Power Supply Susceptibility in Injected 140 Model

Apr 2024 R.Kwas [Comments Added]

Reference Information


Vintage Volvo restorer David Burnham of New Hampshire, has made me aware, that in addition to the Main (multi) Fuseblock located below the dashboard of the injected 140 model, there is a Secondary Fuseblock in the engine compartment, which supplies power to the Fuel Pump, and besides being critical for the reliable operation of the car, this FB is also of the similar riveted construction as the FBs of the earlier 122 (therefore susceptible to same the intercontact corrosion), especially when located in the (less than cozy) engine compartment.  He figured since I rework these already, it would be right up my alley...more on this later... 

Contributing to the weakness and susceptibility because of the construction and location, there is an associated Power Distribution Block located not far away next to the Headlight assembly.  Both components are critically important for supplying reliable and uninterrupted electrical power to the Fuel Injection System!. It is therefore important for these power components and connections to be in good condition, but located where they are, they are subject to environmental attack.


David Burnham pictures used with his kind permission. 

A very clean engine compartment of a late model injected 140 with location of susceptible Secondary Fuseblock and Power Distribution Blocks highlighted.


Wiring Diagram Excerpt showing critical power supply current paths for the Injection System.

Fuel Pump and Injection Power Paths are highlighted.  Note that before engine is started, electrical power is supplied to Power Distribution Block by way of heavy gauge wire from Battery, and power paths to PDB shown in diagram are for normal engine running condition, when Charging System supplies electrical buss power.  Note also that Secondary FB Fuse positions 1 and 2 are tied together but otherwise unused and available for optionally installed lighting equipment.  


Reference Information: 

Pic of Fuel Pump Fuseblock

Pic from Swedespeed thread:  https://www.swedespeed.com/threads/no-fuel-being-pumped.641675/

Good pic of the Secondary FB with no Cover, so the fuse is hanging in the breeze inviting environmental attack, which it has clearly already suffered from to some extent!  Note that only one fuse position has a fuse installed, and this is position 3.  Fuse value is 8A.  The remaining two positions are unused and available.    


Pic of Power Distribution Block

Adam Squire pic permission requested.

Pic of PDT next to Headlight assembly where it is also under serious environmental attack every time the car is driven in the rain! 

Close-up where plenty of surface corrosion is evident...this is most definitely a place where connections with benefit from protection by ACZP.  My tip and recommendation to Adam:  Disconnect Battery, disassemble those Phillips screws, clean all metal surfaces to bright and shiny, and reassembly with a healthy slathering of ACZP on all metal surfaces, then move on to something else, because you will never have to play with those connections again...yes I said never!


If your critical electrical components look like those in the above pictures, you may very well be rewarded/punished with reliability problems.  I highly recommend refurbishing all connections and connectors involved, including eliminating ALL inline Resistances in the stacked contacts of the Fuseblock as detailed here:  https://www.sw-em.com/123GT_FuseBlock_Rework.htm   If an owner is not in a position to perform such a Rework of the FB, contact the author for such services. 


Clean examples of the FB and PDB:  

Joel Glasson pictures shown with his kind permission.

A neatly rewired "heavily modified" Secondary Fuseblock (cover removed...the cover is in place when the car is in service!). 


A picture of Joel's equally nice and clean PDB.  ...but I don't see any signs of ACZP on either component!  I will be supplying Joel will a sample!



Fuel Pump Fuseblock, all by itself:

Secondary Fuseblock is of a stacked brass contact construction susceptible to inter-contact corrosion, which can at some point result in Fuel Pump not being powered!











Externally sourced material is attributed. This information is Copyright © 2024.  Ronald Kwas.   The term Volvo is used for reference only.  I have no affiliation with this company, other than to try to keep its products working for me, help other enthusiasts do the same, and also present my highly opinionated results of the use of their products here.  The information presented comes from my own experience and carefully considered opinion, and can be used (or not!), or ridiculed and laughed at, or worshipped, at the readers discretion.  As with any recipe, your results may vary, and you are, and will always be, in charge of your own knuckles and future!


You are welcome to use the information here in good health, and for your own non-commercial purposes, but if you reprint or otherwise republish this article, you must give credit to the author or link back to the SwEm site as the source.  If you donít, youíre just a lazy, scum sucking plagiarist, and Harvard wants you!  As always, if you can supply corrections, or additional objective information or experience, I will always consider it, and consider working it into the next revision of this article...along with likely the unique metaphor and possibly (likely) wise-a** comment.  


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