40 years ago. That will also affect your timing by a degree or two. After this video the vehicle was test driven and the above symptoms were noted. The timing was dialed back to 12.5 degrees BTDC which resulted in an engine that both accelerated good (this isn't a racecar, so 0 to 60 in 15 seconds is already "better than average" for an Eagle) and could handle a curb idle.

[@computeraidedworld1148]

How comes the vacuum hoses need to be plugged?

[@CelGenStudios]

Open hoses result in vacuum leaks. Vacuum leaks mess with the engine while you are trying to make adjustments.

[@computeraidedworld1148]

@@CelGenStudios oh, yeah duh

[@DandyDon1]

Read The FRIENDLY Manual. :o)

[@DandyDon1]

How will these adjustments effect your SMOG test?

[@SkoddieAltair]

Having any part of setting the timing involve putting the car in drive and opening the throttle is just feral. I guess the wear on the transmission is minimal given that this happens for a fraction of its life, but everything about putting load on the torque converter while not moving hurts. I guess that's the point for setting the idle though? 🫠

[@compu85]

That doesn't wear the transmission at all. If you raise the rpm first then slam into gear that's bad, but going into gear first then raising rpm just warms the fluid some.