Jump to content
SAU Community

Recommended Posts

Hello,

Today I cleaned the throttle body/plenum because it was absolutely caked with black oily/soot/dirt

Now i have performed the Accelerator Pedal release position learning, throttle valve closed position learning, and idle air volume learning.

The car use it idle fine around the 650-700 RPM.

After cleaning the throttle body off all the dirt, i noticed it had a gap all around the body which would let air through.

when performing the throttle valve closed position, i notice that the butterfly valve moves all the way back to the closed position then back to original with a gap. obviosly because our cars dont have idle air control valves this gap is necessary to allow idling.

Now when i perform the idle air volume learning the car starts fine then slowly drops the idle to around 800 rpm, which is still high. when you rev the car a few times it still returns to 800 rpm.

However when you stop the car and restart it the idle goes back to 1000rpm, which means it hasn't learnt the new idle air volume. Also if you put it into D or R it drops back to 800rpm.

Other than putting all the dirt/oil back around the throttle body/butterfly valve does anyone know how to get the idle back down.

Ive tried all the procedured numerous times.

Thanks

Pete

03' V35 Sedan 350GT-8

Link to comment
https://www.sau.com.au/forums/topic/278302-cleaned-throttle-body-now-revs-high/
Share on other sites

  • Replies 46
  • Created
  • Last Reply

Top Posters In This Topic

I feel some sanity. I thought I have been going insane for the last few months with exactly the same problem.

When I had my throttle body cleaned is the same time this problem started for me.

So it sounds like it is some thing to do with the position of the butterfly in the throttle body. It sounds like the adjustment of the butterfly is changed slightly during the cleaning process. It was suggested to me that the screw on the top of the throttle body can be adjusted to alter idle. I want to some reading on this before I change mine and also mine would not move.

I have read in other threads about the calibration be out if the butterfly is moved by hand.

But thank you, at least I now know I need to focus on the throttle body to fix this problem.

Cheers

Andy

Hi Andy,

I dont think it has anything to do with moving it by hand when cleaning.

I to tried adjusting that screw, however its seems to have a loctite sealant holding it in place, plus the lock nut.

Ive been reading the G35Driver, and a 350z forum, and some say that when they took it to Nissan the used consult to reset it. i dont think anything they do with consult is any different to what we do with the non-consult way.

Ive disconnect the battery tonight and will try again tomorrow.

Cheers

Pete

Hi Andy,

I dont think it has anything to do with moving it by hand when cleaning.

I to tried adjusting that screw, however its seems to have a loctite sealant holding it in place, plus the lock nut.

Ive been reading the G35Driver, and a 350z forum, and some say that when they took it to Nissan the used consult to reset it. i dont think anything they do with consult is any different to what we do with the non-consult way.

Ive disconnect the battery tonight and will try again tomorrow.

Cheers

Pete

When I took mine to Nissan they were no help, they said the idle should be 800 even though there is a sticker on the bonnet showing it should be 650 +- 50.

I have been trying all sorts of idea's but it is good to know that it relates to the throttle body cleaning.

I will keep serching and let you know what i find out.

Cheers

Andy

see, i cleaned mine months ago, and it was fine before and after......... i did the same thing to andys car.

andy your plugs have been changed yes? pete how about yours?

i did mine at the same time. but idle was fine beforehand. i had a stutter at low rpm but has now been attributed to the gearbox

see, i cleaned mine months ago, and it was fine before and after......... i did the same thing to andys car.

andy your plugs have been changed yes? pete how about yours?

i did mine at the same time. but idle was fine beforehand. i had a stutter at low rpm but has now been attributed to the gearbox

No, I haven't changed my plugs yet. That is coming very soon.

I have been out in the cold tonight remounting the throttle body as I realized we had the gasket in the wrong way. We had one of the tabs pointing up and apparently the one side without a tab is the top.

I am thinking more along the lines that some how the base setting is out and I suspect the adjustment screw that is fairly firmly fixed is the way of fixing it.

