Hello all, please delete this or let me know if this is the wrong place to post, I've never done this before. I've been happily using ms2 and running a turbo for many years now, and it's been nothing but amazing. 2 weeks ago however, I've been running into a lean issue. Car will slowly lean out and can sputter when cruising at highway speeds around 4k, and will be sluggish and lean when shifting low rpm, but will usually come right back to life. Idle seems fine, tune has not changed in a while. Have also lately have a crank/no start condition sporadically, where I have fuel, spark, and (weak?) injector pulse, yet no sign of catching.
Car has a dw200 pump (several months old), FF640 injectors, and a year old fuel filter. Engine is unopened and in working order, and I tuned the car myself over the last few years.
Please let me know if there's any other information anybody would like, and thank you for your time!

 

Post a log.

 

Ecu is currently out to be cleaned of some minor corrosion, but will take a log and post it asap. Probably tomorrow morning at the latest.

 

Post your tune too. Issues can’t be diagnosed with a paragraph of background by even the best of us, make sure to always included tune/datalog.

 

Will do. Here's 2 logs and my current tune. Both logs were taken today, log2 in the morning and log4 in the afternoon. Had several longer drives in between where the car also behaved well. log2 is where the car was driving pretty well, and log4 is when it was very lean and lazy on tip in, and more lean throughout the rev range. Is noticeable in how the car responds, feels sluggish.
I did another fuel pressure test this morning before the fuel rail right at the rubber hose, and get 54ish fuel pressure in boost, and 48 any other time with no changes. So I think I can say for sure that the pump/filter/regulator is ok.
Will also mention that I know the tune is probably garbage in terms of how it looks, but it's been feeling very good for several years now. Have only had to mess with fuel values here and there when I upgraded parts. Also, I run without and IAC.

 

Nothing is amiss in the logs, there's no giant fuel corrections when you're running lean, aside from EGO adding 10% to try and bring it back down to target, unsuccessfully. MAT and CLT are both at similar values, my only guess is that there may be a crack in the exhaust close to the wideband causing abnormally lean readings.

I also prefer to wire in a permanent fuel pressure sensor, so when intermittent problems like this happen, you can be sure it's not fuel pressure related.

You might try giving the MS more than 10% EGO authority, like try 25%, and allow it to operate 0-100%. I'd be curious if this maintains AFR targets and makes the hesitation go away.

Roughly what was the ambient temperature during log2 and log4? I.E., was log2 just after reaching operating temp, and log4 after it had been running for a while and during a warmer part of the day?

 

Definitely possible about there being a slight exhaust leak, but i'm sure there's no cracks on the manifold or anything. And you can for sure tell that the car is truly just running out of fuel when it happens unfortunately. I will try giving EGO more control and seeing what happens. Would a clogged injector do this? Or would that more be lean all the time? Adding a fuel pressure sensor makes me nervous as fuel fires can happen very fast on track, but I'm sure a quality unit would have no problems.
The ambient temp in the first log was around 40 degrees and was warmed up plenty as it was the second drive cycle in that hour. Log4 was around 50 degrees, and was just after warming up. Will also say that Log4 it had felt weird right away, before and after warmup.
Am currently trying to make it drivable for this coming weekend since I have a track day on saturday with 1.5 hours of driving each way, so just stressed trying to find something wrong.
I'll try changing ego right now and seeing what happens. My only worry is that it wont adjust fast enough to keep the values when I need them.

 

Update, just went for a drive. Of course car is now running perfectly fine, but I changed the EGO settings anyway. Will continue to drive with the laptop in the car until this is resolved, so hopefully I can get the issue on a data log with these changes.

 

Nope, EGO was increasing with boost every gear, target was 11.8, you were running more like 12.7. If you were checking fuel pressure at idle or cruise, that's when the fuel pump is barely stressed, high boost/load and at higher RPM is when they struggle. I've seen a lot of install issues, so don't come back and say "well it's a DW200 which should be fine". Pull it and check it anyways.

If this is a track car, 100% install and log fuel pressure with a quality sensor, I install one on any and all track/race builds. Try low doller motorsports, they have some $40/60 sensors. https://lowdoller-motorsports.com/co...Jr4CnfG-5ljO3p

Then just get something like this and put it in your feed line:

 

I did actually pull this pump assembly out last weekend to verify install, sorry I forgot to mention that. All looked well, I unplugged connections to check for loose/burnt terminals as well and it looked good. Didn't realize ego was increasing with each gear though, that's weird. Also when I checked fuel pressure I did get after it enough to be in boost and it never went below 48. I will look into the sensors in the future though thank you. Would it be worth my time to pull the injectors out and check the filter baskets? Just weird that it's been fine for so long and all of a sudden one day its going lean. In my mind with pressure being good, injectors is the only thing that comes to mind.

 

The main 80amp relay can have its contacts carbon up and make resistance which can make the pump underperform. See if it's warm after a drive. And the wiring beneath it.

All of the engine grounds, ppf ground, and chassis grounds should be cleaned and tightened because the electrical system is being stressed. The DW200 is technically pushing the stock wiring.

 

Yes, it’d be worth it to check injector filters. Any relay/pump issue would show up in logged fuel pressure, another reason to make it a permanent addition.

 

Thanks for this info! I noticed that the bigger (main?) Relay that i always pull to de pressurize the fuel system gets pretty hot after running. It's the one under the hood in the back corner of the fuse box. I have ordered another and will replace just because it's a good thing to have anyway. I did go through all the grounds, and put a new lug on the ppf ground last year and all is well there.

 

I figured this as well, even when my car was having this issue it had 48+psi of fuel pressure under load. I was thinking maybe the pump had some sort of physical issue where it could be cavitating and sending air bubbles or something when it gets hot. I'm putting a dw100 in tonight just to see what happens, and I also have a different known good ms2 from a friend that I can try as a last resort. Thank you for all your help, I will update if this gets resolved.

 

Aha! That's what we call an indicator.

That reminds me, I've got a brand new one that I need to sell now that I sold my car. What was the cheapest you found one for? Mine is the JS10 version.

 

well hopefully a new one of these in combination with a less aggressice pump (dw100) puts less stress on things and works better, assuming that's my issue in the first place.

I found this ry-667 relay on Amazon for 31 bucks, it's a lime green looking one and everyone says they work great, even though Amazon says it doesn't fit a miata for some reason.

 

The JS 10 version comes from an RX7 or something. It is bright yellow. Cost about a hundred bucks.

 

Sorry, it was JE16

 

JE1618811

60$ plus shipping on amayama

 

I think I'm all set for now, I saw last night/this morning that my map se sor reading was being erratic even with key on engine off it would bounce around in a weird way. Luckily I have another ecu getting delivered today from a friend so that should fix it in theory. I'm thinking that the map sensor was just reading off day to day and causing me to have an unstable fuel/timing map.