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LH2.4 Install/Conversion. Just 4 wires to make it run

K-Jet to LH2.4 Details

Here are the main items I needed to convert from K-Jet to Turbo LH2.4

Parts:
- LH2.4 wiring harness and main relay.
- Turbo ECU (cold start injector control needs to match intake manifold setup).
- Turbo EZK (non-EGR unless you're going to install EGR from donor engine).
- EFI Intake Manifold with injector rail, FPR, and throttle body. Earlier setups include a cold start injector, later versions eliminate it.
- Throttle cable and kickdown cable (if auto) for throttle spool on EFI intake.
- Turbo, hoses and turbo exhaust.
- Intercooler, mounting brackets, and electric fan or increasingly rare turbo fan shroud.
- LH2.4 IAC and hoses. There are at least 2 versions of 940T hoses - those for top-outlet intercoolers and those for center-outlet intercoolers.
- Cone air filter and tubing, or Turbo K-Jet air filter&box plus gutted K-Jet fuel distributor and rubber cobra intake hose.
- Low impedance original Turbo Injectors and resistor pack, or high impedance injectors with similar flow rate (no resistor pack needed).
- EFI head, or plugs for K-Jet injector holes (DIY or STS machining).
- LH2.4 MAF and extension wires/harness to relocate MAF from left to right side of engine compartment.
- LH2.4 Distributor, ignitor (power amplifier), coil, CPS and 60-2 tooth flexplate or flywheel.
- Knock sensor, LH2.4 coolant temperature sensor,
- Original Log turbo exhaust manifold or 90+ manifold, and matching 1-wire or 3-wire O2 sensor.
- "TP32352-1 1993 240 Wiring Diagrams.pdf" or similar LH2.4 greenbook.


Machining (click on pics for full size):
- If you're converting to turbo, you'll need to drill the block for the turbo oil drain, or add a fitting to the oil pan, plus tapping off the oil galley for oil feed (there are lots of old treads on this).

- You'll need to drill and tap the edge of the B21 block bell housing for a custom CPS bracket: M6 thread, 1.575" center-to-center, ~0.91" hole depth, centered between trans bolts. Shown below is a '83 B21FT bellhousing (no CPS bump-outs) versus B230 bellhousing (with CPS bump-outs), and B230 CPS bracket:


- You'll need to notch your transmission to clear the CPS - if not pre-notched, you can cut out and file the CPS notch in the older bell housing. Not as strong as the later housing with the factory cutout, but OK for my needs:


- You'll need to make a custom CPS bracket - due to the thinner B21FT bellhousing, the CPS mounting holes will be roughly 0.15" higher than a standard B230F bracket.


- To mount the knock sensor, and to add a turbo support bracket (if not already done), you'll need to drill and tap a few holes.
-- Knock: M8 thread, ~0.86" hole depth, spot faced
-- Turbo support bracket (left&right pads under #3 cyl): M8 thread, ~0.85" hole depth



VSS - Vehicle Speed Sensor
LH2.4 needs a VSS signal to properly control idle speed. You can swap rear axles and clusters/dashes (?), or use a single fixed idle screw adjustment, or convert from a K-Jet cruise control speedometer pickup to VSS - see http://forums.turbobricks.com/showthread.php?t=342812

For pre K-Jet carburated cars, you'll need to figure out fuel pumps, a return fuel line, and maybe a different gas tank (I don't know if the early tanks included a swirl pot section).

Final engine bay picture:


If you have questions, please start a new thread to avoid polluting this one. If you have corrections, PM me and I'll edit this post.

-Bob
 
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Thank you Bob for showing how you did. During my LH2.4 swap I will also swap my transmission to a M90. I appear to have a verry early block without the casting for the PCV system. I also do not seem to have the spot for the knock sensor. Any tips on that? Thanks in advance!
 
Sorry, I can't help with the knock sensor. Try posting something like "Adding LH2.4 Knock Sensor to B21 Block?" in the Performance&Modifications section and see if someone has done this before.

In simple terms, the knock sensor listens to the combustion chambers over a narrow range of tones, and mostly around TDC. It needs to be mounted on the block (iron); head mounting probably won't be good enough (aluminum). I'm pretty sure that LH2.4 requires a knock sensor, and that it needs to "hear" some combustion noise at higher RPMs (say 3000+), or else it will toss a CEL and retard timing.
 
Last edited:
ZVOLV said:
LH2.4 Install/Conversion. Just a few wires to make it run

Right click dead links and open in a new window to view pics.

