Hey guys,

I need a little help.

I am having a weird lean cycling problem during cold idle on Tephra V7.

I've searched through the Tephra threads and believe I've made the necessary cold idle changes and modified my ISCV and fuel tables, but I'm starting to think I have a mechanical issue.

Short story:

1. Starts fine - initial AF=10:1 and idles ok.
2. Leans slightly to 11.5 or so.
3. A/F drops to 18:1 and feels like someone cut an injector off.
4. Rpm's drop and ECU compensates by dropping in 2x the fuel
5. Rpm's and A/F recover and idles fine for awhile.
6. Cycle restarts after 20-30 seconds until car warms up - 120 deg or more

Long story:
See attached log and tune: https://www.dropbox.com/s/hz6bv4oc9n...e%20issues.zip

Theory:

I'm thinking I have a defective injector that stops spraying randomly until it warms up. Notice the IPW does not drop when A:F leans...in fact the ECU tries to add fuel .


BTW - I may have a boost/vacuum leak, but cannot check or resolve right now due to a broken finger However, my LTFT's seem fine (<3%)

Idle at normal operating temps are fine, WOT performance is fine.

What do you guys think?

 

Decided to change the PTE 880's with the new FIC 1100 high Z injectors.

Will report my results after install.

 

My car acts up like that sometimes also. I haven't figured it out yet but every time I cold start it I stay in it and tap the gas every time it leans out. I'm also on tephra v7 and 1050cc fic's.. lookin fwd to seeing how you fix it.

 

have you checked to see if the issue exists with a stock rom?

 

I have not as I don't know how to compensate for the 4bar and UEGO on a stock rom.

Any tips would be appreciated!!

 

Reinstall the stock MAP sensor? If you have a wideband plumbed into the rear O2, that's a bit more work to undo, especially if the rear O2 sensor has been removed entirely.

 

ok, I'll try that if the FIC's exhibit the same behavior.

By chance, have you looked at the logs/tune? If so, any thoughts?

 

Haven't looked. I only have time for quick, probably overly idealistic thoughts. In that vein, I have not ever heard of an injector malfunctioning when cold, so my guess is that its not an injector, and instead, something has gone wrong with disabling OBD, Evap, or other some other ECU setting.

 

Car quite twice while driving during warmup.

Will adjusting the "Relative Air Density vs Temp for Airflow" table allow me to increase IPW during open loop warmup for temps from 20-70F?

I ask because I cannot yet locate a post which explains what each table is used for.

Sorry for the newb question but I've been tuning DSM's for years but Evo's (EcuFlash) is still relatively new to me.

 

just to put it out there i recently experience an injector malfuction only when cold but on a honda, they are bosch 1000cc injectors, just uncertain of the exact brand, when warm and wot everything is 100%, let the car cool overnight and would start the next morning running on 2 cyl.. and nothing would get rid of this unless you rev the car and just finally it warms up and fixes itself, then after that total change and idles perfect. swapped the injectors for a brand new set of ID1000 and problem gone.

i dont think this is your issue since my evo does exactly what your describing..probably to a T ..and i just havent put the time into it to fix it but it has to do with startup fueling tables and such. im on FIC2150 and E85. and is cold here, so thats part of the problem.

 

Thanks for sharing your experience!

To complicate matters, I purchased the car used a few months ago and haven't had time to double check all EGR/Emissions components. On top of that it's my first Evo IX (previous owned DSM's and Evo X) and I have no other Evo around to compare mine too

I'll keep plugging away, the best I can with a broken finger and splint

 

Update:

The new FIC injectors did NOT fix the problem. No biggie, at least I have a nice new set of some nice injectors now

I attempted to perform a boost leak test with my air compressor and couldn't build more than 1psi. At first I thought it might be valve overlap from the kelford cams because I could hear air coming out the exhaust tip and so I continually tried turning the motor to no avail. I could hear air rushing around the TB as well, but could not find a leak anywhere.

Eventually, I discovered that as soon as I disconnect the EGR vacuum hoses, I could build boost like normal during my boost test. With the EGR hoses disconnected, I confirmed no leaks were present.

I left the EGR hoses disconnected and waited for the temps to drop, the same lean/stalling issue was/is present.

At this point I *believe* I may have an EGR valve that is stuck open allowing exhaust gas to enter the intake manifold and cause my idle problems. I've ordered a block-off plate to validate my theory. If the block-off plate resolves the problem, I will buy a new EGR valve as I would like my car to be as stock as possible.

Any thoughts, or have any of you seen anything like this before?

 

This doesnt make sense. With EGR hoses disconnected you would have a big boost leak too. Pull the EGR solenoid valve. Its easy to do and you can bench check it with a vacuum source.

 

Sorry, I forgot to mention I capped off the TB nipples that used to feed the EGR valve.

 

Has anyone seen this behavior from an Egr valve?