Extremely Lean After Enthalpy ECU Install
 

Hey guys, been in talks with Martin over at Enthalpy but thought I'd turn to the forums for some insight. My current setup is as follows:
T3/T4 Turbo
370cc Injectors (stock SR)
Z32 MAF
Walbro 255
Stock Internals

ECU is tuned for T25/28, 370's, Z32 MAF, 91 octane

After installing and wiring up the new ECU and MAF car starts but runs completely rich on the AFR... Not sure if these ECUs run on an open or closed loop? Also, if have a faulty knock sensor (code) would cause it to pull the timing enough to run completely lean like this?

Here is a video of current running conditions:https://www.youtube.com/watch?v=Aqt1...ature=youtu.be

Are you letting the engine reach operating temperature?

Aside from the beginning of the video, the engine was at temp

The knock sensor will not change your fuel maps at all. It's really there to tell if there's crappy gas in the tank and will pull timing under light/no load if it senses knock if I remember correctly.

I'd check if your injectors are leaking past the orings. If they aren't I'd then check the maf.

MAF is brand new, and wired to the specs given to me by Martin at Enthalpy. I'll take a look into the injectors

- do you have a good walbro?
- what's your fuel pressure?
- OEM JECS Z32 / N62 MAF?
- do you have any funky rev cuts? (faulty maf or maf wiring)
- did you follow the JWT wiring diagram? It's backwards from what it looks like btw.
- you haven't retimed the car at all?
- where did you get the SR injectors? (I always opt for buying new fiveO injectors, as they use denso blanks, / they do not redrill injectors, and they flow test with heptane at specific pressure and give you flow sheets. New injectors is just nice so you don't have to worry. Redrills are a bad idea.

The tunes enthalpy sends are usually 99% spot on. My car is close to 600whp, and the tune didn't really need to be tweeked on the dyno. And my setup is far from stock. Most of the tunes he sends are actually dynotunes from other cars with the same setup (they've tuned thousands of cars,... literally) .

Walbro, I believe is good. Working at installing a fuel pressure gauge to monitor under different conditions. The MAF is an OEM reman. No funky rev cut at 2500 like a bad MAF. Wiring I used was directed to me by Enthalpy so Im sure thats on point. Car hasn't been retimed. They're stock SR injectors from what I know... Were cleaned and tested by Deatschwerks a few years ago.

weird, i've never heard about brand new oem remanufactured z32 mafs. As long as it's not one of those crappy 100 dollar isis ones u find in enjuku

Its a reman, but exterior is OEM Nissan, I guess they replaced the internals, and nope not an ISIS brand one haha

Shit I have an ISIS MAF on my car. LOL

What has Martin said about it?

First, get a new knock sensor. I could not hear sound on the video, but starting that lean and keeping that lean could be anything fuel / air metering related. So ...bad fuel delivery (pump/injectors/filter/FPR), bad air metering (faulty MAF, boost leak, leaking BOV), or bad mapping.

I'd try with a known working z32 maf, too. If you know someone with a scope, have him analyze the maf response, i am quite sure you got a chinese copy and these are known to have a very poor, unfiltered response.


Dude, when you don't know, don't post.

When the ECU detects knock, it pulls timing AND uses the alternate fuel map and timing map.

If injectors were leaking, he would have hydrolocked his cylinders too.

Could you explain how a boost leak or a leaking bov (if vented) would cause a lean condition?

Let's try that again France:
https://farm8.staticflickr.com/7310/...d967e1d7_z.jpg
^this is from the full service manual by the way. No where does it say that it will change the fuel map or affect anything under normal driving conditions for that matter. It merely pulls timing when it detects knock when the car is NOT in normal driving conditions(aka light/no load), which is what I stated earlier.

And the orings can leak a little or a lot. There are confirmed cases in which an oring is slightly damaged and leaking enough to cause a rich condition. Hydrolock is more common in cases where the intake pipe sucks up a bunch of water when the car drives through a puddle. I'd say that's unlikey here considering that would be some extreme fuel leakage.

If you have a leak after the MAF (turbo, chargepiping, intercooler, bov, manifold etc.)
in vacuum the engine is sucking in air that isn't metered by the MAF. Therefor the ECU doesn't know about some of the air going in, so it creates a lean condition. This is reversed when there is positive pressure as there is metered air leaking OUT of the system. That makes it so the ECU is putting fuel in for air that's not there.

ISIS MAF should be ok. Hell we dynotuned a stock S13 SR with an "ONLYMAF" ebay maf (haha I cautioned him against it). But Martin dynotuned it and got 258whp out of a t25 370cc setup. Then after it we got 255whp out of another stock SR using a JECS OEM N62 MAF. (obviously the MAF didn't make the power difference, it is simply showing that both mafs did the job).

