Car still has a lean pop at low RPMs....
03-22-2004, 04:33 PM
#1
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Car: 91 GTA and 85 IROC
Engine: 355
Transmission: gear jammer
Axle/Gears: 4.11
Car still has a lean pop at low RPMs....
Ever since the HSR install it's been doing this. This past weekend we tried to go into the AE tables and play w/ the values, but nothing seemed to help. Only make it worse. We went back to a stock bin from a 92 5-speed car (SD) and it ran better, but still has the pop. Tip in throttle is the only time when it does it. O2mv drop drastically down to 100-80.
One thing that's wrong, the speedo sensor isn't hooked up. I need to get a new connector. But even when it was working, it still had the backfire problem.
Any and all help is appreciated.
HSR, protopline 200, and a cc306 cam, 30# inj. and a 58mm TB.
One thing that's wrong, the speedo sensor isn't hooked up. I need to get a new connector. But even when it was working, it still had the backfire problem.
Any and all help is appreciated.
HSR, protopline 200, and a cc306 cam, 30# inj. and a 58mm TB.
Last edited by Free Bird; 03-22-2004 at 04:36 PM.
03-22-2004, 05:34 PM
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Car: An Ol Buick
Engine: Vsick
Transmission: Janis Tranny Yank Converter
You may have to crutch the AE with the VE table.
And, when changing the fuel makes no change, then try changing the timing. Ramp more timing out faster.
And, when changing the fuel makes no change, then try changing the timing. Ramp more timing out faster.
03-22-2004, 07:56 PM
#3
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Car: 87 IROC-Z
Engine: 383 HSR $8D
Transmission: T56
Axle/Gears: 3.42
I have this same problem on occasion with my MAF'd HSR'd car.
I tried the AE tables in MAF with no change...
Timing will be my next thing to try. Thanks for the suggestion Grumpy...
I tried the AE tables in MAF with no change...
Timing will be my next thing to try. Thanks for the suggestion Grumpy...
03-22-2004, 09:21 PM
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Car: '87 IROC-Z/'82 RX7
Engine: SBC 355/1.1L Rotary
Transmission: T56/5 Speed
Axle/Gears: 4.33/3.93
I had the same problem with my HSR protopline heads and MAF.
The fix was easy.
Get the blms in order first. I started with an ARAP bin, and made my own ramped timing table having all 34 deg in by 3000rpm and I idle at 26deg.
Tables I changed are: AE decay factor vs coolant temp. Lower the values and the pumpshot wont go away as fast. at operating temp I lowered the values from 39 to 26.
Accel Enrich%BPW Factor vs Async Pulse: Pulse 1 is 3.59, 3.30, 3.20, and 3 for pulse 4-8
the big change happened here: LV8 Accel Enrichment Coolant factor vs coolant temp.
Stock ARAP: 306F(0), 262F(.05), .05, .05, .15, .35, .43, .43, .43
Modifided: 306F(.3), 262F(.03), .35, .35, .35, .35, .35, .40, .40
And my Min Delta %tps for AE Constant is at 3.13,
and the Min Delta LV8 for AE is at 18.
These fueling changes, along with the timing at 26 idle up to 34deg by 3000 gives me excellet throttle response, no stumble, and NO MORE LEAN POP.
Hope this helps. I know I kept making AE changes and it didn't do anything... with the bigger plenum come to find out, you need pretty BIG changes.
The fix was easy.
Get the blms in order first. I started with an ARAP bin, and made my own ramped timing table having all 34 deg in by 3000rpm and I idle at 26deg.
Tables I changed are: AE decay factor vs coolant temp. Lower the values and the pumpshot wont go away as fast. at operating temp I lowered the values from 39 to 26.
Accel Enrich%BPW Factor vs Async Pulse: Pulse 1 is 3.59, 3.30, 3.20, and 3 for pulse 4-8
the big change happened here: LV8 Accel Enrichment Coolant factor vs coolant temp.
