Anything about Ford EEC tuning. TwEECer and Moates questions dominate, but there's some SCT and OBD-II knowledge too.

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Jtab
Gear Head
Posts: 52
Joined: Sat Oct 21, 2017 8:49 pm

Should N match DSDRPM?

Post by Jtab » Sun Dec 15, 2024 6:33 pm

How is DSDRPM calculated? I assume it is base rpm + act/ect/ect start/buzz adders?

Does it suggest IACV failure if N doesn't meet DSDRPM, or do I need to open my throttle body more with the screw?

Datalog attached.

Thanks in advance!
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1993 F250 460cid. Fiveology Racing is garbage. CBAZA T4M0. Quarterhorse tuned with binary editor.

sswari
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Posts: 9
Joined: Thu Aug 12, 2021 3:33 pm

Re: Should N match DSDRPM?

Post by sswari » Thu Dec 26, 2024 2:38 pm

Everything I have read says, do not adjust the TB screws, Not real sure that it means the IACV is failed, but it might not hurt to give it a good cleaning.
93 F150 Ext cab, 4x4
was 302 now 351w .040
Enginetech ES1020 cam 303 NON-HO firing order
Headman shorty headers
HUG0 EEC
Mismatched axles 10.25 8 lug rear 411 D44 5 lug 3.95 (soon to be converted to 8 lug D44)

Jtab
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Posts: 52
Joined: Sat Oct 21, 2017 8:49 pm

Re: Should N match DSDRPM?

Post by Jtab » Sat Dec 28, 2024 2:14 pm

sswari wrote: ↑Thu Dec 26, 2024 2:38 pm Everything I have read says, do not adjust the TB screws, Not real sure that it means the IACV is failed, but it might not hurt to give it a good cleaning.
[link]https://www.efidynotuning.com/ [/link] says to adjust idle screw as part of base idle reset. I can't say for sure without seeing actual coding/logic, but it makes sense to me to set idle screw for minimum idle to take the load off the IACV.

I'm surprised that I haven't gotten a solid yes or no to this question.
1993 F250 460cid. Fiveology Racing is garbage. CBAZA T4M0. Quarterhorse tuned with binary editor.

JuiceSC
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Re: Should N match DSDRPM?

Post by JuiceSC » Sun Dec 29, 2024 12:14 pm

The stop just needs to be open a little. I set mine to 1 1/2 turns after the screw touched the throttle plate.
As for desired rpm, my Tweecer won't log it, I could never use it. IMO it's not a "must have" in the logs. I find timing advance a good indicator of idle quality, steadier the better.
91 GT, A9P, systemax II, 75mm tb, AFP, 75mm Pro M, 42#, Vortech S trim, GT40 crate 5.0, BBK catted X, flows, Tremec 3550, Pro 5.0, 3.27 gears. Tweecer RT, TunerPro.

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MrsJones
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Re: Should N match DSDRPM?

Post by MrsJones » Thu Jan 02, 2025 2:02 pm

I don't know if I can explain this totally but I'm finding that the closer my fueling is the closer to following DSDRPM the N line gets. Another factor/hiccup I see is the scaling. Sometimes the two lines are separated from each other, other times they are extremely close or on top of each other.

Hope this helped.

Larry
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

sswari
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Joined: Thu Aug 12, 2021 3:33 pm

Re: Should N match DSDRPM?

Post by sswari » Sat Jan 04, 2025 12:17 pm

Jtab wrote: ↑Sat Dec 28, 2024 2:14 pm
sswari wrote: ↑Thu Dec 26, 2024 2:38 pm Everything I have read says, do not adjust the TB screws, Not real sure that it means the IACV is failed, but it might not hurt to give it a good cleaning.
[link]https://www.efidynotuning.com/ [/link] says to adjust idle screw as part of base idle reset. I can't say for sure without seeing actual coding/logic, but it makes sense to me to set idle screw for minimum idle to take the load off the IACV.

I'm surprised that I haven't gotten a solid yes or no to this question.
I forgot about the Base idle Reset.
As for what does the DSDRPM = ??? I thought I had seen notes in one of the strats I have, but Nooooooooooo, Sorry
93 F150 Ext cab, 4x4
was 302 now 351w .040
Enginetech ES1020 cam 303 NON-HO firing order
Headman shorty headers
HUG0 EEC
Mismatched axles 10.25 8 lug rear 411 D44 5 lug 3.95 (soon to be converted to 8 lug D44)

sswari
Gear Head
Posts: 9
Joined: Thu Aug 12, 2021 3:33 pm

Re: Should N match DSDRPM?

Post by sswari » Wed Jun 25, 2025 6:04 pm

Jtab wrote: ↑Sun Dec 15, 2024 6:33 pm How is DSDRPM calculated? I assume it is base rpm + act/ect/ect start/buzz adders?

Does it suggest IACV failure if N doesn't meet DSDRPM, or do I need to open my throttle body more with the screw?

Datalog attached.

Thanks in advance!
Just looking back at this, and turns out, The DSDRPM is the desired RPM at Idle
93 F150 Ext cab, 4x4
was 302 now 351w .040
Enginetech ES1020 cam 303 NON-HO firing order
Headman shorty headers
HUG0 EEC
Mismatched axles 10.25 8 lug rear 411 D44 5 lug 3.95 (soon to be converted to 8 lug D44)

Jtab
Gear Head
Posts: 52
Joined: Sat Oct 21, 2017 8:49 pm

Re: Should N match DSDRPM?

Post by Jtab » Tue Jul 29, 2025 4:50 pm

sswari wrote: ↑Wed Jun 25, 2025 6:04 pm
Jtab wrote: ↑Sun Dec 15, 2024 6:33 pm How is DSDRPM calculated? I assume it is base rpm + act/ect/ect start/buzz adders?

Does it suggest IACV failure if N doesn't meet DSDRPM, or do I need to open my throttle body more with the screw?

Datalog attached.

Thanks in advance!
Just looking back at this, and turns out, The DSDRPM is the desired RPM at Idle
I assumed that was obvious because I asked about IACV. Idle is the only time the ecu can control rpm.
1993 F250 460cid. Fiveology Racing is garbage. CBAZA T4M0. Quarterhorse tuned with binary editor.

sswari
Gear Head
Posts: 9
Joined: Thu Aug 12, 2021 3:33 pm

Re: Should N match DSDRPM?

Post by sswari » Wed Jul 30, 2025 9:22 am

Sorry, not only did I spew out the obvious, but I didn't even really answer the question in the title.
93 F150 Ext cab, 4x4
was 302 now 351w .040
Enginetech ES1020 cam 303 NON-HO firing order
Headman shorty headers
HUG0 EEC
Mismatched axles 10.25 8 lug rear 411 D44 5 lug 3.95 (soon to be converted to 8 lug D44)

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