Runing on the right bank only...

My car is still causing us some headaches... Cylinders 1-6 do operate fine, cylinder 7-12 do not want to burn mixture, with some occasional explosion on the exhaust.

Manifold temperature on the right 220°C, 26°C on the left.

System pressure is 5.2bar on both sides.

All the seals of the distributors are new. All injectors do spray the same amount of fuel +/- 4% (We've removed the injectors, collected approx 12x25g of fuel and measured the weight with a precise scale).

We've set the base mixture as follows: activate the pump, enrich mixture till the injectors do open, the turn 1/8th counter clockwise. This was fine for the right bank.

We've checked the WUR, one had 3.5 bar hot control pressure (no vacuum), while the other was at 3 . We dismantled both and set the hot pressure to 3, cold (20°C) pressure to 1.7 (which is slightly on the lean side). Both pressures are without vacuum (did not check that there is an additional 0.7bar with vacuum). Pressure raises on both WUR in a 3minutes time-frame.

As we had an issue with the WUR, once the WUR were fixed and we knew the one on the right was fine, we just swapped the WUR.

The distributor cap is new (superformance), and when I remove plugs from the left bank I can see some spark. (I have the single 12cyl distributor with Dinoplex). Ignition leads are new. Rotor is stock.

We've removed the iridium spark plugs and put some regular spark plugs that do not foul so easily. Spark plug wet (so there is mixture, but we knew that due to the bang on the exhaust.).

WeI put a transparent spark plug on the right bank I could see the nice blue spark, whereas on the left there I can see no spark.

Any idea ???

 

Today we've progressed as the colombo proudly relies again on its 12 cylinders (pollutes like hell though).

My mechanic wrongly installed the ignition lead. The lead plug order on the distributor is not the same as the ignition order: the distributor has two arms that are 180° appart!

I am immensely grateful to @markcF355 for its sketch :

(see : https://www.ferrarichat.com/forum/threads/distributor-plug-lead-order-and-rotor-direction-help-needed.642979/#post-147933239)

So now the car runs. It does not "hot start" however. The accumulators do hold 3kg of pressure even after 1/2hour, so when hot their is not enough vacuum so as to move the distributor disc... We've managed to feed the car through the cold start injector but this is far from satisfactory, on the plus side we did not need to disconnect the safety plug from the distributor.

As a drastic measure, 2 hours ago we dismantled (again) the WUR and reduced the hot control pressure down to 2.8bar. Slightly better but still need a bit of additional fuel from the cold start injector (not so much hopefully). I would reluctantly further reduce the control pressure, so maybe I will investigate an better thermo time switch.

Will post some pics on the what did you do to your 400 today...

 

I know you have this relay as I was puzzled back then by the lack of it in my own car. On the later car the cold start injector runs at 100/100 duty cycle as long as the thermo time switch tells him to do so (12sec under freezing temperatures, much less when hot).

Is your "flasher" triggered byh the tjermo time switch or by the starter solenoid?

 

Thanks for the reminder.

Based on Paul Bennet's diagram, this module is parallel to the thermo-time switch, so it will add a few more bursts of fuels on top of what the thermo time is already providing.

I've found the following description on the Ford Capri troubleshooter : "There is an extra item fitted to the Capri injection, which you may have heard 'clicking' from time to time. this is the 'impulse module' and is a 4 pin relay mounted under the dash near the fuel pump relay. When the engine is cranked when it is hot, if it does not start after 2 seconds, the impulse module provides an earth to the cold start valve in the form of a pulse, making it spray fuel to aid starting. It pulses for 1 second and then switches off and then pulses at 1 second intervals until starting takes place."

No doubt this is nice to have given my current issue. Time to modify (again) my relay panel...

 

Thanks Steve. My car is from January 1982, but probably manufactured in December (?). There is no socket in my car for the pulsing relay and no harness either. The label is present however but was masked with black paint.

This being said you are probably right, and I presume the problem is related to the (original) thermo switch: I've added a timer that sends some pulses after cranking for 6 seconds. This has actually flooded the engine... As a last resort, once the car is has received these pulses for 2 seconds, I stop the starter, get back to the engine bay, disconnect the bosch connectors of both cold start injectors and the car starts quite nicely. So time to remove my dirty hack and find a proper thermo-time switch.

On the plus side, I've spent quite a bit of time fine-tuning the k-jets with colortune sparkplugs. The sound is actually magnificent, much better than the V12 that sits next to it (no kidding).

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No the bad news. My heads were badly damaged, and the repair did not go so well on the left one: it is leaking coolant in the exhaust (a huge lot of it). My mechanic is even more depressed than I am...

Based on my last invoice, we know for sure that we can dismantle and rebuild this engine in 93hrs, but I think I should take full week break before discussing with the machinist!

 

As far as the relay is concerned, here is a bad picture of my fuel relays (from 2 years ago...), you can see there are only 4 sockets with no additional 5th socket on the left (see green highlight on the left), but there were 5 relay labels. The 5th one was masked (see upper green highlight).

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One should probably assume that the pulsing relay and the thermo-time switch are working in pairs. So one should not use the thermo-time switch from a car without pulsing relay when the car actually has such relay (and vice versa). I've replaced so many parts in this engine that maybe I had changed it actually.