7secpontiac

Got an 01 trans am. Put a carburetor on it recently with the msd 6010 ignition. The motor will not turn off unless it's idles really really low, like 500rpm. Idling normal at about 900-1000 ish it will not turn off. Turn the key off and it just sits there and sputters trying to kill then when it does kill the motor spins the wrong way. It's a daily driver for the most part. It has engine work but a stock bottom end. I know it has to be an octane problem right? I'm running 93. But what should the timing curve be? I'm assuming this must be the problem. I dropped the timing to 6 at 0 rpm. It's at 12 at 1000. Any ideas if this is the problem? What do you guys run yours at? I'm tired of having to turn the fuel pump off to kill the motor. Also, what is the stock max timing for an LS motor? I have an ls2 in it. But idk if the timing on these motors is the same as the old style chevys. Because I'd like to bump the max timing up for a little extra power. Thanks.

WE TODD DID

iTrader: (2)

Where are you getting power to the msd from? Try unhooking the power to the box and see if it shuts off. That will isolate whether or not you have a voltage feedback condition.

TXsilverado

iTrader: (18)

stock compression?


I've tried a ton of timing curves and always come back to the most simple setup on my LS2. give it a shot.


zero out the MAP table. 12* at 0 rpm and ramp it to 32* at 500rpm. flat line it at 32*. also make sure that the + that you tapped is a keyed source.

7secpontiac

Yes stock compression. And I'm not running the map sensor will this still work?

jerr6

iTrader: (1)

I had a similar problem when I put a 6al box on my chevelle. Turned the key off and the engine would lower in rpm and continue to run. I needed to put a resistor on a power wire. Power was getting back fed from dash lights. Maybe you are getting power from somewhere after the key is turned off.

7secpontiac

So pulled the power at its source. It still didn't shut off. So that's not the problem. I lowered the timing to 7° at 900 rpm and still won't shut off.

89gmcs15

iTrader: (7)

What gas are you running? Mine diesels with 87 octane but shuts off right with 91

7secpontiac

93. I raised the timing and took the opposite approach. Shuts off much better. But still isn't perfect. Guess I'll just keep messing with the timing

TXsilverado

iTrader: (18)

your timing is way too low. probably making the motor run hot which doesn't help with dieseling. run 93 pump and get the timing up at idle. it will probably clean up the idle a lot with more timing too.

7secpontiac

I got it up again. Still doesn't really shut off but it's better.

TXsilverado

iTrader: (18)

what's your AFR?

7secpontiac

Air to fuel? I don't know. I have a carburetor now. I have the gauge but the o2 sensor wires for that gauge got ripped in half. I'm gonna buy a new one soon because I still have the o2 sensors chilling there as plugs so I don't have a big hole in my headers. So I might as well make the gauge work again

Danny Lambe

I recently put a 4.8 with a mild cam into a 1980 trans am and have the same issue, I am thinking it may be backfeeding from the tach wire, I never had this issue until I hooked it up so I am disconnecting it today to see if that fixes it and will report back. I also have it stalling when put into gear so I am thinking the timing is to low for it right now at idle. I am going to modify that as well.