Stock ARAP: 306F(0), 262F(.05), .05, .05, .15, .35, .43, .43, .43
Modifided: 306F(.3), 262F(.03), .35, .35, .35, .35, .35, .40, .40
And my Min Delta %tps for AE Constant is at 3.13,
and the Min Delta LV8 for AE is at 18.
These fueling changes, along with the timing at 26 idle up to 34deg by 3000 gives me excellet throttle response, no stumble, and NO MORE LEAN POP.
Hope this helps. I know I kept making AE changes and it didn't do anything... with the bigger plenum come to find out, you need pretty BIG changes.
03-24-2004, 09:48 AM
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Car: 86-IROC Z28
Engine: 327
Transmission: 700 R4
Hi.
Just wanted to say thank's to Twilightoptics for posting his tables.. you saved me lots of time and I guess a tank of gas or something.
I'm in the beginning of my tune and have some issues.
Figured his combo is somewhat like mine (well better I'm sure) I scrapped what I had done so far w. pump shot and stole/lent/was influenced by (choose appropriate) his stuff..
Mucho better... runs much much nicer now.
Still some snow in the air but at least I got a little test drive.
Again, thanks alot!!!
:hail:
Just wanted to say thank's to Twilightoptics for posting his tables.. you saved me lots of time and I guess a tank of gas or something.
I'm in the beginning of my tune and have some issues.
Figured his combo is somewhat like mine (well better I'm sure) I scrapped what I had done so far w. pump shot and stole/lent/was influenced by (choose appropriate) his stuff..
Mucho better... runs much much nicer now.
Still some snow in the air but at least I got a little test drive.
Again, thanks alot!!!
:hail:
03-24-2004, 10:41 AM
#6
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Car: '87 IROC-Z/'82 RX7
Engine: SBC 355/1.1L Rotary
Transmission: T56/5 Speed
Axle/Gears: 4.33/3.93
Sweet. Glad it helped!
Though pay attention to your o2 volts because it may be a bit big for you or a bit small for you.
Have fun drivin w/o a pop!
Though pay attention to your o2 volts because it may be a bit big for you or a bit small for you.
Have fun drivin w/o a pop!
06-17-2004, 01:08 PM
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Car: Iroc-Z
Engine: 355 AFR'd HSR
Transmission: 700R4
Found this post. This lean pop you guys are talking about is intriguing me. Since the install of the AFR 195's and the nailing down of the 6* advance, IAC reset, TPS verification, BLM alignment. I have had time to focus on other things. i.e. my lean pop. I gon't get a lean pop when I stab the pedal. I get lean pops... while high riding the gears. I'm using the .bin from a friend in Arizona... that had a 383 with some fun parts on it. Sounds like he nailed the AE stuff down. However, how would I get rid of the pops? I can hear the exhaust stuttering. This be timing related too I have come to understand (I think)? Also, why so little advance? Are ProToplines iron heads? I'm not certain as I havent looked at them before.
Trending Topics
06-17-2004, 01:23 PM
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Car: '87 IROC-Z/'82 RX7
Engine: SBC 355/1.1L Rotary
Transmission: T56/5 Speed
Axle/Gears: 4.33/3.93
A lean pop when its bad sounds like a big thud in the engine, not so much in the exhaust. If you are driving around and let off the gas or something the exhaust and have a pop sound because the computer hasn't shut off enough fuel (DFCO and Deceleration Enlean)
A lean pop when you get on it means too small a pump shot, not long enough, decays too quickly, or doesn't come in quick enough.
AE tables and the AE constants are what you need to adjust, and add more fuel. Take it slow. Start with the Constants, and the size of the ae.
A lean pop when you get on it means too small a pump shot, not long enough, decays too quickly, or doesn't come in quick enough.
AE tables and the AE constants are what you need to adjust, and add more fuel. Take it slow. Start with the Constants, and the size of the ae.
08-01-2004, 05:07 PM
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Car: '87 IROC-Z/'82 RX7
Engine: SBC 355/1.1L Rotary
Transmission: T56/5 Speed
Axle/Gears: 4.33/3.93
They wont be the same, but the trend should be similar. For me load is figured as LV8, for you Load is MAP. Same kind of differences and trends. Add more one step at a time. If you add alot at low delta map and high delta map, and if fixes the problem you wont know which one fixed it and be using excess fuel when you don't need to at one or the other.
