CA18DET deceleration issues

Nistune topics specific to the 6802 cpu

Moderator: Matt

mattlovo
Posts: 31
Joined: Fri Jan 01, 2016 10:56 pm

Re: CA18DET deceleration issues

Postby mattlovo » Mon Jun 18, 2018 11:43 pm

Hey Matt and whoever is reading this, after much reading on engines and fuel cut, I realise the dragging issue in deceleration was caused by insufficient fuel.
So I tried to raise the TP min while decelerating downhill as suggested by a fellow Nistune user Louis :)
Got the higher end of the rpm range sorted out and it is better now.

However, I am unable to solve the 800 - 1200 rpm where the idles at with perfect AFRs 14.7-15.0.

If I raise TP min, it gets too rich for that range.
If I don't, the engine drags itself to a slow in high vacuum (AFR 22.2) before it jerks back at 1000rpm where the idle takes over and the ecu resumes fuel injection (AFR goes back to 14.7).
If I cut injector timing, I probably screw up the whole map... :?

As for the rest of the map, AFRs are all good when boosting and cruising.

Will appreciate anyone's inputs on this.
Attachments
Screen Shot 2018-06-18 at 20.35.51.png
Screen Shot 2018-06-18 at 20.35.51.png (61.47 KiB) Viewed 439 times

Matt
Site Admin
Posts: 8085
Joined: Sun Jan 29, 2006 1:45 am
Location: Adelaide, Australia
Contact:

Re: CA18DET deceleration issues

Postby Matt » Tue Jun 19, 2018 12:25 am

What about increasing latency, or increasing the values in that area of the VQ map directly? TP min is effectively a clamp on minimum load

mattlovo
Posts: 31
Joined: Fri Jan 01, 2016 10:56 pm

Re: CA18DET deceleration issues

Postby mattlovo » Fri Jan 11, 2019 2:33 pm

Now I am aware that the fueling on these things has a fuel cut when the engine is decelerating with no throttle input. I have read that the fueling comes back in at 900 RPM.

That seems awfully low.
I dont know if that value is accurate.
If I can adjust this value there is a pretty good chance I could help the engine to catch itself and not stall. I cannot however find an adjustment in Nistune, or is this buried in the coding and not adjustable? (something like an overrun table?)

Matt
Site Admin
Posts: 8085
Joined: Sun Jan 29, 2006 1:45 am
Location: Adelaide, Australia
Contact:

Re: CA18DET deceleration issues

Postby Matt » Mon Jan 14, 2019 11:27 pm

Fuel cut / recovery is between 1200rpm and 1100rpm at 80 degC. Not sure where you read at 900rpm?

mattlovo
Posts: 31
Joined: Fri Jan 01, 2016 10:56 pm

Re: CA18DET deceleration issues

Postby mattlovo » Sun Jan 20, 2019 5:04 pm

Thanks Matt. There seems to be no way to change the settings on this too despite playing around with the Fuel Cut/ Fuel Recovery tables.


Return to “Type 1”

Who is online

Users browsing this forum: No registered users and 7 guests