ive been looking around on the forum for alittle bit trying to find anybody who has timed the car alittle different other than the 10 degrees left of center giving it more power.... i couldnt find anything.... does anybody have any insight to this...

Because the Fiero doesn't have a knock sensor, 10 degrees BTDC is used to give maximum performance without detonation under all anticipated load conditions using the lowest grade fuel, 87 octane. That's with a brand new engine. If you're experimenting with advancing the timing on a used engine then you should upgrade to the highest octane fuel you can buy to prevent detonation (ignition of the gases though heat generated by the extra pressure, or an alternate ignition source like red hot carbon in the combustion chamber). No one can tell you the best timing for your engine since no one here knows the condition of your engine. It will be a trial and error process for you by slowly advancing the timing a degree at a time, going for a test drive under heavy load conditions (like bogging the engine in a high gear) and listening for pinging. Keep advancing the ignition until you hear the tell tale sound and then back it off a degree.

hmm i guess ill give that a try than... i do use 93 octane on a 79,000 mile motor...

I always bumped the timing up on my old Mopars for more power & better mileage. Running high octane, I bumped it up until it kicked back starting it, & then backed it off until it quit. Then test drove doing the above (lugging) & if it pinged back off the timing until it quit. Always resulted in better power & mileage. But I've always wondered if it'll work on a Fiero, with the computer adjusting the timing according to load, etc.???
~ Paul
aka "Tha Driver"

This is a very tricky area without proper tools. At a minimum you would need an exhaust temperature gauge and air fuel meter. The problem to start with is that it's very likely you will exceed the maximum benefit of advancing the timing before you actually exceed the limits of the high octane fuel. There is a happy medium where advancing the timing improves performance and then starts to drop off even before you encounter detonation. The object of fuel octane at all times is to run no higher octane than what is needed to keep your engine out of detonation trouble, anymore than that is a waste and in a 2.8L I know first hand the 93 octane will gain you nothing without the proper compression ratio to take advantage of it.

The EGT gauge will give you some idea of what's going on with combution as you increase the timing. Too little advance will cause exhaust temps to climb. Too high an octane fuel will do the same because more of it will still be burning as it enters the exhaust. A baseline egt reading would be helpful before you make changes. A good way to get more power would be to get an extra set of heads, shave about .015" off the deck to increase your compression a little, move up to 89 octane and go. That's a sure thing.

I agree, you realy have to be careful not to get preigniton -knock- when messing with the timing. The best way to fine tune an timing is on a dyno, however if you don't have a very modified engine it's not really worth the cost as the gains won't be much. When I use to race Mopars -back in the 70s before coil pacs etc- I found power-timing to work really good. Whereas; you lock the throttle at around 3.5 - 4.0K rpm and then turn the distributor slowly and lock it in at the spot where the engine revs the highest. That method is not prefect either because the engine has no load on it, but I ran my times that way.

Another time I actually totally agree with Driver I never put a timing light on an old school engine..... and most newer cars cant be timed at all.

quote Originally posted by Francis T: I agree, you realy have to be careful not to get preigniton -knock- when messing with the timing. The best way to fine tune an timing is on a dyno, however if you don't have a very modified engine it's not really worth the cost as the gains won't be much. When I use to race Mopars -back in the 70s before coil pacs etc- I found power-timing to work really good. Whereas; you lock the throttle at around 3.5 - 4.0K rpm and then turn the distributor slowly and lock it in at the spot where the engine revs the highest. That method is not prefect either because the engine has no load on it, but I ran my times that way.

Power timing huh? I thought I was the only one around that remembers that.

Leave the timing light in the tool chest. we also adjusted GM "POINTS" by holding the throttle at 4k and turning the allen key to close the contacts for minimim gap. When she starts to breakup turn the key the other way a quarter turn.

Keeps the dwell meter in the tool chest as well.

