Hot start issue... fixed with BAC, but then everything goes nuts (E6k)
 

Don't know what to do here... This is not a priming/fueling issue!
Like many FC's, I have a slightly annoying hot start issue. When the car is warmed up, it starts kicking and almost wants to start. I can save it by ever so slightly touching the gas. Then it's fine and idles fine. I fixed this using my BAC valve by cranking up the "hot opening position" past 90%. The engine started immediately and I didn't have to touch the gas. Then it all went to shit!
The idle would surge and go bonkers I'd have to run and unplug the BAC. If I lower the hot opening position to under 85% or so, it no longer opens and is no longer useful.
I always thought the "hot opening position" was there for cranking, based on the old hitman guide?

I think my haltech is possessed. TPS is calibrated if that matters. I plugged in a spare BAC valve and kept it right in front of me when playing with the laptop. I noticed some very odd behavior. If I rev the engine, the valve opens. Why? I dropped the target idle speed to 600 to specifically not allow the BAC to kick on because my idle is over 900RPM. IT'S STILL OPENING. Why the hell is it trying to raise my idle when my idle is 300RPM higher than the target? I got frustrated and set every position to 0% and... the valve still opens when I press the gas. Now I'm really confused. I even tried other PWM outputs. I seemed to have created some sort of drive by wire using a BAC valve. Maybe I should disconnect my throttle cable. :rolleyes:

I think I'm going to switch the PWM output from BAC to Stall Saver and see if that helps with hot starts.

fuck it! I bought this thing. I'll do it RIGHT with a proper stepper motor. No use in bothering with the primitive BAC anymore. :)
http://www.risingrpm.com/images/500_...iso_engine.jpg

Nice adapter! Good luck with the new setup!

I really want to try one of those..... Sadly I have a Sprint RE. :( All the awesome ECUness without the features of a 10+ yr old EMS.

Well, it still has much better (modern) software and better features (overboost!). Although the limited TWO outputs is pathetic with all those options... If it had at least 4, I would be willing to give up idle control and have a modern computer.

where can i get the stepper motor for that piece?

Autozone, etc.

Tell them you have an 89 Trans Am turbo. See if they even flinch. The connector is a square 4-pin Weatherpack. The pinout is on the Haltech ECU schematic.

for the stepper motor that fits in the rising rpm piece?

yes

Correct. It was used on a ton of GM crap in the 80s. I like telling the parts guy to get me parts for obscure stuff to see if they even flinch when you offer up a low volume model. If they do happen to ask if you have one, you completely blow their mind when you say, "No. It's going on a Mazda RX-7."

The 89 TAt also uses the GM 3 bar MAP sensor and the 3/8" NPT coolant and air temp sensors.

I bought my valve on summitracing for 34 dollars or so. They are still somewhat pricey I suppose...
The E6k pinout (wiring diagram) just had 4 inline wires labeled Idle1 thru 4, A thru D. It is NO HELP.

The idle valve is SQUARE. It's up to you to figure out which wire goes to what on the GM valve. I searched around online and was able to figure it out. It is NOT pin A from the haltech to Pin A on the valve, B to B et cetera. I can tell you all later what it is when I get home.

Check my other recent thread... I got it all working, it's GREAT.

Wat are the pin for the wires?

Derp... I have to go find out and write it down. Perhaps tonight.

OK here is my FIERCE mspaint schematic. Fierce I tell you!
http://img.photobucket.com/albums/v6.../iacwiring.jpg

Could you elaborate on the wiring colors?