KR - pig to start, then won't stay running

[mikkijayne 0]

Hi guys,

 

Not quite the usual '16V won't start' thread - I searched and couldn't find anything similar...

 

It's a '91 KR, and before xmas was becoming a pig to start when warm, but would start perfectly when cold. That appeared to be the vaccum switch on the fuel dizzy which was stuck closed, and I think it was flooding. I unplugged that, and it was then fine for a while, but then got hard to start hot or cold - it would turn over and cough until the battery was almost flat then fire and be fine.

 

Then, after a couple of weeks of this one morning it just would not start whatever I tried. Fresh battery, plenty of fuel, vacuum thing plugged in or not, big fat sparks. It would spin but just wouldn't fire - it wouldn't even cough, so I left it and bought an A4 instead :roll:

 

So, on to today. I've put some new spark plugs in, and some fresh fuel, and a fully charged battery and after a bit of cranking it finally started, but as soon as it tries to idle it just coughs and dies. I can keep it running at 2K or so, but let it get less than 1500rpm and it will cough and die again. It will start, run and die like this about 3-4 times, then just won't start again, and now the battery is flat again so I've come inside to seek advice!

 

I have tried unplugging the cold-start injector in case its flooding, but then it won't start at all. The WUR measures 24ohms, so that seems fine, the broken vacuum switch is still disconnected, but that never seemed to have any effect anyway. If I unplug the ISV it won't start at all.

 

Any suggestions please? I would like to get it running properly so that I can sell it.

 

Thanks!

[Jim 2]

Good steps for diagnosing K-Jet problems here MikkiJayne..

 

http://www.benzworld.org/forums/w116-s- ... oting.html

 

Also has links to the K-Jet Bosch manual about how to perform all the troubleshooting steps advised in the thread! Yes it's for a Merc but it's the same system :)

[mikkijayne 0]

Thanks ^

 

I tried all that stuff and got nowhere at all :( Cleaning the dizzy cap helped with starting but it still wouldn't run under 1500rpm. It would cough and splutter and was running mega-rich, and would die if I let off the throttle.

 

So... I pulled the injectors to see if one was leaking, making it rich, and they are all perfect (at 200K). Put them all back in, and now its running perfectly. Go figure :scratch: I didn't change a single part, and now its just fine :cuckoo:

[Wullie 1]

Thanks ^

 

I tried all that stuff and got nowhere at all :( Cleaning the dizzy cap helped with starting but it still wouldn't run under 1500rpm. It would cough and splutter and was running mega-rich, and would die if I let off the throttle.

 

So... I pulled the injectors to see if one was leaking, making it rich, and they are all perfect (at 200K). Put them all back in, and now its running perfectly. Go figure :scratch: I didn't change a single part, and now its just fine :cuckoo:

Just a Corrado's way of looking for attention.

[mikkijayne 0]

Yeah probably :roll: The irony is though that is was being so awkward I bought a replacement, so now it is running its up for sale. Shot itself in the foot there I think.

[davidwort 0]

sounds like air leaks around the injector O rings or something, 200K is pushing it a bit for K-ject injectors (100K and they are well past their best) the spray pattern will be poor which won't help on starting and idling particularly, did you do an injector spray pattern test?

[mikkijayne 0]

Well I looked at them spraying in to jam jars while they were out ;) The spray pattern was actually pretty good, and they were all much the same. Not a perfect cone that you see in the pictures, but an even round spray. I was quite surprised tbh.

[davidwort 0]

I wonder if you did that like I did the first time, at full air flap opening, apparently they can behave quite a bit differently at low opening/idle on the air flap from the metering head and dribble more than spray. This explains why a k-jet car can go very well at full throttle but be a pain to start and idle, also gets poor mpg.

But if it's running OK now I reckon it's more likely those o rings on the injectors or perhaps the plunger in the metering head was sticking.

[mikkijayne 0]

Yeah I'm going with the plunger in the metering head too. I tested it on only a small opening, but did pull it all the way open by hand before that. I'll probably run some injector cleaner through it just in case there's some gum or something in there :)

[krnau 0]

Thanks ^

 

I tried all that stuff and got nowhere at all :( Cleaning the dizzy cap helped with starting but it still wouldn't run under 1500rpm. It would cough and splutter and was running mega-rich, and would die if I let off the throttle.

 

So... I pulled the injectors to see if one was leaking, making it rich, and they are all perfect (at 200K). Put them all back in, and now its running perfectly. Go figure :scratch: I didn't change a single part, and now its just fine :cuckoo:

time for new injector seals me thinks