Quick question for anyone who tunes injectors. How often do you have to change the load open loop tables? Im running into an issue where I hit open loop at 2k rpm in 5th because my load is going over 100. This is while cruising at ~25-30% throttle.

 

I personally never need to change these tables when tuning injectors. What is the problem you are running into at 2k in 5th? A log attached will help us to advise you.

 

im not anywhere near 30% throttle while cruising. Sounds like you might be lugging the engine.

 

Sure thing, here you are.
You will notice that my 02 feedback cuts out when I hit 100 load. In 5th gear, low RPM when this happens.

I was able to cure the problem for now by upping those numbers in the tune. Not sure if its the right way, but it does seem odd. Im not pushing boost but take a look at the HZ reading.

Note, I do have a omni 4 bar map. Vacuum isnt 100% accurate in this log, I would disregard these numbers, but regard the change of position. (+-)

Also, what throttle do you cruise at? At idle Im around 13.333%. This is the value I found online.

 

well thinking more about it, there are a lot of variables that could be at play here. It really isn't fair for me to compare my setup to what your seeing. For me 30% throttle would cause acceleration at that RPM not cruise. My TPS sits at 10.9 and ill be cruising between 20-25% in fifth at around 2700 rpm. 2k rpms seems a little low for 5th gear which might be why you are hitting higher loads at that RPM. At what speed are you shifting into 5th and cruising?

 

It very well could be.
Just cruising at 45mph. Its that or keep it in fourth and be around 3k. Only thing effected would be gas mileage. Not a big deal but the car is a tad louder then normal at 3k. Thing is, it never did it on stock injectors. Only reason why I bring it up.

Its fine above, say, 2200rpm.But 2200-2400 rpm is about 50.

 

Your MAF Compensation tables may need tuning and your injectors may need rescaling. They are adding ~10% more fuel from 150-200 Hz (airflow), and ~20% more from 200-250 Hz than your engine actually needs. Your Short Term Fuel Trim (O2 feedback) compensates in closed loop by going negative and removing excess fuel. As a result when you open the throttle slightly and cross into Open Loop at 88 Load, your AFR goes 20% richer than required. This won't harm your engine, but it will make for a slow spool, create clouds of sooty black exhaust smoke, and suck fuel like there's a hole in your tank.

 

I would say that this goes back to the scaling of the injector or something then. Having normal scaling, at WOT, I hit 10.0afr when open loop tables call for 12.0. The open loop table has no effect on my WOT afr. To test I made them all 13 afr from 12. I believe my scaling is around like 900ish when it should be 760ish.

What I might do, save the current rom, load normal injector scaling, retune the fuel trims and see if it still does it. This would make the injector latencies go down about 20-30% from what they are currently set at.

My guess, it would fix it. But then it begs the question, why am I pig rich at WOT. Return line is free and clear to the tank. Maybe fuel pressure reg..? Normally a bad fpr would cause lean conditions.

 

When you say your scaling is around 900 but it should be 760 that sounds like a red flag. What injectors are you running and what do your LTFT's look like? You should definitely be seeing a change when changing values in your fuel table. Just as a sanity check, are you sure your tuning the correct table, not the alt map or low octane map by mistake?

 

Haha yes I am sure. Ive been tuning for some time now, this has been the first time a car has ever reacted in this manner. I actually thought it was something with the alt map setup so making it easier, I placed the e85 maps as the primary so I dont have to press on the pedal every time I flash.
PTE1200. Should be 750ish. Im pushing 900ish. (e85) latency is a little below 1v at 14v. When I do a pull battery voltage only drops to 13.5 so Im not hitting the lower voltage latency. Thinking that was it, I lowered the latency for the 11.7v however nothing changed.

I can tune them at 750 and dial in the latencies at idle and cruise. +-3% which I achieved when I first installed the injectors. End result is super rich at WOT and wot tables have no response. Complete stock long block.

Normally that would mean boost leak. Rich at wot. Leak tested up to 30psi. All good there.

You do make a good point. Ill check to see what my crusing fuel trims are with the current setup.

 

Looking over the trims, they are roughly the same... which leads to more questions. They are below +-5% either way.

 

Start by checking your fuel system thoroughly from tank to rail. When you are sure flow and pressure are in spec. move on to tuning.

 

How many flow meters have you installed in an evo?

I would agree to the pressure. My -6an afpr line should be in tomorrow, so I can verify pressure.

 

if your trims look good then i would say just tune that area where you are crossing over to be around the AFR you want and call it a day. This would be a case where being able to fine tune to your specific driving habits/conditions is the ultimate benefit of being able to self tune.

 

What table would you suggest to tune for crossover? I could pick from a few.