Do you want to know how to install Bosch LH2.4 EFI in your Volvo? Fantastic! It's very simple and only takes a few wires. We installed a 1994 B230FT and LH2.4 into a 1984 240 Turbo and this is how we did it.
Need:
-LH2.4 240 wiring harness.
-B230FT Engine OR drill/tap block for RPM sensor if attempting on a B21/23. If you don't drill/tap PERFECTLY the airgap will be wrong and it won't run at all/well.
-LH2.4 Fuel Computer and Ignition Computer
-LH2.4 Flywheel or Flexplate and RPM sensor
-Complete rear axle or differential from electronic speedo 240
-Electronic speedo cluster
-LH2.4 Idle air motor
-LH2.4 MAF
-LH2.4 Coolant temp sensor
-Greentop injectors and resistor pack OR high resistance injectors like 850 Turbo orangetops
-2 small Custom fuel lines if converting from Kjet OR fuel lines from an EFI car

Process:

-First remove old engine bay harness

-Install B230FT and transmission of choice

-Install electronic speedo rear axle with gear ratio of choice.

-Install LH2.4 engine harness, run it thru firewall, and hook up computers.


-There is a wiring pigtail that goes from the computers and across the dashboard. Updated Nov 2015. Colors may vary slightly by harness year. Make sure you do your homework! But here are the basic few wires to make the thing run. Again, this is using a 1989/1990 wiring harness. Dash pigtail is different on the later models. SLIGHTLY. Don't be a bonehead. Get out a multimeter and wiring diagram and figure out the differences.


Wire 1: Thicker (12ga?) Red/Yellow- Power OUT TO Fuel Pumps.
(Wire 2:) Thinner (16ga?) Red/Yellow: Power FROM fuse to Heated 02. (Vehicle will start without this wire connected)
Wire 3: Blue: Ignition ON signal.
Wire 4: Blue/Black: Signal fom back Speedo (optional. You will get high idle after freeway runs without it. No big deal.)
Wire 5: Power up ignition coil with switched 12v. ( i suggest adding it to 2 wire plug. One wire is yel/red. Other is blue. By adding 12v to this wire, you are powering up the coil and the powerstage)
(Wire 6) entire LH System/Fuel Pumps gets power from a RED fused wire from the battery. At least on 1989-1990. Later model wiring harness is different. Sort thru other guy's posts or look at wiring diagrams to figure it out.

- Relocate the MAF wiring to the other side. This was easy. We pulled all of the wires, except the brown/black ground wire, out of the harness carefully and moved them to the other side. For the ground wire (that black/brown) you cant pull it out because it grounds other things. You need to pull it out as much as you can and then attach it back to your MAF plug.

-Plug in 4 wire connector in your new 2.4 harness into the old firewall connector. Its grey.

-There are a few other wires that need to be hooked up for AC, ABS function, and Check Engine Light but the above wires are all it needs to RUN! Pink one is for Check Engine light BTW.

-For fuel lines you can either get a complete set of EFI fuel lines from a donor car, or you can have a custom feed line and return line made. We went to Parker hose fittings and got hooked up with both for about $20!

-SPEEDO. Considered optional. If you do NOT run a speedo signal, you may have moments of high idle. For the speedo signal you just need to install a electronic speedo rear axle, or attempt to install just the diff and diff cover in your existing housing. You will also need to install a electronic speedo cluster. There are two wires coming off the differential. You run the black wire to the same ground point with the black wire coming of the speedo. The blue wire from the diff cover goes directly to the instrument cluster. Then you need to hook up the red/black wire from the ignition switch to the back of the cluster. This will power the whole cluster up. Use the old wire that powered up your instrument cluster.
Click to expand...
I have a few questions regarding bits that are needed. I have a 1987 Volvo 245 with a B230F in it with the Bosch system. With that being said, would there be any bits that are different compared to your swap, such as not needing the axle, or potentially different wiring harnesses? Eventually, I'll have it linked up to an M90 transmission once I actually order it. I'm aware that this thread is arguably long since dead, but it's one of the best sources I've found so far in regards to what I'm looking for. Hopefully I hear from you soon, and cheers.

Sincerely,
Michael
 
I used this thread 10 years ago to do my first LH-2.2 to 2.4 conversion in a 740 Turbo!

