Bosch K-jetronic - Mk2 Golf Gti 16v - Engine Vacuum System

[@EricTheSwede]

THANK YOU! Explaining what the overrun valve does at 3:13 made me instantly recognize my problem I'm having and ran down to the car - of course I've managed to yank that vacuum line out while replacing my air filter + box some time ago. I have been going MENTAL about my car stalling on me when I'm trying to slow down at intersections etc. I'm going to do my inspections on it tomorrow and if it solved my issue I'll be eternally grateful!!!

[@GreyGooseRestorations]

Hopefully it sorts your issue 👍🤞

[@gavinhibberd1708]

8:44 Love the length of the ‘test derive’ - Really great video.

[@haggardautomotive]

Your the man. Thank you for all of the mk2 content.

[@GreyGooseRestorations]

No problems, plenty more to come

[@danpatrick2175]

Thanks much - great video! My Bentley manual is very sparse on the vacuum line system info for the 16V and your video answered my questions.

[@GreyGooseRestorations]

Glad it helped 👍

[@shootingsaturdays7998]

an absolute fountain of knowledge , great channel !!

[@GreyGooseRestorations]

Thanks 👍

[@MK2GolfStories]

another brilliant video, thanks!

[@Baxkez]

Nice job 👍👍👍

[@javierlopez04277]

Where would you recommend connecting a hose in order to perform a vacuum leak test with a smoke machine?

[@GreyGooseRestorations]

On the back of the inlet manifold where the brake servo pipe connects

[@javierlopez04277]

@@GreyGooseRestorations Thank you!

[@darrentriumph6319]

Great video, just picked up a 5 door 1990 16v and it came on a trailer. 😢 it’s a long term project and got it started and it idles well to get up to temp. When it’s warm and I blip the throttle the revs increase and then the revs drop off and stalls. Could this be the vacuum or shall I look to adjust the brass idle screw to increase this to see if it stops the stalling. Appreciate it could be many different issues but your video got me thinking.

[@GreyGooseRestorations]

It could be the idle valve or Deceleration Cut off Valve not functioning? The DCV catches the engine above 1300 rpm then the idle valves takes over below that, 16vs like to sit at 1000 rpm

[@RudeLubeuk]

My mk1 16v i thrashed about for a good few years, thought it ran great, just did basic services on it no problems. Been in garage for 15 years, now im getting it going again i relise how much stuff is missing, i have no plug on that throttle body micro switch, no plug on idle control valve, dont think i have cold enrichment valve at all, and i used to run it with that 4mm vacuum pipe disconnected. How did it ever work, i guess it has something to do with still having mk1 wiring loom. plenty more pony's to be found then. Whats your thoughts on having a custom wiring loom made, would save alot of weight too, getting rid of any redundant wires

[@GreyGooseRestorations]

Always some ponies to be found somewhere, ref wiring its swings and roundabouts really, could take out defunct wires yourself and save monies

[@DannyRoberts-l8i]

Awesome video, really struggling with mk mk2 16v. Had it running previously however would idle but when applying throttle it sort of stalls, won't rev properly. Is now not firing so am.teying new injectors ( think they're original ones in there )

[@GreyGooseRestorations]

If it idles ok then dies as soon as the throttle is opened then that would be pointing to lean fueling, see what its like after new injectors

[@DannyRoberts-l8i]

Have got ilmy mk2 running. New injectors have done the trick. I think I have a vacuum leak though, when applying throttle I can hear it drawing air somewhere behind throttle body. Can you buy full vacuum line replacement kits ??

[@GreyGooseRestorations]

@user-kr1tg2kc7g its most likely the idle screw O ring or on the rubber boot underneath there is a vacuum part that can leak

[@DannyRoberts-l8i]

Thanks for that, will see if VW heritage have the part. Thanks again

[@DannyRoberts-l8i]

OK that's great. Have done a bit of reading with some horror stories about trying to replace the idle screw o ring, do you have any videos about how to refit ??

[@ktm250sxUbeazy]

Fuck this is the best pl digi I have seen

[@nasotang5]

Hey! Great video, thank you for posting. What size are the small vac tubes? 3.5mm?

