Rough idle....

[donki]

Alright crash course time;

The IACV restrics and flows air at idle (hence its name Idle Air Control Valve). A quick and easy test to see if this is working or not, is to turn the car on to Ign, but dont start it. Wait around 20-30 seconds. You should hear the IACV clicking, because its trying to reset it self back to the "idle position" by extending itself in and out. Sometimes you can hear this clicking as soon as you turn off your engine and it stops rotating.

The AFM, if faulty, will cause a rough idle to a CEL, because its reading the air mass wrong and feeding the wrong info to the ECU (which in turn is injecting the wrong amount of fuel). Usually this will throw the CEL before any other changes though.

 

[Jtrain]

Is the first pic an air flow meter? Pretty sure only the 1.8lt motors have these but correct me if i’m wrong. My car is also running rough and the dissy has oil in it so i cleaned up the rotor and cap and it helped. New o-ring, cap and rotor tomorrow and hopefully a better running car.

 

[donki]

Is the first pic an air flow meter? Pretty sure only the 1.8lt motors have these but correct me if i’m wrong. My car is also running rough and the dissy has oil in it so i cleaned up the rotor and cap and it helped. New o-ring, cap and rotor tomorrow and hopefully a better running car.

The first image is a Air Flow Meter yes, and only the 1.8L has this. If you have a dizzy though, then its a 1.5L, and the 1.5L uses a MAP sensor located at the back of the manifold.

 

[Sai]

Basically that's what I said to them .. They put in my VIN and still came back with that, LOL..

Good thing is that I've got these three items spare now so that's a good start ,though a decent spray with cleaner hasn't made them look any better, but I'll pay with everything later, specially once I've picked up my new dizzy cap.

@Jtrain
How hard is it to change out the o-ring?

I've been thinking about just getting a while new dizzy. About $400 I think it was from supercheap and I can Afterpay it.. I've been thinking of that because it's been mentioned that the oil also fills up the coil pack inside the dizzy...

 

[Sai]

Alright crash course time;

The IACV restrics and flows air at idle (hence its name Idle Air Control Valve). A quick and easy test to see if this is working or not, is to turn the car on to Ign, but dont start it. Wait around 20-30 seconds. You should hear the IACV clicking, because its trying to reset it self back to the "idle position" by extending itself in and out. Sometimes you can hear this clicking as soon as you turn off your engine and it stops rotating.

The AFM, if faulty, will cause a rough idle to a CEL, because its reading the air mass wrong and feeding the wrong info to the ECU (which in turn is injecting the wrong amount of fuel). Usually this will throw the CEL before any other changes though.

After about 2 minutes I've not heard any distinct clicking noises.. Does that help?

 

[donki]

After about 2 minutes I've not heard any distinct clicking noises.. Does that help?

Thats a pretty sure confirmation its gone. The 100% absolute check is to do that same test with the IACV out of the throttlebody, and you'll see it physically move (might need to get a ruler out to confirm it does, its range is about 10mm), but with no sounds from in the engine bay in 2 minutes, i think you've got it.

 

[Sai]

And can you tell me exactly which one of the three things in that picture that it is? LOL

Hard to believe that I've worked on cars my whole life, but never done much with efi vehicles..

 

[donki]

2nd picture, top unit it has three screws that attach it to the throttle body.

 

[Jtrain]

The o-ring itself is a simple job but i’d left mine leak for ages and the dissy is soaked in oil. Also the rotor i got from repco is the wrong type and trying to find the correct one is becoming a pain.

 

[Sai]

2nd picture, top unit it has three screws that attach it to the throttle body.

Thank you, I'll change it out for that one on my next day off (if not before) and see if that makes a difference to the overall running of the vehicle.

Or do you think I should plug it in first and see that it extends itself etc?

There doesn't seem much that I can clean on it either.. Would it hurt to give the end a clean with a toothbrush? (just spraying it hasn't done much)

 

[Sai]

The o-ring itself is a simple job but i’d left mine leak for ages and the dissy is soaked in oil. Also the rotor i got from repco is the wrong type and trying to find the correct one is becoming a pain.

Cool, thank you.

I'll see about ordering an o-ring for mine. It's all got to help.

I'd be interested to know if there is a way to clean it all out nicely, presumably my sensor cleaner should work..

 

[SDate42]

Cool, thank you.

I'll see about ordering an o-ring for mine. It's all got to help.

I'd be interested to know if there is a way to clean it all out nicely, presumably my sensor cleaner should work..

Electrical Contact cleaner or brake cleaner is fine for this job. As you probably remember, the rotor can be cleaned with fine sand paper or a wire brush too.

 

[Jtrain]

I drenched mine in brake cleaner, if it can survive being submerged in oil brake clean can’t make it any worse. There are some complete dissy assemblys on ebay for $130 so i might try one of them if mine decides it doesn’t like being cleaned.

 

[Sai]

So I changed our the IACV today for the one I had spare, turns out the original one was moving, but changed it anyway.

I then discovered some sort of booby trap ** on the plugs for the other two things and decided as it was almost dark I wasn't going to remove them, but I did adjust the throttle position sensor thingo slightly and that's brought the revs up a little... Though switching on the air con almost kills it, haha.

I also have the throttle body a bloody good squirt with cleaner... Basically until it started to run clear back out the throttle body..then started it up and have it a few good squirts while running.. (plenty of black *poo* ran out).

** booby trap, just the metal clips on the electrical plugs, just made it slightly more difficult to just unplug and swap out the unit and as daylight was failing and my back was hurting I gave up and decided they were booby trapped (hahaha, yeah I'm slightly broken)

 

[Sai]

So I've come to a few more conclusions about this engine..

While doing my cleaning up of the throttle body there was a fair bit of oil from the return pipe and also when I pulled the dip stick the oil smells very burnt (4k since I changed it).. Which basically leads me to believe that the rings are probably shot..

Therefore, along with whatever issues are found in the top end it's basically a full rings, bearings, valves, cam etc replacement job ....

I'm not sure it's worth it and I'm probably better getting a replacement engine to put in.

 

[SDate42]

Take it for a comp test if you don’t have the gear at home. Shop shouldnt charge you much as its super easy to do on the 1.5

Really curious about it myself.

 

[Sai]

I'll see if our workshop at work has a compression tester.. They might even give me a hand, LOL..

I try not to bug them as they are heavy diesel mechanics.




Update - they don't have a compression tester, so I'll try someone else..