Cold start problems on 05 GTO with 402

[Gforce1320]

Any suggestions from looking at my tune as to what I need to do to get my GTO to idle better when it is cold out, cold as in 40 and below.
It's hard to keep running until it warms up.
It's an SD tune.
Mods are:
403 ci
Dart CNC heads
246/250 636 cam
11.96 static - 8.6 dynamic compression
fast 90
42 lb inj

Thanks Chris

[Russ K]

Try these settings, your IFR table looks too high for your 42# injectors. Your VE tables needs a lot of work, as it is very spiky. Could you post a scan log showing the AFR?

Russ Kemp

[EC_Tune]

Also look over your IVT gain table. You can generally reduce the values in that table at cold start quite a bit as the engine is probably too rich.

Just look over the startup coolant value on the IVT table and the MAP you are running to locate your idle point. Then about every 5-10 seconds of idling, the IVT temperature value goes up to the next line (guesstimate - as IVT isn't reported in the scanner) up to about 234 deg then it slows somewhat. Adding power will cause the IVT temperature value to increase quite a bit faster.

If you are monitoring your wideband (you do have one right?) check to see that the AFR is at least in the 13's to low 14's at cold idle. If not, make changes, let the engine cool off completely and do it again. Cold idle is about the hardest adjustment to make as you get one shot before the engine warms up...

[Gforce1320]

Thanks guys, I'll take a look at that stuff. I know my VE table is pretty messy looking but it runs really good once it gets warmed up. I need to smooth it, I haven't done that since my last tweak to the ve tables.
And yes I have a WB.
Thanks
Chris

[TwoFast4Lv]

Thanks EC that was the table I have been looking for.

Also look over your IVT gain table. You can generally reduce the values in that table at cold start quite a bit as the engine is probably too rich.

Just look over the startup coolant value on the IVT table and the MAP you are running to locate your idle point. Then about every 5-10 seconds of idling, the IVT temperature value goes up to the next line (guesstimate - as IVT isn't reported in the scanner) up to about 234 deg then it slows somewhat. Adding power will cause the IVT temperature value to increase quite a bit faster.

If you are monitoring your wideband (you do have one right?) check to see that the AFR is at least in the 13's to low 14's at cold idle. If not, make changes, let the engine cool off completely and do it again. Cold idle is about the hardest adjustment to make as you get one shot before the engine warms up...

[EC_Tune]

Glad to help.

[redhardsupra]

EC, are you saying that IVT tables are actually working in E40 cars? i haven't seen any evidence of any sensors or stuff hooked up to intake valves in LS2's. i'm confused...

[Bill@HPTuners]

as per Chris "uses engine speed, manifold pressure, engine coolant temperature, spark advance, fuel ethanol percent and air/fuel ratio. its a complicated linear equation with coefficients etc. the result is then filtered in relation to intake airflow, ie. faster filtering for higher airflows."

[redhardsupra]

if they know it, why not post it?

[Bill@HPTuners]

SE asked chris in the moderators section, chris gave him the answer & im passing it along to you

I don't think it was specifically asked what it was or how it was calculated until now, but either way there ya go

[redhardsupra]

so where's the equation? did you forget to attach something?

[Bill@HPTuners]

Chris is working on it, its not done yet...he's going to add it as an MPID