08-01-2004, 05:18 PM
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Car: 91 Red Sled
Axle/Gears: 10bolt Richmond 3.73 Torsen
Don't trust the narrow band o2, I'm thinking it's timing if adding AE didn't do anything but make it worse. This would make sence if you've got too much timing in the low RPM, medium MAP area where it's just tip in. Try removing more timing. It really sounds like you've got too much timing only because of what you said. If you could be more specific on what you've done. Did you just advance the dizzy by 6 degrees and not change the initial advance in the chip to match? If that's a case then you could be delivery too much timing....
08-05-2004, 03:29 PM
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I fought this with my Miniram for over a year. Never did get it run correctly. Then I convereted to SD and had much better luck. Currently I run a Super Ram on my 396 and I'll never retrun to the Miniram.
06-07-2006, 10:27 AM
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Car: 91 Formula WS6 (Black, T-Tops)
Engine: 383 MiniRam (529 HP, 519 TQ - DD2K)
Transmission: Built '97 T56, Pro 5.0, CF-DF
Axle/Gears: 4.11 posi Ford 9"
89vette - would you mind if I sent you an email with a few questions on your set up?
06-07-2006, 11:50 AM
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Car: 1987 Corvette
Engine: 383 ci
Transmission: ZF 6 Speed
Axle/Gears: 4.10 Dana 44
Originally Posted by Twilightoptics
I had the same problem with my HSR protopline heads and MAF.
The fix was easy.
Get the blms in order first. I started with an ARAP bin, and made my own ramped timing table having all 34 deg in by 3000rpm and I idle at 26deg.
Tables I changed are: AE decay factor vs coolant temp. Lower the values and the pumpshot wont go away as fast. at operating temp I lowered the values from 39 to 26.
Accel Enrich%BPW Factor vs Async Pulse: Pulse 1 is 3.59, 3.30, 3.20, and 3 for pulse 4-8
the big change happened here: LV8 Accel Enrichment Coolant factor vs coolant temp.
Stock ARAP: 306F(0), 262F(.05), .05, .05, .15, .35, .43, .43, .43
Modifided: 306F(.3), 262F(.03), .35, .35, .35, .35, .35, .40, .40
And my Min Delta %tps for AE Constant is at 3.13,
and the Min Delta LV8 for AE is at 18.
These fueling changes, along with the timing at 26 idle up to 34deg by 3000 gives me excellet throttle response, no stumble, and NO MORE LEAN POP.
Hope this helps. I know I kept making AE changes and it didn't do anything... with the bigger plenum come to find out, you need pretty BIG changes.
The fix was easy.
Get the blms in order first. I started with an ARAP bin, and made my own ramped timing table having all 34 deg in by 3000rpm and I idle at 26deg.
Tables I changed are: AE decay factor vs coolant temp. Lower the values and the pumpshot wont go away as fast. at operating temp I lowered the values from 39 to 26.
Accel Enrich%BPW Factor vs Async Pulse: Pulse 1 is 3.59, 3.30, 3.20, and 3 for pulse 4-8
the big change happened here: LV8 Accel Enrichment Coolant factor vs coolant temp.
Stock ARAP: 306F(0), 262F(.05), .05, .05, .15, .35, .43, .43, .43
Modifided: 306F(.3), 262F(.03), .35, .35, .35, .35, .35, .40, .40
And my Min Delta %tps for AE Constant is at 3.13,
and the Min Delta LV8 for AE is at 18.
These fueling changes, along with the timing at 26 idle up to 34deg by 3000 gives me excellet throttle response, no stumble, and NO MORE LEAN POP.
Hope this helps. I know I kept making AE changes and it didn't do anything... with the bigger plenum come to find out, you need pretty BIG changes.
One question - at what LV8 value are you using 34 deg @ 3000 rpm? Across the board, or only at lighter loads?
06-07-2006, 11:52 AM
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Wow this and old thread!