The hot wire element in the ebay MAF was a weird coiled spring instead of the antenna looking element of JECS.

Realize a hotwire maf is simply a wire that is heated by the system to create resistance. So your 5V signal through the MAF is resisted down to .45V or so, and as air flows through it it cools the wire, reducing resistance and increasing voltage. This works realyl well as it accoutns for temperature and air density changes and can accurately meter air MASS instead of using a calculation. This is why OEMs use MAF instead of MAP on turbo application.

-how sure are you on those injectors? (can you try known good sr 370cc injectors from a running stock SR?)
- boost leak test
- test fuel pressure

If it was stuck open, it could pull unmetered air while under vac. It would run rich under boost though so his theory doesn't work here.

- Not exactly sure on the injectors, haven't been tested in a while
- Will also test for boost leaks, but not sure how that would cause me to run lean
- Installing a fuel pressure gauge most likely tomorrow to see how the fuel pressure is

Sent ECU to Enthalpy.... Turns out ECU was tuned for N60 not Z32 as advertised by the guy who sold me the ECU.... Problem solved... Shout out to Martin at Enthalpy for always being extremely helpful.

the only way a leak would cause a lean at idle condition would be if it's past the throttle body. Otherwise, it would run rich. Anything leaking before the TB (Between turbo and throttle body) would cause a rich condition, including a leaky bov.

Ah, and this is straight from Nistune's web page, #2 clearly states not to use fake mafs:
http://i1081.photobucket.com/albums/...psa0e21e60.png

UPDATE: So, after having the ECU retuned and getting bigger injectors, now once installed it is running very rich... 12.3-12.6 at idle and 10.0 while driving... I can get it into boost but bogs heavily and doesn't pull at all.

Any ideas? Not running a boost controller, just the 7lb spring in the external TiAL 38mm wastegate...

Ideas?

Did you get it tuned for the bigger injectors

Yes... was running stock SR's, upgraded to Deatschwerks 550's and had it tuned for them...

Are you still running that Isis maf? Try getting an OEM used one.

For the record my enthalpy tune runs about the same as yours. Idles around 11-12.5 cruises anything over 10% throttle at 10 AFR.

Sucks.

Then you have something wrong with your setup, not the tune.

Didn't saw that answer at the time...

Ask any tuner using a nistune, and he will tell you are wrong. The ECU has 2 sets of fuel & timing maps, when it detects knock it uses the alternate knock maps (and may pull timing on top of that, many users reported this when copying normal maps to knock maps). Or you could just seach the internet for the ECU address file. You will see there are 2 sets of maps. If you are still not convinced, reverse engineer the ecu code. It is an old and simple mcu, so while tedious, it still is easy.



Anyway, mail order tune have their limits and injector modification is not that easy, esp. with a different FPR. Either your injectors are actually bigger than you think, and have a shorter latency than what is in the tune, or you may have a problem with the FPR, or ... the mail order tune is actually very rich on purpose, as no one wants a blown engine because the fuel system is weak.

It is not hard nor to set latency and K correctly, but the tuner really needs the car to get it spot on. It cannot be done without.

UPDATE: Turns out I had a knock sensor code, and I sent back to Enthalpy to have the code erased, got the ECU back and runs much better now, its actually drivable now, but I may get an SAFC II to fine tune.

Big thanks to Martin at Enthalpy for being extremely helpful and handling all of my questions in a timely and thorough manner.

OP what do you mean Enthalpy "erased the code"? Couldn't that have been achieved with an OBD scanner or simply disconnecting the battery? Or did he disable the knock sensor circuit? curious..

I think you might be confusing the functionality of the knock sensor on reflashed ecu's. I wouldn't doubt that those might have additional fuel maps and features should the knock sensor encounter any issues.

I'm not completely ruling out the possibility that Nissan designed the stock ecu's with two fuel/timing maps, but I just have a hard time believing that they wouldn't have mentioned it in the FSM. Case in fact: My engine was producing devastating knock on boost which ended up cracking ring lands on #4 and there was no apparent change in the driveability. Even JimWolf himself told me that the knock sensor is there to retard timing under light loads and was mostly used to "protect" (although very minimal) the engine from bad gas, etc.

Great question... Not sure the exact process in what he did, basically he made so I don't have to replace the knock sensor in order for the ECU to not run in "safety mode" ... so basically ECU doesn't detect the bad knock sensor and throw the code, no more codes..... Maybe thats disabling the knock sensor circuit??

Prob disabled the knock sensor. After changing 4 knock sensors and 3 sub harnesses I told martin to just rid me of that shit. Had no issues for a year, then he came and tuned me on the dyno without it.

Thus were my thoughts as well... Knock sensor could go again, and again, just solve the prob for good

Wish he would come and tune me on the dyno... make my life a little easier ...