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1981 245 EFI Conversion

Turned on the ECU, saw throttle position, intake temp, coolant temp, turned over the motor by hand, measured 30 RPM!! Need to calibrate the temp sensors.

I'm mostly confident I wired the outputs spark/fuel in the correct order, I guess we'll find out soon.

Next step is relay and starter wiring. I think I need to research these. Can anyone point me in the right direction?

IIRC, MS spark order is A-B-C-D, and redblock firing order is 1-3-4-2. You can try this from the CANbus/Testmodes dropdown menu. You may need to turn on your fuel pump first.

I forget what MS version you're installing. Start with the color relay/fuse wiring diagram near the beginning of the MS ??? Hardware Manual. Be careful if you're adding any other relays that connect to unswitched +12v (aka battery), since they can sometimes back-feed MS power.

Look on Dave Barton's 240turbo.com site for plug wiring diagrams (and replacement parts). The big gray 2x4 connector in the center of the bulkhead in the engine compartment has the gauge, alternator, and starter wires.
MS3X. I'm reasonably confident I got the A-B-C-D / 1-3-4-2 firing order set up correctly for both fuel and spark. I reviewed the manual and checked the pinouts before I soldered pins, but testmodes will be helpful to confirm I got the injectors correct, and I can flow test them before first start.

Thank you for the heads-up on the relays and terminals documentation. I'm going to need to rewire all of that - the engine side of the harness was deteriorated. More things to repin, I suppose.

The more i read, the more 70s-era safety functions I find to bypass. The whole thing with distributor pulses required to make the fuel pump relay turn on is cool for the 70s, but not needed with megasquirt. It just has a solid state output that turns off the fuel pump relay if the engine stops.
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Tested the fuel pumps, but did not get fuel to the front of the car.

I cut the two red/yellow wires at the fuel pump relay and connected them to a battery at ~13v.

I grounded the other side of the battery to the chassis.

When I connect the battery to test the fuel pumps, I hear a buzzing and a gurgling of fuel from the in-tank pump, but I hear nothing from the exterior pump. What's my next diagnostic step? Should I remove and bench test the high pressure pump?
Pulled the high pressure pump, it's completely seized as far as I can tell. I'm converting to a high pressure in-tank pump.
Wired the key switch for run/start, wired up a new relay box.

5A - megasquirt + crank angle sensor + cam angle sensor
10A - injectors and wideband
15A - fuel pump
20A - coils and idle air valve

A few loose ends to tie up, but once I get a battery and install the new fuel pump I should be ready for first start. Probably in 1-2 weeks.
Found the underlying problem why the car would idle but not drive back when it was on k-jet.
The hose connecting the fuel pump to the tube had completely dissolved over 40some years. This explains why the main pump is now seized and why I heard gurgling coming from the tank when I tested this pump.

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Lots of progress! Since discovering that the main pump was seized, I ordered an in-tank pump from a later model volvo s60. I then modified the original pump hanger to accept a volvo S60 fuel pump, but I have not yet installed the fuel pump. need to make some fuel lines for the tank end of the system.


I put together a simple fuse+relay box


engine bay as it sits, need to plumb vacuum system, haven't put belts back on, nor cooling system. needs an air filter solution


trigger logger while cranking, shows 36-1 teeth


composite logger while cranking, shows teeth pulses and cam state


I confirmed that the firing order is correct A-B-C-D is 1-3-4-2 by putting the ECU in test mode and testing each spark channel. Next, I checked ignition advance by fixing it at 10 degrees btdc and #1 seems to spark at around 10 degrees btdc when i crank it.

I think once we get the fuel and vacuum systems worked out we'll be ready to start this thing.
I fried my distributor sensor somehow!

last time i bench tested it it worked, now it's kaput. I saw a vendor somewhere that sells a replacement sensor for these vane-type sensors...

Yup, they exist on ebay for like $20. Let's give thay a shot.

Also I have good news.
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Beware, some of the LH2.2 distis are an utter PITA to disassemble. I'd carefully inspect the wiring first, and see if it can be repaired in place, before trying to swap the sensor.

Okay weird problem: when it's running the cabin fan does not turn on.
When the key in in the "run" position the fan works, but if the motor is running the fan does not work. What the heck?

This was really simple. The key was slightly too far clockwise. A little key jiggle fixed it.

Installed the blockoff plate over the balance shaft


gutted the distributor

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  • Replaced the hall sensor in the distributor
  • Wired exciter wire for the alternator (did need a diode so the car would turn off .. that was fun)
  • Started basic tuning
  • timed engine (was 8 degrees off)
  • adjusted cam angle sensor for full sequential squirt and spark
  • putted around the block!
We've got a few dozen miles on it now, it's doing well!
We had a great time street tuning it. I'm running a conservative max of ~45 degrees of ignition advance.

I'd like to maybe get it on a dyno, but we need to do suspension, brakes and crankcase ventilation before it's ready for primetime.

Had to replace the TPS sensor, for some reason the one we'd used was floating all over the place and giving garbage values.

We hooked up the tacho output from the MS3 to the dashboard, I can confirm that you need to connect the MS3 output to both wires that go into the fuel pump relay.

Next step is to wire up a solid state relay to handle the alternator charging control. Right now I just have a diode in place temporarily. Unfortunately this means the alternator is in the "charge always" state.

Weird problem with the headlights.
I tested all of the bulbs, they are all good.

When I turn on the low-beams, none of the headlights illuminate.
When I turn on the high-beams, both of the left headlights illuminate.

On this diagram, what the hell is E?

I checked and cleaned the grounds on both sides, and when i turn on the low beams I see 12v on the line between "A" and "E" but I have no idea where "E" is.

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E is the Bulb Failure relay, a round can about the size of a baby food jar. The high-beams don't run through it, only the low-beams.

If you flash your brights, with the light switch off, what happens?

With key off, lights off, can you measure the resistance (ohms) side-to-side on the headlight connectors? Each pin should be directly connected, ~0 ohms (the low-beams through the bulb failure relay may be a bit higher resistance, IIRC).

What alternator are you using? The standard volvo ones include a voltage regulator, so you shouldn't need any charging control.
When I flash the brights with the light switch off, both of the left bulbs illuminate.

It's not clear to me what you mean when you say "side-to-side on the headlight connectors" - I made a quick sketch of what i think you want me to check. 1->2 and 3->4


I'm using the original alternator, Bosch AL70X (A2927). good to know it's got a VR.
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For the headlights, it sounds like there is more than one problem. The bulbs should be wired together side-to-side. For the high-beam bulb, there are 2 pins on each bulb. Pin 1 left bulb should connect with ~0 ohms to pin 1 right bulb. Likewise for Pin 2. The high/low bulbs have 3 pins. Pin1 to pin1, pin 2 to pin 2, pin3 to pin3 should all be ~0 ohms. In addition, one pin on each bulb should connect to ground. You could try to measure this too. If you're not getting ~0 ohms on any measurement, the wiring is suspect.

I think the same headlight relay is used through 93 on the 240s, so you could just fire the parts cannon at it if you have a donor.

On the headlight relay, the front connector is 3 pins. Center pin is +12v from the headlight switch, and the 2 side pins are high-beams or low-beams. You could unplug this connector, turn on the headlight switch, and jumper the center pin to one of the side pins to see if the headlights behave better. You may also want to clean up the ground rings on the bracket.