If you don't have an axle with a speedo sensor, you don't need one, but like OP says, without a speed signal your idle will be wacky. I thought 1987 240s had electronic speedos though. If that's the case then you will be able to pick up the signal using the output wire on the back of the cluster.

The easiest way forward for you will be to get the LH-2.4 wiring harness from a later 240 and just swap it into yours (assuming your 240 is LHD).

LH-2.2 and LH-2.4 have totally different wiring, the ECU plugs look superficially identical but they have different pin counts and you can't plug a 2.4 ECU into a 2.2 loom.
 
jamesinc said:
I used this thread 10 years ago to do my first LH-2.2 to 2.4 conversion in a 740 Turbo!

If you don't have an axle with a speedo sensor, you don't need one, but like OP says, without a speed signal your idle will be wacky. I thought 1987 240s had electronic speedos though. If that's the case then you will be able to pick up the signal using the output wire on the back of the cluster.

The easiest way forward for you will be to get the LH-2.4 wiring harness from a later 240 and just swap it into yours (assuming your 240 is LHD).

LH-2.2 and LH-2.4 have totally different wiring, the ECU plugs look superficially identical but they have different pin counts and you can't plug a 2.4 ECU into a 2.2 loom.
Click to expand...
My 240 is indeed LHD. As for the electronic speedo, I'd have to have a look at some point or another. As for that wiring harness, I could probably poach one from a 1990-1993, I'd imagine, or possibly poach one from a 740/940 turbo. Thank you for the reply, by the way!
 
JamesBond00797 said:
My 240 is indeed LHD. As for the electronic speedo, I'd have to have a look at some point or another. As for that wiring harness, I could probably poach one from a 1990-1993, I'd imagine, or possibly poach one from a 740/940 turbo. Thank you for the reply, by the way!
Click to expand...
No worries, but I would avoid taking one from a 740/940 as they do not have separate engine wiring harnesses, it is all integrated with the main body harness.

The speedo question is pretty easy to answer, if you shine a torch on the diff from the rear of the car, if it's electronic speedo you'll see the plug for the sender about half way up the diff cover.
 
jamesinc said:
No worries, but I would avoid taking one from a 740/940 as they do not have separate engine wiring harnesses, it is all integrated with the main body harness.

The speedo question is pretty easy to answer, if you shine a torch on the diff from the rear of the car, if it's electronic speedo you'll see the plug for the sender about half way up the diff cover.
Click to expand...
Good to know, especially with the wiring harness thing. I imagine you could get one from ipd? And I'll have a look at the diff cover later, thank you for the tip!
 
ZVOLV said:
LH2.4 Install/Conversion. Just a few wires to make it run

Right click dead links and open in a new window to view pics.

Do you want to know how to install Bosch LH2.4 EFI in your Volvo? Fantastic! It's very simple and only takes a few wires. We installed a 1994 B230FT and LH2.4 into a 1984 240 Turbo and this is how we did it.
Need:
-LH2.4 240 wiring harness.
-B230FT Engine OR drill/tap block for RPM sensor if attempting on a B21/23. If you don't drill/tap PERFECTLY the airgap will be wrong and it won't run at all/well.
-LH2.4 Fuel Computer and Ignition Computer
-LH2.4 Flywheel or Flexplate and RPM sensor
-Complete rear axle or differential from electronic speedo 240
-Electronic speedo cluster
-LH2.4 Idle air motor
-LH2.4 MAF
-LH2.4 Coolant temp sensor
-Greentop injectors and resistor pack OR high resistance injectors like 850 Turbo orangetops
-2 small Custom fuel lines if converting from Kjet OR fuel lines from an EFI car

Process:

-First remove old engine bay harness

-Install B230FT and transmission of choice

-Install electronic speedo rear axle with gear ratio of choice.

-Install LH2.4 engine harness, run it thru firewall, and hook up computers.


-There is a wiring pigtail that goes from the computers and across the dashboard. Updated Nov 2015. Colors may vary slightly by harness year. Make sure you do your homework! But here are the basic few wires to make the thing run. Again, this is using a 1989/1990 wiring harness. Dash pigtail is different on the later models. SLIGHTLY. Don't be a bonehead. Get out a multimeter and wiring diagram and figure out the differences.


