Apparently I don't know how to use the search function correctly. I must have used a 1/2 dozen different phrase's and I either get a thousand different hits or virtually none. So does anyone know what the correct timing is for the 3.4 I swaped for the 2.8 or what works the best. We never used a light when we did the swap, just set it by ear. You can tell it's off a little, the starter drags a little sometimes, especially when it gets warm and you restart it. It still idles a bit high and I hope this will help that too.

You can't properly set timing on these unless you disable the ESC (Electronic Spark Control). The ESC wire is in the center console, typically under the removeable tray in the front. It's the only single wire in there with an inline connector.

Once you disable the ESC by disconnecting this wire from itself, you'll get a Check Engine lite and the ECM will throw a trouble code for ESC. No worry, when you're done you reconnect the wire and the trouble lite will go away. The code will reside in the ECM for a certain amount of restarts until it clears out.

With the wire unplugged, set max spark advance to around 13 deg BTDC. This'll give the motor a bit more response than the stock setting of 10 deg BTDC. If you find you get more than a trace amount of pinging at 13, dial it back a bit.

Note: adjusting timing by ear on vehicles with an electronic spark control circuit is almost useless. You can't even tell what the timing setting is on a Trooper with 60 deg V6 unless you disable ESC.

I expect you'll find she runs much better after making the adjustment!

HTH............ed <img src="/forums/images/graemlins/kewl.gif" alt="" />

The "correct" timing is now not published because the engine is no longer stock. when I did my 3.4, I hooked up a scan tool and watched the data list while I drove it. Look at knock sensor activity, set the timing so that the knock sensor only retards the timing under low speed high load conditions. Basically you want as much spark advance as you can without pinging or detonation. also use your fuel economy as a guide. As you approach the ideal timing advance your fuel economy gets better until it is too advanced where it drops significantly. The Knock sensor will of course hide this to a degree by retarding the timing in over advanced situations.

Most people don't have a scan tool. What did you come up with as an optimal spark advance setting?

Hey Ed, have you found the sweet spot for timing yet on the 3.4's? Also I am curious about timing by ear. So if I disconnect the wire and time it by ear what am I looking for? Just for the engine to appear to be running good (higher rpm, no sputtering) without ping?

I guess you could try it and see what you end up with. The old "timing by ear" works OK with Small Block Chevy's but not sure it's effective on motors with ESC.

Mine does have trace pinging under load at 13 deg so somewhere between the stock setting of 10 deg and 13 is probably a happy medium.

Perhaps HondaGuy could share with us what his optimum setting was after checking with a scantool.

I noticed when I was changing my timing the other day that when I disconnected the ESC (Electronic Spark Control) wire located in the center console that the engine seemed to idle better (more consistent sounding and higher rpm with no sputtering). I was curious what is bypassed when you disconnect this wire? I was thinking there still might be some sensor that is sending the ecu wrong data that could be affecting the idle. Maybe TPS??

Ed also mentioned a sensor that I was curious about on another thread:

"I bolted mine to the block, using the screw which holds the (now useless and only filling a hole) cam position sensor (under the exhaust man on pssgr side and best accessed in the vehicle by going thru the pssgr's wheelwell)."

I looked and it appears that I do have a wire hooked into a sensor in that location. I was assuming it was a knock sensor, but now I'm not sure.

Funny, mine always runs slower and a bit rougher with the ESC wire unplugged!

My old post referred to attaching the large bundle of ECM ground wires. On the 2.8 block, there's a specific place for the wires to bolt to. On the 3.4 the bolt hole is not present, but the crank sensor does go in the side of the block at approx the same place. So, after scratching my head for a while I decided that the bolt holding in the sensor would do just fine as a grounding point! Works great.

Note that if this doesn't sound familiar to you, there may be, laying loose somewhere in the pssgr side, a big bundle of wires all ending in one large "ring" or "lug" which must be grounded directly to the engine. If this bundle of wires isn't grounded, it messes up all kinds of stuff with the computer. And if I recall, may also serve as a ground point for the ESC system.

On the knock sensor, the 3.4 had one in the forward, upper side of the pssgr block. The 2.8's sensor was located aft, and lower down. Both holes are present on the 3.4, the one not used is plugged. I just moved the sensor to the aft lower hole and plugged the former sensor location with the plug removed from the aft hole.

At any rate, the difference between the ECM ground bundle and the single wire that plugs into the knock sensor should be obvious. If that wire bundle isn't grounded, it could explain your engine's strange behavior.

Maybe a fishing expedition is in order!

Thanks ed, I'll take a look tomorrow. I do remeber having a large group of grounding wires but they are located near the top of my engine on the drivers side of my rotor. I have them all grounded to a valve cover bolt. I wonder if maybe my wiring harness is tweaked a bit and rotated more around my engine then yours. In any case the ground wire from the engine to the body (using a bolt on the wiper motor plate) is also right near where my group of wires are. I think I will add an extra large wire and make sure it's grounded good.