TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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I feel kind of stupid for asking such a simple question, but how to you advance the timing in an engine? All I know is that it requires turning the distributor or somethin. Could someone explain how to do it and what I need. I have also seen MSD units that allow you to change the timing by just a knob on a box hooked to the igntion system. Does anyone know how this works? Thanks!
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'83 Firebird 2.8
'89 Firebird Formula 350
Red/grey, t-tops, and a 3.27:1 rear
K&N, TB bypass, no MAF screens, CAI, full Accel ignition, no cats, Hooker Supercomp shorties, Hooker 3-inch catback
No real ET yet...
Changing to timing is done by loosening the distributor hold down and turning the distributor. In this case cw advances the timing and ccw retards the timing. You need a timing light to check your timing. The msd unit you have seen is known as a dial back which means the you don't need timing tape or need to look at the timing tabe. They are super dope but the are of course more expensive than a non dialback unit. Snap on sells a sweet on for ~$250. if you have problems reaching the holddown bolt they sell a tool for that too.
In order to check and set the timming you have to disconnect the {EST}. It is the single wire connector next to your distributor. It is a tan wire with a black stripe. Set your timming to 6 degrees then plug the connector back together and you are done. The computor will do the rest.
don't adjust your timing,
a. you probably wont notice a difference
b. your cars gonna run a lot hotter
c. it screws with the ECM
d. you hafta run more octane
e. it may backfire/run bad
f. you may not pass emissions
for older non ECM controlled motors its a great idea and a good free mod, but since the computer pretty much "learns" and "knows" how you drive it does a good job of adjusting fuel curves and timing to fit your needs. adjusting a computer controlled motor is more of a nuisance than a potential power gain.
FWIW, it sure wouldn't hurt to check the timing. I read in Hot Rod(April 200) that not all TPI cars came with timing set correctly. When I got my car, it ran at 6* with the est connected, but you could see it wander. With the est disconnected, it ran steady at 0* . Advanced to 6*, the car ran better and my intermittent MAF ses went away. Go figure.
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88 Formula 350
[This message has been edited by DMan (edited April 29, 2001).]
<font face="Verdana, Arial" size="2">don't adjust your timing,
a. you probably wont notice a difference
b. your cars gonna run a lot hotter
c. it screws with the ECM
d. you hafta run more octane
e. it may backfire/run bad
f. you may not pass emissions
for older non ECM controlled motors its a great idea and a good free mod, but since the computer pretty much "learns" and "knows" how you drive it does a good job of adjusting fuel curves and timing to fit your needs. adjusting a computer controlled motor is more of a nuisance than a potential power gain</font>
a. The car really cant get any slower, Ive got nothing to lose
b. Ever felt the engine bay of a header-equiped 350? Im used to the heat
c. You may have a point
d. I only run 91 or 92, otherwise *gasp* the car doesnt run right
e. It already does backfire, alot of the fuel isnt gettin burned and it goes out into the exhaust, advancing the timing should allow the fuel to burn more completely
f. I dont have emissions
Sorry to sound sarcastic and I really appreciate the suggestion, but this car runs like sh*t and I am willing to do anything to make it even a bit better.
<font face="Verdana, Arial" size="2">Originally posted by MouseCamaro305: don't adjust your timing,
a. you probably wont notice a difference
b. your cars gonna run a lot hotter
c. it screws with the ECM
d. you hafta run more octane
e. it may backfire/run bad
f. you may not pass emissions
for older non ECM controlled motors its a great idea and a good free mod, but since the computer pretty much "learns" and "knows" how you drive it does a good job of adjusting fuel curves and timing to fit your needs. adjusting a computer controlled motor is more of a nuisance than a potential power gain.</font>
[list=a][*]You probably WILL notice a difference. I know alot of 3rd genners that have gained a tenth or two from advancing your timing[*]A few degrees of advance, no. If your cooling system sucks, and is already overheating, maybe.[*]The ECM has no clue. It was programmed thinking timing is set @ what the emission label says (usually 0*). If you add 6*, the ECM has no clue, and it won't effect it.[*]Depends on how much you advance it. A few degrees, probably not. Ten degrees, definatly.[*]Only if you advance it by like 20* or your engine is in very poor condition.[*]Not necassarily, hell, it may even help pass. The ECM does have the ability to "learn" and adjust fuel via the Fuel Trim Cells (Block learn and Integrator) but there is NO "learning" of spark. Whats programmed is what it runs unless it senses detonation, then it retards, and once the detonation is gone, it puts the spark right back untill it detonates again.[/list=a]
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In order to check and set the timming you have to disconnect the {EST}. It is the single wire connector next to your distributor. It is a tan wire with a black stripe. Set your timming to 6 degrees then plug the connector back together and you are done. The computor will do the rest.
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Lossen the bolt on the dist then disconnect the EST.start the car point the timming light at the balancer and the timming pointer.Turn the dist until the line on your balancer lines up on 6 degrees.tighten the dist bolt down. Double check the timming is correct, somtimes it will move when you tighten it.Hook the EST back up and you are done.It is good to check your timming every time you do a tune up.
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406
accel supper ram
6000 rpm Hyd roller cam
afr heads
t-56 trans
9" ME rearend
The timing like is an inductor light that runs off of the electricity in the spark plug wires. You need to connect the timing light to the #1 cylinder plug wire as close as possible to the plug.
