@turvolvo_kid writes:
So the deal is that the speedo doesn't work because i have removed any remnant of the abs system, this then means the speedo doesn't work as the pickup from the diff runs through the abs module first then into the speedo.
Not really. The connection to the ABS module runs in parallel to the connection to the speedo. IOW, you don't need the ABS module to run the speedo. (You do need the speedo to run LH2.4 properly, but that's another story).
I'm presuming yours is a 1993 model 940? (Mother Volvo changed the wiring colours here and there over the years, so the wire colour descriptions below are for a 93 - let me know if it's a different year).
The speedo connection is made at the speedo via Connector [5-1]D (a four pin connector at the instrument cluster).
[5-1]D has the following connections:
[5-1]D, terminal (1) = green-white wire, speedo signal, via Connector [C1] terminal (12), to the junction box, then to the diff sensor
[5-1]D, terminal (2) = brown-white wire, speedo signal, via Connector [C1] terminal (11), to the junction box, then to the diff sensor
[5-1]D, terminal (3) = brown wire, a ground, from the electrical distribution unit
[5-1]D, terminal (4) = blue-red wire, to {15R+} aka the12V supply when ignition switch is on
There is also a reference ground for the speedo supplied via an 8-pin plug, Connector [5-1]A, terminal 2, which is a brown-green wire that runs to the left A-post.
And what is Connector [C1] , you may ask? Well, it's the big fat 53-pin instrument panel harness to the door sill harness.
Worst case scenario is that when you've deleted the ABS, you may have cut all the wires at [C1] T(11) and T(12), which have (or rather, had) a parallel connection up to the speedo, but they also had a connection at Connector [C155] terminals (5) and (6), which is an 8-pin connector that cross-connects to the ABS module plug, terminals (7) and (9).
So you ought to be able to pull a speed signal from the diff via Connector [C1] at T(11) and T(12). If you can't, there's a problem up the back.
Best case scenario? Just a missing ground somewhere.
Now.... if you'd lost the speed signal altogether, with LH2.4 you'd be experiencing weird (high) idle and backfiring on throttle overrun, since the Vehicle Speed Signal to the ECU (at terminal (34)) is sent via the speedo - this is done via Connector [5-1]E, the violet-white wire which plugs into that double-spade connector on its lonesome. But you don't mention that, so it may be just a missing ground.
Good luck!