ohno idle tunning

[Proven Power]

this is log from russ idle log config need some help never tuned g5x3 cams and engine was built by some other shop also tune all stock but injector flow and timing 99 vette was told is 408 bbk 80mm intake and throttle body no info on lobe sep heads or other after getting idle down taking to dyno for wide band vehicle stalls and is running real rich will post other logs also

[Russ K]

What size injectors are you using? Plug your Maf back in & enable it. You have WAY too much main spark timing! Also return the idle over & underspeed spark table to stock. You should change the cyl volume for your 408.

The LTFT RPM & MAP boundary table need to be set up to match the idle RPM & Map of the engine.

Then you need to read up on how to set the trans tables.

Russ Kemp

[Proven Power]

42# green tops
what would be good timing

and can not find these tables
idle RPM & Map of the engine.

thanks alot for the help russ k

[Russ K]

You want to enable all of the fuel trim cells. Say if your idle speed is 950 & the idle map kpa is 55, then set the low range rpm to 1000, the mid to 1700 & the high to 2400. Set the low range map to be 60, the mid to 70 & the high to 80.

As for spark timing, 22*-28* total timing, depending on the octane and CR.

Russ Kemp

[Proven Power]

is this better

[Proven Power]

log from a few min. ago using idle config frist and normal config afterwards engine stalling will not idle unless i hold to 1200 rpm with pedal

[Russ K]

Give this tune a try. The G5X3 cam shouldn't need a lot of idle airflow. Is the LSA 112 or 114? Flash the tune & bring the engine to operating temp, then scan with my Maf .cfg file to check the fuel trims. Drive the car around at moderate speed & load, stay out of PE.

Then do a idle scan again with the engine at operating temp. For the cold start scan, let the car cool down for at least 3 hours.

Russ Kemp

[Proven Power]

still stalling when put into reverse. cant get out of drive way. hear is log from cofig you posted. just setting in drive way you can see when it stalls out and i restart i have to hold throttle and let off slowly to get to idle again .thanks for helping me RUSS this car is a burr in my side. i did not build it and vic does not have specs on cam the guy that built it does not remember lsa ether he is in his 70 s and built it like old school engine builder slap it together and hope it works vic is good friend and i told him i have hp tunners and would help him. car has been down for weeks now but he is being cool about it. i have dyno time for it but cant get it to stay running long enough to drive it 42 miles to dyno

[Russ K]

I would do a compression test, as there may be a reason for the engine needing so much RAF. How does the engine run at speed (30-70 mph)?
Any misfires or hesitation/surge/buck?

Russ Kemp

[Proven Power]

i will check compression this weekend. i have not been able to drive vehicle since i repaired broken vacuum line at back of intake manifold and found intake gaskets damaged. i guess i should expect the worse due to i dont know anything about this engine the more i do to fix it just seems to make it worse i will get back to you after test will also do cly balance test fuel pressure is around 61 psi at idle it does not make any abnormal noise knocking and just realy sounded like cam caused miss runs rough at idle but if not in gear if you raise idle to around 1200 smothes out

[Proven Power]

russ i have not done compression test yet talked to vic and found old school tech that built engine ported and polished heads him self with out flow bench could that be problem with airflow will still do compression test but if heads are problem how can i tell that if engine has good compression

[Russ K]

I just finished the install of a G5X3 114 LSA camshaft in my 2001 ZO6. The heads are LPE ported LS6 castings, 2.02/1.57 valves milled to 61 cc. I'll post an idle scan tomorrow. The car started right up with the tune from the LPE 229/242 camshaft without touching the throttle.

Just do a normal compression test, you may have bent valves, as I only have .056 intake PTV! If your G5X3 is on a 112 LSA, the intake PTV will be less. How much were the heads milled, and are the valves larger than stock? What thickness head gasket was used?

Russ Kemp

[Russ K]

This is the cold start idle scan of my 2001 ZO6 with the G5X3 114 LSA camshaft. The tune is from the LPE 229/242 camshaft.

Russ Kemp

[Proven Power]

Thanks russ i am pullng heads off this weekend due to low compression on many cly. preformed pressure test on low cly with rockers off and can hear air pressure in intake manifold
will get back as soon as runs again

[Proven Power]

russ when doing maf tune i would log with maf config you posted and then what do you do just copy and paste or X by percent info on how to do this please thank you

[Proven Power]

looking at lgs afr 225 mongoose heads anyone have info for me about them engine is 408 bored and stroked ls6