Spoon

------------------
Two yeast spent their entire life "about 2 days" discussing what the purpose of life could be and not once did they even come close to the fact that they were making champagne. Quoted by: Unknown

[This message has been edited by Spoon (edited 01-05-2011).]

read up on timing for MBT- sometimes increasing the timing more doesn't help.

I've run mine at 12*
I have gone as far as 14* - but seemed to like 12* the most
there is also the fact that the stamped steel timing scale is not all that accurate. especially at the angle you are seeing it. so - if you wanna go more - do just as Tha Driver above said: kick it up - try it - and adjust as necessary. it is easy enough to do.

quote Originally posted by gmctyphoon1992: hmm i guess ill give that a try than... i do use 93 octane on a 79,000 mile motor...

Just realized that post. You'll very likely get a boost in performance by dropping down to 87 octane. There's no way your engine is burning 93 octane efficiently with its stock compression. Amoco was forced to stop advertising 93 octane as if it would improve the performance of the average vehicle some years ago for that very reason. As engine wear increases compression tends to decline further reducing its ability to effectively compress and ignite higher octane fuel. Not trying to put a damper on your plans, this is factual information. As far as advancing your timing a little as long as it's a little there should be no harm, but as mentioned earlier the effective timing advance is not just how far you can advance it without detonation. You can reach and exceed the most effective advance angle without detonation and start moving performance in the opposite direction. Don't forget, one of the greatest causes of discounted 2.8L Fiero purchases is a rod knock. Advance the timing too much and that's where you maybe headed.

Another reason this is a sticky area for a computer controlled car is that unlike old school engines, computer controlled cars take into account idle air temp and engine temperature when estimating your delivered timing, so what may seem fine at first, may turn out to be a disaster at higher operating temps liking to what you can expect in Florida during the summer.

[This message has been edited by Joseph Upson (edited 01-06-2011).]

quote Originally posted by Pyrthian: there is also the fact that the stamped steel timing scale is not all that accurate. especially at the angle you are seeing it.

Plus the fact that the outer ring (with the timing marks) on the harmonic damper has a tendency to "slip" eventually. So yeah, using a timing light is kind of a hit and miss affair.

I'm also from the old school, and I advance the ignition timing until the engine pings under load (accelerator to the floor in high gear up a hill) and then back it off a hair. Every engine is different, but I run my '86 GT at 14° BTDC. At this setting I get better performance and better gas mileage. However, exhaust emissions are higher at this setting and I have to back it off to 8° to pass the smog test (without a cat).

You can read my experience regarding ignition timing and my last smog test Here. You might be surprised at the results!

[EDIT] Thought I better mention that I always run Regular gas.

[This message has been edited by Patrick (edited 01-06-2011).]

I´m happy to see some intresting threads and questions about ignition timing for the V6. I mean the 2,8 V6 has a very lazy timing curve. The starting point (10 degrees advanced) is one of the questions but even more important is the further timing curve.
How much advance do you get when the rpm is rising and how quickly does it rise. My own experience, before Fiero, come from older Pontiac 455 cid and Chevy smallblock there the ignitiondistributors has vacuumconnection to the manifold and centrifugal-weights to adjust the timingcurve depending on load and rpm.

I have adjust my -86 GT Fiero to around 14 degrees. The Idle RPM will rise of course but no more than 1200 rpm. The respons from throttle is much better and on the road you get a heavier punch from lower RPM and more lively caracter when you drive in the upper RPM region.

BUT there is more to do, if you could adjust, not only the ground setting at idle, but also the timingcurve further upper rpm. But with the original Fiero ECM is that impossible -as other answers has indicate.
I asked Hypertech about the ignitioncurve in theres computerchips for the Fiero. I get a very friendly answer but no verification of the timing parameters.

I will say the 2.8 V6 in the Pontiac-version should respons very good with a much more aggresive ignitioncurve than the original. One option is to change the original distributor to another aftermarket elcectronic distributor with direct adjustable vacum- and RPM influence. Whith a solution like that you must "cheat" the distributor that the Ignition ECM has no failure, but that is quite possilble.

