Cold startup rpm

Decipha's custom GUFX strategy covers all 89-93 foxbody ecu's including the 88 mass-air california ecus.
PaulC-turbo5.0
Posts: 104
Joined: 2021 Feb 15, 21:56
Location: Lancaster New York
Vehicle Information: 1989 fox GT convertible
5.0 stock block, E7 heads, stock cam
Explorer GT40 intake flipped to driver side inlet
Single 67mm On3 BB turbo
Flipped JBA headers, custom SS 2.5" hotside built by me
custom 3" coldside thru On3 intercooler
tuning with Moates QH + TPRT
Dechipa's GUFX and supporting files, couldnt have tuned it myself without him!

Cold startup rpm

Unread post by PaulC-turbo5.0 »

When it fires off initially the rpm is at 1500 instead of the commanded 1200, but the weird part is ispibr is right around zero? I’m still fine tuning isc multiplier but it’s pretty close.
It’s starts smooth and does come down to what’s commanded fairly quickly so I’m fine leaving it as is, but curious as to why it’s overshooting right off the bat?
decipha
Posts: 5033
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Cold startup rpm

Unread post by decipha »

dadrpm adders kick up the commanded idle rpm at startup thats normal

fn82x
PaulC-turbo5.0
Posts: 104
Joined: 2021 Feb 15, 21:56
Location: Lancaster New York
Vehicle Information: 1989 fox GT convertible
5.0 stock block, E7 heads, stock cam
Explorer GT40 intake flipped to driver side inlet
Single 67mm On3 BB turbo
Flipped JBA headers, custom SS 2.5" hotside built by me
custom 3" coldside thru On3 intercooler
tuning with Moates QH + TPRT
Dechipa's GUFX and supporting files, couldnt have tuned it myself without him!

Re: Cold startup rpm

Unread post by PaulC-turbo5.0 »

I pulled out some fuel in the first 15 secs and it’s brought the initial rpms down much closer to what’s being commanded
decipha
Posts: 5033
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Cold startup rpm

Unread post by decipha »

thats not good

if you yanked fuel and rpms dropped then that means it wants that fuel

its best to do it the correct way and put the startup enrichment back in and lower the isc multiplier instead
PaulC-turbo5.0
Posts: 104
Joined: 2021 Feb 15, 21:56
Location: Lancaster New York
Vehicle Information: 1989 fox GT convertible
5.0 stock block, E7 heads, stock cam
Explorer GT40 intake flipped to driver side inlet
Single 67mm On3 BB turbo
Flipped JBA headers, custom SS 2.5" hotside built by me
custom 3" coldside thru On3 intercooler
tuning with Moates QH + TPRT
Dechipa's GUFX and supporting files, couldnt have tuned it myself without him!

Re: Cold startup rpm

Unread post by PaulC-turbo5.0 »

But it’s overshooting the commanded rpm by about 250 for the first 10-15 secs while ispibr is fairly close to zero? My wideband is in warmup mode at this point so I don’t really know what the afr is. I’ve had to pull fuel after 15 secs so I thought it made sense to try it before then too.
decipha
Posts: 5033
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Cold startup rpm

Unread post by decipha »

No
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