Will talk to North Shore Prestige tomorrow along these lines.

Cheers

Andy

Did you reset the ECU and take it for a 20min drive???

No, I haven't reset the ECU, but I have done a 20 minute drive after setting the idle speed through the idle learning procedure.

I am not 100% sure how to reset the ECU on the M35.

I have seen that on the C34 people have said to disconnect the battery, pump the brake to remove residual power and then reconnect battery.

Can any one confirm if this is correct?

How do you reset the ECU on the V35?

Cheers

Andy

Tried and FAILED.

Reset ECU (battery disconnected and brake pumped), drove 10 mins to warm up. Reset TPS, Throttle body and Idle volume learning. Idled at 725rpm. Drove 50 minutes to work, idle now at 800 rpm.

Turned car off, restarted, idle still at 800 rpm.

Got to be that adjustment screw.

this is the right procedures of doing it.

How to reset your ECU and perform the Throttle Pedal Release and Idle Air Volume Learning procedures on an Nissan 350Z.

Before attempting any of the following procedures, it is advisable that you read through the instructions thoroughly and familiarize yourself with them.

A stop watch or an analog clock with a second’s needle will be useful.

**a quick reset can be accomplished by disconnecting the negative battery terminal, and depressing the brake a few times.

ECU Resetting Procedures

Timing is extremely critical. If it is NOT DONE within the specify time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON.

Operations Procedures

1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.

2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.

2a. Fully depress the accelerator pedal (HARD).

2b. Fully release the accelerator pedal.

3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.

4. Fully release the accelerator pedal (while the CEL is still blinking)

5. Wait about 10 second.

6. Fully depress the accelerator pedal and keep it for more than 10 seconds.

7. Fully release the accelerator pedal (The CEL light will continue to blink).

8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.

If the CEL light continues to remain ON, repeat the above steps. Timing is EXTREMELY critical to resetting the ECU.

Accelerator Pedal Release Position Learning

Operation Procedure

1. Make sure that the accelerator pedal is fully released.

2. Turn ignition switch “ON” and wait at least 2 seconds.

3. Turn ignition switch “OFF” wait at least 10 seconds.

4. Turn ignition switch “ON” and wait at least 2 seconds.

5. Turn ignition switch “OFF” wait at least 10 seconds.

Throttle Valve Closed Position Learning

Operation Procedures

1. Make sure that accelerator pedal is fully released.

2. Turn ignition switch to “ON”.

3. Turn ignition switch to “OFF” wait at least 10 seconds.

Make sure that the throttle valve moves during above 10 seconds by confirming the operating sound.

Idle Air Volume Learning (Throttle Position Learning)

It is better to count the time accurately with a clock. 1. Perform “Accelerator Pedal Released Position Learning”.

2. Perform “Throttle Valve Closed Position Learning”.

3. Start engine and warm it up to normal operating temperature.

4. Turn ignition switch “OFF” and wait at least 10 seconds.

5. Confirm that the accelerator pedal is fully released, then turn ignition switch “ON” and wait 3 seconds.

6. Repeat the following (steps 7a, 7b) procedures quickly five times within 5 seconds.

7a. Fully depress the accelerator pedal (HARD)

7b. Fully release the accelerator pedal.

8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the Check Engine Light (CEL) stops blinking and turned ON.

9. Fully release the accelerator pedal within 3 seconds after the CEL is ON.

10. Start engine and let it idle.

11. Wait 20 seconds.

12. Rev up the engine two or three times and make sure the idle speed and ignition timing are within the specifications.

i cleaned my throttle bodies just by spraying by not Touching the fly. Lot's of people that touched it stuffed up the idle.

but my idle is still normal now at 700 - 600rpm after the cleaning.

My mechanic cleaned mine when this happen so I don't really know what was done but this is starting to make a lot more sense.