Around the octane- question; I live in Sweden and the lowest Ocanenumbers i 95 and we have also 98 octan petrol. But my impression is that the 2,8 V6 is not a "pinging/knocking" - engine

quote Originally posted by firre871: The Idle RPM will rise of course but no more than 1200 rpm.

I've found that the IAC valve compensates for the increased idle speed (due to the advanced ignition timing) and still brings the idle speed back down to 900 RPM (when the engine is up to proper operating temperature).

ok so i should use 87 octane than... im so used to running high compression engines and turbo engines i didnt realize what you said earlier but it makes alot of sense... it is true tho when i first started my car after rebuilding the distributor the idle was higher and the car seemed like it had a quicker throttle response.. i checked the timing and it was way off like 14 or 15 degrees left of top dead center.. i timed it to 10 degrees and the car has much less throttle response now and feels less torquey..

quote Originally posted by firre871: I´m happy to see some intresting threads and questions about ignition timing for the V6. I mean the 2,8 V6 has a very lazy timing curve. The starting point (10 degrees advanced) is one of the questions but even more important is the further timing curve. How much advance do you get when the rpm is rising and how quickly does it rise. My own experience, before Fiero, come from older Pontiac 455 cid and Chevy smallblock there the ignitiondistributors has vacuumconnection to the manifold and centrifugal-weights to adjust the timingcurve depending on load and rpm. I have adjust my -86 GT Fiero to around 14 degrees. The Idle RPM will rise of course but no more than 1200 rpm. The respons from throttle is much better and on the road you get a heavier punch from lower RPM and more lively caracter when you drive in the upper RPM region. BUT there is more to do, if you could adjust, not only the ground setting at idle, but also the timingcurve further upper rpm. But with the original Fiero ECM is that impossible -as other answers has indicate. I asked Hypertech about the ignitioncurve in theres computerchips for the Fiero. I get a very friendly answer but no verification of the timing parameters. I will say the 2.8 V6 in the Pontiac-version should respons very good with a much more aggresive ignitioncurve than the original. One option is to change the original distributor to another aftermarket elcectronic distributor with direct adjustable vacum- and RPM influence. Whith a solution like that you must "cheat" the distributor that the Ignition ECM has no failure, but that is quite possilble. Around the octane- question; I live in Sweden and the lowest Ocanenumbers i 95 and we have also 98 octan petrol. But my impression is that the 2,8 V6 is not a "pinging/knocking" - engine

The timing curve is not lazy, the last time I looked at it if I recall correctly there are areas with as much as 42 degrees of advance programmed in the spark table. Is the quicker throttle response because of the additional advance or because you're accelerating from a higher than normal idle rpm. Regardless cruising around in stop and go traffic with as much as 300 or more rpm than necessary at idle can't be good for your mileage. That's one of the benefits of a heavy flywheel, being able to idle at a low rpm and one of the reasons manufacturers use them paricularly on cars you'd think would have a lighter flywheel like the corvette and G6 GTP. None the less every little bit helps, if it makes you feel faster I guess it's worth giving a try.

well it feels alittle sluggish though right now somewhat because my idle is very low... but i am pulling code 22 TPS low voltage so that could be part of this issue on idle.. idk im just gonna fool with the timing abit and see what i come up with...

quote Originally posted by gmctyphoon1992: well it feels alittle sluggish though right now somewhat because my idle is very low... but i am pulling code 22 TPS low voltage so that could be part of this issue on idle.. idk im just gonna fool with the timing abit and see what i come up with...

Fix your code first, a malfunctioning TPS sensor will definately affect your acceleration as well as driveability as a whole. The ECM uses it to determine your pump shot, throttle position and rate of oppening the throttle. I got water in one and it made driving the car a bear, high idle, low idle, stalling, abrupt acceleration and deceleration.

Yes the ECM try to compansate the idle rpm via the IAC. But there is a limit ( have anyone investigate this) . But therre is no problem with 14 degrees advance even with cooler engine.