[@GreyGooseRestorations]

Technically 4mm but i use 3.5mm just so they are a solid fit 👍

[@SoreHands]

thanks for the detailed and clear vid, will be checking the vacuum system on my valver. Thought that it sounded pretty rough at idle - did you get that sorted and what was the issue? Subscribed :)

[@GreyGooseRestorations]

Thanks 👍 much appreciated. Yes it was a air leak from the throttle body idle screw

[@nateslack1205]

Where do the vacuum tubes go that go back through the firewall? I have two that go back through the firewall and I’m not sure where they go or what they do

[@GreyGooseRestorations]

There should only be one going through the bulkhead, one goes to the back of the speedo unit and the other should go to the ecu

[@totte1015]

My vacuum line to the control unit is right now busted and i have plugged the vacuum hose for now. What difference does it do to the ecu? Does it affect anything? Also what are the measures on the vacuum lines? Is there any kit for replacing?

[@GreyGooseRestorations]

@totte1015 the vacuum line is a ref for the ECU load table and adjusts ignition timing advance accordingly. Use 3mm ID vacuum hose

[@totte1015]

@@GreyGooseRestorations Thank you so much, best guy on 16v!

[@KevRWDstarlet]

I've got a vacuum pipe coming off the bottom right hand side of the airbox and going nowhere just running along the top of the chassis. Where should this go? Also on startup the car idles at 3k rpm and only dies back when I pinch the pipe going between the isv and airbox closed

[@GreyGooseRestorations]

The small vacuum pipe is for the warm air flap thing in the base of the air box, just pull that small pipe off or block it as its close to useless. Sounds like the ISV is stuck as the engine is drawing air through the ISV into the engine instead of the ISV bypassing air into the air intake

[@KevRWDstarlet]

Got the high idle sorted, it was indeed the ISV stuck open. Started and idling ok. Once it got up to temp any time the fan cut in the idle shot up to 2.5k, quite strange. Also when I knock it off now when up to temp it refuses to start

[@GreyGooseRestorations]

@KevRWDstarlet it could the ISV again as when the fan cuts in the idle control module raises the idle to take into account the extra load

[@colevincent8563]

I have previously cleaned my ISV with petrol, but some say that carb cleaner is better as it is more safe on the internal ISV rubbers. Any truth to this?

[@GreyGooseRestorations]

A bit yes as the rubber is close to 30yrs old so will be degreaded anyway, add fuel to that with modern additives and it'll most likely do more harm than good, best to use something thats designed for cleaning

why the ECU needs a vacuum? thanks!

[@charlesbradley7277]

what is the number of the idle valve please

[@GreyGooseRestorations]

037906457C

[@TheGameLoverTv]

Nice vid. A question, where do you get all your clips?

[@GreyGooseRestorations]

The coloured hoses clips? If so they were from type19.com

[@anthonyalvarez6735]

Very informative. Nicely articulated concise and to the point. Thank you for your video

[@rajloyal]

@@GreyGooseRestorations Hi nice info, I wanted to know specifically where you got the injector tidy line clips and HT lead clips especially the ones that fit onto the 2 inlet brackets

[@GreyGooseRestorations]

@@rajloyal all from dubstock facebook.com/groups/140698986707056/?ref=share

[@ravenmaster6364]

Hi great video again 👍👍, this car is a beauty! I think i may replace my vacuum lines on mine just to have knowledge that they are new. I have suspected that my idle microswitch is faulty for a while now, if it clicks it is working ok is the golden rule then? Did you say you can get the seal for the idle screw off the shelf thesedays at all tool? *I'll try and get the pics of my sensor wiring to you soon, sorry was busy at weekend 🙈. Keep up the great work! 👍

[@ktm250sxUbeazy]

Why are alot of 16v missing cold enrichment valve. That t plug from the intake is non existent aswell in alot of 16v

[@GreyGooseRestorations]

They may well of revised the need for that part in later cars

[@ktm250sxUbeazy]

@@GreyGooseRestorations. Maybe. It seems your vacuume system is a better design. Very simplistic. Or maybe it was the crackhead who worked on my car before me

[@timarublitzkrieg4498]

couldnt help but laugh at the hubcap falling off, lucky it happened in the yard rather than down the road somewhere

[@GreyGooseRestorations]

Yeah i walked back out to get the camera and was like 'wtf' hahah yeah good job it wasn't down the road, its only because ive got temporary wheel bolts in, got a freash set to fit