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Fuse box

Nerodino, thanks for responding.... OK I will say it there is no way that the pumps should continue to run in an ign ON situation.... unless there is a inertia switch to detect impactas in an accident... I am using nothing other than logic. to explain my thought processes.

I suggest if possible/practical you proceed by the method suggested before driving yourself nuts... been there done that.

And there is no doubt that deMort is THE man...

Wiring diagrams are great but it helps if there is a description of the circuit operation or design function specification and in this case I suspect SAFETY is the design element prioritised.. :?:

Which Bosch system is fitted to your 930..?
 
Thanks for the heads up on your system which is very similar to that on the Capri I mentioned in terms of operation it being 3 litre 6 cylinder and Bosch continuous injection

just above the Turbo section in the listings you will find some thinking on the system where you will find this link also.

https://www.zeepoort.nl/jetronic/K-Jetronic-troubleshooting.html

Hard to believe that unplugging and plugging back up can resolve any such issue but it has, and more than once...so well worth a try.. :?:
 
OK Nerodino, so I looked at deMort supplied diagram, I am unfamiliar with the component designations though note that there are two separate supplies to the fuel pump relays which to me suggests the method of operation I suggested, in that one supply may come from the START position on the ign key switch and the other from the RUN position..?

A GENERIC description from official Bosch manual describes a CONTROL RELAY through which the fuel pump is switched by the IGNITION & STARTING SWITCH. Apart from it`s switching functions the CONTROL RELAY also has a SAFETY function..

STARTING FROM COLD voltage is applied to the COLD START VALVE and the THERMO TIME SWITCH from terminal 50 of the IGNITION STARTING SWITCH

If the cranking process takes longer that 8-15 seconds the heating element built into the THERMO TIME SWITCH heats, during that time period the heat bends the bi-metal strip inside the THERMO TIME SWITCH to the extent it breaks the supply to the COLD START INJECTOR to avoid flooding the engine. ( air boxes on 911s have blown apart as the result of over fuelling caused by the cold start valve in start to get out of the garage and the car washed then fired up to take it back in after washing!!)

Given the operation of the bi-metal strip in the COLD START DEVICE, if the engine is warm during a start +35Deg C, the COLD START DEVICE receives no voltage thus no extra fuel is supplied.

Voltage from the ignition and starting switch is still present at the CONTROL RELAY which switches ON as soon as the engine runs.

The engine speed reached when cranking the engine is high enough to generate the engine running signal which is taken from the ign coil terminal 1. An electronic circuit in the control relay evaluates these pulses

after the first pulse the fuel pump is switched on as the AUXILIARY AIR DEVICE and the WARM UP REGULATOR. If the pulses to the CONTROL RELAY stop, as in the case of an accident, then approximately one second later the supply to the fuel pump is cut off....

From the above and all else I can find it seems that the operation of your circuits as you describe seems contrary to expectations and contradicts my logic also, but then I have been wrong before...(-:

Good luck in resolving your issue. :thumb:
 
Well you deserve a medal for typing all that!
Interesting info.......I will look at this asap
However my newly rebuilt turbo on my completely newly rebuilt engine decided to haemorrhage oil up into the inter cooler and on to the fuel intake producing lovely thick black smoke at the exhaust!
The turbo which the specialist told me was tested at 4.0 bar tells me that newly rebuilt 930 engines can do this? Really?....I have removed it and returned it for inspection.......this could be interesting!
 
Nerodino... No medals required, just been in your position more than once and at a time long before the internet, a time when finding solutions was not quite as simple as it can be today. Just happy to TRY to help a fellow petrol head..(-:

The Capri I typed of was a rebuild by a meticulous friend everything was painted and protected the idea being preservation in use.... which added it`s own degree of complication relative to chasing electrical earths... Spent days following circuits trying to figure out the logical operation, the fuel pump control being the last... Had access to spare relays and much else to swap things over in a bid to resolve the issues.... having worked through the system with difficulty, the final act was unplugging and plugging back up the connectors a few times and miraculously it operated as it should.... go figure..!!!

Sorry to read of your new issues... !!! So you end up with oil in the exhaust... have heard of turbos using up all their lubrication oil as fuel due to the seal in turbo bearing failing allowing the lube to enter the induction tract until the engine ran out of oil in a process of self destruction..! Well at least you spotted the issue early enough to avoid damage and you do not have an oil fouled cat to replace...but it will run smokey even when repaired and rebuilt if you do not try to clean out the exhaust system...?

Thanks for taking the time to provide an insight to your trials and tribulations... Good luck..and let us know how you get on... any pics..?
 
Here's one
 

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Looking GREAT nerodino, my 77SC had the same colour scheme and trim package, I liked it a LOT. THANKS for posting the pic just as in a pic of a pretty thing, it is always best to leave us wanting more...(-: Hope your engine issues are sorted soonest, but no point in rushing it in this weather..!!!
 
Try this
 

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