Originally Posted by 89vette
I fought this with my Miniram for over a year. Never did get it run correctly. Then I convereted to SD and had much better luck. Currently I run a Super Ram on my 396 and I'll never retrun to the Miniram.
06-10-2006, 12:09 AM
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Car: 1992 Camaro RS - not real slow anymore...
Engine: SPDC 360 MAF EFI /w a Holley Stealth Ram
Transmission: T5 untill it blows up from to much torque
Axle/Gears: Ford 9" /w auburn pro & 3.89's
Originally Posted by 87 Vette Owner
Thanks very much for posting this information - it helps a lot!
One question - at what LV8 value are you using 34 deg @ 3000 rpm? Across the board, or only at lighter loads?
One question - at what LV8 value are you using 34 deg @ 3000 rpm? Across the board, or only at lighter loads?
06-10-2006, 10:58 AM
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Car: '87 IROC-Z/'82 RX7
Engine: SBC 355/1.1L Rotary
Transmission: T56/5 Speed
Axle/Gears: 4.33/3.93
Originally Posted by Dirtbik3r
Originally Posted by 87 Vette Owner
Thanks very much for posting this information - it helps a lot!
One question - at what LV8 value are you using 34 deg @ 3000 rpm? Across the board, or only at lighter loads?
bump
Thanks very much for posting this information - it helps a lot!
One question - at what LV8 value are you using 34 deg @ 3000 rpm? Across the board, or only at lighter loads?
bump
You'll run 34º across the board 3000 on at your highest load value. At light cruise 1500-2000 LOW load you'll want 39-41º.
06-10-2006, 12:46 PM
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Car: 1992 Camaro RS - not real slow anymore...
Engine: SPDC 360 MAF EFI /w a Holley Stealth Ram
Transmission: T5 untill it blows up from to much torque
Axle/Gears: Ford 9" /w auburn pro & 3.89's
This is getting to be a nightmare... Vortec HSR, lt4 hot cam, and vortec heads with a timing table is a PITA. -lol
06-10-2006, 12:54 PM
#19
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Car: '87 IROC-Z/'82 RX7
Engine: SBC 355/1.1L Rotary
Transmission: T56/5 Speed
Axle/Gears: 4.33/3.93
Originally Posted by Dirtbik3r
This is getting to be a nightmare... Vortec HSR, lt4 hot cam, and vortec heads with a timing table is a PITA. -lol
I'm running the Pro Topline Irons and they have the heart chamber design just like vortecs and it wasn't too bad.
RBOB posted the closest he's ever found
https://www.thirdgen.org/forums/diy-...ht=vortec+7747
as an LT1 Iron Headed table. You'll have to figure in some of the bias' and such.
I idle at 26deg spark and work up from there with all 34deg in at about 2800rpm.
around 40 at cruise (50kpa or half your LV8 reading) around 2000ish rpm.
and then feathered into all the spots from there.
06-11-2006, 04:49 PM
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Car: 1992 Camaro RS - not real slow anymore...
Engine: SPDC 360 MAF EFI /w a Holley Stealth Ram
Transmission: T5 untill it blows up from to much torque
Axle/Gears: Ford 9" /w auburn pro & 3.89's
Thanks for the insight Twilight. I do wonder if GM used different timing tables for the lt4 than the lt1... If so, I wonder how far apart they are?
06-18-2006, 11:46 AM
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Car: 1992 Camaro RS - not real slow anymore...
Engine: SPDC 360 MAF EFI /w a Holley Stealth Ram
Transmission: T5 untill it blows up from to much torque
Axle/Gears: Ford 9" /w auburn pro & 3.89's
.....
Last edited by Dirtbik3r; 06-29-2006 at 11:34 PM.
06-29-2006, 11:10 PM
#23
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Made my own ramped timing table having all 34 deg in by 3000rpm and I idle at 26deg.
Can you somehow make this easier to understand
I mean the way I understand it is that you suggest having from 1000-3000rpm 34 deg spark advance in all locations?
Just trying to get a better idea.
