The Silver Buick's 1969 Firebird OHC six project.

[TheSilverBuick]

For the idle, there is settings that when it recognizes it's at idle (via TPS, RPM and MAP (and VSS if wanted) parameters) then it uses separate small 4x4 tables for the fueling and timing. I have my timing locked at 15º and the VE table essentially flat, but a little richer if the rpm's drop (like putting into gear).

This is the idle rpm targeting table, on my Skylark it usually just moves the IAC valve to meet the target, but since I don't have one on this car I've started to delve into the timing modifier (next picture). I think when the Skylark is back on the road I may make use of the next table there too.


Here is the timing modifying table. If it see's the rpm's are higher or lower than the targeted value then it applies the programmed change to the timing to bring it to the targeted rpm (previous picture). Mind you, I haven't fully tuned this table and a reminder that the base timing is currently programmed in as 15º.


According to DieselGeek, OEM's use timing corrections to meet idle rpm targets more than the idle control valves. Something like, slow valve movements and active timing corrections to quickly meet rpm targets, and given my experience with the IAC valves, I can see timing being more consistent and accurate.

[Bob Holmes]

We put together a box with two knob turn-able rheostats. One was to control ignition timing, the other fuel. We could vary idle by as much as 1,000 rpm by just fiddling with the knobs. It was fun to play with.

[TheSilverBuick]

Had in interesting moment today. When I took the car out to get some lunch, I got on the throttle and when I lifted the throttle got hung up! I shut the engine down and pulled over and popped the hood and didn't see anything odd. Messing with the throttle under the hood it was obvious something was keeping the throttle from returning all the way, but what? I was thinking maybe the carb/throttle body was sticking. I fired the engine up and soon as I hit the gas it wouldn't idle down, but it wasn't so bad I couldn't get it home. Got home and was pushing the gas pedal with my hand to see if something was hung up under the dash and sure enough, the carpet was stuck to the pedal. WTF?

Pulled it apart and it appears a previous owner used a nail to hold the gas pedal on..... A nice carpet catcher.




I've removed the nail =P and have done a variety of small things. I glued the fender chrome "air extractors" trim on the fenders using emblem adhesive. Wired up the vacuum pump to the megasquirt to come on above 1500rpm (it's noisy!). I pulled the steering wheel off and re-centered it, and while I was there, I sorted out the turn signal cancel cam/horn piece and now the turn signals cancel themselves when turning. Since I was doing that I figured I'd see if I could get a horn working. The car came with two, but one doesn't work, but the other did so I hooked it up and the horn buttons work on the steering wheel. Winning. The right kick panel was off the car, which makes it kind of cold in the car while driving, so I scrubbed it down and painted it black and left it to dry for the night. Got the neutral safety switch sorted out so it starts in Park reliably. I played with the accel enrichment tune a bit as well. MAP based enrichment tuning is a bit more challenging than TPS based it seems. But I got it so it doesn't backfire when it's at idle and I stomp the pedal to the floor, which is good.

The big thing I tried today was to get the hood tach working. I built this small circuit from the MegaSquirt documentation that should be similar to an MSD Tach adapter, but it doesn't seem to be working. I tried a different relay, I've modified the relay even (pulled a resistor out of it that I think is designed to kill the voltage spike). Pulling out my old school dwell meter with a switch for rpm, it would read the rpm from the MegaSquirt tach output wire, but did not pick up the rpm from the relay connector to the hood tach, so it's definitely not making it through either the transistor or the relay. I'm pretty sure I used a 1k resistor, but it might be worth double checking that it's not a 10k or 100k one, which might over filter the MegaSquirt signal.

[TheSilverBuick]

Oh, and the car seems to nose over before 5,100rpm. My laptop battery died on me before lunch so I did not get a chance to see what rpm it was nosing over at, or if the tune was causing it to nose over. I'll be looking into that tomorrow.

If it's valve springs then I'll set the shift light just below that point.

[NewEnglandRaceFan]

Might want to make up a charger cable to power port(cig lighter) for laptop.. should be cake.. my dell the battery is 11.1volts the ac adapter is 19.3v so the laptop running with it plugged into the cars 12.5-14.3 volts should keep the battery from die'n

[74NovaMan]

Cool stuff! Great progress!

[milner351]

Great stuff Randal - you already have the most technically advanced skylark on the planet - now you will also have the most tech infused 69 firebird on earth as well.

[TheSilverBuick]

Thanks and thanks.

Might want to make up a charger cable to power port(cig lighter) for laptop.. should be cake.. my dell the battery is 11.1volts the ac adapter is 19.3v so the laptop running with it plugged into the cars 12.5-14.3 volts should keep the battery from die'n

On the "to do" list is a power point under the dash on the passenger side near the center console. The right most switch and circuit breaker will control it. Will make it nice for my satellite radio as well, I get tired up plugging and unplugging it. I already have the same set up in my Skylark.

Great stuff Randal - you already have the most technically advanced skylark on the planet - now you will also have the most tech infused 69 firebird on earth as well.

They are high-tech for sure, maybe some day they'll be quick =P

[TheSilverBuick]

Got new tires for the Firebird today. Made a quick burn out video

(Looks like I have a brake light out. Got to check the socket.)

[DanStokes]

Usin' up the old tars?

Dan

[NewEnglandRaceFan]

needs line lock

[STINEY]

I really like the sound of that thing! Quite knarly and seems to be able to back it up to boot!

[TheSilverBuick]

Seems I can get some 4.56 gears for the Skylark's old 8.5 with a GM limited slip for a hair over $100 as well. The only thing wrong with the old axle assembly was one of the axle bearings ate into the axle and a bearing saver was installed. When I was swapping the 4.56 gears onto the 8.2 in the Firebird I tried out the 8.2 axles in the 8.5 rear end and it seemed to match up perfectly. They are the same spline count and length. So I may start cleaning out the 8.5" housing, give it new standard bearings, some 4.56 gears of it's own and switch them out at some point.

[Scott Liggett]

Seems I can get some 4.56 gears for the Skylark's old 8.5 with a GM limited slip for a hair over $100 as well. The only thing wrong with the old axle assembly was one of the axle bearings ate into the axle and a bearing saver was installed. When I was swapping the 4.56 gears onto the 8.2 in the Firebird I tried out the 8.2 axles in the 8.5 rear end and it seemed to match up perfectly. They are the same spline count and length. So I may start cleaning out the 8.5" housing, give it new standard bearings, some 4.56 gears of it's own and switch them out at some point.

That's an interesting development and an inexpensive fix.

[TheSilverBuick]

I picked up some stuff from the parts stores today. I got a universal 14" electric fan as it gets warm just sitting in place and cools off fast moving along so the fan should help. I also picked up a coolant overflow bottle with a pressure cap on it because the water neck is goofed up and the cap doesn't seat very well and it'll blow coolant out the overflow port fairly easily. That should solve the problem until I get a new radiator in a year or two. Comes with a non-pressure rated vented cap for use as a regular overflow bottle later on. Also got some PVC pipe fittings to make a small breather canister for the vacuum pump. Currently it's just venting onto the engine crossmember. Now to put all that stuff on =P I'm a bit concerned about the alternator output, I need to get another high amp alternator. I have a lot of electric gizmo's going on here.


I pulled the 400 emblems off the hood and to humor myself I popped the left scoop out to see where the filter was in relation to it. Maybe I should double up the filters?