High Idle VE and Lean Acceleration
07-26-2018, 09:37 PM
#1
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Car: 1985 Camaro
Engine: 2.8L v6
High Idle VE and Lean Acceleration
I have a stock chevy 350 engine. I have a tpi setup on the engine. I had a fuel pressure issue that I resolved recently. In the process of resolving that issue I swapped my injectors from a generic ebay set to a set of eight 22lb injectors from south bay. Before I had the engine running and did not have any issues with the tune. However now when I start the engine it will die within about 10 seconds. The only way I have been able to resolve this is by changing the injectors in the .bin to 20lb and setting the idle VE cells to 65. Before the idle VE cells were about 45. Also as soon as I touch the pedal even a little when I am driving the engine goes dead lean (18-19AFR). I have the AE set pretty high but it seems to make no difference no matter what I set it to. When I am looking at the logs I will be going down the road at a constant speed/rpm like 1200rpm. The AFR is somewhere at about 13AFR. Then the moment I try and accelerate at all it goes lean like I mention before. Its just strange that the VE is so different and I am having lean issues as soon as I hit the gas when driving.
AE
800 - 1.44
1600- 1.54
2400 - 1.59
3200 - 1.62
4000 - 1.65
4800 - 1.69
Some of the things I have done
Checked Fuel Pressure (High 30s FPR under vaccum // Low 40s with no vacuum on FPR)
Tested all power and grounds at ECU and both are getting 12V
hooked up my spare ECU no change
tested each injector with a noid light found no issues
ohm tested each injector
sprayed carb cleaner at the base of each injector at the manifold to check for vacuum leaks
Verified initial timing with timing light
New Gas Tank
New Fuel Lines Supply/Return front to back
New Fuel pressure regulator
New Wolboro GSS340 Fuel Pump
Verified pump is getting good voltage
New Fuel Filter
Inline check valve on supply line
AE
800 - 1.44
1600- 1.54
2400 - 1.59
3200 - 1.62
4000 - 1.65
4800 - 1.69
Some of the things I have done
Checked Fuel Pressure (High 30s FPR under vaccum // Low 40s with no vacuum on FPR)
Tested all power and grounds at ECU and both are getting 12V
hooked up my spare ECU no change
tested each injector with a noid light found no issues
ohm tested each injector
sprayed carb cleaner at the base of each injector at the manifold to check for vacuum leaks
Verified initial timing with timing light
New Gas Tank
New Fuel Lines Supply/Return front to back
New Fuel pressure regulator
New Wolboro GSS340 Fuel Pump
Verified pump is getting good voltage
New Fuel Filter
Inline check valve on supply line
07-26-2018, 09:45 PM
#2
Re: High Idle VE and Lean Acceleration
In your tuning have you changed the injector offsets ?
https://www.thirdgen.org/forums/diy-...or-sticky.html
https://www.thirdgen.org/forums/diy-...or-sticky.html
07-26-2018, 09:49 PM
#3
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Car: 1985 Camaro
Engine: 2.8L v6
Re: High Idle VE and Lean Acceleration
Yah for the 22lb southbay injectors I set the msec vs volts in the bin. Below is what I found on thirdgen.org. Hopefully that is right? Also my bin does use msec not usec. So if the following are correct then that is what I have in my bin.
Injector Bias Vs Battery Voltage:
4.80V - 3.07msec
6.40V - 3.07msec
8.00V - 1.85msec
9.60V - 1.30msec
11.20V - 0.99msec
12.80V - 0.76msec
14.40V - 0.61msec
Injector Bias Vs Battery Voltage:
4.80V - 3.07msec
6.40V - 3.07msec
8.00V - 1.85msec
9.60V - 1.30msec
11.20V - 0.99msec
12.80V - 0.76msec
14.40V - 0.61msec
Last edited by K1ng0011; 07-26-2018 at 09:56 PM.
