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Author Topic: Rich limit, rpm too low on decel  (Read 1929 times)
golfputtputt
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« on: November 11, 2019, 09:59:09 AM »

Will post logs when i get home.

I’m performing some extracurriculars and getting interesting changes.

First example is using the stock 710N dv valve (pneumatic). No codes. No overt symptoms.

Then i switch to a 710G. EDV, rubber diaphragm type driven off the n249 circuit. (new, not ripped). And i get a 17705/P1297/004759 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) code.

It has also started to hit rich limit and very low rpms (sub 400 sometimes) and stalls when trying to return to idle setpoint after a load change (ex: idling in the garage, stabbing the throttle quickly, as it returns back down to idle rpm, it will dramatically undershoot rpm and afr) Switching back to 710N symptoms and code disappear. The 710G only opens when throttle angle delta is more than a certain percentage and is sticking to this rule according to data. Using a cable with the 710N plumbed in and the 710G in the cabin, i can confirm it is actuating when the n249 circuit asks it to.

The 710N is usually open whenever the intake manifold sees vacuum (bench test shows an initial cracking of 5 inhg). From my FR studies and logs, It seems the n249 is responsible for opening the 710N a little sooner to get better safety margins for preventing pressure backing up into the turbo)

I messed with the P air path variables of idle PID (raised all values by .1 excluding the 10, -10 rows) which helped a smidge in the rpm/afr recovery after it plummets but doesn't solve. Its hard to know if the car is over enriching and thats causing it to stall or if the rpm PID is off and its enriching to try and keep the motor alive....?

I messed with KFVAKL which also helped a bit but didnt solve the issue.

As i said, i’m just messing around right now, i could easily put the 710N back and call it a a day and the car will run...ok. Decent. But it’d be cool to have this running/working properly.

Gotta try idle PI functions, check trims and try FKKVS areas. Anyone have any ideas/insight?
« Last Edit: November 11, 2019, 10:10:41 AM by golfputtputt » Logged
golfputtputt
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« Reply #1 on: November 11, 2019, 08:35:46 PM »

Here's the log
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