Can you somehow make this easier to understand
I mean the way I understand it is that you suggest having from 1000-3000rpm 34 deg spark advance in all locations? Just trying to get a better idea.
07-31-2006, 08:30 PM
#24
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Car: 1992 Camaro RS - not real slow anymore...
Engine: SPDC 360 MAF EFI /w a Holley Stealth Ram
Transmission: T5 untill it blows up from to much torque
Axle/Gears: Ford 9" /w auburn pro & 3.89's
Originally Posted by Twilightoptics
I'm running the Pro Topline Irons and they have the heart chamber design just like vortecs and it wasn't too bad.
RBOB posted the closest he's ever found
https://www.thirdgen.org/forums/diy-...ht=vortec+7747
as an LT1 Iron Headed table. You'll have to figure in some of the bias' and such.
I idle at 26deg spark and work up from there with all 34deg in at about 2800rpm.
around 40 at cruise (50kpa or half your LV8 reading) around 2000ish rpm.
and then feathered into all the spots from there.
RBOB posted the closest he's ever found
https://www.thirdgen.org/forums/diy-...ht=vortec+7747
as an LT1 Iron Headed table. You'll have to figure in some of the bias' and such.
I idle at 26deg spark and work up from there with all 34deg in at about 2800rpm.
around 40 at cruise (50kpa or half your LV8 reading) around 2000ish rpm.
and then feathered into all the spots from there.
The following is an lt1 table converted to LV8 values:
Code:
34.10 34.10 34.10 34.10 34.10 29.88 28.13 24.96 23.91 22.15 20.04 18.98 34.10 34.10 34.10 34.10 34.10 29.88 28.13 24.96 23.91 22.15 22.15 21.09 34.10 34.10 34.10 34.10 34.10 29.18 27.07 23.91 22.85 21.09 20.04 18.98 34.10 34.10 34.10 34.10 33.05 31.29 29.18 25.31 24.26 22.15 20.04 19.34 34.10 34.10 34.10 34.10 32.34 31.29 30.23 25.31 24.26 22.15 20.39 19.34 34.10 34.45 34.45 34.45 32.34 31.29 28.13 24.26 22.15 21.45 19.34 18.28 33.05 33.05 33.05 33.05 31.99 30.94 28.13 23.91 22.15 21.09 18.98 17.93 31.99 31.99 31.99 31.99 30.59 29.53 26.72 22.85 20.74 19.69 17.23 16.52 30.94 30.94 30.94 30.94 28.83 27.77 24.96 21.09 18.98 17.93 15.12 15.12 29.88 29.88 29.88 29.88 27.77 27.07 24.26 20.39 17.93 16.52 13.71 13.71 28.83 28.83 28.83 28.83 26.72 26.02 23.20 18.98 16.88 14.77 12.30 12.30 28.13 28.13 28.13 28.13 26.37 24.96 22.50 17.93 15.82 13.71 10.90 10.55 27.07 27.07 27.07 27.07 25.31 23.20 21.09 16.17 14.06 12.30 9.14 8.09 26.02 26.02 26.02 26.02 24.26 21.09 18.98 13.01 11.25 9.14 5.98 5.98 26.02 26.02 26.02 26.02 22.15 20.04 16.17 11.25 10.20 8.09 5.98 5.98 26.02 26.02 26.02 24.26 18.28 17.23 15.12 10.20 9.14 8.09 5.98 5.98 26.02 26.02 26.02 24.26 18.28 17.23 15.12 10.20 9.14 8.09 5.98 5.98
08-05-2006, 01:48 PM
#25
Okay, I have a 383 HSR SD running 28.8 LS1 Injectors at 58 PSI. Now, I'm having the Intake pop after initial throttle up. I was told to adjust my VE tables. After adjusting it, that didn't help that much. What can I change in my Enrich Accel Tables to correct my popping off initial throttle? I just have a hard time understanding the Enrich Accel Delta tables and constants.
Can somebody help please? If I can't get this fixed, I'm going to stay in Open Loop.
Can somebody help please? If I can't get this fixed, I'm going to stay in Open Loop.
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