07-27-2018, 02:00 PM
#4
Re: High Idle VE and Lean Acceleration
So here is some info on the bosch 280155700's. Hope this helps. They are rated
19lb at Ford pressure and 22lb at GM pressure:
Bosch EV6 19 lb/hr @ 39.15psi
0-280-155-700 / 710
Low Slope 23.76
High Slope 19.26
Breakpoint 0.00001
VOLTAGE OFFSET
voltage ms
16.00 0.78
15.00 0.78
14.00 0.78
13.00 0.936
12.00 1.093
11.00 1.25
10.00 1.47
19lb at Ford pressure and 22lb at GM pressure:
Bosch EV6 19 lb/hr @ 39.15psi
0-280-155-700 / 710
Low Slope 23.76
High Slope 19.26
Breakpoint 0.00001
VOLTAGE OFFSET
voltage ms
16.00 0.78
15.00 0.78
14.00 0.78
13.00 0.936
12.00 1.093
11.00 1.25
10.00 1.47
07-27-2018, 02:12 PM
#5
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Car: 1985 Camaro
Engine: 2.8L v6
Re: High Idle VE and Lean Acceleration
Yah I saw that provided by southbay in that forum post. Is there a difference between the two voltage tables? I was able to get my throttle response back. I had to increase my acceleration enrichment to near max though. The max for the table is 2.55. I have my AE set to 2.20 for all RPM in the table. I was running out of ideas and that is the only thing that I could think of. If I am using the wrong table it will be easy to switch.
voltage ms
16.00 0.78
15.00 0.78
14.00 0.78
13.00 0.936
12.00 1.093
11.00 1.25
10.00 1.47
Injector Bias Vs Battery Voltage:
4.80V - 3.07msec
6.40V - 3.07msec
8.00V - 1.85msec
9.60V - 1.30msec
11.20V - 0.99msec
12.80V - 0.76msec
14.40V - 0.61msec
15.00V - 0.55msec
voltage ms
16.00 0.78
15.00 0.78
14.00 0.78
13.00 0.936
12.00 1.093
11.00 1.25
10.00 1.47
Injector Bias Vs Battery Voltage:
4.80V - 3.07msec
6.40V - 3.07msec
8.00V - 1.85msec
9.60V - 1.30msec
11.20V - 0.99msec
12.80V - 0.76msec
14.40V - 0.61msec
15.00V - 0.55msec
07-28-2018, 10:36 PM
#6
Re: High Idle VE and Lean Acceleration
How do you know your TPS sensor is ok? What ECM are you running? MAP sensor?
if you have a scanner, (key on engine off) monitor the TPS while you push the throttle. voltage increase should be smooth and linear.
that much AE is abnormal... even my Miniram ( which is one of the AE hungry manifolds there is) only has 1.50 max AE delta TPS.
if you have a scanner, (key on engine off) monitor the TPS while you push the throttle. voltage increase should be smooth and linear.
that much AE is abnormal... even my Miniram ( which is one of the AE hungry manifolds there is) only has 1.50 max AE delta TPS.
Last edited by ULTM8Z; 07-28-2018 at 10:39 PM.
07-28-2018, 10:59 PM
#7
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Car: 1985 Camaro
Engine: 2.8L v6
Re: High Idle VE and Lean Acceleration
Yah my TPS is fine. All of the logs that I have taken show the tps working fine. I also just went out with the engine off and pressed the gas pedal while I watched the tps voltage and it was fine. I also set the TPS voltage to .54. When I started my project I bought all new sensors CTS, TPS, IAC, IAT, Distributor, and MAP. I had a random set of injectors I bought from ebay. Turns out they were injectors from a volvo so not the right ones. I kept having fuel leaks with them. I ended up making them work long enough to get the engine tuned with no issues. In the end I ended up getting a set of southbay 22/lb injectors like I should have done. I expected some changes in the VE table and maybe some other minor changes. However with these injectors my AE went from less than 1 all the way to over 2. My VE table went from the VE idle cells from being in the 40s to the 60s now. As far as I can tell it seems like there is something that is wrong. I just dont know what. I am running a 165 ECU with OSE12P. Basically turns the 165 ECU into a MAP ECU. I just wanted to see if anyone might have any ideas for the high VE and AE issue. I was able to tune out the lean acceleration by turning the AE way up.
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07-29-2018, 06:55 PM
#8
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Car: 1985 Camaro
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Re: High Idle VE and Lean Acceleration
I figured out the issue. Apparently I had a massive exhaust leak. Both of my header flange gaskets were totally destroyed. For this setup I installed a wideband in my headers a few months ago. The gasket was fine then. So between then and now my header gasket got blown out. This must have caused and exhaust leak. Which caused by AE problems. I had my AE set at over 2.0 at 800RPM. All I did today was replace the header flange gaskets and the gaskets where the headers meet the block. From the picture below you will see what I mean by destroyed. After changing the gaskets I set the AE down to .31 at 800RPM and when I hit the throttle I get about 12AFR now. The issue has been fixed and I have better drivability with open loop being forced than before when I was using closed loop. Thanks for the information and everyone's suggestions.
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