Set timing w/which wire

[Bucky1]

OK. Dumb one. Checking my timing on 90' p30 TBI. Start up, unplug wire, hear rpm fall, check timing on #1 wire. Can't fing the mark, anywhere that I can see from under motorhome. I painted the mark and tried again, no way. Do you use a different plug wire to check timing on these?

[Bucky1]

OK. Dumb one. Checking my timing on 90' p30 TBI. Start up, unplug wire, hear rpm fall, check timing on #1 wire. Can't fing the mark, anywhere that I can see from under motorhome. I painted the mark and tried again, no way. Do you use a different plug wire to check timing on these?

[YosemiteBobR]

Isn't your timing controlled by the engine computer?

[Bucky1]

Yes, but you still have to give it the baseline with the computer unhooked I believe.

[YosemiteBobR]

I guess we still learn, that is one on me. Perhaps someone else will chime in soon

[Bucky1]

I was checking it because it has never once pinged, so a dragracer takes that as "not enough timing". It has Thorley headers and a flowmaster and a K&N for what that is worth. I checked without computer, and it was about 9 degrees, which suprised me. It didn't stop me from adding 2 degrees anyhow. I will test it before our next trip, and I always have tools to set it back.
Thanks for the help...Oh..It was #5.
When I restarted with the computer hooked up, the rpm were up again and the timing was up above the chart. I think that is normal. Anyone else with experience on how much is good for base timing with a few mods?

[Mutha]

Bucky1, With your engine cold, remove your #1 spark plug. Place your thumb over the spark plug hole or use a compression gauge and jog the starter until you begin getting compression. Your #1 cylinder is now coming up to the firing position. Use a short piece of wire ( 6" piece of coat hanger wire) and hold it on top of the piston while turning the engine balancer with a socket on a break-over bar or by using your fan belt if it is tight enough to turn the engine, until you feel the upward piston movement stop and start to reverse direction - YOU ARE NOW AT TOP DEAD CENTER in the FIRING cycle on #1. Now look at your balancer and see where your timing mark on it is in relation to the timing mark metal degree tab. If the distributor has been installed correctly your balancer timing mark should be lined up (or very close to lined up) with the "0" degree mark on the metal timing degree tab.

If your balancer mark is not anywhere near the Metal Degree Tab, it may be that your balancer has been replaced with a incorrect balancer or your Distributor has been put in 180 degrees off. If your engine seems to run good where your timing is presently set, and you just want to check the timing, then remove the rest of your spark plugs and find which other cylinder(s) are also at TOP DEAD CENTER and try your timing light on that(those) other cylinder(s) until you can see your Balancer mark lining up with your Metal Degree Tab.

Good luck - Glenn

[Bucky1]

I get what you are saying..I do that all the time on the engine stand. In a motorhome is a little tougher. Plus, if the standard on these chassis is #5, wouldn't I check the #5 plug instead? A very good idea I think.

[Mutha]

Bucky1, as far as I know ALL engines time from the #1 cylinder from the factory.

Glenn

[Bucky1]

That's really what I thought until this experience. I can't see the mark at all using #1, and it wouldn't run if it was that far off. #5 at lease got me on the scale. It runs ok, just could run a little better.
I really scratched my head when #1 didn't work.

[JimElliott]

Well good luck trying to find the timing mark from #1, You cannot see it cuz the fan shroud and other items are in the way.

IF and thats a big IF the other timing tab is at the drivers side (4:30 position) just hook up your timing lite to #5 plug wire and your good to go.........

Establish the base timing before anything is moved and a tan/black wire MUST be removed (at the distributer) so the ignition will follow the distributer movement.

Jim

[Bucky1]

Just reporting back: It seemed to really like the extra 2 degrees (11 now base). No trailer, but my test drive proved no pinging no matter what I did. It drove more effortlessly for sure.

[tech@brazelsrv]

Bucky1,
You may be missing a step in checking your timing, you must time it off #1 but you must also disconnect the SET TIMING connector (tan/black wire) located in harness close to distributor. This will disable computer control and allow you to time it at base. DO NOT disconnect 4 wire connector at distributor.Tighten hold down and recheck the timing. Stop the engine and connect SET TIMING connector. Clear ECM trouble code by disconnecting ECM power source.

[Bucky1]

I did do everything but clear ECM trouble code. I'm not sure that I know where the light (check engine) is on this unit. I guess it would be safe to assume that I did trip the code when I disconnected the computer wire. Everything else was in the correct order that you mentioned. Except: It had to be timed off of #5. #1 had the marker no where in the area from under the motorhome. Is this not correct? All looked reasonable after I started using #5. I even looked after reconnecting and starting it up. It was well off the scale then, but within view. Thank you Steve. Let me know if I am goofing here.