mck684 0 Posted October 25, 2009 Report Share Posted October 25, 2009 hi all,my obd1 93 vr has a high pitched hoover style noise on startup (stone cold startup only) if its warm it doesnt do it. i have heard rumours about a secondary air pump that blows air thorough the cat from stone cold for some reason or another and that it falls apart after a certain amount of time. i think i may have a vacuum leak of some sort to as sometimes i get this chirping noise (when driving off from stone cold and also when very hot).the car runs great when warm but sounds horrid when cold. any ideas? ian. Link to post Share on other sites
ingham 5 Posted October 25, 2009 Report Share Posted October 25, 2009 just cold oil in oil pump, there is no air pump that blows air thorough the cat Link to post Share on other sites
UnitedMotorsport 55 Posted October 25, 2009 Report Share Posted October 25, 2009 i have heard rumours about a secondary air pump that blows air thorough the cat from stone cold for some reason or another and that it falls apart after a certain amount of time.This is only on MK4 and newer. This system isnt fitted to OBD1 VR6. Link to post Share on other sites
mck684 0 Posted October 25, 2009 Author Report Share Posted October 25, 2009 oh thats odd. i only said that because of this review (and a few others that are floating round on the net) heres a snippet below.Questioni tried to get my 97 GTI VR6 inspected 2day and it failed. they gave me a p0171 system too lean bank 1 code, and p0411 secondary air injection system incorrect flow detected. what should i do i need helpAnswerHello, Jason here to help. On the P0171 If the fuel filter hasnt been done, Do it as a first step, alot of times it solves it. I fuel filter doesnt fix P0171 then a vacuum leak,bad mass air flow sensor would be the next diagnosis step. On the P0411, If you hear a loud whine type noise on a cold start, the SEC air pump is working, but check these: At air cleaner, you will see a 1.5" ribbed hose going down under intake, follow it and you will see a pump attached to it, Look at the rivits that hold pump together. If they are loose then the sec air pump is falling apart. if not then look for a broken vacuum hose broken at Secondary air check valve, silver in color. the other hose off of the pump will lead you to it. From there it would be a dealer or a good VW shop to test further and clear codes and then set readiness code(why you failed the test was a code stored or readiness not set. Hope this helps, Jasonif you say its cold oil in the pump then surely everybody's would do it? or do they? cheers. Link to post Share on other sites
UnitedMotorsport 55 Posted October 25, 2009 Report Share Posted October 25, 2009 That snippet is taken from an american based text,The car is question in that snippet is a 97 car, which is OBD2, yours is OBD1.Americans have VERY different emissions standards to us, and have secondary air injection on their OBD2 engined MK3 golfs.Hope this clears things up. Link to post Share on other sites
mck684 0 Posted October 25, 2009 Author Report Share Posted October 25, 2009 no that makes sense thanks. just a bit weird how the car sounds so crappy when its started up from cold (sort of like a metallic grinding noise coming from somewhere teamed with this hoover style noise! its really odd how after the car hits 50 degrees c it dissapears and turns back into its gruff vr6 sounding self. you can start and stop it as many times as you like but the noise is only there when stone cold, this obviously points to something to do with the oil temp. my old gti 8v sounded fine when started from cold, is it a vr6 characteristic? (?) Link to post Share on other sites
UnitedMotorsport 55 Posted October 25, 2009 Report Share Posted October 25, 2009 Could it be the ISV (idle stabilisation valve?)This is located to the right of the throttle body as you look at the engine bay. Link to post Share on other sites
mck684 0 Posted October 27, 2009 Author Report Share Posted October 27, 2009 thanks for the suggestion. if it were the isv would the car not have a dodgy idle all the time? the car idles perfectly when warm and the idle is controlled when cold but just quite high which i believe is normal. its the actual noise that is disturbing. Link to post Share on other sites
UnitedMotorsport 55 Posted October 27, 2009 Report Share Posted October 27, 2009 The ISV allows air to pass through it, controlling the idle. It could be this air passing through the ISV making the noise? Just like a whistle? Link to post Share on other sites
mck684 0 Posted October 29, 2009 Author Report Share Posted October 29, 2009 anyone got a picture of the idle stabilization valve in the engine bay? Google images was most unhelpful surprisingly. Link to post Share on other sites
mck684 0 Posted November 1, 2009 Author Report Share Posted November 1, 2009 hi all, the whistling i noticed has started to get worse and this has given me the chance to identify where it is coming from. please see the attached picture. i have circled in red the part of the engine that the noise is coming from. can anyone tell me what this part is please? when i rev the engine it's like there is a vacuum leak or something coming from around here. Link to post Share on other sites
mck684 0 Posted November 1, 2009 Author Report Share Posted November 1, 2009 hang on just gotta figure out how to upload this damn picture... Link to post Share on other sites
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