1984 mondiel QV hard to start.

Very common for the K-Jet equipped Ferrari like yours to have a warm restart problem, but much less common to have a cold start-up problem (and your post implies that you have that trouble, too) -- so you may have more than one issue to fix.
One of the easiest things for a new K-Jet owner to learn how to do is to unplug the safety switch on the airflow metering unit. This will cause the fuel pump to run with just the key "on":

Image Unavailable, Please Login

whereas, normally, with it plugged in, the fuel pump will run only: 1) during starter motor cranking or 2) if the key is "on" and the engine is actually drawing in air. So a simple test for a cold start-up is:

1. Unplug the safety switch,
2. Turn the key "on" -- you should hear the fuel pump run,
3. With the fuel pump running, then turn the key to start, and see if it starts more easily without needing to pump the acc. pedal.

If this does help cold start-up = you probably have a problem with the ...101 relay (Relay S - "Fuel injection delivery pump starting relay" per the 241/82 euro version OM) controlling the ...113 fuel pump relay.

If no change in the behavior (and you are having a cold start-up issue), another thing to do would be to unplug the cold start injector and connect a 12V test light bulb to the two terminals in the harness connector -- during cold start-up motor cranking, the bulb should illuminate for a second, or two, and then go out. If it doesn't, you'd then need to dig into the Thermo-Time Switch operation (or really non-operation as that's the gizmo that should be providing this +12V pulse to briefly squirt the cold-start injector and add enrichment for cold start-up).

Do you have a copy of the 241/82 OM if yours is a euro version 1984 Mondial QV?

 

Hi Brian, welcome to the forum, and congratulations on your 'new' Ferrari! Steve is one of the most knowledgable members here, so you will certainly benefit from his guidance.

I would also suggest browsing or searching in the 308/328 and Mondial forum sections - while this section is called 'Technical Q&A', because it covers all models it's harder to find helpful history for the 3.0 QV cars. Most of the technical information and threads specific to these is in those 2 sections I mentioned.

Oh, one more comment - pumping the throttle doesn't have any effect such as squirting extra fuel like with a carburetor's accelerator pump - "all" the throttle pedal does is open the throttle blade on the manifold. No more or less fuel is moved based on the throttle position when starting, just the amount of air is varied (which indirectly affects the fuel based on air flow through the K-Jetronic, but not like an accelerator pump).

Regards,
Gordon (a fellow Euro 84 3.0 QV owner, but in a 308 GTS)

 

Won't agree with that yet if what you described below happened during cold start-up.

If this was during cold start-up, it's more an indication that the mixture is just way too rich. The cold start injector is supposed to squirt for a second, or, two during cold start-up. If that's making things so rich that it won't start either the manual mixture screw is set too rich or the cold control pressure is too low. Maybe the cold start injector could be "over-squirting" (so getting a new one is no harm, and, if that fixes things, great; however, it wouldn't hurt to confirm/deny the correct on-then-off electrical operation of the cold start injector during starter motor cranking and after releasing the key to run) -- but still think that you just have a way-too-rich problem (and unplugging the cold start injector isn't really a "fix" ).

PS "...the fuel pump now only runs when cranking the key..." -- More importantly, now the fuel pump shuts off if you have a bad accident where a fuel line gets severed, you're unconscious in the Driver's seat, and the key is still "on".

 

No, it should be about the same voltage that the battery droops down to when the starter is drawing 150~200 A -- this might be as low as 9~10V. Throw in some small voltage drops for the many connections and the long small wiring = makes ~8V measured at the cold start injector connector not so unreasonable. For an extended cranking period, the battery voltage may continue to droop down even more and more, but this is not a normal situation -- on a working system, starter motor cranking is usually quite brief.

 

Glad that you got it sorted -- the F K-Jet models are old enough now that maybe every Gremlin hunt should start with "look for questionable prior mucking about with the wiring"

Don't think that you can correct the spelling in the title (even if done within the 20 minute editing window after posting) -- maybe if you contact a Moderator, they might be able to do it.