I am hoping (please, please, please) that the adjustment screw on the top will help resolve this problem. Enquiries are being made.

Cheers

Andy

ok after looking at the throttle body online, that screw probably doesnt adjust the throttle position, but it MAY adjust the sensor attached to it. this might be why its idling high. that said, it shouldnt have really affected the idle at all, and that screw probably only adjusts the 'idle' voltage sent to the ecu which is calibrated from the factory. short of opening it up, you wont really know.

but if you were going to muck around with it, check the idle voltage (while engine is at operating temp) BEFORE you stuff around with it. maybe adjust it down a few 0.xs of a volt to see how it goes. if it doubt. put it back where it was before.

maybe a few cars can measure their idle voltage and post it in this thread. both 'working' and 'not-working' cars.

also might be the engine water temp sensor is stuffed causing the high idle thinking the engine is still slightly cold and keeping the revs up.

OK UPDATE

I have just been down and NorthShore Prestige have a further look at the problem and exploring solutions.

The adjustment screw is FAIL. It will not move so no hope of checking it.

I have thought this through further and now I do not think it is anything to do with the throttle body, except that by cleaning it I changed the volume of air that gets past at idle.

We pulled off the hose that comes from the PCV valve on the right bank in to the manifold.

* If this is blocked off the idle is lower.

* When the motor is revved a couple of times, when the car comes back to idle a hissing noise can be heard from this pipe. (it is not leaking, pipe has been replace and checked for leaks).

* This suggests that the one way valve in the PCV is not shutting off at low RPM as it should.

I have had 2 problems that I thought were unrelated.

1. when pulling up fast (hard braking) idle would dip and sometimes stall. I then had the TB cleaned and the TPS / Idle volume reset.

2. The car now can have the idle set correctly by the set out procedure. Go for a drive and the idle creeps back up.

Whilst I first thought these were unrelated I now realize that the dirty throttle body was creating the dipping idle and covering the leaking PCV valve.

Fixed the TB (cleaned) and the volume of air getting through is now higher and add to that the air from the leaking PCV valve and I think this is leading to the higher idle. As I said earlier, I can set it correctly and then it sticks open and idle increases.

This sort of explains why no ECU faults are showing.

I have ordered the new PCV. Got to come from Japan so about 7-10 days I will know some more.

Fingers and legs crossed now this is right.

