Cold Start , MFA, Rough Running and steaming up . .

[mallydgti]

Hi all, help required, I recently bought a MK2 Gti 8v 1990 to use for track days, the car was bought from a salvage yard having been rear ended below the tailgate, but did come with 17's and a stainless exhaust, on the day I bought it I drove from Dumfries to Carlisle (35 miles) and all was well. I then had to replace the alternator and starter because the muppets had filled them with water pressure washing the car, I have since replaced steering rack, battery, plugs, leads, dizzy cap and rotor arm, the car however refuses to start, has been into a local specialist and they cahnge the ECU/Airbox/Airflow meter and temp sensor and this solved the poor running. The car is still an absolute b*stard to start from cold and just turns over and over for ages, when it does start it runs rough for a minute or two then ticksover fine, I have then took it for a soin and it drives fine and will restart no problem when warm, it is also chewing fuel and the local garage could not get the emissions within the required range either. When its cold though no chance of starting, If I jump it off my Leon Cupra it will eventually start, HELP!! MFA oil light and rev counter are also inoperative. after car has been ran and warmed up windows steam up also, and it is not using water!

[Rain]

dunno about the steaming is the fan blowing hot/cold air to the windscreen? as for poor starting as you have replace dizzy/leads etc only thing i can think of is the lift pump or main fuel pump, fuel relays etc.. or the injectors. how does it start from warm? if it starts perfectly when its been running for a while id check the injectors.

[rubjonny]

Steaming is probablt the heater matrix has gone, you should replace it sooner rather than later or it'll probably go in a big way!

For the poor starting, replace the blue temp sender, will only be £12ish from VW and should solve the cold starting, then you'll want to set the idle & CO with a CO meter ideally:

1. Get the engine up to temp, at least 80 degrees on the MFA oil temp display
2. Turn the engine off and remove & plug the intake side of the breather pipe between the rocker cover & air intake
3. Hold the MFA button in and turn the ignition on, off and on again, then start the car.  This puts the MFA into a 'secret' mode.  Put the MFA switch to setting 2 and press the button till you get the digital rev counter, position 2 I think
4. Unplug the blue temp sender and rev the engine cleanly over 3k rpm 3 times, letting it return to idle between each rev.
5. Check the rev display, adjust the idle with the idle screw on the throttle body to about 850-900 rpm. Clockwise to decrease, anticlockwise to increase
6. If you have a CO meter, block off one of the talipipes (i use a load of duck tape) and shove the probe up the pipe.  Follow the manufacturers instructions, and set the CO to about 1.8ish using the allen screw on the MAF, clockwise to increase, anticlockwise to decrease.
If you don't have a CO meter, turn the screw in until the engine starts to sound rough then back it out gradually till the idle sounds smooth & even.  Check the aerial or bonnet stay for vibration, you want it smooth as possible.  This will get you close, then take it to a garage to get it set properly
7. Reset the idle to 850-900 rpm if it has changed, and adjust the CO accordingly, repeat till you get about 1.8 at 850ish rpm

[IRONCROSS 8V2.0]

Rev counter and MFA failure is usually an easy fix, just had it on my 90 spec 8v.Remove fuse 21 for 30 seconds and then replace,MFA should reset and come on.When car is started rev counter should work.If not check the earth to the back of the clocks.

[mallydgti]

  Cheers Guys, The car runs absolutely fine after a minute or two, and once warm will start every time. I think the MFA, rev counter and oil light will require a little more investigation, there is obviously an electrical gremlin or two as now the horn is working when you turn the indicators on (I suspect the switch wiring), the heater matrix is probably on the way out but I might just bypass this altogether as the car is only going to be used for trackdays.