I still mean that the timingcurve a lazy. But not in the meaning af the maxinal advance in the highest rpm. "Lazy" is more a question of how fast the advance will be rising. And that means respons under driving circumstances.
Do any of you, in this ( I really mean) outstanding forum seen a verfication in the riming curve of the original Fiero V6 from idle to maximal rpm.

The ECM can adjust the idle in stock form from about 500 rpm to about 3000 rpm. Because the IAC is a stepper motor it can make those adjustments from limit to limit with no problem. I doubt the ECM is programmed not to use it's full range to attempt to obtain the target idle speed.

The evidence I have is anecdotal but I think will stand none the less. The chip burners have said there is little to no power to be gained with THEIR altered chips. Along with mixture, I am sure they have played with advance. Therefore the way I see it, the stock advance curve is fairly decent. The other anecdotal evidence is that the people running 7730 ECM's with accelerated advance tables buffered by knock sensors see little performance gains. Again this points to the idea that there is little to be gained by altering the advance from stock.

I really think what is happening is a case of "Thread Think".

Here is what I think might be the key.

quote gmctyphoon1992 I checked the timing and it was way off like 14 or 15 degrees left of top dead center.. i timed it to 10 degrees and the car has much less throttle response now and feels less torquey..

So gmctyphoon1992 retarded his timing 5* because it was 'off' and now the engine has low power.

Patrick hinted at what I think in his thread

quote ...plus the fact that the outer ring (with the timing marks) on the harmonic damper has a tendency to "slip" eventually. So yeah, using a timing light is kind of a hit and miss affair...

To me it really sounds like gmctyphoon1992 has a slipped balancer ring and is now 5 degrees retarded from where he should be.

Anyone thought about advancing or retarding the cam itself?

quote Originally posted by phonedawgz: ..........

Back so soon?

quote Originally posted by Jackdaniels: Back so soon?

I'm not sure if the balancer ring can come all the way off, but if it can I felt the need to say something before someone got hurt.

quote Originally posted by phonedawgz: To me it really sounds like gmctyphoon1992 has a slipped balancer ring and is now 5 degrees retarded from where he should be.

Anything is possible, but more likely he returned the timing to the proper setting and started experiencing the side effects of running 93 octane fuel on a low compression motor. It would have afforded him the ability to over advance a bit without problems and make the car feel normal. It's kind of like an offsetting penalty, advance one degree above optimum and go up one octane rating, no problem, do that "walk" for 5 degrees and 5 octane points then drop 5 degrees on the same premium fuel and you experience what I experienced when I put 93 octane in my 2.8L Firebird, an immediate sensation of loss of power and in my case a hotter running engine. I never did it again.

It's not a good idea to suspect the balancer or timing before the TPS code is addresssed.

one thing... how do you know it has slipped? take it to compression one and see if it is a the 10 degree mark or not? i dont think it has slipped too badly because the idle isnt too low and still runs fine it just isnt as responsive as before which makes sense... honestly im better off timing it by ear anyways since i can do that best... i just figured since im not such a computer controlled engine tech and more used to mechanically driven engines with carbs and mechanical fuel injection that i should listen to what the manual says.. but good thing on the 93 octane it makes sense..i always just thought the hotter the burn the more efficient and more power... but your right compression has to be at a higher rate for a better burn.. by the way what is the compression of these motors 7:1? 8:1?

[This message has been edited by gmctyphoon1992 (edited 01-08-2011).]

To see if the ring has slipped compare yours to this picture. You will need to take the pulley off to do so.


Note how the X of the center web lines up with 4 of the 12 holes in the outer ring. Also note the key way of the crank lines up with the X. This pic shows the balancer in the correct position. Now if you were to turn that engine slightly clockwise so the keyway would line up with tube thing right next to the timeing tab, you would also find that the timing indicator lines up exactly with the timing grove at 0* tdc.

if your ring is 5 degrees retarded then the 12 holes would be slightly skewed back by an amount equal to the skew between the keyway and the existing timing grove in this pic. So if the 4 holes were skewed back then the apparent position of the grove would be even more back compared to the keyway. If you are not sure, take a straight on pic of the balancer and post it on here.

