#10 fuse blows trying to start

Ciuld it be a shirt of pump to car body? Have you checked that wiring. Stert there

 

First, just unplug both the cold start injector and the thermo-time switch (and also inspect the local wiring going to both as you do that for a wire being pinched or shorted to a sharp edge). Then try cranking the starter and see if a fresh fuse #10 still blows (doesn't matter if the engine actually starts or not):

If blows = not a good sign, and we don't want to go there...
If not, then plug the thermo-time switch back in (with the cold start injector still unplugged) and try starting again:

If blows = probably a bad thermo-time switch, but could still be in the wiring between the thermo-time switch and the cold start injector.
If not, then plug the cold start injector back in and try starting again:

If blows = bad cold start injector needs to be replaced.
If not, the trouble has gone away

 

Attached are the wiring diagrams for the 3.2, hope it helps.
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After Steve's steps...

Take a look at the W connector on the fuse box as well. The ignition and fuel pump circuits go through that and are prone to failure.

 

Yes, the one on the right side when looking forward.
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Well, that really should eliminate the W connecter as a problem and possibly the fuse box as well.

I installed one of those on my ex 88 3.2, huge improvement. However, I don't recall how it changes the circuitry off the top of my head.

 

If you have enough spare fuses it is possible to find the root cause by excluding all other possible causes. If you don't have enough fuses an resistance or multimeter is very handy.

If you have enough spare fuses you can try to remove relays i, t and v.
Try if the fuse blows.
If not, reinstall relay v and try if the fuse blows.
If not, reinstall relay t and try if the fuse blows.
If not, reinstall relay i and try if the fuse blows.

Depending on the results you can eliminate parts of the circuit as the cause and narrow down your search.

 

One high probability = a short on/in the PCB itself, or

Low probability = a piece has broken off inside the ...101 starting relay or the ..113 fuel pump relay and it's shorting things out inside the relays - i.e. follow Johan's suggestion to remove the two relays related to the fuel pump operation (and when removed them give them a shake to hear if anything is rattling around inside), then see if fuse #10 stays intact with the starter motor cranking (the engine will definitely not start):

If fuse #10 still blows with both relays removed = almost certainly something wrong with the PCB.
If fuse #10 stay intact = reinstall them one at a time - starting relay first, then retest, then add the fuel pump relay next and retest. If one of them seems to cause the fuse blowing, you can always steal some of the same type from other functions as a test to see if it solves the problem

Of course, removing and installing relays is a fairly violent act that gives the PCB a good shaking/wiggling so just doing that can affect such a fault.

No, it probably doesn't. As Wade noted, that fix is for bypassing the flaky white connectors so that prevents the "fuel pump dead" symptom -- a "shorting" symptom is something else.

 

I should've read your original post more carefully (I wasn't getting that fuse #10 was blowing with just turning the key "on"). However, there's no fault at relay v that can cause fuse #10 to blow so that's more just a bad sign for the PCB and things have changed just because you wiggled things around.

To go forward from here, I'd unplug the safety switch on the airflow metering plate near the fuel distributor and turn the key "on" = you should hear the fuel pump run -- do you?

 

Here:
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You lost me here, but once you get the fuel pump running with just the key "on" (however you can), just try starting the engine.

 

Don't like the sound of any of that. Have you tried using a different ...101 relay for the starting relay and a different ...113 relay for the fuel pump relay?

The relays in question are in the same physical positions for euro vs US, but they are named differently in the documentation:

Euro version (as per the pdf Wade posted)
relay i = starting relay (top row, far right)
relay t = fuel pump relay (middle row, far right)
relay v = key services (bottom row, far right)

US version (as in the US OM)
relay S = starting relay (top row, far right)
relay R = fuel pump relay (middle row, far right)
relay U = key services (bottom row, far right)

 

No, not really, but that (unusual) symptom still seems like something on/in the PCB itself being amiss.

No difference. The cold start injector = the cold start electro-valve in F-speak.

 

Where's your car located? Sounds like it needs some extensive troubleshooting.

Have you considered Tim Stanford? He knows these cars inside out and he's just a bit south in Fort Lauderdale. You can bring the car to him. My friend takes his Mondial Cab there for service and such.

Tim's number
954-764-7824

 

Can you post the VIN for your car?

The US Spec Owners Manual for the 88 Mondial shows fuse #10 as the "L.H. main beam and relevant warning light"
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