Idle for 224/224 Roller

[455 Buick Regal]

I know part of my current battle with idle control is this "big" cam, coupled with ported heads, and 120# inj with E85. I am working my way to getting the throttle blades open enough and conversely the IAC counts low enough (10-20) for a controllable and decent idle, but it got late and gave up last night. Timing trim is zero for now.

1- Cam wants more air? Is 1000 rpm idle too low to achieve for this cam?
2- Cam wants more fuel? How rich is too rich for idle? With carbs we try to lean em out to the max at the idle RPM.

Prior tuner had IACs in the 100s to keep it idling.

 

[20psiofevil]

I run a 218/224 .580 114cam and I don't like to give it a lot of fuel at idle because it will cause a lot of suit running 14.3 af using 10% ethanol pump gas. 15.2-15.4 af with spark 25* advance it does pretty good on my combo. I have a table in my tuning software that allows me to cut fuel correction off per rpm..

 

[bison]

Depends on the lobes. If they have a lot of overlap then more rpm is needed. We've gotten cams with a lot of overlap to idle nice

 

[Street Lethal]

I know part of my current battle with idle control is this "big" cam, coupled with ported heads, and 120# inj with E85. I am working my way to getting the throttle blades open enough and conversely the IAC counts low enough (10-20) for a controllable and decent idle, but it got late and gave up last night. Prior tuner had IACs in the 100s to keep it idling.

Wasting your time. Get a larger throttle body, or drill a hole in the blade to get your steps down. You can play tug of war with the TPS like I have with my big cam, ported heads and stock throttle body, and be happy with higher than normal steps (mine are 75 steps at idle) but in the end you need a larger throttle body...

 

[delcowizzid]

i run a 292/297 adv 222/222 @0.050 111 LSA roller in a turbo converted LN3/L27 style buick SD tuned 20 degrees idle timing 12.8-13:1 fueling 850 rpm no problem.i have another one thats twin turbo with 231/231@0.050 on a 113 LSA idles at the same rpm same fuel same timing.
dont beleive what the wideband says at idle with a decient cam just use it for a sanity check they tend to lie at idle with overlap .tune to what idles strongest smoothest and handles clicking into gear

and the bigger one

 

[455 Buick Regal]

Thanks all. Its a larger throttle body.

I got it to idle ok now from cold start to warm up. It's not great, but it's a start. I am at 1000rpm, IAC counts in the mid-20s. That's in open loop.

But it seems to like AFR of around 8:1 (E85). That's way too rich, but if it likes it there, who am I to argue? Maybe as you say overlap is causing the rich sensing at idle (raw fuel going through exhaust valve) .

 

[Street Lethal]

Thanks all. Its a larger throttle body.

I got it to idle ok now from cold start to warm up. It's not great, but it's a start. I am at 1000rpm, IAC counts in the mid-20s. That's in open loop.

Lower the fast idle screw to whatever RPM you want, counts shouldn't go higher than 30 - 40 from 25 if you bring RPM down from 1000 to 900, and that is excellent with a big cam. Why was your tuner having such a problem? He is the reason why I assumed stock throttle body, as you said he had the counts over 100 at idle...

 

[455 Buick Regal]

Lower the fast idle screw to whatever RPM you want, counts shouldn't go higher than 30 - 40 from 25 if you bring RPM down from 1000 to 900, and that is excellent with a big cam. Why was your tuner having such a problem? He is the reason why I assumed stock throttle body, as you said he had the counts over 100 at idle...

I'm helping a friend get his car running again. Two different people have had their hands on this to tune it. Neither were able to nail down the tune due to fuel system problems which they failed to consider or diagnose; I think they simply crutched the root of the problem with the tune. Neither person mentioned to my buddy that the IAT should be converted to MAT (the first guy was the installer). And the there were other oddities with the tune as well.

Now that mechanical things have gotten fixed, we were trying to get it to idle correctly. It's not perfect, not even close, but it doesn't stall. I am waiting for it to cool down to confirm we have our cold start, after start, and idle adequate.

We'll then start on the part throttle drivability stuff. That should be a challenge. WOT can wait for someone who races these cars to tune on it. I'm a big-block carb guy...not many variables to mess with.

 

[455 Buick Regal]

I did a whole cold to warmup log. Log and cal files attached (need to increase the log time to 10 or 15 min as 5 min was too short). I feathered the throttle for about the first 30 seconds. It idled OK. Needs tweaking.

Something else is going on after closed loop, but did not show up on this log because it was too short.

 

[norbs]

I been looking at your tune, but since you don;t have the newer software I can;t send you anything without causing alot of issues...

 

[455 Buick Regal]

Can I run the 2.0 software with the "1.0" hardware?

 

[norbs]

Can I run the 2.0 software with the "1.0" hardware?

No it would not connect to the ecu, you have to flash the box with the 2.0 firmware and 2.0 option file which is $50 from fast... You have an older version of 2.00 I see from your uploads, but its not the latest version. Click on the about tab on your fast screen whats is say????

 

[455 Buick Regal]

C-Com software is version 1.340. FAST box is the red XFI (not the 2.0).

I had a good friend look at that log and he noticed some things, which I reconfirmed today with another cold start to warm up/closed loop idling recording:
(1) In open loop, as startup enrichment decays and it warms up, it runs worse and worse (it obviously likes more fuel at idle).
(2) Startup enrichment to full decay is way too long at 5-6 minutes. (If I am seeing correctly, the addition of warm up enrichment to the start up enrichment is nearly 70-80% total!).
(3) In closed loop, its maxing out the corrections trying to get it richer due to the AFR tables. (The AFR readings where it idles range from about 9:1 to 11:1. Any leaner and it dies.)

New question: Lambda and AFR don't seem to correlate properly. It looks like as Lambda approaches 1, AFR is approaching stoich for gasoline. The car has a fresh new tankful of E85 and in the Fuel Calc Parameters we have the Fuel Energy Constant set at 0.680. What's up with that? And yeah, the pump at the gas station said E85 and I filled it with 15 gallons myself. It smells like corn alcohol. Even if its E80,70,60, whatever its definitely not straight gasoline for the Lamba and AFR to be correlating approaching 14.7:1 Am I needing an education?

 

[norbs]

Lots of things have changed since the firmware and software upgrades. Your going to have to re-tune everything anyway with the new software, since alot of those issues your talking about have been addressed. Email fast get the 2.0 option file to start.

 

[BEATAV8]

mine likes to idle really rich too. 11.8, 12.0 at the leanest.

215/220 cam, E85, 120's

but normal driving around stuff it will run much much leaner and it's fine.

 

[455 Buick Regal]

Thanks, I will contact FAST. I am going to make a new post asking about the Lambda vs AFR wierdness.

 

[norbs]

Thanks, I will contact FAST. I am going to make a new post asking about the Lambda vs AFR wierdness.

That is addressed in the new software, it will be fine once you upgrade..