Golf VR6 Hard Starting/Misfiring (Now running, but right?)

[MiniDan]

Hi folks,

I'm having some trouble with my 95 Mk3 Golf VR6 and I'm hoping the good people of RR can advise on what to do.

The car takes probably a minute of cranking and pressing of the accelerator to get it spluttering in to life but it immediately is misfiring and running rough. After a minute or so of it running there is a really bad overfueling smell from the exhaust.

I initially thought it was either the coil pack, as it was the original, or the leads, as the previous owner had put some cheap and nasty ones on. I changed the coil pack, leads and spark plugs at the weekend but the car is running exactly the same.

I've ordered a new temperature sensor as I've read these can cause starting and misfiring issues and I have a fuel filter to fit as that is the original as well. Is there any other likely suspects I can try?

At the minute I don't have VAGCOM or a code reader so can't get codes and there's no engine light one.

Any help would be greatly appreciated Thanks in advance.

[Soopahfly]

Not familiar with the engine, but in "Moderns" that I've had, these same symptoms have been down to a dying crank or cam position sensor, however they have usually thrown a code.

I'm not sure a '95 car would be OBD2, so may not throw a code. Can't remember if OBD1 was clever enough for cam/crank position.

If it is OBD2, a cheap bluetooth scanner is worth a punt. TorqueApp on Android can pull live data out so you can see what's happening, or even if there is an engine code stored/pending but hasn't triggered the light.

I'd be reluctant to just throw parts at it.

[SamJ]

It probably only had OBD1 not OBD2, so you have to find the correct scanner to work with the car... or at least that has the correct leads to work with the car. OBD1 has two small connectors, I think in a MK3 they are behind a blanking plate on the dash, underneath the heater controls. Depending on exact age it might be OBD1 or an early OBD2 car.

www.outilsobdfacile.com/location-plug-connector-obd/Volkswagen-golf-3-non-standard

You can also try the blink codes that are read out from the engine management light, or you can make LEDs that you put across the OBD port pins and flash in sequence with the error codes... google VW Blink Codes and you should find all you need.

As for the actual issue, are you getting fuel pump priming correctly? Does the pump run and turn off when you turn the ignition from off to run, but not all the way to start?

[mht]

Remove the ash tray. There’s a blanking plate next to it that will slide out with it removed. If there’s one large 15 pin connector there it’s OBD2.

I think 95 was the changeover year.

[2p2g1m]

This engine does suffer with timing chain issues. Possibly the timing is out?

[vitesseefi]

Obviously overfuelling and possibly the reason why it takes a long time to start is that it is really overfuelling during cranking and you are needing to engage flood clear mode (hold throttle all the way down) to get it to fire.

Could be the engine temperature sensor as if the ECU thinks it’s colder than it is it’ll be tipping more in than it should. Alternatively there may be a problem with the fuel pressure regulator or even the return line, causing the fuel pressure to be too high.

Nick