the thing i find strange is that the eml light does not come on , so in my mind it can only be a mapping issue not a major ecu fault, had a message last night from previous owner cant find the paper work for map but hes 100% sure it was a revo re mapp so kinda maybe helps knowing what make of map was put on maybe! so today ill check md performance the error code and hopefully get it smoked checked if they wont smoke check it ill no what type of "performance garage " they are! 

The EML doesn't always come on when a code is thrown, that doesn't necessarily mean it's a software issue. There aren't normally problems with Revo maps, if that is what it is. If it is a Revo map this would lean it towards a different issue such as air, lots of people on here run Revo maps and are reviewed consistently as one of the better options. Not saying its not that, but it is unlikely. But yes like you say, keep the software in mind but focus on that code and get it smoke tested. Good luck.

funny did a readiness test on my vs450 scanner today this came up as a fail

 

" sec.air sys  fail "    any ideas what this means?

That's the secondary air intake which basically is another air pump which warms the cat to improve cold start efficiency. It can however cause running issues if the pipework isn't right with it. It is under the car near the sump. Check to see if any hoses are damaged or popped off. One hose is ribbed plastic and comes all the way up, along the front of intake manifold and clips on to the airbox. It could be the pump itself as pipework problems would normally be associated with a rough idle and EML would probably come on. If it is the pump the cheapest easiest thing would be to remove it and delete it from the system. I would check it's associated pipework first though, could be something as simple as a hose popping off.

Is it noisy on cold start by the way? I had a hose pop off mine and it sounded like a lawnmower. At least you have an area to focus your search.

on start up its makes a strange noise but only for a while then whoosh, sounds fine.   the guy i bought it off says its always like it as its the pcv valve???

Sounds like secondary air pump to me, it runs for a little while when cold, gets cat up to temp then cuts back and let's system take over. Hence more noise on choke, then quieter. With an issue with it could be very noisy on choke, then quieter/normal. Basically they're noisy on cold start because of sai anyway, fault or no fault, but could be very noisy. Was it badger bill who mentioned PCV as well? If so keep it in mind, but I'd stay focused on the secondary air intake and pump unit.

no badger aint seen it too busy!    the guys i bought it off his old man was garage owner. just said its the pcv valve, ill get a film of the noise , having never owned one i cant tell if its normal noises!   the bora never made sounds like this!! 

Oh ok, thought someone had mentioned it. Definitely sounds like sai to me, question really is whether it's a simple pipework thing or the pump itself. Think you're on the right track now and you've got some information to give to md.

would it cause the issue with the revs tho?   and like you said wouldnt it cause a eml light?

Probably if it was pipework related, which leads me to think it may be the pump itself. If idle is steady, I would say pump, if that fluctuates would say pipe. Either would result in it being noisy on cold start. Whichever it is I think you're on the right track. I'm surprised EML hasn't come on, but to be honest unless the ecu recognises something as outside of its tolerances and parameters it won't normally do so.

It's difficult to say how it would effect the running I suppose, too many variables. Airflow will effect revs somehow though, although it will vary.

well idle is solid at just under 1000rpm never fluctuates, well see what md come back with should be anytime now!

I reckon it's the pump then, see what happens, be cool like Fonzy

ok hear goes,   just got back from md performance.    code for ecu read as this,   "no deteced ecus 1.  active protocol iso9141-2 id$10 engine controller." 

 

but they smoke tested it and found the intercooler had a leak itself,  enquired whether this would cause my issue and the answer is yes!   and tells me the ecu code is just cos its been mapped! why didnt he know or say this yesterday. 

 

im glad i pushed for a smoke test. 

Well I didn't see that coming lol. What was it that read the secondary air fault then? Anyway that does make sense, so basically it's a big pressure drop in the cooler before the charge builds again?

So you need a new cooler? Question now is, standard, uprated side mount or front mount? Hehe

it was my own vs450 scanner tool. basic but im wondering if the car wasnt 100% warm thats why it failed that test. 

 

question is what options do i have to replace the standard one >?????????? i dnt wanna mess about with remounting so rather just stick it in same place, so am i stuck with standard one?

I fitted one of these

http://www.briskoda.net/forums/topic/352298-proper-mod/

Goes onto existing pipework no problem. Turborevs one often needs 12mm MAP sensor though. Ours can have 12 or 17mm fitted as standard so will need to check. They're only 100 new (ebay) but I got mine used but never fitted for 60. Only go turborevs as they come off the same line as Godspeed, there are alloy ones on ebay that look similar but aren't as good quality. You may need the remap tweaking if you get any lag but I didn't get any, I think there's plenty of psi in my map to go around. They're big, but do fit, need to cut down plastic duct behind bumper though.

Or you could get a genuine golf 4 one from the breakers (or new), again check map port as they also have either. They slightly larger than octy ones but gain is marginal. Turborevs one will drop your intake temps by a fair chunk and that's what it's all about.

ok how do i check the map sensor mm?   

Literally take it out and measure it where the O ring sits. Its on the top of the top end tank plugged in. You may have to take headlight out to get to its bolts, but you can do that without taking bumper off if you carefully angle it. Indicator is clipped in with little bolt on top, headlight is 4 torx screws.

think i may gop standard eurocarparts have offers on theres a eis one reduced to £66 may just take that says 18mm map connector

Yeah that translates to 17 there's only 2 sizes, it's likely yours is 12, best to check as it needs to be airtight. If you end up needing a different sized MAP you're talking £40-50 for a genuine one.

pain in the ass checking first!

A little bit but will only take 5 minutes

i no your right! 

ok i cheated got the part number off the existing map. 038906051b says its 12mm!