As the engine runs and sends electricity to the #1 plug, the timing light will light up. Pointing the timing light to the timing marks as it flashes at the same frequency at which the engine is turning will cause the timing marks to look like they are standing still. You need to move the distributor in such a way that the timing mark on the crank points to the timing mark that is specified under your hood.
For starters you should just get a timing light and see if you can get a reading of your engine timing. Once you have confirmed you can do that properly, then you can worry about adjusting your timing.
where is the timing pointer? And what am i looking to see happen with the timing light? I'm lost. Can someone dumb this down for me? i'm an idiot. lol
The timing light is like a strobe light that is activated by a little pickup that clamps around the #1 spark plug wire. The balancer is set to be in a certain position when the number 1 cylinder is at top dead center, and the balancer has a mark on it that lines up with a tab at exactly that spot. So when you put the pickup around the #1 plug wire and it senses that there is a spark going through the wire, it tells the strobe-ish kind of light in your timing light to light up.
The effect is like a strobe light, so it looks basically like your running engine's balancer is effectively sitting still in a certain position. (It may wander slightly from that but you'll see what I'm talking about)
If you by any chance have never dealt with or seen a strobe light, if a strobe light flashes at the same frequency at which something is rotating, then the exagerration of the flash will make it look like it's completely still to the naked eye, because you see it much more clearly when there's a bright light on it than when you don't. Since the number 1 plug wire gives it the signal to flash, it's always going to match the RPM's of your engine, and therefore the balancer will look like it's sitting relatively still so you can observe where the timing is set.
The key is to note the position of the identifying mark on the balancer relative to the timing tab.
Just to help you out I went and took some pics of mine so you'll know what I'm talking about:
Remember, this isnt a stock engine, so my setup is different from yours. My balancer has little hash marks on it so you can see the timing throughout a wholer ange. The metal jagged tab has numbers inset on it indicating degrees before and after 0, but I have a hard time seeing them well so I went ahead and marked zero with a sharpie.
If I remember right, the timing on my L03 was under the water pump. You had to look straight down through at it. You dont have an L03 so I dont know what you've got, but you'll see something that is, at least, similar to this, and your balancer will only have one mark on it that tells you were zero degrees is.
It's a lot simpler than it seems. THe positive lead for the gun goes to the battery terminal. The negative to a nice ground (strut tower bolt works for me) and the pickup goes on the #1 plug wire. The light has a trigger that when pulled will activate the strobe, you use that to look at hte balancer. That will tell you the timing.
To adjust it, since you've got an EFI car it shouldn't need to be adjusted anyway, but since you asked Ill run you through it. You'll need a distributor wrench. You can make one, or go buy one. There is a bolt that holds the clamp against the dizzy that is very awkward to get to, hence the wrench. It's just a bent wrench that will allow you get to a bolt under hte distributor.
AFter you disconnect the EST connector, loosen teh hold down a little so that you can turn the distributor, and then as you watch the timing with the light, reach over and turn the distributor just a little bit one way or the other and watch how it affects the timing mark on the balancer.
Take the timing to where you think it needs to go. STock 305 TBi cars are stock at 0 degrees, but I think the TPI cars are stock at 6 degrees. So if you want, see if it's at 6 degrees, if it is, then try maybe 9-12 degrees.
When I advanced my TBI 305 to 6 degrees advanced and put some 93 octane in it, it lugged realy bad when the torque converter engaged. The 2.73s had a lot to do with it Im sure, but it just didnt like it so I dialed it back to zero.
A timing light and distributor wrench are good things to have though.
First of all, those distributor wrenches pictured above are worth their weight in gold!
They're only $5 too.
I recommend putting some "white out" in the timing mark. To do this, turn the bolt on the front of the alternator slowly (give it about 5 seconds after turning 1/4 turn before turning again. It has to pick up the slack while you wait) until you can see the recessed line on the hub below the timing marks. Put a line of white out in that recessed line. Makes it easier to read the timing.
Loosening the distributor bolt, may or may not be easy to get to. It's way down there in the back. In my instance, my coil is mounted over top of it making getting to it even with the distributor wrench tricky. I don't have the stock coil mounting though. So it may be easier for you.
It doesn't take much turning of the distributor to change the timing. Personally I find that the stock 6° works the best. But I have a custom chip made for premium gas.
When I lived in Canada, I could get away with 8° and premium gas. Mid-grade gas would ping..... Now that I'm in Texas, I found that 8° would ping at WOT or when the car got hot (lots of traffic) even with premium.....going back to 6° made everything work without pinging.
Car seems to get better gas mileage with the stock timing, although I haven't actually measured it yet.
Shining a flashlight at the timing marks while at the same time pointing the timing light strobe at it tends to make it a tad easier to read the actual timing number (6°, 8°, 4° etc)
Advancing would be going from 6° to 8° (more performance)
Last edited by Reid Fleming; 05-04-2008 at 03:42 PM.
Reason: Automerged Doublepost
If you have the stock manifolds, hook up the #1 spark plug wire probe when the car is cold. You WILL burn your thumb on the AIR pipe if the car is warmed up. Those AIR tubes warm up faster than anything else in the engine. They'll be hot even if the coolant temp is only 100° (car running for 2 minutes)
You may need to unhook the AIR tube that goes around the back of the engine. I un-did it at the passenger side AIR box and moved it away from the back of the engine to point up towards the hood. Couldn't get the wrench in there with that hose in the way.
Reid Fleming- you said you think it'll get better gas mileage with the stock timing but haven't tested it.
Has anyone tested gas mileage related to timing (stock engines would be most helpful)?