Car Still Idles Rough And Now Stalls Once Engines Warm After Replacin

[lee.kendallmi16 2]

Hi all,

 

I've still got problems with the idle on my pug 205 mi16. I changed the ICV for a new bosch one thinking that this was the problem, I have also cleaned out the throttle body and all the hoses as best as I can, also checking for any vacuum leaks and the problem is still there but now even worse. The car is the same on cold start up as it used to be but now once the car is warm and the rpm drop to around 1000 the rpm hunts up and down a little and then the engine stalls.

 

I'm thinking it now may need a new mass air flow sensor

 

Does anyone else know what could be causing the problem?

 

Also I've had alook for a replacement MAF sensor (part number 0280202202) but unable to find one anywhere. Does the sensor have to be replaced with one with the exact same part number? Also is there a company which refurb them?

 

Not having much look at the min

 

Help would be much appreciated.

 

[lee.kendallmi16 2]

I have removed the AFM today and decided to remove the induction kit.

 

Once I removed this I could see 2 little electrical wires, abit like a diode and only really small. These are covered with what I would call an oil type residue.

 

Does anyone know what these wires are for and could this be causing my problem? If so how's best to clean them?

 

Also before removal I tried running the car without the AFM plug connected and the car idle wasn't perfect but it didn't stall and the rpm didn't move up and down. Does this indicate that the AFM is the problem?

[Jemehan 3 1 Cars]

Personally, I would say that this sounds like a idle control valve issue. Either that or an air leak, they are the two most common things that would cause this kind of issue... Could be wrong but that's where I would start.

[lee.kendallmi16 2]

Personally, I would say that this sounds like a idle control valve issue. Either that or an air leak, they are the two most common things that would cause this kind of issue... Could be wrong but that's where I would start.

 

 

I have replaced the idle control valve for a brand new bosch one. Also I have squirted around all the intake hoses with carb cleaner to try and find a leak but couldn't find one anywhere.

 

Do you know of any particular hose which is more commonly known for leaking?

[Jemehan 3 1 Cars]

I have a s16 so slightly different, I'd look around and pipes that are tight and could be leaking from the end. The only other thing that could potentially cause this would be tps, but that's a bit of a long shot...

[lee.kendallmi16 2]

I have a s16 so slightly different, I'd look around and pipes that are tight and could be leaking from the end. The only other thing that could potentially cause this would be tps, but that's a bit of a long shot...

 

Are you saying that this cant be the AFM? There are 2 videos on You Tube if you type 'rejuvenating a bosch AFM' and it shows the wear on a wiper track within the electronics of the AFM. This tends to wear around the idle location when the car has been mainly used for town use, when the track is worn it shows the wiper arm moving back and forth on the track when at idle due to not picking up the correct reading between the two and therefore not giving the correct mixture required to keep engine at a steady idle.

 

That's why I'm thinking the AFM. Take a look if you get chance and let me know what u think.

 

Thanks for replies

[Jemehan 3 1 Cars]

It won't do any harm to clean it. My maf sensor is part of my ecu, so if mine goes wrong then its a new ecu required. Clean it, see if it helps. The icv would be my suspect. Check the inlet for cracks etc too, my old 8v had a bolt missing from the right side of the intake and that use to hunt really badly too.

[lee.kendallmi16 2]

Just an update and help still needed please.

 

I have changed the ICV for a new bosch unit, changed temp coolant sensor for new, changed dizzy cap and rotor arm for new, cleaned out the throttle body, checked the TPS for correct operation using a meter, had the AFM refurbished by ATP electronics and also checked for vacuum leaks by spraying carb cleaner around joints and on hoses and cannot find any leaks. All around inlet manifold looks ok too.

 

Since refurb of the AFM the car now idles alot better at 1000Rpm but the idle is still not solid and drops slightly when on tickover but then almost immediately increases back up to 1000. The car also does not stall anymore.

Due to the slight intermittent idle problem I don't think my problem is fully resolved.

 

The only other thing I have noticed is that when the brake pedal is depressed when at idle tickover the RPM drops to around 800 and feels as though its about to stall but once released goes back to 1000.

 

Does anyone know what could cause this?

 

Also what other problems could cause this not so perfect idle as I'm lost as to what to try next.

 

The car is running a non standard exhaust and air filter

 

More help would be much appreciated.

 

Thanks

[welshpug 1,657]

block the brake servo vacuum takeoff and try again.

[lee.kendallmi16 2]

Thanks for the reply.

 

I am not a mechanic so not 100% sure what you mean. Is this the main vacuum pipe which runs over the engine from air inlet to the brake servo unit that you want me to disconnect and block or is it the small pipe which T's off the main pipe via a blue cone shape connector?

 

Should this sort the idle issue or just the revs dropping when brake is depressed or both?

[welshpug 1,657]

the main large braided hose where it comes off the manifold, block the port on the manifold and try it.

 

If this stops the problem, or the symptoms change you'll be more clued up as to what the problem is.

[lee.kendallmi16 2]

At work at the moment but i will give that a try tomorrow and update the post when I have results.

 

Thanks again

[kyepan 291]

Yes that might be your vacuum leak'

,

[lee.kendallmi16 2]

I've now disconnected the brake servo vacuum takeoff pipe from the inlet manifold and blanked off at the manifold and this made no difference in the idle, it still fluctuates up and down slightly. Also the brake pedal went hard to press immediately.

 

Other than all the parts I've already changed and vacuum leaks, is there anything else that can cause this because I can't find any vacuum leaks and I've spent ages looking to try and find one?

 

Also what is the correct RPM at idle bearing In mind I have a non standard exhaust and air filter?

[Richie-Van-GTi 71 2 Cars]

How are you checking for air leaks? I had an absolute swine of a time with my old 5 series hunting and stalling when the engine was changed. I knew it was an air leak and only way to find it was spray carb cleaner all around every single seal and component on the intake. Turned out to be a split O ring on an injector. Everything you have mentioned so far suggests an air leak, in particular the change in engine with the servo connected and pressing of the brake.

[lee.kendallmi16 2]

I've been checking using carb cleaner but today tried the cigar smoke trick and I've got a leak on the throttle body were the accelerator cable goes through. See pic

 

I also serviced car and its running rich. Black soot on plugs, not oil.

 

 

Does anyone know if this can be fixed or at worst were I can source a good throttle body? Also do these throttle bodies exist on another make of car?

[welshpug 1,657]

VW's use a similar throttle body which was once used as an upgrade on these.

 

that brass coloured takeoff should have something on it I would imagine, though I'm unfamiliar with the layout of the 1.9 MI.

[lee.kendallmi16 2]

Thanks for reply

 

Yeh the brass takeoff's do sometimes have something off them but I think it's correct as it is as I know miles (pug racing) fitted engine and the lad I bought it off wasn't very mechanically minded and wouldn't change this sort of thing.

 

Does anyone know which VW has this throttle body fitted if they do?