1996 D21 Surging after 'bad idle speed adjustment'

[Duct Tape and Bubble Gum]

Pretty certainly the KA24E! Looks nothing like the other two. Haven't had a chance to setup an Imgur account and upload pics as I've been occupied fighting with a seized brake caliper slide pin Still scratching my head on the surging issue...

[Duct Tape and Bubble Gum]

Actual shop manuals are amazing, thanks XoXSciFiGuy! Getting better, still got a ways to go.



With the engine cold, I adjusted the adjustment mark on the Fast Idle Cam to be centered back on the roller, as per manual. Corrected clearances when engine was WARM using a stack of thinner feeler gauges to get the clearance between cam and roller within tolerances. Some improvement.


Turned the idle adjustment screw counter-clockwise 1 1/2 turns. Still surges at lower engine speeds while driving, but at least now it doesn't do it so bad that it dies if left idling unattended. Good enough to take to the shop and borrow a code reader! (also, the check engine light came on after the adjustment )


The codes that came up:
P0110
P0120
P1130

[jp2code]

Originally Posted by Duct Tape and Bubble Gum

The codes that came up:
P0110
P0120
P1130

You know what those are, right? Usually a Google search with the code pulls up exactly what is going on.

If you want to get CRAZY
you can put the word Nissan in front of your search word.

The sites engine-codes.com and obd-codes.com are good resources for troubleshooting codes.

P0110 - Intake Air Temperature Sensor
P0120 - Throttle Position Sensor
P1130 - Swirl Control Valve Solenoid

The Intake Air Temperature Sensor will definitely make the engine run bad because it is trying to operate the engine at a different temperature.

[Duct Tape and Bubble Gum]

Yes, thanks!



Any thoughts on testing the AIT sensor? I checked the connections. Gets 4.86 volts supplied to the plug. Good continuity between each side of the little resistor-looking thing and the corresponding leads, so I'm guessing a broken/corroded connection is not the issue.


The testing the two sides/leads of the AIT itself show 'Open Lead' (infinite resistance if I understand my meter correctly) both in the cold garage (Pretty cold, I'm in Alaska) and after hanging it over the stove where we are canning some jam. Anyone know what the normal resistance values are for these? Hard to find that bit in the manual, but I'm guessing this might be toast.

[jp2code]

The 1997 Service Manual has good information on the codes. EC-107 shows that the AIT should be 3.5 V at 68F and 1.23 V at 176F. It says to clean the connections or replace the sensor when it is not.

[Duct Tape and Bubble Gum]

Well,put in a new AIT sensor, codes are still the same and it doesn't run any smoother. I have a Throttle Position Sensor and Swirl Control Valve Solenoid on order, so I guess those are the next steps...

[jp2code]

The MAF is easy to clean and put back in.

[Duct Tape and Bubble Gum]

I put in the new TPS and set it up as per shop manual.... made a HUGE difference. The truck no longer jumps and surges forward while driving. Idle is still a bit inconsistent and after clearing the codes and taking it for a 250 mile test drive it came up with:


P1130 Swirl Control Valve Solenoid


P0500 Vehicle Speed Sensor A


The second one I'm guessing is not related and probably has more to do with the speedo that just works when it feels like it.


I think next step is to troubleshoot and the SCVS circuit and maybe replace the thing.

[PorknBeans]

Just an FYI about P1130...

Be certain to follow the vacuum hose diagram in the service manual drawing(1997 manual is in Engine Control System/ Pg.EC-13 for the vacuum line connections very carefully. The vacuum hose gallery(metal piping/tubes) that the small rubber hoses attach to take twists and turns. So trace them out using your fingers several times to be certain you're on the correct tube/circuit. It is VERY easy to lose your place and which tube/circuit you are on and think you're on the correct one. Only to find out you're on the wrong one. It took me a little while and several tries to find the 2 small vacuum lines that I had inadvertently connected incorrectly and caused my Check Engine Light to come on and stay on until I corrected these 2 connections. I went through each page/component per the service manual and I even checked every component like the solenoid(I even changed it out against my better judgement and it tested good). Even though it clicked when I applied 12VDC to the terminals with alligator clip jumper wires and a small piece of paper between the pins to act as an insulator to keep the alligator clips from shorting each other out. I also used my Mity Vac vacuum pump to test vacuum to the swirl valves inside of the intake manifold at the vacuum line that connects to the SCV. I also went so far as to pin out the output voltage of my ECM using my Fluke 87-V DMM(was reading 0.914VDC and should be showing 11VDC - 14VDC @ under 3.6k rpm) and 2 safety pins while revving the engine in neutral to the specified rpm.

I guess I'm just saying follow the diagram and trace carefully. If you change the vacuum hoses. Change them out ONE BY ONE!

[SBJ]

Originally Posted by PorknBeans

Just an FYI about P1130...

Be certain to follow the vacuum hose diagram in the service manual drawing(1997 manual is in Engine Control System/ Pg.EC-13 for the vacuum line connections very carefully. The vacuum hose gallery(metal piping/tubes) that the small rubber hoses attach to take twists and turns. So trace them out using your fingers several times to be certain you're on the correct tube/circuit. It is VERY easy to lose your place and which tube/circuit you are on and think you're on the correct one. Only to find out you're on the wrong one. It took me a little while and several tries to find the 2 small vacuum lines that I had inadvertently connected incorrectly and caused my Check Engine Light to come on and stay on until I corrected these 2 connections. I went through each page/component per the service manual and I even checked every component like the solenoid(I even changed it out against my better judgement and it tested good). Even though it clicked when I applied 12VDC to the terminals with alligator clip jumper wires and a small piece of paper between the pins to act as an insulator to keep the alligator clips from shorting each other out. I also used my Mity Vac vacuum pump to test vacuum to the swirl valves inside of the intake manifold at the vacuum line that connects to the SCV. I also went so far as to pin out the output voltage of my ECM using my Fluke 87-V DMM(was reading 0.914VDC and should be showing 11VDC - 14VDC @ under 3.6k rpm) and 2 safety pins while revving the engine in neutral to the specified rpm.

I guess I'm just saying follow the diagram and trace carefully. If you change the vacuum hoses. Change them out ONE BY ONE!

^^^This.

Definitely see if it holds a vacuum first.The swirl control valve is on the very back of the intake manifold and there's a good chance the screws holding it on won't play nice when you try and remove them. You want to make 100% sure the valve is actually bad before you commit to replacing it. Really the best way to do it is to pull the intake since you can't get the angle on the screws otherwise. And if you do have to replace it, replace the screws with regular hex head bolts so if it happens again you'll be able to sneak in there with a wrench and get at it.