Jump to content
Sign in to follow this  
bighands

dodgy starting 1.8 16v

Recommended Posts

right lads, got one for the 1.8 16v peeps out there, when i start my beast from cold, or after it has been left a while with no throttle it starts n cuts out again, then if i try with a bit of throttle, it starts, i have 2 put my foot down and it fires on about 2-3 cylinders untill i rev it a few times, and then it settles out as tho nothing was wrong! it has always done this, its just annoying! why? should it do this? does anyone else have this prob?

Share this post


Link to post
Share on other sites

Sounds like the 5th injector to me....next time you do a cold start, disconnect the blue plug on the end of the manifold and crank the engine over. If it makes no difference, the 5th injector isn't switching on. Check it's earth and also the connections around the thermotime switch (the big brass lump on the side of the head above the gearbox).

 

If not that, it could be a sticky valve in the idle stabilisation valve.

 

Kev

Share this post


Link to post
Share on other sites

oh right cheers fella, so does this affect the performance? when u say if it doesnt make a difference do u mean the way it starts? what is the idle stablilisation valve n where is it? can i fix it? is this expensive 2 sort any of these things? its comming off the road for a few months next month so i can take the bloody thing 2 bits n fix everything that is broke n falling off! i cant afford 2 fix stuff and keep it running, lol :roll:

Share this post


Link to post
Share on other sites

The 5th injector only comes on for a few seconds during cold starts. It's governed by the thermotime switch. It's job is merely to chuck loads of petrol into the plenum to aid cold starting and also gives full throttle enrichment - I think. It's been a long time since I've faffed around with a NA valver, so this is all from my crumbly old grey matter!

 

The idle valve is that metal smarties tube next to the distributor with Bosch written on a white label. Sometimes tapping that with a hammer helps as they also cause hot starting issues when the internal valve sticks.

 

A more conclusive test of the 5th injector would be to put a voltmeter across the blue plug and get an assistant to crank the engine over - no voltage = no juice :x

 

The 5th injector never fails outright but it's earth is it's biggest weakness. The idle valve is expensive, over £100 but they rarely fail completely. They rather enjoy a bath in carb cleaner to remove the carbon/oil sludge build ups.

 

K

Share this post


Link to post
Share on other sites
Sometimes tapping that with a hammer helps as they also cause hot starting issues when the internal valve sticks.

 

I lost count of the ammount of times I did that on my first 'rado! :lol: They're pretty much the same unit used on MKI Gtis too, and they often need a little "persuasion" from a hammer to work properly! :wink: :lol:

Share this post


Link to post
Share on other sites

Ah the MK1 8Vs borrowed the Auxillary air valve from an Audi 80.....no overly complicated ISVs like on MK2s....but a 10lb lump hammer was a key tool during MK1 ownership!

Share this post


Link to post
Share on other sites
but a 10lb lump hammer was a key tool during MK1 ownership!

 

Especially if you'd bodged a 1.8 16V in during a boring summer holiday! :wink: :lol:

Share this post


Link to post
Share on other sites

im glad 2 see im not alone!! tried 2 sort it 2day, but bloody multi meter fuse is blown. :oops: not 2 good with em! so got 2 wait till tues when the local DIY shop man has a delivery! will have a go then people! keep u posted, if i remember!! :D

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...