2001 cavalier 2.4L turbo Larger injectors.

[Charger]

I installed 650cc injectors and changed the injector constant to 0.15432 because I had 310cc with 0.32359 so 0.32359*(310/650) = 0.15432
The car idle is very lean 18+:1 and when I step on it it seems very rich. The car would stall cause it's so lean I don't have the wideband logged but I was looking at the aem gauge in the car....

So for now I've put a higher injector constant so I can idle and not stall at every light.

Any input? Thanks!

[Rodimus_Prime]

You calculated your constant wrong it should be your stock constant * stock size cc/650

Also I wouldnt mess with the IPW vs Pulse might want to set that back to what it was stock

Might want to send it all back to stock and start over with the proper constant

[Charger]

Rodimus: That's what I did for the injector constant and I didn't play with that IPW vs MAP, it's 1 all over from the beginning.

I should mension this before. 2001 2.4L Turbo 60 trim .60/.63 with no major engine mods.

I found that I can idle with the injector constant at 0.18238 but it's running very lean around 18:1 AFR. When I touch the gas pedal and the engine goes to 2000 RPM it is very rich(between 10-11:1 AFR) and it don't recover idle well, he want to stall(lean).

Now I tried adding 2 and more everywhere the Idle VE table and it do the same thing.

Should I try a bigger injector constant so I can idle a little richer and drop the idle VE table so I won't flood the engine like it do now??

I will do complete VE tuning with AEM WB but I just can't figure out how to have a good idle and when pushing the TPS to 1-2% and don't go to 10:1 AFR.

Thanks you guys!

[Charger]

Here's a log!

[Charger]

I tried a higher injector constant 0.19500 so I can idle and it was rich on the startup but 20 sec or so after each start the AFR goes lean to 18:1. It's like no mather which injector constant I put, it will always lean out after a couple of second....

I noticed the AEM WB goes lean but the stock o2 voltage don't move...

Can it be the o2 sensor that is bad???

[redhotjamedjimi]

it could be bad considering you delay is 0 rpm for pe and running 12 afr. at low torque your engine doesnt benefit from extra fuel. its best to start at close to max ve for the best driving experience and clean o2 sensors. ive killed many o2 sensors on my turbo 2.2 with this. thats why after a couple of seconds closed loop comes into play after the delay and its reading false readings. it might not be your inj constant but messing with that makes it all much worse.

with a bad injector constant in closed loop especially at idle it should still be around stoich. also try to keep the stock idle timing or the fuel doesnt have enough time for a complete burn and more weird o2 readings

[Charger]

I first tried to find an idle in open loop so I disabled close loop and changed the injector constant. Had the same leaning issue.

I don't know if it can be something else that the o2 sensor if we look at the log and see the WB goes from 11:1 to 18:1 and the stock o2 doesn't move at all...

Close loop is ok around 14.7. It's the open loop that's lean it out to 18:1 AFR...

What do you mean by its best to start at close to max ve???

[redhotjamedjimi]

its best to start PE enable at max Volume efficiency usually halfway up the rpms. also widebands are somewhat inaccurate at idle ive heard so u might want to think about that.

If open loop is a problem after reseting trims you are going to need to change VE higher until its 14.7. try adding 20-30 % to idle VE ive noticed yours is low for a high ve turbo set up. if that doesnt solve it its the wideband accuracy.

[Russ K]

You need to log the commanded AFR. Since there is no open loop tables for your car yet, the commanded AFR will be all over the place when not in PE.

Russ Kemp

[Charger]

Here's a log with the commanded AFR.

[Charger]

Here's some other logs...

[redhotjamedjimi]

I would fake the stock o2 with your wideband try a log. That did wonders for my truck and staying out of lean. But my opinion i dont know what is making you commanded so crazy. it should be stoich 99% for best results.

[Charger]

You can see LTFT goes to 25%+ at idle around frame 12250 in the startup_idle.hpl log.

This is a newbie question but when the trims are positive, it mean that there's too much or not enough fuel????

I notice there's 2 VE tables for idle( Idle VE and Low RPM VE). I'm wondering wich one is used and when???

[Charger]

I have a AEM wideband so is there a 0-1 Volt output so I can try to fake the o2 sensor with the wideband?

I looked at the manual and didn't find it....

[redhotjamedjimi]

After histogramming add 20% to your low end tables, idle, single and double. and see what happens. I'm also guessing you have a large exhaust and long intake so dont be surprised stock tables arent accurate.

Idle table at 0 tps. Single and double are anything other than that. Adjust all the same.

And you may not have a faking option narrwband option.

[Charger]

I now have tuned VE so the car can run good but one thing is that I see AFR of 11:1 (very rich) at idle when I start it cold and when it's at operating temperature the AFR goes to 15:1 in Open Loop.

Is there a IPW vs ECT or something like that so I can lean AFR at idle when cold.

The car run great and would not stall anymore so that's a good thing...

[redhotjamedjimi]

there isnt a ect vs stoich for your car. if it stumbles when its cold at 11 then add timing.

[Charger]

It don't stumble at 11:1 so I guess I can leave it like this. Thanks!

I've done some more VE tuning and everything is ok exept LTFT at idle.

It's seems LTFT are good at idle when the car is stopped but as soon as it idle while moving slow, the LTFT goes up to 15% or so..

Is that the idle VE or Low RPM VE table that is used in those conditions?

[redhotjamedjimi]

low rpm ve is with any tps. add 20 % to the table in the low end more than idle. Or mess with the inj pulsewidth vs map. i use that. i found its whne i lose vacuum at low rpms i will bog.

[Charger]

Ok I tried many things but couldn't figure that idle LTFT thing.

In this log I don't even touch the TPS and you can see LTFT goes from 0 to +13 as soon had I get to 4 mph or so.

Does it go on the Low RPM coastdown VE table???

I've mess with the Idle and Low RPM Dbl and Sgl VE table and always see that +13 LTFT.