Wire 1: Thicker (12ga?) Red/Yellow- Power OUT TO Fuel Pumps.
(Wire 2:) Thinner (16ga?) Red/Yellow: Power FROM fuse to Heated 02. (Vehicle will start without this wire connected)
Wire 3: Blue: Ignition ON signal.
Wire 4: Blue/Black: Signal fom back Speedo (optional. You will get high idle after freeway runs without it. No big deal.)
Wire 5: Power up ignition coil with switched 12v. ( i suggest adding it to 2 wire plug. One wire is yel/red. Other is blue. By adding 12v to this wire, you are powering up the coil and the powerstage)
(Wire 6) entire LH System/Fuel Pumps gets power from a RED fused wire from the battery. At least on 1989-1990. Later model wiring harness is different. Sort thru other guy's posts or look at wiring diagrams to figure it out.

- Relocate the MAF wiring to the other side. This was easy. We pulled all of the wires, except the brown/black ground wire, out of the harness carefully and moved them to the other side. For the ground wire (that black/brown) you cant pull it out because it grounds other things. You need to pull it out as much as you can and then attach it back to your MAF plug.

-Plug in 4 wire connector in your new 2.4 harness into the old firewall connector. Its grey.

-There are a few other wires that need to be hooked up for AC, ABS function, and Check Engine Light but the above wires are all it needs to RUN! Pink one is for Check Engine light BTW.

-For fuel lines you can either get a complete set of EFI fuel lines from a donor car, or you can have a custom feed line and return line made. We went to Parker hose fittings and got hooked up with both for about $20!

-SPEEDO. Considered optional. If you do NOT run a speedo signal, you may have moments of high idle. For the speedo signal you just need to install a electronic speedo rear axle, or attempt to install just the diff and diff cover in your existing housing. You will also need to install a electronic speedo cluster. There are two wires coming off the differential. You run the black wire to the same ground point with the black wire coming of the speedo. The blue wire from the diff cover goes directly to the instrument cluster. Then you need to hook up the red/black wire from the ignition switch to the back of the cluster. This will power the whole cluster up. Use the old wire that powered up your instrument cluster.
Click to expand...
Okey I'm doing exactly what you've done here,
The wires 1-6 that are listed.
They're all attached to the white 9 pole male connector coming into the cabin, Correct?
If so, then now I know what they all do, but where do I connect these too? This is my first time wiring something up and I've never been so lost😂
I've already taken off the original green fuel relay, and wired it into the white one on the 93' engine harness.
But wires 1-6 that you've mentioned, I have no clue where to put them.
Would be fantastic if you can help me out

Thanks
 
As the title mentioned I am looking for a 1994 940 LH2.4 Engine Wiring Harness (also would like a EZK shell but it doesn't have to work) and a LH2.4 Throttle Body (also willing to ship the items to Hong Kong).

Some background, I am looking if a local (currently in Hong Kong) shop can make Microsquirt Plug and Play harnesses (basically converting a standard 8' harness into a Plug and Play harness for a 940 LH2.4 to start with). not sure how many people is interested, we'll see since the LH2.4s quite a lot of wires going left right and center, I do want to try simplify the wiring and built in optional sub harness for LS Coils (full sequential if add in a LH2.2 Dizzy?) and LS Throttle bodies.
 
willaim22 said:
As the title mentioned I am looking for a 1994 940 LH2.4 Engine Wiring Harness (also would like a EZK shell but it doesn't have to work) and a LH2.4 Throttle Body (also willing to ship the items to Hong Kong).

Some background, I am looking if a local (currently in Hong Kong) shop can make Microsquirt Plug and Play harnesses (basically converting a standard 8' harness into a Plug and Play harness for a 940 LH2.4 to start with). not sure how many people is interested, we'll see since the LH2.4s quite a lot of wires going left right and center, I do want to try simplify the wiring and built in optional sub harness for LS Coils (full sequential if add in a LH2.2 Dizzy?) and LS Throttle bodies.
Click to expand...
Starting with a 940 harness does not seem like the way to go. 240 LH2.4 harness will connect to the motor as required and doesn't go through both sides of the fuse box. Last time I tried to properly pull and convert a 7/9 harness to stand alone we decided it would be easier to drive to the yard and pull a 240 harness to mess with.
 
James M said:
Starting with a 940 harness does not seem like the way to go. 240 LH2.4 harness will connect to the motor as required and doesn't go through both sides of the fuse box. Last time I tried to properly pull and convert a 7/9 harness to stand alone we decided it would be easier to drive to the yard and pull a 240 harness to mess with.
Click to expand...
Its true, I'm the one that had the smart Idea to convert a harness from my parts 90 760 to my good 85 760. It was a nightmare. At least james got and engine out of it.
 
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