Neither I nor the tuner I am working with are having much luck getting my Evo8 to run good when the ECU is in closed loop. It leans out, sputters, and completely loses power until there is enough momentum going to switch to open loop, where the car runs like a champ! It does start and idle without issue.

What information can I provide to the gurus here to get some help figuring out this issue? Does anyone have a working tune off a smoothly running car on e85, SD & the omni 4 bar sensor that I can use to test if I have an issue with my ROM?

 

If you don't mind me asking....who is your tuner?!

 

A local guy here in Phoenix.

 

Well if you nor your current tuner can't figure it out I would suggest taking it to a different tuner. Contact Tony at UMS Tuning or Phuong at Wingz Performance.

 

I appreciate the suggestion, but at this point I really dont want to switch tuners. As I was saying, a fresh set of eyes might be helpful in trying to troubleshoot this issue so what information can I provide?

 

So more information - when the car is cold (sat overnight) it starts, idles like crap, but runs in closed loop at least acceptably. After its been driven for a while, it idles fine but the closed loop issue makes it pretty much un-drivable.

The tuner thinks the injectors (FIC 1750's) might be sticking, but Im not convinced...

 

Bump - anyone?

 

Sticking? As in not clicking? Put a stethoscope up to each injector. I had a couple of customers with injectors working intermittently. One was a new set, so it's possible it's the injectors.

Do you have another set of injectors you could swap out and see if the problem goes away? If it is the same then it's the tune.

Sounds to me like a scalar and/or latency issue. What are your fuel trims, low and mid?

Good luck.

 

I did the stethoscope test while it was sputtering and to me it sounds like they are firing, which is why I am not convinced of the tuners diagnosis :P

Low fuel trim doesnt register due to the car sucking alot of air at idle, and mid is around 3%.

I was able to fix the cold start idle using the "Unknown" ignition table.

I unfortunately dont have any other injectors to test with :/

 

This... you're wasting your and your "tuners" time.. Go to Tony, and he'll take care of you. It's that simple.

 

If there is more air at idle then you need to change your mid to low transition Air Hz table so you can have a separate idle trim. It comes in handy. You want your trims at idle to be separate than cruise. So if cruise trims are -3 and your idle really needs +3 then you could be 6% off. Still not enough for the o2 sensor not to compensate.

Log your o2 voltage. It should read @ 0.1 Volts if it's truly lean. Tap the throttle and the voltage should bounce around up to .9 and everywhere in-between. Could be a bad/lazy o2 sensor.

I'm pretty slammed right now, but you could send me your rom and logs and I can take a look when I get a chance. PM me.

 

Again, Im not ready to switch tuners just yet, or paying twice to get it tuned (you can PM me if you want to know more details) :P

Id appreciate keeping the discussion focused on how to diagnose what the actual issue is.

 

"you need to change your mid to low transition Air Hz table so you can have a separate idle trim"

This. I have actually spent some time searching for how to edit the table in Tephramod V7 but have so far come up short. I actually posted on it in the Tephramod thread earlier today.

 

Did he incorrectly apply the wideband o2 correction patch? Certainly log the o2 voltage and see what is going on.

Also, telling someone to go get it re-tuned by another tuner completely defeats the purpose of this forum. We're all here to educate and mentioning such things is completely counter intuitive.

 

I agree that the main purpose of this forum is to learn/educate, however when someone starts off a post saying "Nor my tuner or I are luck with my Evo etc etc" and here it is 6 days later and the issue has yet to be resolved, then it might be time to have someone else take care of it.