Anyone notice upper band power loss with a KL02 VAF?
Anyone notice upper band power loss with a KL02 VAF?
Installed it recently and noticed a slight increase in low rpm torque but a large loss at high RPM's. Am I crazy?
Is this on a K8 (1.8L)? I know Corksport tried it with their project MX-3 on the 1.8L and lost about 10 hp to the wheels.
I would guess that the voltage from the VAF is too high (it decreases as airflow increases), and the ECU thinks there is less air going through the VAF than there is. My reasoning for thinking this is that the ECU from a K8 will work on a KL, as long as you are using the KL VAF and injectors, although it might run a bit rich. This leads me to suspect that the calibration of the ECU's is actually pretty close, and that the different VAF's are calibrated to the matching injectors.
If I am correct, you are likely running pretty lean, and are risking some serious damage to the engine. My recommendations would be to either get a VAF from a 1.8L or get the injectors from a 2.5L. I think either will work.
I would guess that the voltage from the VAF is too high (it decreases as airflow increases), and the ECU thinks there is less air going through the VAF than there is. My reasoning for thinking this is that the ECU from a K8 will work on a KL, as long as you are using the KL VAF and injectors, although it might run a bit rich. This leads me to suspect that the calibration of the ECU's is actually pretty close, and that the different VAF's are calibrated to the matching injectors.
If I am correct, you are likely running pretty lean, and are risking some serious damage to the engine. My recommendations would be to either get a VAF from a 1.8L or get the injectors from a 2.5L. I think either will work.
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jschrauwen
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I'll let you know in a week or so when I remove the KL02 VAF and I put a JE50 VAF and a KL31 ECU in. I'm hoping to see a little improved performance all across the board as well as a more stable idle, once I finally sort the EGR plumbing correctly with a suitable vaccum source while incorporating the K8 PRC solenoid and Kl02 FPR. Those manual diagrams are a real bear but trying to find an EGR layout from the Millenia is almost impossible. Will see, probably a few trial in errors are on the horizon.
Tatsu, I recently read somewhere about introducing a variable controlled type rheostat/resistor that would jump across certain leads on the VAF wire harness to fool the ECU into a richer/leaner config. It seems to fall in line with your statement.
Tatsu, I recently read somewhere about introducing a variable controlled type rheostat/resistor that would jump across certain leads on the VAF wire harness to fool the ECU into a richer/leaner config. It seems to fall in line with your statement.
Last edited by jschrauwen on April 13th, 2005, 1:55 am, edited 1 time in total.
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jschrauwen
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A vaccum/emmissions layout for a Millennia ('95 I beieve??) that identifies specifically the the EGR, FPR, PRC solenoid. I believe that would get me going in the right direction.yvan wrote:hey i can help you out, which diagram do you need, and be specific, i am the diagram man, anything you need just say it.
Overclock, I'll butt out of your thread right now.
'92 GS-ZE - sold, '95 GS - sold, '02 Protege LX - Daughter, '00 Audi A4 2.8 QTip, Ducati TT2
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Hold on a second - my theory has to do with running the KL VAF on a 1.8L (K8), not a ZE.
With the KL-ZE, I would imagine that the calibration of the VAF is likely very similar to that on any other KL, and I'm pretty sure the injectors are the same, so that particular part of my theory is not applicable.
The problem with increasing your fuel pressure (with an AFPR) is that it affects fuel delivery throughout the entire rpm range - you are increasing the amount of fuel delivered by the injector for any given pulse length. If you richen up the top end, you are also richening up the bottom end, and you are also richening up the mixture during part-throttle operation. You are potentially causing a lot of problems (driveability, emissions, mileage and low-end power) to resolve one issue.
All that being said, at this point it is not clear what is going on with your mixture, or even if that is the issue. It may be a faulty VAF...really any number of things.
Let's start from the beginning - what VAF were you using before and which ECU are you running? How was it running before? Why did you change?
With the KL-ZE, I would imagine that the calibration of the VAF is likely very similar to that on any other KL, and I'm pretty sure the injectors are the same, so that particular part of my theory is not applicable.
The problem with increasing your fuel pressure (with an AFPR) is that it affects fuel delivery throughout the entire rpm range - you are increasing the amount of fuel delivered by the injector for any given pulse length. If you richen up the top end, you are also richening up the bottom end, and you are also richening up the mixture during part-throttle operation. You are potentially causing a lot of problems (driveability, emissions, mileage and low-end power) to resolve one issue.
All that being said, at this point it is not clear what is going on with your mixture, or even if that is the issue. It may be a faulty VAF...really any number of things.
Let's start from the beginning - what VAF were you using before and which ECU are you running? How was it running before? Why did you change?
