Idiling Problems

[speedypete101]

I've recently changed the air filter on a 2000 1.7 Millenium Puma. No problems installing the new filter but shortly afterwards the engine would not idle properly. When stationary it loses revs and eventually stalls. The revs fluctuate only when completely stationary. Went back to the standard air box and the problem persists? The issue is getting gradually worse but it only happens when the engine is at tick over and the car stationary.

No problem with responsiveness from tick over, although using the more 'power hungry' features on the car (Such as both windows and the heated screens) do cause the revs to drop (and stall sometimes)

Any idea what could be causing it?

Thanks

 

[red]

Have you tried disconnecting the battery for 30 mins to reset the ecu after changing the filter to I assume a cone? Then reconnecting it and performing the idling process?

Might help.

 

[ScubaSteve]

maf sensor probs

 

[speedypete101]

Thanks for the replies, ill try the battery disconnect although wont this upset the immobiliser? I don't have an after market one fitted or anything but an engineer who came to do the windscreen a while ago said something about not disconnecting the battery because it would stop the car from starting?

I could be wrong

 

[yippeekiay]

Shouldn't be a problem as your immobiliser is triggered from your key/fob. The only problem might be losing your radio code.

I'm just guesstimating here but I'm pretty sure it's an fairly educated guess...lol.

As for the MAF problem Steve suggests, try cleaning the sensor wires in the MAF with errrm...shoot, I forget as it's late but pretty sure it's carb cleaner - I have a tin in the car but I'd fall asleep on the drive before I get to it...lol. The sensors go black after a while which make them less efficient and a good clean sorts them out usually. Have a search as I'm sure there's a guide on doing it.

Sorry I couldn't be more certain of my answers but I'm on auto pilot at the moment...lol

 

[ScubaSteve]

battery disconnect wont effect the imobiliser, carb cleaner is fine

 

[speedypete101]

Thanks, I did the battery disconnect and it improved things for about 5 minutes. Although now its gone back to a bad tick over and the throttle has become very unresponsive. Its as if it isn't doing anything for a second or so then it cuts in and revvs the engine. This happens only sometimes though and when I turn the car off and back on it occasionally fixes itself? The manual thinks that the car needs about 5 miles to 're learn' parts of the ECU but I've driven it about 15 now and no real luck. I've spoken to a mechanic I know who has advised that I clean the butterfly valve in the pipe coming from the air filter with clutch & brake cleaner but I cant get at it well enough to do a good enough job so he will be doing it next week.

I'll mention the cleaning the MAF sensors to him (as he knows more about it than I do) and hopefully that will fix the problem.

Once again, thanks for the help and any other suggestions are gratefully received

 

[EvilDonut]

Could you have damaged the MAF itself or perhaps the butterfly valve on the throttle body when changing over the filter?

When you changed it, did you disconnect the main rubber pipe at the throttle body's end at all? If not then you probably didn't damage the butterfly valve, but it could well be the MAF. Careful with those valves by the way, they have to make an air-tight seal or you will get idle problems!

Theres also an idle control valve which, when clogged up, can cause rough idling and stalling. Theres an how-to-clean guide for the ford Ka's ICV here: http://www.kaklub.co.uk/pwpcontrol.php?pwpID=1898. EDIT: The puma's ICV is kind of above the TB and sticking out a bit I think.

I'd be surprised if the problem is something needing clearning, as your problem was suddenly triggered by the filter change, it did not slowly build up over time....although its possible the filter change could have pushed it over the edge I suppose.

I think the MAF is the best bet...those things are delicate and expensive unfortunately so lets hope its not damaged :/ Dumb question....did you reconnect the MAF properly? i.e. did the connector's clip click into place when you connected it? And are the metal terminals clean?

 

[speedypete101]

Hmmm, all I did when changing the filter was to simply remove the box top of the old one and put the new one on. That was it.

As for the MAF valve without a photo I'm not sure which is which.

 

[yippeekiay]

MAF doesn't have a valve. It has 2 very fine sensor wires (like light bulb elements) that often get dirty and need spraying with carb cleaner.

The MAF is the silver round thingy connected between the air intake pipe and the airbox. Very easy to get off and inspect/clean. It has a black electrical connector going to it.

 

[speedypete101]

Ahh, thanks,

I'll have a look in the morning and try that

 

[skint]

This is relating to a totally different make of car (Leon Cupra) but the maf sensor was sensitive to 'longlife' air filters like k&n that have to be oiled to work properly. If any oil gets sucked through it will coat the wires on the maf and stop it working properly.

Try removing the maf and leave in a sealybag submerged in 85% Isopropyl alcohol for a couple of hours, that should remove any oily residue..

 

[yippeekiay]

Spraying carb cleaner on the wires takes about 5 seconds...saves soaking them for hours

 

[speedypete101]

Thanks again for the suggestions. Today I was forced into taking the car to the office (emergency with the PC network there) and although it was a nightmare to begin with (almost un-drivable!) it stalled at a set of lights going into Gloucester because of the dodgy tick over and when I re-started it, all was fine. It still had a problem while idling but the throttle response was back to normal, albeit possibly 2-300 revs higher but I'm not sure. Stalled again at another set of lights on the way back and is now back to the throttle problems. Sometimes it works normally until it stalls or you switch the engine off and sometimes it seems to be a pain?

Its booked into a garage in Cirencester on Monday so I'll see what they make of it. I've mentioned all the suggestions on here to the bloke at the garage (he is an acquaintance of mine) and he seems to think it could be the MAF sensor or butterfly valve in the air pipe. Hopefully not £OMG! to have put right again!

 

[yippeekiay]

If it is just a dirty MAF or butterfly valve they're a very easy fix. I had a sticking throttle and it turned out to be said butterfly valve as it was actually coked up around the casing when in the closed position. I gave it a gentle scrape and polish and my throttle doesn't stick anymore. If yours is the same i.e. coked up, it may be letting in air when it shouldn't which may be casuing it to idle a little higher as it's basically slightly open.

Not 100% how the MAF works but if the two wires are coated in crap that would mean the exact air flow measurement isn't getting to your ECU which means it is probably adjusting your engine incorrectly....as I say, I'm not 100% on this diagnosis.

 

[speedypete101]

Hmm, that's always a relief to know. According to 'mechanic man' the air valve getting a bit oily and dirty is a know issue on Fords and he says the outcome is very similar to the problem I've got which is reassuring.

Just a quick (probably silly) question. Which end of the hose (which goes between the filter & and engine) are the MAF wires located? I'm assuming its the engine end but there was a plug going into the old air box at the bottom which I've not removed. Could they have been in the silver metal bit attached to the top of the old filter housing which I took off?

Probably a silly question but I'm no expert on car mechanics.

 

[yippeekiay]

It sounds like it's the 'silver metal bit' that you took off...lol.

The MAF is connected directly to the airbox not to the engine end. It is aluminium (silver) and has a connector going to it. Inside this are the two wires we are referring to.

 

[speedypete101]

Ahh, well. **feels a bit silly** in that case its not attached to the car at all i'll go and replace it and see if things improve.

 

[ScubaSteve]

lol if you removed the maf the car will run like a piece of crap

 

[speedypete101]

ScubaSteve > Understatement there. lol. Replaced it and things seem to have improved. I haven't had time to give it a run as it has next to no fuel in it and the petrol stations are closed so I'll try it tomorrow and hope its solved the issue. Tick-over on the drive was much improved.

I think it was a case of PBSAW (Problem Between Seat and Wheel)

Thanks to everyone who helped out though :thumbs: