Rich after Flash

[07GTS]

the EQ ratio min v ECT is just the minimum that u can command during OL operation so if any of the OL gas/IVT ect tables command lower it will stop and that min table, so it dosnt lean the tables out it stops them from going leaner than set EQ ratio for ECT, for the rich issue i found that with mine after a drive if it sits for bout 20-30 mins and then i flash then key off for 20 sec or so then start it will be fine but if i stop and flash within 5-10 mins ill get the rich issue for bout 5 mins of driving, also im in constant OL and it only affects the OL table the PE and BE fueling remain correct

[10_SS]

the EQ ratio min v ECT is just the minimum that u can command during OL operation so if any of the OL gas/IVT ect tables command lower it will stop and that min table, so it dosnt lean the tables out it stops them from going leaner than set EQ ratio for ECT, for the rich issue i found that with mine after a drive if it sits for bout 20-30 mins and then i flash then key off for 20 sec or so then start it will be fine but if i stop and flash within 5-10 mins ill get the rich issue for bout 5 mins of driving, also im in constant OL and it only affects the OL table the PE and BE fueling remain correct

So, nothing that hasn't been said before. We are really hoping for someone to pinpoint an obvious parameter.. so HP can add it to the tables. What we are afraid of, is GM baked it so deep into the code that it cant be modified, AKA no "adjustment" avail.

[SultanHassanMasTuning]

i have found that it doesnt take 10-15 minutes. if you just flash and run the car on the dyno/road and go for a WOT and relog your trims should be fine/nomral.

[10_SS]

i have found that it doesnt take 10-15 minutes. if you just flash and run the car on the dyno/road and go for a WOT and relog your trims should be fine/nomral.

[10_SS]

Yep. In other words, every time you flash, you have to waste a WOT dyno run, or a full 1/4 mile run down the track. Were looking for solutions, not things we allready know.

[fido]

Hello, I'm experiencing exactly the same problem but I came to completely another cause. I found that only thing that correlate with the too-rich condition is high fuel pressure. Normally, with large injectors I command ?350kPa on low load to keep IPW around 0.8ms on idle but after every reflash, or battery disconnection the fuel pressure jumps up to 425kPa and slowly descend to my commanded value. I don't have 425kPa in any parameter. It's just something that ECM make up. Pressure is high, injector flow is high as well, so ECM commands lower IPW (0.5ms-0.7ms), but this is either too low for injectors, or their Short pulse adder is bad. I just tested this problem on Camaro ZL1 with ID850 injectors and I have proof for it in logs. The problem is much worse under 0.8ms IPW and its exactly the spot, where Short pulse adder map climbs up.
you can check it in attached logs. It's clear that on start after reflash is fuel pressure 350kPa for a second and then it jumps up to 425kPa and slowly descend. It's slower when you just let it idle (it takes about 20minutes). When you do some WOT, it descend faster.

I don't have a solution for that yet. Only thing I know is that ID injectors either don't work well on IPW lower than 0.8ms or their calibration data are off. The problem is much less severe with stock injectors.

[schpenxel]

This happens on cars with static fuel pressure also, though I'll try logging commanded fuel pressure next time just to see if it changes for some reason?

[10_SS]

Hello, I'm experiencing exactly the same problem but I came to completely another cause. I found that only thing that correlate with the too-rich condition is high fuel pressure. Normally, with large injectors I command ?350kPa on low load to keep IPW around 0.8ms on idle but after every reflash, or battery disconnection the fuel pressure jumps up to 425kPa and slowly descend to my commanded value. I don't have 425kPa in any parameter. It's just something that ECM make up. Pressure is high, injector flow is high as well, so ECM commands lower IPW (0.5ms-0.7ms), but this is either too low for injectors, or their Short pulse adder is bad. I just tested this problem on Camaro ZL1 with ID850 injectors and I have proof for it in logs. The problem is much worse under 0.8ms IPW and its exactly the spot, where Short pulse adder map climbs up.
you can check it in attached logs. It's clear that on start after reflash is fuel pressure 350kPa for a second and then it jumps up to 425kPa and slowly descend. It's slower when you just let it idle (it takes about 20minutes). When you do some WOT, it descend faster.

I don't have a solution for that yet. Only thing I know is that ID injectors either don't work well on IPW lower than 0.8ms or their calibration data are off. The problem is much less severe with stock injectors.