Cheers

Andy

PS. Ben also said that the PCV is replaced on a lot of V35's

Edited by andy65b

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Next on the to-do list was an oil and filter change. Nothing exciting to add here except the oil filter is in a really stupid place (facing the engine mount/subframe/steering rack). GReddy do a relocation kit which puts it towards the gearbox, I would have preferred towards the front but there's obviously a lot more stuff there. Something I'll have to look at for the next service perhaps. First time using Valvoline oil, although I can't see it being any different to most other brands Nice... The oil filter location... At least the subframe wont rust any time soon I picked up a genuine fuel filter, this is part of the fuel pump assembly inside the fuel tank. Access can be found underneath the rear seat, you'll see this triangular cover Remove the 3x plastic 10mm nuts and lift the cover up, pushing the rubber grommet through The yellow fuel line clips push out in opposite directions, remove these completely. The two moulded fuel lines can now pull upwards to disconnect, along with the wire electrical plug. There's 8x 8mm bolts that secure the black retaining ring. The fuel pump assembly is now ready to lift out. Be mindful of the fuel hose on the side, the hose clamp on mine was catching the hose preventing it from lifting up The fuel pump/filter has an upper and lower section held on by 4 pressure clips. These did take a little bit of force, it sounded like the plastic tabs were going to break but they didn't (don't worry!) The lower section helps mount the fuel pump, there's a circular rubber gasket/grommet/seal thing on the bottom where the sock is. Undo the hose clip on the short fuel hose on the side to disconnect it from the 3 way distribution pipe to be able to lift the upper half away. Don't forget to unplug the fuel pump too! There's a few rubber O rings that will need transferring to the new filter housing, I show these in the video at the bottom of this write up. Reassembly is the reverse Here's a photo of the new filter installed, you'll be able to see where the tabs are more clearing against the yellow OEM plastic Once the assembly is re-installed, I turned the engine over a few times to help build up fuel pressure. I did panic when the car stopped turning over but I could hear the fuel pump making a noise. It eventually started and has been fine since. Found my 'lucky' coin underneath the rear seat too The Youtube video can be seen here: https://www.youtube.com/watch?v=uLJ65pmQt44&t=6s
    • It was picked up on the MOT/Inspection that the offside front wheel bearing had excessive play along with the ball joint. It made sense to do both sides so I sourced a pair of spare IS200 hubs to do the swap. Unfortunately I don't have any photos of the strip down but here's a quick run down. On the back of the hub is a large circular dust cover, using a flat head screw driver and a mallet I prised it off. Underneath will reveal a 32mm hub nut (impact gun recommended). With the hub nut removed the ABS ring can be removed (I ended up using a magnetic pick up tool to help). Next up is to remove the stub axle, this was a little trickier due to limited tools. I tried a 3 leg puller but the gap between the hub and stub axle wasn't enough for the legs to get in and under. Next option was a lump hammer and someone pulling the stub axle at the same time. After a few heavy hits it released. The lower bearing race had seized itself onto the stub axle, which was fine because I was replacing them anyway. With the upper bearing race removed and the grease cleaned off they looked like this The left one looked pristine inside but gave us the most trouble. The right one had some surface rust but came apart in a single hit, figure that out?! I got a local garage to press the new wheel bearings in, reassemble was the opposite and didn't take long at all. Removing the hub itself was simple. Starting with removing the brake caliper, 2x 14mm bolts for the caliper slider and 2x 19mm? for the carrier > hub bolts. I used a cable tie to secure the caliper to the upper arm so it was out of the way, there's a 10mm bolt securing the ABS sensor on. With the brake disc removed from the hub next are the three castle nuts for the upper and lower ball joints and track rod end. Two of these had their own R clip and one split pin. A few hits with the hammer and they're released (I left the castle nuts on by a couple of turns), the track rod ends gave me the most grief and I may have nipped the boots (oops). Fitting is the reversal and is very quick and easy to do. The lower ball joints are held onto the hub by 2x 17mm bolts. The castle nut did increase in socket size to 22mm from memory (this may vary from supplier) The two front tyres weren't in great condition, so I had those replaced with some budget tyres for the time being. I'll be replacing the wheels and tyres in the future, this was to get me on the road without the worry of the police hassling me.
    • Yep, the closest base tune available was for the GTT, I went with that and made all the logical changes I could find to convert it to Naturally Aspirated. It will rev fine in Neutral to redline but it will be cutting nearly 50% fuel the whole way.  If I let it tune the fuel map to start with that much less fuel it wont run right and has a hard time applying corrections.  These 50% cuts are with a fuel map already about half of what the GTT tune had.  I was having a whole lot of bogging when applying any throttle but seem to have fixed that for no load situations with very aggressive transient throttle settings. I made the corrections to my injectors with data I found for them online, FBCJC100 flowing 306cc.  I'll have to look to see if I can find the Cam section. I have the Bosch 4.9 from Haltech. My manifold pressure when watching it live is always in -5.9 psi/inHg
    • Hi My Tokico BM50 Brake master cylinder has a leak from the hole between the two outlets (M10x1) for brake pipes, I have attached a photo. Can anyone tell me what that hole is and what has failed to allow brake fluid to escape from it, I have looked on line and asked questions on UK forums but can not find the answer, if anyone can enlighten me I would be most grateful.
    • It will be a software setting. I don't believe many on here ever used AEM. And they're now a discontinued product,that's really hard to find any easy answers on. If it were Link or Haltech, someone would be able to just send you a ECU file though.
×
×
  • Create New...