Engine Hunts when warm :O(

[EvilScotsman]

ok, I cleaned the TB out wi petrol, it wasn't very dirty anyway but did it and the plastic air tube leading to it. It did seem to help but not much.

It still feels like the engine power "pulses" when accelerating up to 3k, it hunts on idle, and sometimes cuts out or won't start for a few secs.

I disconnected the MAF plug and it ran like a bag of nuts, so im assuming its ok. Also disco'd the IAT, that made no difference at all - could be that?

Does the 8v have an idle control valve? if so where is it?

And the silver thing on the rhs end of the fuel rail connected to the TB wi a thin rubber tube - is that the fuel pressure reg and could that be the prob....?

Havent tried the relays yet. 

[boneybradley]

Simos engine's don't have an isv..and yes the fuel pressure reg is located where you said in your pm
just a few question's
1. Have you changed the ecu temp sensor???
2. Check the relay's like len say's
3. check all the breather pipe's to make sure there's no leak's (also check valve on the back on the engine breather as they have rubber seal's which can dry up)
4. check the coil is ok as they crack letting in moisture

next thing i would think if all these are ok is the hall sender on the dizzy

please reply if you would like further detail's

[EvilScotsman]

Thanks guys. I will do all of the above tomorrow or monday, as i might not get parts round here over the weekend.

I checked the hoses, the FPR tube was cracked at both ends so i trimmed it and refitted.

It did a funny thing tonight, stopped after a long drive, went to restart and it would fire, idle, then cut out. Revving it didnt help, it still cut out even when revving....switched all off, checked/wiggled all the sensor wires in the engine bay, and finally it fired up. Its never done that before and it didnt want to start for about 5 mins - weird. Will check all the wires in the daylight to see if anythings loose, and im going for relays and an ECU temp sensor asap.

It seems to misfire when accelerating AND has lumpy idling - but its a soft misfire, like dodgy fuelling - not sparks, if that makes sense. Thats why I asked about the FPR. It seems very loose too - for what it does, I would expect it to be a tight-ish fit, but its not (rotates easily even wi clip fitted)

The previous owner changed the dizzy cap, leads, plugs and rotor to cure the fault (which obviously it hasnt) so I know they are ok. Its annoying because my job is electronic fault-finding and I didnt know enough about gti common faults etc to make a good start, but thanks for helping :O)

[EvilScotsman]

btw when it was cutting out continually tonight, like it had run out of petrol, you know - start, fire, idle for a sec then snuff out, made me think of the fuel pump relay maybe dodgy & chattering etc. Will do the relays and the temp sensor first (one at a time tho obvsly so i know what cured it )

[EvilScotsman]

Boney - I found tonight that i have the same 5k rev limit as the other guy whos post you answered about the timing belt being 1 tooth out? weird as my car had its belt changed in oct when the tensioner siezed and broke it.

Does this change your estimation of the fault?

Thanks for all your help mate :O)

[boneybradley]

That could be the cause....if the timing is out by 1 tooth on the belt the rev limiter comes in earlier and can cause bad running as the valve's open and close wrongly... best to have the timing checked (which is a pig to do without the correct tester) and to change the timing you will need the belt taking off and resetting but still check the relay's as before as these are one of the worst golf fault's

[EvilScotsman]

Thanks mate will do. Spot on advice btw, I read the BIG post from scooterist lol, so much for VW reliability eh