Project, re-wiring engine??

[MattHart]

Hi guys, I have a gti 16v which started life as an 8v, It has been off the road for the past year due to an issue that seemed to happen once every 4 months where the car would start surging down the road on and off underload however would idle fine, checked maf meter, wasnt stuck, checked injectors all seemed fine, checked fuel pump both all fine. I have since had the golf on the road once and drove it for 20 miles and ran perfectly not a fault in site and rather than sell on as a project I want to keep it and re-build it back to glory. My question really is, is could the fault be from wiring, after having to replace the door solenoids I was re-wiring the new ones in and saw the state of the wiring under the dash and how I couldn't make head or tail of anything with the messy diy job that a previous owner had done with the engine swap there are wires not connected from old immobilisers just left and the wires dont seem to follow any colour coding, so could this have caused the irregularities with the engine if there was a bad connection on a cable? my dad is a faily competent ex-mechanic and I wanted to give a go re-wiring the engine back to colour coding it correctly and making a hell of a lot neater? Could the wiring have caused the problem I had before though?

Cheers Matt

[rubjonny]

what engine is it and where is the hazard switch?

[MattHart]

Sorry havn't any experience with these cars yet, so where would I find an engine code? and the hazard switch? as in fuse box or located on the car?

[Sam]

Sorry havn't any experience with these cars yet, so where would I find an engine code? and the hazard switch? as in fuse box or located on the car?

Nah the button yo press to turn the hazzard lights on, its in on the dash or steering collum and the engine code should be on a sticker in the boot along with your paint codes ect. Think its also on the inside of the door if you open it

[rubjonny]

do didnt spot you mention its a 16v now, is it a standard mk2 16v lump running on the factory 16v engine managment? if so the only thing i need to know is where the hazard switch is. if you arnt sure about the engine, post up a piccy and we can id it for you

[MattHart]

As far as I am aware standard engine and ecu, the hazard switch is on button to the right of the stereo so main centre console. Could it be the ecu, the really frustrating thing with this problem is it happened once took things apart checked things then put it back together and ran like a dream, then 6 months later did it again, I took it off the road then started using it again about a month later and was fine didnt dismantle anything, I then laid it up for a while as my commute was getting to far in petrol so was using something more economical then other week charged battery fired up drove it for a fair few miles with no issue. as the problem isnt consistent I can't seem to get the bottom of it which is making me think more electrical than mechanical, as if an injector pump etc had a problem I would expect not to carry on working for months on end and quite a few thousand miles re appear dissapear then re appear. Could it be a malfunction in the ecu reading a sensor or a faulty sensor?

[rubjonny]

pm me your email address and i'll send you some diagrams
also check the 3 single pin sensors on the side of the head, they should all be black. give em a clean and check the wires are in good nick, swap them round a bit and see if anything changes.  have a good look over the engie for split vacuum hoses, and in the folds of the inlet boots for splits