Help with building your Speeduino, installing it, getting it to run etc.
By soultron
After checking some things out with the vacuum, when it's cold the engine will start and run without the map sensor plugged in for quite a while but will die if I get on the throttle. Over the weekend I installed a spare Mega to see if that solved the TPS issue. It seemed like it did at first but the signal descends slowly and still wanders around when the car is running. The 5 volts to distributor seems to be working properly so I need to check back through my wiring we'll find out where the noise is coming from. It's also hard to start as it gets warmer but I was expecting that for some reason. I'll get a tune and log up once I find my thumb drive.
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soultron wrote: Thu Apr 11, 2024 12:25 amwhen it's cold the engine will start and run without the map sensor plugged in for quite a while but will die if I get on the throttle. … It's also hard to start as it gets warmer
You are artificially enriching the fuel to high-VE with MAP disconnected when cold to let it run. The MAP must be connected. It is running cold without MAP, because your engine needs more fuel when cold than it is getting with MAP connected. See how that's working? With MAP connected, increase fuel at cranking and idle so it runs, and adjust as it warms until fully warmed.

Tune idle when warmed. Tune warm restart (prime, cranking, ASE). Now you have the cells tuned that it will use for cold start, where the cranking, ASE and WUE will add fuel for the colder temperature, to the cells you just tuned. 8-)
Let's all have a laugh for second. There's trash in my 40 year old car's gas tank.
My fuel filter was clogged... Yes, I should have tough of that sooner.
It stays running better now, and will rev above 2k if I blip it, HOWEVER, my TPS is still moving around with my foot off the pedal. My AFR starts out a bit lean but gets better. ... sp=sharing
PSIG wrote: Wed Apr 17, 2024 12:33 amTest your TPS.
On the plug side of things with the key on my 5v reference is stable. The signal lead is fluctuating, (anywhere between 1.5 and 1.8v) much like the logs.
With the TPS connected the lead signal is showing 2.66 volts and raises to over 3.7 when pulled. After sitting a while the resting voltage dropped to 2.57

That seems high compared to calibrating the TPS on my Firebird years ago. It does seem like I have other issues.
I rewired a few grounds and tested the TPS and related wiring and finally figured it out. I trusted the layout I was given for this TPS and didn't check it myself. I don't know how it was functioning because I was running the 5 volts into the ground.
I spent half an hour depinning the connector and swapped the wires. Tps is dead still. It started up and ran surprisingly smooth although quite rich (10:1). I haven't tried a hot start or done any acceleration enrichment yet, but things are looking up.
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