If the 1.8 ECU and KL02 VAF will run the 1.8 engine lean, will the same not apply with a 2.5 engine in it's place?
I'm using the 1.8 ECU and was using the JE50 VAF. Made the engine run ULTRA rich. Now I popped in the KL02 per the recommendations of many people on this site because the fuel consumption was absurd. Now it doesn't seem to be running rich but I lost some high end torque. If the Corksport 10hp loss test applies to my setup, it would make a lot of sense.
I'm using the 1.8 ECU and was using the JE50 VAF. Made the engine run ULTRA rich. Now I popped in the KL02 per the recommendations of many people on this site because the fuel consumption was absurd. Now it doesn't seem to be running rich but I lost some high end torque. If the Corksport 10hp loss test applies to my setup, it would make a lot of sense.
'96 MX-3, KLZE, ZE Curve Neck Intake, KL68 TB, K8 ECU, CAI, KL-02 VAF.
I've pasted in a link to another post I made today - I hope this explains things a bit more clearly, but the short version is that it is not the VAF/ECU combo that is the most critical, it is the VAF/injector combo that is most important. Here's the link:
http://www.mx-3.com/phpbb2/viewtopic.php?t=37432
And in answer to your question, no, running the K8 ECU on a KL with KL VAF and injectors should not be running lean, but it will not be optimal.
Running the VAF from a K8 on a KL with KL injectors, as you were before, will run VERY rich regardless of which stock ECU you are running. Again, check out the other post for more details...
http://www.mx-3.com/phpbb2/viewtopic.php?t=37432
And in answer to your question, no, running the K8 ECU on a KL with KL VAF and injectors should not be running lean, but it will not be optimal.
Running the VAF from a K8 on a KL with KL injectors, as you were before, will run VERY rich regardless of which stock ECU you are running. Again, check out the other post for more details...
Nice post. Makes sense however doesn't actually explain my upper band power loss.
My derived theory from your post: the fuel mapping of the 1.8 ECU doesn't provide enough fuel to the ZE at higher RPM's and since I was running ultra rich before the ZE had more than enough fuel at all RPM's.
But here's the clencher... the ZE ECU (KL31 or KL36) uses the 1.8 VAF (JE50) which would give a 1.8 VAF + ZE injector + ZE ECU combo. That means the ECU itself definitely plays a large part in this equation and it's not only about the VAF and Injectors.
That said, the fact that the KL02 wasn't designed to function with the 1.8 ECU to begin with, one might surmise that there is potential of a misalignment between fuel mapping of the ECU and the air/fuel ratio provided by the KL02 VAF + ZE injectors.
I'm thinking there is either a slightly lean mixture across the board or maybe only at higher RPM's.
Let me know what you think...
My derived theory from your post: the fuel mapping of the 1.8 ECU doesn't provide enough fuel to the ZE at higher RPM's and since I was running ultra rich before the ZE had more than enough fuel at all RPM's.
But here's the clencher... the ZE ECU (KL31 or KL36) uses the 1.8 VAF (JE50) which would give a 1.8 VAF + ZE injector + ZE ECU combo. That means the ECU itself definitely plays a large part in this equation and it's not only about the VAF and Injectors.
That said, the fact that the KL02 wasn't designed to function with the 1.8 ECU to begin with, one might surmise that there is potential of a misalignment between fuel mapping of the ECU and the air/fuel ratio provided by the KL02 VAF + ZE injectors.
I'm thinking there is either a slightly lean mixture across the board or maybe only at higher RPM's.
Let me know what you think...
'96 MX-3, KLZE, ZE Curve Neck Intake, KL68 TB, K8 ECU, CAI, KL-02 VAF.
Interesting - so it would seem that the ZE ECU uses and allows the bastardized combo of K8 (JE-50) VAF and KL injectors. I wonder what the logic was behind that? Parts availability in Japan, I would guess...
So allowing that the KL-DE and KL-ZE use the same injectors (which as far as I know, they do), the KL-ZE ECU seems to be the oddball here. I wonder whether the KF-ZE uses the same combo - I would venture a guess that it does, because the injectors from a K8 probably wouldn't be able to support 175 hp.
This would also lead me to believe that running a ZE ECU with a KL VAF would run very lean, just as running a KL VAF on an otherwise stock K8 does.
So here are the combos that should generally work:
If you look at the power curve of a K8 and a KL-DE (ignoring the actual power figures), they are roughly similar, and roll off quite a bit above 6500 rpm. The ZE, on the other hand, with its more aggressive cams keeps pulling right up to redline. I would imagine that the top-end fuel/timing mapping as well as the VRIS activation points in the ZE ECU are different to allow for this. The fact that some of the guys on Probetalk saw a difference of 6 hp peak with a ZE using a ZE ECU and VAF instead of a DE ECU and VAF would seem to agree with that.
