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        General >> Problems >> Engine Idle Problems/ Stalling
        
(Message started by: Scooby on Apr 2^nd, 2004, 9:50am)

Title: Engine Idle Problems/ Stalling
Post by Scooby on Apr 2^nd, 2004, 9:50am

Guys, Can any of you please help me?!
I am a complete novice when it comes to Mechanical Engineering so I have always relied on the 'stab in the dark' approach to troubleshooting my problems!

Let's start from the beginning!

Ever-since I had my 12V Scorp the Idle (arround 1000 in Neutral and 800 in Drive) has been 'hunting' slightly.
This has never bothered me too much as it has been the only (minor) fault on my beast.
However, sitting in traffic the other day (edging all the time- so ticking over in drive with my breaks on) the car suddenly stalled (due to the idle speed struggling at 600ish and then dropping off). The car has never done this before, even in far worse traffic.
I started up again....no problems there, but a minute or two later it stalled again.
I managed to prevent this from happening again by slipping in and out of drive/neutral (neutral idling at about 8/900) for the rest of the jam. I was a little worried!
The next day, she started as she always does...but stalled straight-away (something else she has never done) and I struggled to get away in drive by keeping the revs up and break on. I was juggling my accelorator and break for the best part of 3 minutes (when stopping/approaching roundabouts etc) before she stopped idling too low for me to stop briefly or slip into neutral when stopped.
I suffered a considerable loss in acceleration/power when driving (only briefly), which added to my worries! - something that hasn't happened again since.
When I stopped last night (having gone through all the above when starting my journey) the idle was still struggling in drive....I slipped it into 'Park' and the revs shot to about 1500 - Again a new one!
I lifted the bonnet and revved the car from the butterfly and the idle dropped to normal.
The same low rev idle occured this-morning and the same processes insued, getting me to work....but not easing my now Very worried mind.

Could someone please, please help me?!! I love my Scorp.

P.S. Sorry about the essay, just trying to give the full story!

Title: Re: Engine Idle Problems/ Stalling
Post by JohnJ on Apr 2^nd, 2004, 10:51am

Try cleaning the MAF (mass airflow sensor) its makes up part of the air intake circuit and is located the engine side of the airbreather filter, dont touch it only sray carbcleaner at the two fine wires to remove carbon.

JJ

Title: Re: Engine Idle Problems/ Stalling
Post by Scooby on Apr 2^nd, 2004, 10:58am

JJ, Thanks for the advice...
The only problem with that is that all I have read about faulty MAF units indicate the oposite problem to the one I am encountering (rich running and higher revs, as opposed to the low idle revs I am getting). Also, I don't seem to be suffering any of the other symptoms, such-as gearbox faults???
Can anyone confirm this?
Once I have had a few suggestions I will attempt to sort the problem (including MAF cleaning - Thanks JJ).
I am not yet convinced.

Title: Re: Engine Idle Problems/ Stalling
Post by TonyS on Apr 2^nd, 2004, 2:21pm

Mk4 12v does not use the PCM to manage the gearbox, it uses the earlier EEC-iv module for engine management only.

Usual poor idle control problems are due to the Inlet Air Bypass valve, a strange looking appendage to the throttle assembly at the front of the engine. Check the pictures on the main site for it's location and it's only two nuts to remove it.

Clean and make sure it's working and/or swap with a known good one. A sticking valve will mean the ECU cannot raise the engine airflow to stop a stall condition.

Check also for airleaks although the 12v has a pretty simple and solid inlet system.

Title: Re: Engine Idle Problems/ Stalling
Post by Scooby on Apr 5^th, 2004, 11:55am

Thanks Tony.
I'll take a look. This does seem like a more likely option, I have noticed that whilst driving (occasionaly) I am loosing acceleration....the car suddenly feels heavy and is not responding to my right foot!....This only happens for a short while, but may continue to happen during the journey. Is this behaviour condusive to a sticking valve?

Title: Re: Engine Idle Problems/ Stalling
Post by Snoopy on Apr 5^th, 2004, 5:13pm

The 12 v does NOT havea MAF the ICV (Idle Control Valve) at the end of the air intake pipes is the beasty that is most likely causing your problems.. try cleaning inside there and removing any sticky gunge that might be there and also the plugs on the side for good electrical contact... A new ICV unit is/ was about £35 last time I looked..
Hope this helps
Snoopy

Title: Re: Engine Idle Problems/ Stalling
Post by wsmorrisuk on Apr 20^th, 2004, 3:54pm

Hi everybody. I have used this site considerably and have found all the members to be extremely helpful and suggestions I have been given by members have indeed solved most of my problems. However!!!! this problem with irregular tickover/HUNTING/lack of power and stalling is a well documented subject and always raises questions. I put up with these problems for months checking airflow,Maff, Throttle control valve, EGR etc.until it came to the M.O.T when I had to do something about it which meant spending lord knows how much money or scrapping the car. After spending £££££ssss on garages and OBD checks, diagnostics etc, I found the problem and maybe a simple way to resolve it. Process of elimination, but I've cured mine and she purrs now.

What was the problem? IT WAS AIR !!!!!

Firstly, listen very carefully to any hisses under the bonnet or obvious sucking noises, trace the noises back and try and pinpoint where the hisses are coming from, seal them.

If you look from the front of the car into the engine bay on the back left hand side of the engine, there is a small metal linkage with a pipe held on by Two small nuts. There's a little gasket in between the pipe and the linkage, It rots and will suck in air. Wobble the pipe a little to see if it has any effect.

2. Check the EGR gasket (located on the right hand side of the engine, one pipe screws into the exhaust manifold, the other end goes off somewhere else). here you will find another gasket, it's paper thin and made of metal, again wobble the pipe slightly and check for hisses and change in performance.

3. Finally, check the Lamba sensor at the top of the catalytic converter, thats the main sensor and can affect the car's running dramatically.

Nine times out of 10, these running problems are associated with an air leak somewhere at the pipe unions or linkages. Do what I did, take a little time, have a little patience and check carefully for any sign of air leaks. Saves a little time and money.

Sadly, although a beautiful car when they run properly, mine has now been sold to a new owner with no known problems, I've gone back to Vauxhall.

Hope this helps people.

Wayne

Title: Re: Engine Idle Problems/ Stalling
Post by Scooby on Apr 21^st, 2004, 1:42pm

Thanks Wayne, thanks to all who have parted with their advice!
As soon as I get time, I'll lift the lid and have a thorough check of all suggested possibilities. I't'll be nice to have my baby running the way she used to again.

Scoob.