FIX: erratic idle, low speed driveability, possibly more - Infamous Nissan

SkinnyG · 02-03-2013, 12:37 AM

(QUESTION for Admin: Should this be in Electrical, or Engine & Drivetrain? - It's an electrical problem, but it's related to Engine and Drivetrain. Please move (or cross post??) as you see fit.)

PROBLEM: Erratic idle, missfire, driveability issue, possible stalling.

My truck would sometimes idle at 1500 rpm for no reason. It would also sometimes surge/buck/fart at low speed cruise. Sometimes a re-start would fix it. Sometimes a quick rev in neutral would fix it. It seemed to be returning more frequently, and getting worse.

The Snap-On MODIS at work suggests ripping into the wiring harness, near the back of the valve cover near the firewall. It says there is a crimp connection in there that runs the injectors. The connection may ~look~ good, but cut it apart and resolder it. So I did.

FIX:

Remove the air filter.* This connection was previously "tweaked" by me with a couple zap straps.* That's the bundle I'm going into.

Unsheath everything.* You will find two connections taped up.* I opened up both.

There five white wires are crimped together near the top.* Below them, you can see some green wires crimped together.

I cut the connection out, and wrapped the wires all together after sliding some heat-shrink tubing up and out of the way (not shown).

Then soldered.

Then heat-shrink tubing.

The white wires are next - vice-grips holding the heat-shrink tubing out of the way.

And heat-shrunk.

And then re-wrapped.

Here's what the wires actually do:

RESULT: Smoother idle, no return of the weird cruise issues or 1500 rpm idle. Cold-start fast-idle works much happier.

Cbohannan101 · 02-03-2013, 01:05 AM

This is what I referred to in the pictures posted to this forum!
http://www.infamousnissan.com/forum/...ad.php?t=25108

SkinnyG · 02-03-2013, 01:13 AM

OH SWEET MOTHER OF NISSAN!

THAT is super helpful!

Makes TOTAL sense now, now that I know what the wires DO.

AWESOME!

hrd_bdy · 02-03-2013, 02:06 AM

anything for Z24i? i checked at work and found nothing. ive got the same problem, it will buck bad once if i accelerate hard or when i cruise at around 2000rpm. so to accelerate, i have to short shift to make it not jerk. it only happens every 3 or 4 months for a week at a time which is odd

a couple of days ago it started happening again, and yesterday i gave every wiring harness connector in the engine bay a tap and went for a drive after and immediately the problem went away.

SkinnyG · 02-03-2013, 03:34 AM

In searching, I found the same sort of thing for the early Z24 - the harness issues were (in the forum I found) on the passenger side of the engine compartment, near the fuel filter sort of thing.

Linkie: http://forums.nicoclub.com/86-5-z24i...d-t491625.html

Imagery (not mine):

hrd_bdy · 02-03-2013, 04:24 AM

thanks for the info, gonna check those harnesses tomorrow. i usually nudge some wires changing the oil filter in that area so that might be causing it

SkinnyG · 02-03-2013, 05:08 AM

Switched pictures to Photobucket for the time being.

sicnis · 02-03-2013, 05:00 PM

i just saw this bulletin from a link dvdswan posted the other day, basiclly the full img of what cbohannan posted
thanks for doing the real work and pics skinnyg i love this forum!

dvdswan · 02-03-2013, 06:18 PM

they also have answered it on http://www.nissanforums.com/hb-truck...ut-solved.html

Cbohannan101 · 02-03-2013, 07:53 PM

If I could figure out how to post more I would! My shop's data software is a straight a-hole when it comes to sharing.
I can post any of the diagrams, but i cant get any words to save or even give me options related to saving...
Anyway, glad you got some good info Skinny G.

02-03-2013, 12:37 AM	#1
SkinnyG UYFBR Join Date: Sep 2008 Location: Okanagan Valley - Canada, eh?! Posts: 1,500 Vehicle: 1994 Hardbody Thanks: 0 Thanked 205 Times in 147 Posts	FIX: erratic idle, low speed driveability, possibly more (QUESTION for Admin: Should this be in Electrical, or Engine & Drivetrain? - It's an electrical problem, but it's related to Engine and Drivetrain. Please move (or cross post??) as you see fit.) PROBLEM: Erratic idle, missfire, driveability issue, possible stalling. My truck would sometimes idle at 1500 rpm for no reason. It would also sometimes surge/buck/fart at low speed cruise. Sometimes a re-start would fix it. Sometimes a quick rev in neutral would fix it. It seemed to be returning more frequently, and getting worse. The Snap-On MODIS at work suggests ripping into the wiring harness, near the back of the valve cover near the firewall. It says there is a crimp connection in there that runs the injectors. The connection may ~look~ good, but cut it apart and resolder it. So I did. FIX: Remove the air filter.* This connection was previously "tweaked" by me with a couple zap straps.* That's the bundle I'm going into. Unsheath everything.* You will find two connections taped up.* I opened up both. There five white wires are crimped together near the top.* Below them, you can see some green wires crimped together. I cut the connection out, and wrapped the wires all together after sliding some heat-shrink tubing up and out of the way (not shown). Then soldered. Then heat-shrink tubing. The white wires are next - vice-grips holding the heat-shrink tubing out of the way. And heat-shrunk. And then re-wrapped. Here's what the wires actually do: RESULT: Smoother idle, no return of the weird cruise issues or 1500 rpm idle. Cold-start fast-idle works much happier. __________________ No longer an active member - The Hideous Hardbody has been sold Last edited by SkinnyG; 03-14-2018 at 11:59 PM.

02-03-2013, 01:13 AM	#3
SkinnyG UYFBR Join Date: Sep 2008 Location: Okanagan Valley - Canada, eh?! Posts: 1,500 Vehicle: 1994 Hardbody Thanks: 0 Thanked 205 Times in 147 Posts	OH SWEET MOTHER OF NISSAN! THAT is super helpful! Makes TOTAL sense now, now that I know what the wires DO. AWESOME! __________________ No longer an active member - The Hideous Hardbody has been sold

02-03-2013, 02:06 AM	#4
hrd_bdy my pen is huge Join Date: Nov 2012 Location: Edmonton, AB Posts: 1,155 Vehicle: 1988 D21 Thanks: 18 Thanked 96 Times in 93 Posts	anything for Z24i? i checked at work and found nothing. ive got the same problem, it will buck bad once if i accelerate hard or when i cruise at around 2000rpm. so to accelerate, i have to short shift to make it not jerk. it only happens every 3 or 4 months for a week at a time which is odd a couple of days ago it started happening again, and yesterday i gave every wiring harness connector in the engine bay a tap and went for a drive after and immediately the problem went away. __________________ ex 1992 Nissan Maxima GXE VG30E auto- retired at 429k 1988 Nissan D21 KingCab Z24i 5spd- retired at 248k current 1979 Toyota Supra 4ME 5spd 1981 Toyota Hilux longbox 22R 4x4 4spd 1991 Toyota Crown Royal Saloon 7MGE auto imported from Tokyo 2000 Chev Silverado 2500 6.0 4x4

02-03-2013, 03:34 AM	#5
SkinnyG UYFBR Join Date: Sep 2008 Location: Okanagan Valley - Canada, eh?! Posts: 1,500 Vehicle: 1994 Hardbody Thanks: 0 Thanked 205 Times in 147 Posts	In searching, I found the same sort of thing for the early Z24 - the harness issues were (in the forum I found) on the passenger side of the engine compartment, near the fuel filter sort of thing. Linkie: http://forums.nicoclub.com/86-5-z24i...d-t491625.html Imagery (not mine): __________________ No longer an active member - The Hideous Hardbody has been sold

02-03-2013, 04:24 AM	#6
hrd_bdy my pen is huge Join Date: Nov 2012 Location: Edmonton, AB Posts: 1,155 Vehicle: 1988 D21 Thanks: 18 Thanked 96 Times in 93 Posts	thanks for the info, gonna check those harnesses tomorrow. i usually nudge some wires changing the oil filter in that area so that might be causing it __________________ ex 1992 Nissan Maxima GXE VG30E auto- retired at 429k 1988 Nissan D21 KingCab Z24i 5spd- retired at 248k current 1979 Toyota Supra 4ME 5spd 1981 Toyota Hilux longbox 22R 4x4 4spd 1991 Toyota Crown Royal Saloon 7MGE auto imported from Tokyo 2000 Chev Silverado 2500 6.0 4x4

02-03-2013, 01:05 AM	#2
Cbohannan101 ChrisXer92 Join Date: Dec 2012 Location: Atlanta, Georgia Age: 25 Posts: 161 Vehicle: (RIP)1992 Nissan Hardbody & 1996 Nissan 240sx S14 Thanks: 12 Thanked 11 Times in 11 Posts	This is what I referred to in the pictures posted to this forum! http://www.infamousnissan.com/forum/...ad.php?t=25108

02-03-2013, 05:08 AM	#7
SkinnyG UYFBR Join Date: Sep 2008 Location: Okanagan Valley - Canada, eh?! Posts: 1,500 Vehicle: 1994 Hardbody Thanks: 0 Thanked 205 Times in 147 Posts	Switched pictures to Photobucket for the time being. __________________ No longer an active member - The Hideous Hardbody has been sold

02-03-2013, 05:00 PM	#8
sicnis Join Date: Nov 2010 Location: SanAntonio Tx Age: 35 Posts: 1,483 Vehicle: 1993 D21 Reg. Cab Thanks: 164 Thanked 150 Times in 139 Posts	i just saw this bulletin from a link dvdswan posted the other day, basiclly the full img of what cbohannan posted thanks for doing the real work and pics skinnyg i love this forum! __________________

02-03-2013, 06:18 PM	#9
dvdswan Super Moderator Join Date: Mar 2009 Location: Port Orchard, WA Posts: 4,538 Vehicle: 96 HB Thanks: 154 Thanked 597 Times in 527 Posts	they also have answered it on http://www.nissanforums.com/hb-truck...ut-solved.html __________________ Dave 96 HB XE SAS'd D44 3-link on 35s http://www.cardomain.com/ride/2618002

02-03-2013, 07:53 PM	#10
Cbohannan101 ChrisXer92 Join Date: Dec 2012 Location: Atlanta, Georgia Age: 25 Posts: 161 Vehicle: (RIP)1992 Nissan Hardbody & 1996 Nissan 240sx S14 Thanks: 12 Thanked 11 Times in 11 Posts	If I could figure out how to post more I would! My shop's data software is a straight a-hole when it comes to sharing. I can post any of the diagrams, but i cant get any words to save or even give me options related to saving... Anyway, glad you got some good info Skinny G.

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