Go Back   Infamous Nissan - Hardbody / Frontier Forums > Tech Area > Engine and Drivetrain

Reply
 
Thread Tools Display Modes
Old 09-27-2021, 12:31 AM   #1
low&slo ka24
 
low&slo ka24's Avatar
 
Join Date: May 2021
Location: Xenia, Ohio
Posts: 45
Vehicle: ‘93 Nissan 850 L4
Thanks: 3
Thanked 0 Times in 0 Posts
Default Dumb Idea

Alright, suppose a guy has become tired of bad launches (I beat on my truck) and wants something those kids have gone out and done to every car they touch. A cool thing called “2 step” or “launch control” might be what I’m talking about. Upon some testing, disconnecting the MAF limits engine at 2,500 RPM, about where I want it. Previous guy that had the truck took windshield sprayers out but left the harness. Suppose I want to use the switch for the sprayers as my switch and ground out one of the wires for the MAF to limit it at 2.5K. Top wire on MAF is 12v, middle is signal 0-5v, and bottom is ground. How would one go about this without needing a fire extinguisher upon the first test?
__________________
“Great, now that it runs you can drive it to the junkyard!”
low&slo ka24 is offline   Reply With Quote
Old 09-27-2021, 12:51 AM   #2
alabama_lowlife
Owner and Administrator
 
alabama_lowlife's Avatar
 
Join Date: Sep 2008
Location: jack, alabama
Age: 42
Posts: 10,617
Vehicle: 2012 370Z, 1970 Datsun 521, 1995 Nissan Hardbody x2
Thanks: 1,044
Thanked 2,167 Times in 1,780 Posts
Default

I’m just getting in so I don’t feel like looking it up right now, but remind me later and I’ll look at the diagram and tell you which wires you need to use. You won’t need a fire extinguisher but you may want a big drain pan in case the engine or transmission shit themselves
__________________
alabama_lowlife is offline   Reply With Quote
Thanked by:
Foul_Mouth (09-27-2021), low&slo ka24 (09-27-2021)
Old 09-27-2021, 12:59 AM   #3
Deerhurst
4/86 SE-V6 2 tone 4x4 HB
 
Deerhurst's Avatar
 
Join Date: Apr 2013
Location: Oregon
Posts: 7,897
Vehicle: 1986.5 SE-V6 4WD D21, 2003 Audi A4 Avant 3.0 Quattro
Thanks: 905
Thanked 1,047 Times in 946 Posts
Default

If you piss off the ECM you'll probably see 2500RPM Max as it goes into limp mode.
__________________
1986.5 SE-V6 4X4 D21 Hardbody
Pacesetter Long Tube Headers
Morimoto Mini D2S HID Projectors and Hella 500s
VG33i
Deerhurst is offline   Reply With Quote
Old 09-27-2021, 01:27 AM   #4
low&slo ka24
 
low&slo ka24's Avatar
 
Join Date: May 2021
Location: Xenia, Ohio
Posts: 45
Vehicle: ‘93 Nissan 850 L4
Thanks: 3
Thanked 0 Times in 0 Posts
Default

That’s basically what it is, it limits at 2500 until you give it signal again and it pops right back to normal. Auto ECM in a manual swap so not too worried about limp mode.
__________________
“Great, now that it runs you can drive it to the junkyard!”
low&slo ka24 is offline   Reply With Quote
Old 09-27-2021, 01:43 AM   #5
Deerhurst
4/86 SE-V6 2 tone 4x4 HB
 
Deerhurst's Avatar
 
Join Date: Apr 2013
Location: Oregon
Posts: 7,897
Vehicle: 1986.5 SE-V6 4WD D21, 2003 Audi A4 Avant 3.0 Quattro
Thanks: 905
Thanked 1,047 Times in 946 Posts
Default

You should worry about limp mode. It doesn't affect the tranny but it does affect the motor. You are stuck with a 2500rpm limit in limp mode
__________________
1986.5 SE-V6 4X4 D21 Hardbody
Pacesetter Long Tube Headers
Morimoto Mini D2S HID Projectors and Hella 500s
VG33i
Deerhurst is offline   Reply With Quote
Old 09-27-2021, 01:56 AM   #6
low&slo ka24
 
low&slo ka24's Avatar
 
Join Date: May 2021
Location: Xenia, Ohio
Posts: 45
Vehicle: ‘93 Nissan 850 L4
Thanks: 3
Thanked 0 Times in 0 Posts
Default

Right, but that’s the thing. I tested it, it is only in limp mode until it gets signal again. It being in limp mode and limiting at 2500 is the purpose of the switch, and any amount of time with the maf unplugged, plugging it back in puts it right back to normal because it gets signal.
__________________
“Great, now that it runs you can drive it to the junkyard!”
low&slo ka24 is offline   Reply With Quote
Old 09-27-2021, 01:59 AM   #7
low&slo ka24
 
low&slo ka24's Avatar
 
Join Date: May 2021
Location: Xenia, Ohio
Posts: 45
Vehicle: ‘93 Nissan 850 L4
Thanks: 3
Thanked 0 Times in 0 Posts
Default

I can see what you are saying though, and that was the concern for me, and that’s why I tested, and I have easy access to the ECM to reset the codes if need be.
__________________
“Great, now that it runs you can drive it to the junkyard!”

Last edited by low&slo ka24; 09-27-2021 at 02:23 AM.
low&slo ka24 is offline   Reply With Quote
Old 09-27-2021, 12:33 PM   #8
Deerhurst
4/86 SE-V6 2 tone 4x4 HB
 
Deerhurst's Avatar
 
Join Date: Apr 2013
Location: Oregon
Posts: 7,897
Vehicle: 1986.5 SE-V6 4WD D21, 2003 Audi A4 Avant 3.0 Quattro
Thanks: 905
Thanked 1,047 Times in 946 Posts
Default

I know my truck, which electrically is different Frome every following year, does not recover without a power cycle.
__________________
1986.5 SE-V6 4X4 D21 Hardbody
Pacesetter Long Tube Headers
Morimoto Mini D2S HID Projectors and Hella 500s
VG33i
Deerhurst is offline   Reply With Quote
Old 09-27-2021, 03:32 PM   #9
low&slo ka24
 
low&slo ka24's Avatar
 
Join Date: May 2021
Location: Xenia, Ohio
Posts: 45
Vehicle: ‘93 Nissan 850 L4
Thanks: 3
Thanked 0 Times in 0 Posts
Default

Maybe something different between VG and KA? And it was the MAF limit, I checked and you get a CEL after around a minute and a half, that engages limp mode and a permanent limit at 2500 until the codes are reset. But for my purposes it would only be for 2-3 seconds at a time.
__________________
“Great, now that it runs you can drive it to the junkyard!”
low&slo ka24 is offline   Reply With Quote
Old 09-27-2021, 04:53 PM   #10
Deerhurst
4/86 SE-V6 2 tone 4x4 HB
 
Deerhurst's Avatar
 
Join Date: Apr 2013
Location: Oregon
Posts: 7,897
Vehicle: 1986.5 SE-V6 4WD D21, 2003 Audi A4 Avant 3.0 Quattro
Thanks: 905
Thanked 1,047 Times in 946 Posts
Default

86.5 is special. I don't even have a CEL.
__________________
1986.5 SE-V6 4X4 D21 Hardbody
Pacesetter Long Tube Headers
Morimoto Mini D2S HID Projectors and Hella 500s
VG33i
Deerhurst is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 03:57 AM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.