|
We originally bought the IPD box to use with an old 145E with a 2.1L B20 (which I later snagged for my PV). All it really does is modify the coolant temp sensor readings to trick the ECU into altering the fuel injection amounts. They modified the ECU by removing some resistor off the board, then adding wires to some connectors hooked through the case. Then the switch box hooked to that. The switch box just has a variety of resistors inside, from the same type removed from the bos to some with higher and lower resistance. Click click click - the ECU sees different engine temps and adjusts the mixture up or down accordingly. Originally the ECU shipped with a separate resistor you could put on the box to return it to stock specs, I had it taped to the outside of the case, no clue if it's still there.
The 1800E was eraly enough to have a short-lived version of D-Jet that used the ECU to control the cold start valve directly. Later on (for most of the D-jet useage on Volvos) they used a simpler system with a wire leading from a sterter terminal to a thermal switch on the block under the #4 exhaust port, to the cold start valve - that simply ran the valve when a cold motor was cranked. The ECU died on the 1800 (it's rare, no clue why, it just died when I was driving it along one day) and I wasn't able to find a proper replacement in the per-internet days. So I ended up using a later model ECU, and without a cold start valve it got tricky starting it in very cold weather. One trick was to turn the key on and then 'pump' the accelerator pedal several times. Eventually, I snagged the adjustable ECU out of the 145E after I got the motor for the PV, and then I could turn the ECU up to +30% which worked well as a sort of electronic choke. You really only needed to do stuff like that to get it started when it was really cold, like < 15 degrees.
--
'63 PV544 rat rod, '93 Classic #1141 245 +t
|