The only way to know for sure would be to hook up a wideband air/fuel ratio meter to figure out whether the fuel mixture really is leaning out up top, or if it is maybe more ignition timing related.
So, my suggestion to you would be to get a KL-ZE ECU and switch back to the JE-50 VAF, buy the Corksport reprogrammed ECU, or have your K8 ECU reprogrammed. The problem with the ZE ECU is that it apparently doesn't do EGR, so if you want to stay more emissions legal, the Corksport ECU or reprogramming your K8 ECU is the only choice.
As I said before, using an AFPR to just bump up the pressure will get you more fuel, but you will get more fuel EVERYWHERE, not just where you need it, so emissions and low to mid-range power will likely suffer for the sake of having it pull right to redline like a ZE should. DON'T DO IT!!!
So allowing that the KL-DE and KL-ZE use the same injectors (which as far as I know, they do), the KL-ZE ECU seems to be the oddball here. I wonder whether the KF-ZE uses the same combo - I would venture a guess that it does, because the injectors from a K8 probably wouldn't be able to support 175 hp.
This would also lead me to believe that running a ZE ECU with a KL VAF would run very lean, just as running a KL VAF on an otherwise stock K8 does.
So here are the combos that should generally work:
- K8 or KL-DE ECU + K8/ZE (JE-50) VAF + K8 injectors (only on 1.8L due to injector size)
KL-DE or K8 ECU + KL VAF + KL/ZE injectors
ZE ECU + K8/ZE (JE-50) VAF + KL/ZE injectors (optimal for ZE or for DE with cams, etc.)
If you look at the power curve of a K8 and a KL-DE (ignoring the actual power figures), they are roughly similar, and roll off quite a bit above 6500 rpm. The ZE, on the other hand, with its more aggressive cams keeps pulling right up to redline. I would imagine that the top-end fuel/timing mapping as well as the VRIS activation points in the ZE ECU are different to allow for this. The fact that some of the guys on Probetalk saw a difference of 6 hp peak with a ZE using a ZE ECU and VAF instead of a DE ECU and VAF would seem to agree with that.
The only way to know for sure would be to hook up a wideband air/fuel ratio meter to figure out whether the fuel mixture really is leaning out up top, or if it is maybe more ignition timing related.
So, my suggestion to you would be to get a KL-ZE ECU and switch back to the JE-50 VAF, buy the Corksport reprogrammed ECU, or have your K8 ECU reprogrammed. The problem with the ZE ECU is that it apparently doesn't do EGR, so if you want to stay more emissions legal, the Corksport ECU or reprogramming your K8 ECU is the only choice.
As I said before, using an AFPR to just bump up the pressure will get you more fuel, but you will get more fuel EVERYWHERE, not just where you need it, so emissions and low to mid-range power will likely suffer for the sake of having it pull right to redline like a ZE should. DON'T DO IT!!!
You're right about the wideband air/fuel ratio meter being our answer. I think that will be the deciding factor to this KL02+KLZE+K8 ECU combo debate and will also give us a good idea of what needs to be changed/tweaked to make this combo work optimally (perhaps even close to a ZE ECU). This could make a lot of happy MX3'ers and save many people big bucks from avoiding the whole ECU purchase/hunt game.
I can't afford to plump down $400 for the sake of testing this now. There must be a ZE driver out there with a wideband air/fuel ratio meter already?
I can't afford to plump down $400 for the sake of testing this now. There must be a ZE driver out there with a wideband air/fuel ratio meter already?
'96 MX-3, KLZE, ZE Curve Neck Intake, KL68 TB, K8 ECU, CAI, KL-02 VAF.
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jschrauwen
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I wish I could get somewhere even close to leaning mine out. The black crap that pukes out at idle is rediculous. Just switched from KL02 VAF/KL01 ECU to JE50 VAF/KL31 ECU. No change or improvement on the richness or idle side. I can't believe that the J-Spec cars these ZE's came from produced that crappy mileage and were this difficult to acquire a reasonable mixture setting. These are not hopped up engines and it should not be such a big pain to get a reasonable powerband or idle mixture. Were using all the correct ancilliaries, I believe, so what's missing? What's the show-stopper here. *As he walks away scratching his head....*
'92 GS-ZE - sold, '95 GS - sold, '02 Protege LX - Daughter, '00 Audi A4 2.8 QTip, Ducati TT2
90 JDM RHD 300ZX TT - 572.1 RWHP | 590.0 RWTQ | 21 PSI | Pump gas
90 JDM RHD 300ZX TT - 572.1 RWHP | 590.0 RWTQ | 21 PSI | Pump gas