Idle control valve - a favour needed.

[Tetleysmooth]

Right, help me out here chaps please.
I bought a good used secondhand idle control valve, and at first I thought I'd cracked the problem, but alas, no.
When I start the car from cold, everything is fine, nice low idle etc. As the car warms up, the idle speed starts to rise, then when the temp guage reaches normal operating temperature, the idle speed tops a thousand revs, not by much, but enough to put the EML on.
I've looked around the various vacuum lines and elbows, and can find nothing wrong there.
So, I suppose the next port of call will be the throttle body and throttle position sensor.
When I first bought the car, I was getting the P0171 code. A replacement MAF sorted that, so I went ahead and cleaned out the throttle body and icv. This is when the current problem started. I now keep getting the P0505 code.
I've already PM'd Minty about a replacement throttle body and TPS, but if anyone else on here has said items for sale, I'd be happy to receive a pm from you.
My car is a '98 V70 2.5 turbo with the cable throttle. I don't know if throttle bodies from normally aspirated 2.5 engines are the same, perhaps someone can tell me
I'd like to hear any suggestions as to what may be putting this EML, as it's getting to the stage where I'm so cheesed off with this problem, I'm thinking of moving the car on.
Problem is, the car always starts first shot, and runs extremely well, EML light or not. It's just frustrating me now.

[Tetleysmooth]

Well, I changed the throttle body last Wednesday, and I thought I'd cracked the problem, but unfortunately I haven't. As I pulled up outside my house this morning after finishing work, the light came on again. Same code - P0505 idle air control.
I really don't know where to look next. Could it be the coolant temp sensor sending a false message to the ecu?
I'm frustrated and rather hacked off now.
Any suggestions welcomed.

[amazondean]

Hi. To help your mental state of mind, the best option, and cheapest option would be to pull the bulb out and just use the car as it is. I would have given up long ago, so I bow to your determination.

Best of luck.

[Tetleysmooth]

Originally Posted by amazondean

Hi. To help your mental state of mind, the best option, and cheapest option would be to pull the bulb out and just use the car as it is. I would have given up long ago, so I bow to your determination.

Best of luck.

Noooo, I can't do that, this problem must be solved.
I'm now wondering if it's the cheapo (new) MAF I fitted. I've ordered a can of MAF sensor cleaner and I'm going to clean the Bosch sensor I took off.
I changed the MAF because the Bosch was throwing up a PO171 code, too rich bank one.
We'll see what that does.
By the way Dean, there's a t5 manual on Facebook marketplace.

[Luxobarge]

Originally Posted by Tetleysmooth

Noooo, I can't do that, this problem must be solved.

Quite right too - I'm the same!

Originally Posted by Tetleysmooth

I'm now wondering if it's the cheapo (new) MAF I fitted.

These cars are indeed quite picky about MAF quality, there's quite a few threads on here where members have had similar problems with cheap replacement MAFs, then fitted the correct Bosch MAF and that's fixed it. You might well find a good one from a scrappy, but just make sure it's the same Bosch part number as the original. You may get away with cleaning it, but if so I doubt it'll stay good for very long - hope it works for you though of course!

[SteveSarre]

Hi TetleySmooth,

When you replaced the throttle body did you replace with a new one? Was it programmed for a Turbo (since yours is a turbo)? Or was it used and taken off a turbo?

As far as IACV, this post is for Porsches but contains lots of useful info

http://forums.pelicanparts.com/porsc...dle-valve.html


Steve

[Tetleysmooth]

Hello Steve. Sorry it took so long to reply, but I had to work last night.

The throttle body I fitted was exactly the same as the one I took off. I used a brand new gasket when fitting it.

It's bloomin' annoying because the car runs so well, and is very reliable.
We'll see what the MAF spray does - if anything.
I may be selling this soon, not because I'm trying to offload it, but because after all the work I've done to it, this silly problem has taken the shine off of owning it.
If anyone fancies a '98 2.5 turbo, give me a shout, although I'd rather cure this idle air problem first, before I sell.
It's an auto by the way, with MOT until December 10th.

[Tetleysmooth]

Right, that's enough for me. This car is now for sale. It's absolutely doing my head in.
I've changed the throttle body, idle control valve, thermostat, coolant temp sensor, cooling fan relay, found a vacuum pipe adrift, so replaced it, and I'm still getting the P0505 code - idle air. There may be another vac pipe adrift that I can't see, but that's enough for me now. As said in the best car ads, it could be an easy fix for someone.
The cooling fan doesn't seem to want to work, but the temp stays bang on 3 o'clock. I still use the car most days. It's very reliable.
I paid £500 for this, and I've spent a few bob getting things working again, but I realise I'm never going to get my money back.
It's got a new battery. I've replaced the rear wiper, but the wash still doesn't work, so probably the pump. I've had all four locks out and repaired the microswitches, so all interior lights work as they should. It had new pads and tyres before I bought it, and the front discs look new.
All in all, it a pretty good motor with mot until December 10th, but this idle air problem has defeated me I'm sad to say.
I have some pictures, but getting them on here is a real mystery.
If anyone fancies taking it on, drop me a pm. It runs and drives very well, and I'm confident it will get to to where you want to go.