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Won't start, tick over, or run properly


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Got an OBD2 VR6 engine in my Sharan and it's got problems.

It's a bitch to start, when it starts it won't tick over, and if it does eventually go it runs like a bag of crap. It's better when it warms up but who wants to sit outside their house for five minutes before going anywhere ?

Changed the MAF several times (2nd hand, 2nd hand, new but not OEM) but it hasn;t made any difference.

There is a whining noise coming from the throttle body when I first turn the ignition on. Plugged another one in and it made the same noise.

The non- return valve that goes into the air intake is split, and there's a fair bit of oil round it, and in the air intake.

The airbox is cracked and loose and one of the clips that hold the maf on t the airbox is missing.

Would any of these things cause the starting/running problems ?

I've had it looked at by three different mechanics. One reset the codes, but couldn't give me any more help than that.

One fitted a new coil, plugs, and leads (ouch) which didn't make any difference.

And the last one siad it was all down to the LPG system which was fitted when I got the vehicle.

Thing is, it's runs much much better on gas ?

I'm on the point of scrapping or breaking it, anyone got any ideas ? Or know someone knowledgable who can take a look at it for me ? I'm in Harwich, Essex.

cheers

.

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firstly the whine from the thottle body is the ECU calibrating it as the idle control is via a servo motor in the TB. You should allow it to do it's thing if the battery has been off or the TB changed. 10 to 15 mins should be fine. prob a lot less.

Oil everywhere won't help as it may clog the TB closed / open. And unmetered air getting into the system through spilts / gaps won't help the running as the air fuel ratio will be out.

Hope that helps if not one of our essex boys, or girls, might volunteer to help out.

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As goth said, let the throttle body do it's thing. It does it every time you turn the ignition on before starting it but if the batteries been off you need to let it finish completely before it'll run right.

It'll sit there whining and clicking for 10-15 and end with a small clunk. Once it goes quiet it should start up fine every time you try.

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The throttle is whirring, then clicking after about 15 seconds. Cold tickover is all over the place, It just won't settle down.

I was thinking of replacing the various sensors one at a time to see of that solved the problem.

Might be a daft question, but where is the Thottle Position Sensor ? That was showing an earth fault last time the diagnostic thing was plugged in to it, so I reckon it's the first thing I should replace. After the non-return valve thing. So it'd be the second thing.

ANywayyyyyy.........

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I think on obd2 TPS is built in to the throttle body.

Have you tried unplugging the MAF and starting it? It will run without the MAF, if unplugging the MAF suddenly sorts it out you probably need a new one.

Swap with a known working one if you have one to hand.

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Another thought, this valve thing is letting oil into to the airflow, which can't be good. The parts diagram shows it as a bleed valve for use in cold clmates, so do I need it ? If I disconnect and block it off will it still run ? There's a sensor on top of the pipe before it goes into the inlet pipe- what is this for ? The plug has metal connectors but there's nothing in the sensor for it to connect to ???

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you can block the pipe the sensor does nothing there are no connectors in it. put a small airfilter on the breather for the head to breath try using a maf off of someones car that is working correctly pointless buying new if you can substitute to find the problem have you tried disconnecting the battery leave for 15 minutes then reconnect turn ignition on for a while for tb sensor to stabilise then try starting

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