Yes I see it starts at 67psi, and ends at 62psi. My LS3 E38 2010 Camaro starts at 58psi and ends at 58psi. ZL1's are the only LS E38 combo that come factory supercharged, so obviously a different OS. Are they even E38? All of the Rich After Flash are definately E38 non-boosted from factory OS's having this problem. But.. Higher fuel pressure after flash can be the same strategy as added pulse width that we see... so I'd be curious how your pulse width looks. Do what I did. It's free. Either way, GM wants it nice and rich after flash, or reset. That's for sure.

[SultanHassanMasTuning]

I believe the E67's (LSA,LS9) has the same issue.

[schpenxel]

I think I posted this somewhere else... but earlier today I tried re-flashing my truck for the hell of it (E38). I logged commanded fuel pressure, fuel pump PWM and whatever else I could find related to fuel pressure. Basically, nothing changed when I restarted after flashing. It stayed 58psi / 95% PWM after a flash.

This model doesn't have a PWM fuel pump controller, so it must be hard coded to think fuel pressure is 58psi or something.

[waynehartwig]

I can't say I've ever seen this issue, but I do way more GENIII trucks than anything else. But my race car is GENIV, and I have done other GENIV's on the dyno....

Try this... Make your changes and upload them. After it's done writing, shut the ignition off and remove the key for over 30 seconds. Then start it. I do this with GENIII and GENIV.

[fido]

Try this... Make your changes and upload them. After it's done writing, shut the ignition off and remove the key for over 30 seconds. Then start it. I do this with GENIII and GENIV.

Might be a good idea. Usually this process invokes storage of actual adaptation from RAM into flash memory (I observed this behavior on another automotive ECUs). And I've feeling that few times
it happened that I had no this problem so there must be some coincidence. I'll try it next time.

[waynehartwig]

Might be a good idea. Usually this process invokes storage of actual adaptation from RAM into flash memory (I observed this behavior on another automotive ECUs). And I've feeling that few times
it happened that I had no this problem so there must be some coincidence. I'll try it next time.

Basically just that. The way I understand it, there are two sections of memory in the computers. Not really long and short term, but when you run the vehicle, it pulls from one section. When you write to the vehicle, it saves it in another part. Then when you shut the ignition off, the PCM moves it to the run side. Hence the reason for giving it 30 seconds of off time... I do know if you have the ignition off for too long after programming a PCM, you can loose the data you just put in. I've seen that before. We're talking loose complete VIN and etc. data.

I don't remember where I saw it, hell it might be on every vehicle in SI, but I remember seeing in the programming instructions to do what I described. So I've always done it when I tune and program PCM/TCM's, since they are both basically the same deal...

[MikeOD]

Yes I see it starts at 67psi, and ends at 62psi. My LS3 E38 2010 Camaro starts at 58psi and ends at 58psi. ZL1's are the only LS E38 combo that come factory supercharged, so obviously a different OS. Are they even E38? All of the Rich After Flash are definately E38 non-boosted from factory OS's having this problem. But.. Higher fuel pressure after flash can be the same strategy as added pulse width that we see... so I'd be curious how your pulse width looks. Do what I did. It's free. Either way, GM wants it nice and rich after flash, or reset. That's for sure.

ZL1's have E67's. E38 and E67 both seem to do this.

[jsllc]

My 2012 ZL1 has this issue. The only correlation I could find was related to injector tip temperature. On a hot reflash the temp is over 190 degrees F. As they cool down the AFRs go up.

[schpenxel]

Have you looked at intake valve temp?

I know intake valve temp starts at engine coolant temp and works up.. I wonder if injector tip temp starts at ECT and goes down based on IAT?

[openwheel25]

I am very grateful for all of the efforts that 10_ss has put in to trying to figure this problem out. It is a very big problem and in my opinion would be worth hp tuners putting some time into adding tables or helping us out with this. I love hp tuners and everything they do. I would love them more if I could flash my car and not have to wait over night to see how my changes took effect.

[cc-rider]

I am very grateful for all of the efforts that 10_ss has put in to trying to figure this problem out. It is a very big problem and in my opinion would be worth hp tuners putting some time into adding tables or helping us out with this. I love hp tuners and everything they do. I would love them more if I could flash my car and not have to wait over night to see how my changes took effect.

I am just learning what a pain this is.

And I'll echo the thanks to 10_ss for his work. Not just on this issue...but on many (transient fuel, boost enrich, etc). Not to mention the fact that I stole his VE table as a base for my project. I've learned a ton from his posts and threads.

[GHuggins]

No need to wait over night, just 15 minutes then a pull with deceleration fuel cut confirmation and you should be good to go.

[jsllc]

I did look at the IVT temp. I found no correlation. On a 30 minute drive the averages were close to the same across the board. My injector temps however went from rich to lean.