16v starting problems

[casinoblue]

hey guys,

had my '89 16v on the road for a few weeks now, but it has been struggling to start since i got it.

cold starting involves turning over and over with the throttle open until she splutters into life. this says to me its a fuel issue, possibly leaky injectors flooding it over night.

it's a bit wierd when hot starting though. it starts normally, first time, then dies instantly. then i have to turn over and over again with throttle open until it starts.

the car runs well once it's going, a little hunting when cold, but no stalling and plenty of power throughout revs. all ignition timing is spot on.

starting it is the only problem. am going to look at injectors at the weekend, as i definitely think it's an over-fuelling issue somewhere. is there anything else i can check while i'm at it. the thermo-time sensor and temp senders can affect starting can't they?

did try searching this topic, but most of the stuff is about digi's and the blue temp sender.

thanks in advance for any info or experiences,
cheers

[rubjonny]

pull the plug on the 5th injector (blue thing on de side) as its a free test.  could be the WUR is kaput as this is responsible for regualting fuel flow during the warmup phase, or the fuel pump isnt working properly.

To do an injector spray/flow test pull the injectors and drop em into a 4 containers of equal size.  Jump the fuel pump relay so pump is constantly pumping, then lift the metering head flap throughout its movement range.  You should see an even spray on all 4, plus once done all 4 containers should have an equal volume of fuel.
Apart from pulling the injectors to test for drips after engine shutoff there isn't much more you can diagnose on the fuelling side without a fuel pressure gauge!

[casinoblue]

thanks rubjonny,

have already unplugged the 5th injector and WUR thinking they were the problem, but it still isn't keen to start.

did try the injector cone shape when i fitted new seals, doing pretty much what you said above, and all seemed to fire a nice spray. was just thinking one of them was leaking slightly, causing a flooding affect on start up. didn't measure they were all firing the same amount though.

the reason i think it's fuel related is because opening the throttle helps it start, adding more air to the extra fuel. and because a bit of white smoke can be seen after starting, but then it clears.

it's the hot start that confuses me, cos it starts first attempt, then instantly dies and i have to open the throttle to get it going 

cheers though

[Conker]

Once when I was trying to re-tune the CO2 setting, I got it running nicely (i.e. it sounded smooth), but once you turned the engine off it wouldn't start very well. IIRC I had set it too rich.

Might yours just need the C02 re-setting to 2% ??

[rubjonny]

yeah have you set the idle & co as per the faq post?

[casinoblue]

thanks both,

i have set the CO mixture as best i can without a gas analyser. following the posts on here, i warmed the engine, disconnected the red coil connector, wound the metering head screw out until the engine virtually dies, then wound the screw back in in 8th turn increments until a smooth idle.

i did notice that the mixture adjusting screw was very sensitive, in that putting any pressure on it by pushing the driver in caused the engine to almost stall. did get it smooth eventually with very ginger little adjustments. is that normal or does it sound as though the metering head is up it?

conker, did you get the CO set to exactly 2% at a garage, or did you play around until you got it spot on?

the car is running pretty well, it just won't start very easily

[rubjonny]

yeah the screw is very sensitve to adjustment and alo when you push down, if you do that you're actually moving the metering head flap which would reduce the air that can get into engine and the fueling too!  after every adjustment you're supposed to take out the allen key then rev the engine, and allow it to settle again, right pain in the arse.