Check valves

[philmas]

Sorry if this has ben discussed many times before.…
I’ve had this « 5 cylinder » cold starting issue for as long as I own the car (over 30 years…), this happens  mainly when the car has sit in the garage for more  than 24hrs, and resolves after 5 or 10 min.
Until very recently, I was convinced that there was a faulty check valve somewhere.…
But when searching this forum, I understood that a leaking valve should lead to a difficult hot start…
Could  someone shine a light on this, and tell me if that points rather to an injector problem , or does it mean a valve gets « stuck  » or « sticky » in the closed position when cold?
Thanks for your precious knowledge (and help!)

[ja17]

I guess your saying it starts well but on 5 cylinders at first?  Could be a leaky injector, faulty IP check valve, or possibly one of the IP fittings not properly torqued.

[rwmastel]

30 years?!?!?  You should have come here sooner.  We've been online 20 years.

I would first determine if in fact (we should always work with facts) it is running on only 5 cylinders at start up.  It could just be running roughly on all 6.

Pull one spark plug wire, start it.  Put that back and pull the next and start it.  Proceed (even it it has to sit overnight) through all 6 to determine which cylinder is faulty, if any.  Of course when the faulty cylinder has its wire pulled, start up will sound "normal".

Then, work to determine if the fault on that cylinder is fuel, air, spark, or compression.

Let us know what you find!

[philmas]

Thanks for your help…
I guess this sounds like 5 cylinder running… I should inquire further to determine which is the faulty one.
How a spark issue could resolve by itself after 5 min…? More probably a fuel delivery problem…
Btw, I found  some sites that claim still having the valves on stock for about 200€ …probably fake news!