DIY: How To: Cleaning IACV, MAF, throttle: ECU Set, Setting base idle & Timing

pinecitygarage

Known Member
Senior Member
Aug 22, 2009
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SoCal & Baguio
baguioautoforums.com
I tune & work on Nissan B13 and B14 cars daily, specially with the GA16DE and GA16DNE as well as SR20 including chassis set-up, brakes, suspension, engine drivetrain and transmission.

Do a lot of Trackdays, Hillclimb Events and Slalom as well

Enjoy guys!!!

Love & Kisses,
Tevs

Alright guys:

I know a lot of people have had problems with

1. Rough/bad unstable Idle
2. setting timing
3. Setting ECU into timing mode
4. Cleaning and identifying : IACV, MAF, TPS, throttle
5. Setting Base idle and timing
6. Lack of power
7. rough power delivery
8. Hesitation and rough accelaration
9. Fluctuating Idle
10. Engine Dies when A/C is turned off
11. idle drops when turning or doing 3 point turns or when decelerating (slowing down and when in gear putting gear into Nuetral)
12. Engine Dies at any point due added load

This Write-up Most likely will Solve your idle / timing issues as long as everything else in your car is in good working order and their are no other issues like Electrical and Mechanical gremlins

Tools/cleaners you will Need:
1. Carb Cleaner

10, 12 mm sockets and combination wreches, including extensions and ratchets

flathead and philips screwdrivers

large adjustable wrench

pliers and longnose type as well

rags or toilet paper, shop towels or any cloth/papertowel


You Ready Amigo? Lets Get it on!!!

Our BAF forum member Caly brings in his B13 SuperSaloon (GA16DE) ready to get down and dirty
"whats that thing called under the hood? is that the almighty GAY-16DE?"


1st off remove the C-clip securing the MAF pigtail to the MAF assembly

remove the clips that hold the top part of the factory airbox to access the air filter and loosen the 10mm bolt securing the MAF to the airtube, dont forget there are also 2 more 10mm bolts securing the top half to the resonator box connected to the airtube


Here is the MAF assembly connected to the top half of the airbox


look through the hole of within the MAF assembly


you will notice within the small hole, will be the Hotwire Sensors for the MAF - these get dirty overtime - from a distance of about 6 inches away spray some carb cleaner, be careful not to be too close as not to damage the hotwire sensors - keep the carb cleaner tube at a distance when spraying but close enough just to remove dirt and grime on the hotwire sensors


WARNING: use some electrical tape and wrap around the straw of the CARB Cleaner to prevent the straw/tube from flying inside the intake manifold

Next Step - loosen the 10mm bolt that holds the clamp of the Airtube connecting it to the throttle body, open the throttle plate and spray some carb cleaner in there, let it soak


---------- Post added at 12:52 PM ---------- 6 hour anti-bump limit - Previous post was at 12:50 PM ----------

Next step in the cleaning process:

Loosen the IACV actuator plunger with an adjustable wrench, to loosen pull up (remember - Righty Tighty, Lefty Loosey) once loose, just leave it in there and do not remove - Yet
Removing may cause the plunger to fall off as well as the spring - they may get lost and you can easily screw yourself over)



Now loosen the 3 10mm bolts connecting the IACV assembly to the intake manifold then unsnap the electrical socket connectors from the IAC and AAC valve plus use a set of pliers to move down the clamp holding the rubber tube to the AAC valve then remove the assembly - be careful not to tear the gasket


--------------------------------------------------------------------

when disassembling remember how the plungers and springs are oriented within the Actuators and assemblies and be careful as not to lose any springs or plungers

Be Meticulous and organized as not to lose anything, pay attention to Detail

- Disconnect the AAC valve from the IACV assembly using a philips screwdriver
- twist out the IAC plunger assembly - see that littel plunger peeking through - remove that and be careful not to lose the springs.

both Round Assemblies have plungers and springs - remove and disassmble em and clean everything with carb cleaner

Caly has the updated AAC model with the sealed AAC unit with plunger and spring inside - just wipe the outer part out - dont worry about disassembling the AAC

spray carb cleaner on everything, clean the IACV assembly, plungers, springs and actuators with carb cleaner


here is a sample pic of a plunger removed from an AAC (the AAC can be dissembled and the plunger removed on dec 91 to late 92 models) the 92 to 95 models have a sealed AAC, within the early model AAC's (round thingy) there will also be a small spring - remove and clean - dont lose it!



once you are done cleaning everything, reassemble everything once the carb cleaner has evaporated.

Start Engine - (you will have a hard time starting as there still might be carb cleaner left within the intake manifold) Get the engine started and rev no more 4,000RPM until all the smoke stops coming out of the tailpipe then let idle for at least 10 minutes

---------- Post added at 12:56 PM ---------- 6 hour anti-bump limit - Previous post was at 12:52 PM ----------

Now for Setting Base Idle and timing


do the following procedure right after cleaning your IACV, AAC, MAF and intake Manifold

I have Borrowed Pics from a NF forum member, as i DO NOT AGREE with some of his Procedures, follow my steps carefully and use his pictures as a guide to location of parts in engine.

My Procedure is what i have used to Set and Tune Several Philippine Spec GA16DE's with Great Success


Now to set ECU into timing Mode.

with engine running and in operating temp


1. Rev Engine 3 times Not Exceeding 4,000 RPM

2. Turn Off engine

3. Very Important - Do NOT skip this
loosen your 12mm dist bolts



Center your Distributor Position - with everything in working order a centered Distributor should put you within the 10 Degree Timing mark - slightly tighten bolts


4. Pull/Disconnect TPS



5. Start engine

6. Adjust Base Idle Screw until you get 800RPM at idle (adjust idle only when Fan's are NOT ON



7. Once you have base idle Set, Check Timing and Make sure you get 10 Degrees of timing, loosen distributor bolts and adjust as necessary

8. attach timing light inductive cable to #1 Sparkplug wire


9. point your timing light until you see the 6 marks visible up on top the crankshaft pulley - the timing marks will illuminate)


10. here is what you should see and a guide to what the marks mean (the timing marks will illuminate when crank pulley is spinning and you have the timing light pointed at the perfect angle - you will need to adjust the way you point your timing light in order to see the marks), what you want is 10 degrees for stock timing, with the quality of fuel we have here in the Philippines i would go no more than 12 degrees advance, my personal preference is to stay at 10 Degrees


11. adjust distributor position to either advance or retard timing.
Forward to advance
downward to Retard


12. Remember to adjust timing only when FAN is OFF

13. once you have adjusted Base idle and timing, turn off engine and reconnect your TPS.
 
Jul 5, 2010
3
0
501
johor
Hi sifu..and otai2 here…
i need advice here..
my car timing not stable, cannot get below 1200rpm without air cond lar...
this car engine same with you GA16DE
i buy this car last month..
after cleaning and tuning still not ok..
i already lepak with this problem..
the last workshop i go, he said this car engine not complete..
have three pipe with no tubing..
can you help me to check where this pipe connect to?
pleaseeee help me bro,....
 

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dennislnw

Junior Member
Senior Member
Nov 9, 2007
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1,501
Thanks for sharing . i spend $150 at SC and the problem never solve. with your help i spend $15 my problem is solve . :top::top::top::top::top::top::top::top::top::top::top::top:
 

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