help: running rough

[Jmac]

Dont try the battery trick that will fry the ecu. Check your charging rate mate should be around 13.9 volts at 2500rpm. Check your earths on your cylinder head on the right above your gearbox. I just done one here and i rewired the ECU earth and it cured it. Let me know how you go. If you want to run a new earth let me know and ill guide you. Also could be coolant temp sensor, that directs the ecu to alter injection time. Also how is your fuel filter???
Cheers and by the way is it a Digifant motor???? if it is the above applies mate

[joshyd-mk2gti]

hey, yeh all aus delivered mk2s are digi2. im going back home next weekend so ill test the voltage. test it at the battery terminals? i put in a new blue coolant temp sensor last year, is that the one that goes to the ecu? i think the fuel filter is old, so thats probably not helping the cause. ill try get it booked into the mechanic this week. are fuel filters universal, or will they have to order one in?

[Jmac]

Hi mate , yes you will have to order one not universal. Can be a real bummer to change on them. Its at the back right. I know back home the pipes used to rust something terrible and the rubber mounts used to break. Anyway the answer to your question about the temp sensor is yes it is the one for the ecu. By the way also check them earths they are really bad for that especially the one for the ecu.
Good luck mate

[joshyd-mk2gti]

cheers jmac. yeh i cleaned a few grounds around the battery, but didnt get to the one on the head unfortunately. ill have a better look thou.
ive seen where the fuel filter is, and decided its a job for the pro's.

[Lukev85]

Dont know too much bout the mk golf's, is it a carby engine?

If it is, it could be the fact that when a carby engined car isnt started for a while, dirt and grime builds up in the carby itself. This causes the engine not to idel property. Its happened to me many times with past Beetles.

Try pulling the carby apart and cleaning it out. It may work, has for me in the past.

[Jmac]

Mate they dont fit carbies to GTi hence the I part of GTI

[joshyd-mk2gti]

so its in at the mechanics now. he did a compression test and it showed #4 was low. he took the head off and said there was a bit of metal floating around that was holding the valve open. :/

[Jmac]

????????????? piece of metal thats strange,very strange where was the metal sitting and did he show you? carbon was bad for holding valves open but a spray of the subaru decoke spray always done the trick.

[joshyd-mk2gti]

na i didnt go down and see it. should get it back next week, so hopefully its running properly. the thing is, after it had been sitting for a while, it would idle perfectly for around 30 seconds, then run rough. if the valve wasnt working properly, wouldnt it run like ass all the time?

is that subaru decoke spray the same thing as Seafoam? the yanks love that stuff. they suck it into the engine, it cleans off all the carbon and makes a ****e load of smoke, then it runs sweet.

[Jmac]

Similar mate and yes you are right it would run **** all the time mate