Idling problem

[Tripplec84]

Hey guys

I currently have a 3.5 V6 NM.

Shortly after I purchased the vehicle, 2 years ago, I had a issue with the idle speed going up to around 1400rpm, I tried numerous things like cleaning the throttle body, changed air filter etc etc and eventually with the help of this forum I replaced the IAC valve and did a ecu relearn for the idling and that cured the problem.

The IAC valve I fitted was just a cheap eBay one so after doing a lot of reading here I’m thinking of ordering a original one, but before I do so I thought I would see if anyone has had a similar problem.

So at the moment the idle speed drops to around 300rpm, but the problem is intermittent. I actually re fitted the old(original) IAC valve and have the same symptoms. After doing a ecu relearn she will idle fine for a couple of days and then just out of the blue starts playing up again and the idling is so low that I need to flick it into neutral when I stop in traffic to prevent the engine from stalling.

My wife took the paj out today to run some errands and there was no issues when she left home then when she wanted to come back home the paj wouldn’t idle and kept stalling. This happened twice and with the 3rd restart of the engine everything was fine again.

So am I over looking something or do you guys also think it’s the IAC valve playing up again.

The air filter is clean and fairly new. I cleaned the throttle body a week ago and also fitted a new fuel filter.(All the symptoms were there before doing any of this work)

Appreciate any feedback or advice you guys can offer.
Cheers


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[chrisall]

I had a similar problem but with low idle. I replaced the IAC with a cheap ebay job but then found the TPS was faulty so changed that, worked OK for a while but then was stalling again. I assumed the IAC was fine as it was relatively new, but when I took it apart found the ferrite core in the motor to be in several pieces.

In the end I managed to repair my origional genuine IAC with a piece of the new one, and problem solved.

[nj swb]

I suspect IAC, and suggest an overhaul of the original (if you still have it). They're fairly simple devices, can only really fail with an electrical problem (broken wire) or mechanical problem (drag from crud).

On the 3 litre V6 they're simple to remove (three screws?) and pull apart (or was that the three screws?). I once removed, disassembled, cleaned, reassembled and reinstalled while on the phone - it's not rocket surgery. Or is that brain science?

[Tripplec84]

Thanks for the advice guys, I didn’t realise the little motor could be disassembled, but then again I didn’t even bother to check because I thought it was a sealed unit.

I will pull the cheap eBay one apart and see if there are any gremlins in it.

Strange thing is since I originally posted this question, the problem hasn’t come back. Go figure?

[Having Fun]

If you have no success with the suggestions above, maybe have a look at the brake booster; worn brake boosters can cause the issues you describe (by drawing excess vacuum from the engine). Have a quick Google

[Tripplec84]

If you have no success with the suggestions above, maybe have a look at the brake booster; worn brake boosters can cause the issues you describe (by drawing excess vacuum from the engine). Have a quick Google

That is very interesting you say that. Now that I think about it when I had this issue I found that if I approached a red traffic light I would start slowing down really early and basically coast to a halt and then as I stop the idling would drop really low (almost stalling) and then it would pick up again just a couple of hundred rpm.

You might be right on the money with it being related to the brake booster, will definitely check it out. Thanks for the suggestion.


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[Having Fun]

That is very interesting you say that. Now that I think about it when I had this issue I found that if I approached a red traffic light I would start slowing down really early and basically coast to a halt and then as I stop the idling would drop really low (almost stalling) and then it would pick up again just a couple of hundred rpm.

You might be right on the money with it being related to the brake booster, will definitely check it out. Thanks for the suggestion.


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[Roofchop]

I thought these used the dreaded HBB pump instead of vacuum...Or is it both?


Cheers
Dave

[Tripplec84]

Just had a look. So mine has the HBB with electric motor, so there goes that idea that it could be consuming too much vacuum. Really thought that could be the problem.

Also I checked out my ICV and seems like it is a sealed unit. Maybe the earlier models had ones which could be pulled apart.

O well, let’s see how long she behaves herself for.
This is my spare ICV. Can’t see how to pull it apart without breaking it.

[Roofchop]

Coolant temperature sensor??


<$20 part, the ECU uses it and other inputs to set the idle, (cold starts etc)


It's probably the original and "brittle/fragile/unreliable"


There are two sensors, one for the gauge and one for the ECU.


Worth a try....


Cheers
Dave


Edit, I paid $20 for mine last year, now they seem to be $40+ ish....

[tommo123]

. Can’t see how to pull it apart without breaking it.

The brown bit pushs into the black housing like a tail light bulb but with 3 locating pegs instead of 2. So you need to turn the brown bit with pliers and then wiggle it out. Then just clean the bit up with carby cleaner. As someone said crud builds up and they stick.

[Tripplec84]

The brown bit pushs into the black housing like a tail light bulb but with 3 locating pegs instead of 2. So you need to turn the brown bit with pliers and then wiggle it out. Then just clean the bit up with carby cleaner. As someone said crud builds up and they stick.

Thanks Tommo! This worked a treat. So mine looks pretty clean inside and the little bearings feel good and everything seems to turn and move smoothly.

So onto next suggestion.... will check out the coolant temperature sensors.


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[stevecarstens]

Idle problems

I have a 2005 np pajero with some idle issues once warmed up just wondering what it could be? thanks again.

[4ePikanini]

I have a 2005 np pajero with some idle issues once warmed up just wondering what it could be? thanks again.

likely the throttle body idle adjustment screw

Check link below

http://www.pajeroclub.co.za/forum/viewtopic.php?t=3035

[chrisall]

Thanks Tommo! This worked a treat. So mine looks pretty clean inside and the little bearings feel good and everything seems to turn and move smoothly.

So onto next suggestion.... will check out the coolant temperature sensors.


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Did you test the TPS yet?