Trouble . . .

[Guest YrWyddfa]

Hey chaps - need some advive and some of you lot seem to know what you are doing . . .

 

If I turn the ignition on I sometimes get fluctuating revs; normally between 800-1200. If it's an unlucky day then the engine revs will eventually die out and the car will stall.

 

This sometimes happen when I depress the clutch as I approach a junction - the revs will fluctuate then die.

 

When it's cold there's no sometimes about it - it always happens.

 

I can push the accelerator in order to keep the engine alive but as soon as I take my foot of the engine dies.

 

I have changed the air-filter.

 

I have the 2.8 V6 Ghia model

[Guest YrWyddfa]

Well, I've just driven it with the MAF sensor unplugged and the acceleration problem intensifies.

 

Does anybody have a clue what the problem here is?

[Guest vr6galaxy]

Depending on the year and what engine you have? (ODB1 or ODB2) if you have one you could try cleaning the ISV (Idle Stabilisation Valve) if you dont have one then it could be a duff throttle position sensor causing you tick over problems?

as I see it if your MAF is duff and you unplug it and your problem gets better slightly then you have a duff MAF :D if you unplug it and your problem gets worse them it's not the MAF thats at fault!

I have a similar problem where once a month the revs hang when you release the throttle! usually around the 1800/2000 RPM mark then drop back to tick over, so far I have checked the wiring which seems ok? and cleaned the throttle body with out removing it! as removing it means that it may need to be reset by the use of VAG COM or such like to reset its parameter's

I think the throttle position sensor is breaking down but till it dies completely I'm not going to change it, plus I have my eye on an enlarged throttle body :D which hopefully will cure my problem and release a few more horse's :D

[Guest YrWyddfa]

Being a complete 'non-mechanic' and I've started learning as I go along (from around 8am this morning) how do I know which engine I have? The car is an 'N' registration 1996, I think.

 

In my Haynes manual there's something called the Idle Air Control Valve - is this the same thing?

 

I have to thank you for replying this has been driving me up the wall :D

[Topbloke]

yes the idle air control valve and the idle stabilisation vale is one and the same thing, its not unusual for the idle air to get gummed up, remove wash in a little petrol/carbcleaner or wd at a push if it cures it great if it dont you wont have harmed it and you will haved rulled that out as a fault. it could have completely failed but as the problem comes and go's i would suggest that its gummed up . give it a go and let us know what happened pls

[Guest vr6galaxy]

IIRC ODB1's have an ISV, ODB2'S dont have one they have the electronically operated throttle body sensor set up, with yours being a 96 I would say you have an ODB2 engine and no ISV, also ODB1 engines had a distributor where as ODB2 engines have a coil pack

the Haynes manual doesnt cover the VR6 Galaxy so for engine diagnostics it's not a lot of use :D although for tearing apart the interior or running gear it's ok as that doesnt change much across the range

[Ivor_E_Tower]

how do I know which engine I have? The car is an 'N' registration 1996, I think.

You seem to have identified it as having 6 cylinders, so from 1995 (or "N") it will be the VR6 2 valves per cylinder (12-valve) producing IIRC 176 bhp or thereabouts, rather than IIRC 204bhp of the later, 24-valve units. First step will indeed be to clean the idle air control valve as already suggested. Good luck, let us know how you get on.

[Guest YrWyddfa]

A quick update . . .

 

Completely broke down yesterday - thank goodness for friends with tow-ropes. Now the engine will not idle at all. You turn the ignition and although it turns over it never splutters into life and idling.

 

Checked the air sensors - checked the fuel system. The fuel system appears fine (ie if you take the pipe off after the filter fuel comes out and it's clean.

 

Decided to get 'Hometune' out for diagnostics (

[Guest YrWyddfa]

Well the man with the plug-in machine has come and gone and says to replace in the following order:

 

Sparks

Fuel Filter

Lamda Sensor

Catalytic Converter

 

What do you guys think?

[Guest pnwheels]

The lamda and the cat won't prevent the car from starting! Not very good advise for

[Ivor_E_Tower]

The cat will prevent the car from starting if it is blocked, and we've had a number of posts where the cat insides have self-destructed. I take it that the car still won't start? Can you take the plugs out and have a look at them (did the diagnostics person do that?) Are they all roughly the same colour and if so, grey, black, etc?

