Help On Initial Startup

[Dale]

I am needing some help on my initial startup. It will now crank and fire and run for a few seconds then stall unless I give it gas. Sometimes I have to give it gas to start it. Once its running I gotta keep the rpms up for about 15seconds then slowly bring it down... or it will stall. Does not matter if its a cold start, or a hot start(hots slightly better).

I have adjusted B3201 to add a bit more fuel, helped a bit.
I have adjusted B3604 from 10c to 50c across the board to add more fuel. Helped a bit also.

But now I'm thinking, since it will start, thats not the area I need to tackle. Either way I went with them 2, I still have to keep the rpms up for a bit or it will stall. Where do I need to edit?

Attaching my first attempt at a scan and log file. If there is a pid(s) that is not shown that you need, please let me know and I will re-log.

Vin for log is 1ghg39r611104618
os 12212156
It is installed on a 350 TPI engine.

[SSpdDmon]

It most likely needs more air, not more gas.

Try increasing the Startup Friction Airflow Correction table in the Idle>Startup folder.

[Dale]

so add more grams to that, and put my B3201 and B3604 back to where it was? Or leave them?

[SSpdDmon]

Yes, try adding 5 grams/second across the board to B4343 if you're having startup issues. If it's more of a problem at one of the table then the other, add a little more where there's a problem and less where there isn't so much.

That table does (thru the IAC) what your right foot has been doing. It allows more air into the engine right after startup that decays out over the first 15~30 seconds. If you want it to stick around a little longer, reduce the numbers slightly in B4344.

I'd put the startup fueling back to stock - yes.

[Dale]

Ok, I put fuel back to stock.

I added 5gs across the board. It stayed running longer, but still stalled. Then would not re-start on its own. I HAD to give it gas to start it.

So I need to modify B4344?(whats the name on that one?)

Also, what about B4604 "startup offset"? I'm full 0 across. How about adding 50-100rpms?

[SSpdDmon]

B4344 is simply the decay table for the Startup Friction Airflow Correction table (B4343).

I didn't see this is a TPI engine. I thought this was an LSx based setup. If it liked more fuel, maybe you should keep those changes.

I still believe it needs more airflow though. When you say you give it gas, you're really cracking open the throttle body and letting more air in. The PCM matches that extra airflow with more fuel. That's why I'm assuming you're not getting enough airflow for a cold idle. Have you tweaked your desired idle airflow table (B4307) at all yet?

[Dale]

So I may need to leave the 5gs in. Put the fuel back up as well? Then drag out the B4344(add more GPS?)

Have not touched B4307. I have looked at an old tune file for a TPI vette and trying to cross reference any charts. Thats not one I have found.


BTW, do you have wire diagrams for an 01/02 LS1? There is one sensor I need to wire up like an LS1 and need the diagram to know where to pin it.

[Dale]

Have you tweaked your desired idle airflow table (B4307) at all yet?

If my searching is correct, this is "how far open the IAC is" chart? If so, I think this may very well be my culprit to many problems.

[SSpdDmon]

Desired Airflow is the table that tells the PCM how much air it needs at various coolant temps to let past the IAC so that it can maintain an idle.

If you're going to change the decay rate in B4344 so that the values in B4343 stick around longer, you need to make B4344 smaller. Those are the increments that are subtracted away from the extra airflow B4343 adds in.

Sorry, no diagrams. Did you try finding some service manuals to see if they help?

[Dale]

Well at idle, the IAC is what allows air thru. So my simple mind calls it "position of the IAC". So I think were talking alike. This should help my stalling, and fluxuating idle, and should help startup too.

I added fuel back in, didnt help. So tomorrow afternoon I'm going to set all these back to original settings, and play with the B4307.

Tonight on way home I got rich codes left n right bank, so I'm going to do a mass VE scale down.

I have to go order some ebrake cables tomorrow, so I'll look at the haynes/chiltons manual, maybe buy it. Hopefully it will have what I'm looking for. I need to wire in clutch switch.. that may be part of problem too.