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Hi all,

I have a 95 CX with a K20Z1, Hybrid Racing harness and KPro. The motor is all stock besides a CAI and exhaust required for the swap. The car has either a 190 or 255lph fuel pump in it. I went to have it dyno tuned last night and ran into some issues. The dyno I was on is a load based dyno, so we can do part-throttle stuff as well. The problem I am having is that the KPro doesn't seem to be responding to changes in the fuel maps. When we add fuel, the car either 1) doesn't respond 2) runs leaner!?! or 3) gets richer temporarily, then reverts back to where it was on the next pull. Yes, we are running in open loop and yes, we are modifying the correct cam angle maps. We thought of a bunch of possibilities that I have listed out below, along with any pertinent information:

1) my O2 is bad - I doubt this is the case, we swapped to my tuner's wideband and his showed the same results as mine

2) there is a fuel problem - the pressure gauge stays rock solid at 55psi the whole time. It is located after the fuel filter, on my FPR.

3) my injectors aren't big enough - I made 225hp on the baseline pull and the stock injectors never went above a low-mid 70% duty cycle...this doesn't sound like the issue to me. We also can't even richen the car at idle.

4) possible wiring issue - this may be...I bought the car as a shell with the wiring already done. It runs and drives fine in closed loop though and I can't think of any wiring issue that would cause the problem we are seeing.

5) the calibration file is corrupt - we based my tune on the "k20a2-rsx-2005" calibration. We then tried switching to another cal (K20a2-rsx-coldair) and got the same results

6) something wrong with the KPro - this is the only thing that I can't come up with any evidence against. Unfortunately, we didn't have another KPro lying around to test and see if we got the same results.

Some more odd things we saw were that we could lean the car out at idle by subtracting fuel, but couldn't richen it past ~14:1 by adding fuel. We added fuel back after leaning it out and it responded to that, but wouldn't continue to richen as we added more fuel. There is also a lean spot between 2800 and 3000rpm where the car wants to run as lean as 20:1 in open loop at part throttle. Again, we tried adding fuel, but it didn't richen up. Sometimes it looked like it did, then after another pull it would go back to being super-lean.

As far as next steps, I am changing the fuel filter just because it is a good thing to do, but I don't expect that to solve anything. I have a set of RDX injectors and may put those on, but again I don't expect it to solve anything. If I can get my hands on someone else's KPro to test with I will, but I don't know anyone who has one.

I datalogged at the last autocross I went to and am attaching the files. It isn't ideal because I am on and off the throttle very rapidly, but in Closed Loop the car doesn't seem to run lean, in fact there are places where it is running pig-rich when I am part throttle (< 30%) with high vacuum and there is a lot of negative s.trim (-25%, that's the computer pulling out fuel, right?). I will try and get a better datalog soon, but it is raining here for the next few days so I am driving my daily driver.

Is there anyone that works for Hondata on this board? I need to reach out to them as I am leaning towards this being an ECU issue, but would like to get your feedback or hear if anyone else has experienced similar issues as well.

Thanks in advance.
 

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Are you uploading the CAL? K-pro is not realtime updating.

Other thing is that, If you are making 225hp, you would be well over 70 duty cycle on stock injectors. Or you are on a high reading dyno.

Short term trim is what the ECU is trim fuel to get it to the CMD a/f. If you have -25%, your maps needs to be tuned.
 

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Discussion Starter #4
Are you uploading the CAL? K-pro is not realtime updating.

Other thing is that, If you are making 225hp, you would be well over 70 duty cycle on stock injectors. Or you are on a high reading dyno.

Short term trim is what the ECU is trim fuel to get it to the CMD a/f. If you have -25%, your maps needs to be tuned.
I am pretty sure we are updating it correctly, this isn't the first KPro my tuner has done. The dyno could be reading high...it was also about 55 degrees when we made the pull. I am going to try and re-upload the cal from my street tune, datalog it, add some fuel, upload and datalog again. I'll upload the cals and the datalog files here when I get them, hopefully early next week.

Have you replaced your fuel pump? I would suggest checking your hoses on the pump its self. if not

what size injectors are you running?
The fuel pump is either 190 or 255lph, I don't remember. The injectors are stock, 310cc. I have a set of RDX injectors to throw on over the winter, but I don't think that is the issue. We are having trouble getting the car to respond to changes at part throttle and idle, where there definitely shouldn't be a problem.
 

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Put your ear up to your tank and see if you can hear fuel spraying inside your tank.
I'd suggest this as well. My buddy put his Turbo kit on his B16, and couldn't figure out why he couldn't get enough fuel to it with AEM. He ****ed with shit, and changed injectors, and scratched his head for 4 days. He couldn't figure it out, so took it all off and returned it to stock, and then he realized he didn't double check his fuel pump. Sure as shit, the clamp broke and even though the pump was pumping fuel into the line still, it wasn't sealed around the pump and was spraying some back into the tank. He's waiting till we move into the new house to put it all back on, but he wasted a TON of time and stress on something so simple.
 

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I'd suggest this as well. My buddy put his Turbo kit on his B16, and couldn't figure out why he couldn't get enough fuel to it with AEM. He ****ed with shit, and changed injectors, and scratched his head for 4 days. He couldn't figure it out, so took it all off and returned it to stock, and then he realized he didn't double check his fuel pump. Sure as shit, the clamp broke and even though the pump was pumping fuel into the line still, it wasn't sealed around the pump and was spraying some back into the tank. He's waiting till we move into the new house to put it all back on, but he wasted a TON of time and stress on something so simple.
Sounds good. I'll check that out, at the very least I will be able to rule it out if nothing is wrong. One question - wouldn't my fuel pressure gauge read low if the pump wasn't sending enough fuel through the lines?
 

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Sounds good. I'll check that out, at the very least I will be able to rule it out if nothing is wrong. One question - wouldn't my fuel pressure gauge read low if the pump wasn't sending enough fuel through the lines?
that's what i would think. if it was spraying back into the tank, wouldn't fuel pressures be lower? hmm... this is a tuffy. i guess your best bet would be to go to the hondata forum and ask the pro's son.
 

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Sounds good. I'll check that out, at the very least I will be able to rule it out if nothing is wrong. One question - wouldn't my fuel pressure gauge read low if the pump wasn't sending enough fuel through the lines?
yes sir, you are right...I already had this problem with a loose clamp on the fuel pump and my fuel pressure went jumpy crazy...like a fuel pump going bad.
I'm lost on your problem as well...when you change the settings on the parameter or tables, do you turn off the car to let it upload or do you just upload it when the car is still running? I don't know...just a thought...cause a buddie of mines has a s300 and he can add/decrease fuel when the car is running (realtime)but our kpros doesnt seem to be able to do that...It might just be the kpro's that we have...but someone with more kpro experience can correct me if i'm wrong..
 
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