 

Can you by-pass the fuel filter to eliminate it as the cause? Sounds unlikely to me - if it were getting blocked then idle would usually be OK, but as you needed more fuel, higher revs, higher speeds etc, it would restrict the flow of fuel and show its effects at speeds other than idle.

[Guest MATT]

I had this problem with my old galaxy (2.3 petrol), and when i traded it in for my new one they said it had been clocked! luckily they found out it was done before i had it - few. With mine it was the sparks, apparently a lot of them had gone, thus causing serious problems, but from previous experience and from my hobby (Flying RC Planes) i know that the Carburettor can be a problem (Air in, Air/Fuel mix etc) i would check the sparks, air filter, air intake, the Carburettor. i doubt it would be a fuel problem because of the way the problem has developed - but then again ime not a mechanic!

[Dave-G]

and from my hobby (Flying RC Planes)

 

:P Aw you fixed wingers :o

[seatkid]

Well the man with the plug-in machine has come and gone and says to replace in the following order:

 

Sparks

Fuel Filter

Lamda Sensor

Catalytic Converter

 

What do you guys think?

Wouldn't take much notice of his advice, he might have well said

 

1) Change Engine

2) Change Vehicle

 

 

It could be (and is likely to be) something simple - I suspect the stalling and lack of starting may be two different faults.

 

When you said fuel was coming out of the filter, is the filter high up in the engine bay and does the fuel come out at considerable pressure/volume? The reason I ask is the in- tank pump unit can split internally and the fuel delivery is then virtually nil - giving no start syndrome even though you can hear the pump working.....

 

As for irregular idling speed - if its a rough idle then it could be an ignition fault - ht leads are often culprits. They also give the no start symptoms..

Examine plugs and change if necessary esp if its been 30k miles or more since last change...also give the coilpack a good inspection.

 

Remember over 90% of no start or rough running problems on all petrol engines are ignition faults. (leads/plugs/coils)

[Guest MATT]

:P Aw you fixed wingers :o

Helicopters?

[Masked Marauder]

Make sure all your induction pipework is tight with no splits.

[Dave-G]

Helicopters?

 

:P Rotary wings old chap :o

[Guest YrWyddfa]

Well I changed the Sparks and the fuel filters fine - (there is fuel going into the injector rail)

 

I've taken it to a garage and he reckons (after advice from his computer) that I have a MAF sensor fault.

 

I guess I'll find out if he's right on Wednesday. I shall be very unhappy if he's wrong as a MAF sensor costs

[Guest vr6galaxy]

If the MAF sensor has gone it wont stop the engine from running, I have ran mine with out it plugged in and with the throttle body sensor plugged in as well! both with out realising!

if the engine is turning over and you have fuel at the fuel rail then that leaves the sparks? have you got a spark at the plug end of the lead? if not, is the coil pack plugged in? is the coil pack ok?

[seatkid]

100% agree with VR6galaxy. MAF sensor has nothing to do with ability to start,run or engine idle speed, smoothness etc.etc. You are being RIPPED OFF by Fraud dealer - (a MAF sensor over the counter is about

[Guest vr6galaxy]

Also check all the fuse's and the relay's for the fuel and ignition system, another thing is, what's the LED on the door doing when you turn the key in the ignition? is it flashing more than usual?

[Guest YrWyddfa]

HT Leads are fine, spartks have been changed, getting fuel into the injector rail. How do I test the coilpack (I am getting sparks from my new spark plugs - so is this relevant?)

 

What fuses and relays should I check? How do you test a relay?

[Guest YrWyddfa]

Well, the guy replaced the MAF sensor (as per his computer read-out) and the car now again works.

 

So to rectify this problem I have changed:

 

Air Filter

Sparks,

Oil and filter,

MAF Sensor.

 

In that order. Looks like it was the MAF sensor afterall.

[seatkid]

Think I'll file this one under "strange but dealer did charge an awful lot?" section.

Bet he did something else as well as MAF...

[Guest YrWyddfa]

Possibly . . .

 

The guycharged me the going rate for a MAF Sensor for the 2.8 VR6 (which is