Hi all, my 16v mk2 is an absolute ***** to start once its warmed up. its perfect from cold although it idles lumpy but after that it wont start. Starter has been overhauled, new plugs and leads fitted and even wired in a flick switch so i can control the cold start valve operation so i know its not that. Any ideas please?
On the K-Jetronic system you have a fuel accumulator within the fuel pump assembly. The purpose of this accumulator is to maintain fuel pressure for half an hour or more after the engine is turned off. The purpose of this is to prevent vapour lock, which would otherwise cause hot starting to be difficult. A way to know for sure is to get a pressure gauge on the system and ensure fuel pressure is maintained after engine shutdown. Trev
The car has been converted from an 8valve and i dont think that the fuel pump was changed at the time. Would this cause it?
That will be the answer then, because the 8V (assuming a Digifant) does not have an accumulator in its fuel pump assembly! The Digifant fuel pump assembly is NOT suitable for CIS (K-Jetronic). Get yourself a proper 16V fuel pump assembly and fit that and see how you go.
Yeah it was a Digifant. I'll give that a shot as i have one in my pile of spares!! Would leaking injectors or metering head cause this also?
Right, have finally changed the pumps over and the problem is better but still there. I've checked the fuel pressure and i've got 5.2bar running pressure but when i switch it off the pressure immediately drops to 2.2bar then even further over the next half hour or so. Should the pressure be held nearer to the running pressure?
theres a guide in a faq somewhere, ill try to dig it out found it, look right above this thread in faq's for engine. It called wur setting up, you can do a mod here but its the same principle for testing the system. Tomo IWO just added a handy guide part