Also check to see if the outer ring is moving in or out. Surely if you see the ring has moved and is about to fall off, then your balancer needs to be replaced and is dangerous.
--
8.9 : 1 Compression Ratio
---
I really didn't follow the explanation given reguarding octane rating. Here is what wikipedia says about octane ratings of fuel.

quote Octane rating does not relate to the energy content of the fuel. It is only a measure of the fuel's tendency to burn in a controlled manner

http://en.wikipedia.org/wiki/Octane_rating
---

quote i dont think it has slipped too badly because the idle isnt too low

Remember the ECM will adjust the IAC, Idle Air Control, to adjust the idle speed to it's target of 900 rpm. So advancing the timing or retarding it won't change the idle speed, as long as the engine is still running and the ECM can still adjust the idle speed.
---
You did jumper A-B when you set the timing right? The SES light was flashing during the time you were setting the timing right?

If not, you are about 10* retarded. When people leave out putting the jumper in from A-B they find that the power is way off after adjusting the timing.

[This message has been edited by phonedawgz (edited 01-08-2011).]

It's not the energy of the fuel, it's the rate of burn and the ability to extract the energy, higher octane = slower burn (that's the control), add more compression to speed it back up and get the benefit of the higher compression. If the air fuel mixture does not completely burn/combust before the exhaust valve opens, you don't get the full force of combustion, hince the hotter exhaust system due to fuel burning in it.

Part of the combustion process involves the compression prior to ignition. If you don't have enough of it the air fuel mix might not ignite at all. You loose combustion energy, mileage and emissions go up. We all are pretty much aware of the fact that the gasoline laced with ethanol produces less miles per gallon in our cars than pure gasoline and that ethanol increases the effective octane rating. We've also come to see how the industry is taking advantage of that by producing cars with higher compression ratios for example my engine with 9.8:1 compression and an 87 octane rating or even better the 3.6 DOHC non direct injected with 10.2:1 compression and an 87 octane rating.

If you have 18 inches of vacuum at idle or a little better, chances are pretty good your timing is correct as that's another method you can use to set timing. Although it's plausible I would not suspect the balancer before correcting the code and running 87 octane.

Good catch on asking if the proper timing proceedure is being used.

[This message has been edited by Joseph Upson (edited 01-08-2011).]

I disagree with the statement that "Higher octane fuel will cause the stock 2.8 to get worse gas mileage"

Any chance you have qualified references to back it up?

To state the air fuel mixture does not completely burn/combust before the exhaust valve opens" makes me wonder at what RPM? Surely if this is significantly happening at 2,000 RPM, it would imply the engine would barely run at 5,000 RPM.
-----

I don't see any advantage of running high octane fuel in the 2.8, but I also see no disadvantage of it other than cost.

yeah i jumped the A and B jumpers and the light flashed... the distributor has been rebuilt and put back in correctly and timed from what i know correctly(if the balancer hasent slipped)... yeah i need to fix that code 22 TPS low voltage...

quote Originally posted by phonedawgz: I don't see any advantage of running high octane fuel in the 2.8, but I also see no disadvantage of it other than cost.

Obviously you've never had an engine knock or pre-detonate before (at least that you were aware of). Higher octane fuel lessens the likelihood of these conditions for a given ignition timing. Conversely, higher octane fuel allows further advancement of ignition timing without causing these conditions. So the advantage becomes clear if you start playing with your timing (which is directly related to the OP's original question), or if you've got an older engine with glowing carbon deposits in the cylinder head.

I used 87/89 octane in my 3.1 turbo high performance engine with no problem at all. I was always told, even by my engine builder (Nascar engine builder) that turbo engines have less compression and dont need high octane gas....it was just a waste of money. Mine had right around 300 hp on regular.