16v warm starting problem

Matt H · Post by **Matt H** » Tue Feb 08, 2011 3:35 pm

This is something that has plagued BX 16vs since they rolled off the production line... And mine is suffering

The problem only occurs when the car is fully warmed through, and then shut down. Come back 10-15 minutes later, try to start it and it will fire up, but when the HP pump kicks in the revs drop and it dies. Then it will not re-start. Give it 10 minutes and it's fine, and so long as I blip the throttle and hold the revs steady for a few seconds it will not stall again. It can be avoided with a careful amount of throttle on start-up, but I'd love to get to the bottom of it... and it could be a pain if I have to leave it 10 minutes each time it happens.

Where should I start? I was thinking AFM or idle control valve? It's absolutely spot on when it's cold, seems like the idle speed is just a tad low when it's warm and under load from the HP pump.

Also, does anyone know why it won't restart after it stalls but is fine if you turn it off with the key? Flooding?

Cheers,
Matt

Leobx16v · Post by **Leobx16v** » Tue Feb 08, 2011 3:39 pm

could be a sticking idle air control valve, i have the same problem sometimes but it isnt fatal so i fix the major problems first :p check all the pipes are connected also they can tend to slip off

Matt H · Post by **Matt H** » Tue Feb 08, 2011 3:57 pm

I changed it on my last 16v, which was the opposite problem of revving too much from cold... and it cured it. Might try swapping it with a spare I have.

Keep meaning to spend a weekend servicing it, but something always crops up, or the weather is totally out of order... and it's dark when I get home during the week.

mds141 · Post by **mds141** » Tue Feb 08, 2011 6:14 pm

Matt in the handbook for the bx 19 it does say to "only depress the throttle pedal slightly".

prm · Post by **prm** » Tue Feb 08, 2011 8:01 pm

A few points you could try, to run through a process of elimination.
Before switching off when warm. Hold the throttle at 1500-2000 rpm, Then switch off to see if this improves a restart.
It could be heat soak while stationary. Usually that comes into play when the temp gets over 90 plus.
If the IMCV is ok. The resistance reading across the terminals should be in the region of 7.9 -8.3? @ approx 20?C..

Check the throttle stop setting.
Remove the rubber intake ducting to the throttle body. Super glue a small length of 5 amp fuse wire to a cocktail stick
Add an ice cube and stir !!!!

Back-off the stop screw by one turn, remembering its original position. Open the throttle by hand and place the fuse wire in centre of the lower valve.
Gently lower the flap onto the wire
Adjust the stop screw until you’re just able to very gently withdraw the wire. It breaks easily.

Increase the stop screw by a further 1/8 of a turn and see if there’s any improvement.
You could also try increasing in stages of 1/8 increments to a max, 1 turn, to find the best setting.

Check you’re not tripping the TPS with any adjustments. May require resetting?
Inspect the throttle cable for snags. Might be worth lubricating the inner cable.