That's right people where you at? I've been trying to find you but I think time has swallowed you up.Im looking for other people that own or drive a 240 with LH 3.1 injection.Thru research I've found that there were also 740s that came with 3.1 and that's fine I'm just looking for some feedback from the present day.Also thru research I've found there basically the same system as a 2.4 except a hot film air flow sensor instead of a potentiometer and a throttle position sensor that knows the exact point of the throttle plate instead of it just being a switch that turns on and off with throttle and idle.So where u at? I promise I will only keep it to a three question minimum 😉

FYI, I have working spars for all the LH3.1 units I had as backups for my 91 245
TPS,AMM, and another unit... Forget which one. Gotta dig out the box.

But if any LH3.1 user needs the parts for a decent price let me know

mrnabiscoAThotmail

Hi,

I’ll accept the Roll Call, in that I don’t own one! How’s that?

You named the only differences, that I know of, between the 2.4 and the 3.1. The potentiometer is the biggest one for input to the ECU. The AMM might be semantics, to some extent, as it’s just not as fragile as a hot wire.
As far as the ICU why would they change that from the setup of the 2.4. Spark is spark isn’t it?

What kind of issues are you having that you can “the minimum” of only three questions? (:-). Something is is in conflict about that statement.
Besides there is no charge for the number of questions, as we leave it up to you, to sort through all the Possibly answers or guesses? (:)

Phil

Well when I got the car unknowingly to me it had the wrong ECU in it.It had a 556 ECU installed😯the car is a 90 240 Dl wagon 5 speed btw.After let's just say a few people who call themselves mechanics told me I "needed an engine" I realized that I'm gonna have to fix this car my dam self,so thus started the shit abyss of LH 3.1 and how little it was used on 240s and the special parts needed for it,so I purchased an eBay 572 ECU because that's the right one so I was really starting to think maybe they used a different ICU,but you are right spark is spark.But furthur in the saga I have a 131 code in diagnostic port 2 for engine rpm signal missing and also a 144 code in Port 6 for load signal missing from LH unit.computer assumes the engine is at full load🤔I have already changed the crank sensor with a new burigord one idk if that's the right name but it was oem.The car runs great but has a higher than most idle and kinda "takes off"up to like 1500rpm then settles back at around 1000 plus looking at the check engine light makes me wanna break shit so I'm just looking down all avenues because what the in the funk else gives the ECU load signal than the Crank sensor? I know obd1 is a piece of work and just trouble codes in general but I want that check engine off and to stay off😤so yea really don't know what to do about that now.

Hi,

I’m trying to break down what you are saying into segments of maladjustment somewhere and a signal that’s incorrect for the ECU program.

The throttle is telling the ECU is at a partial load and in the program itself expects certain things to be such and such.
When something is out of perimeters of the program will then throw a code(s) OR what I call a SHOTGUNS blast towards a barn wall. The bits of the shell hit many things, but the code says it’s this wall of that barn, not all the others! The trick is deciding of that wall was the area most hit that affects other planks and which one is now more loose than the others!

The whole idling too fast issue, IMO, is the engine is capable of getting more air than it needs!
The engine does not have a way to open the throttle more, so in considering this it’s must be maladjusted or air is getting around the control of the IAC valve.
You really need to get the throttle plate adjust closed and put plastic-wrap over ports that could let air into the engine.
The engine is turning more that it should for various settings.
That Unsafe condition throws a code in a heartbeat.
Uncontrollable fast idle is a big no-no!

The AMM is part of the load program but it’s going to feed signals to adjust mixture to keep the engine running.
The throttle switch is a load monitor on both systems but most likely more critical on the 3.1 just because it is variable.
As I remember socket six on the 2.4 checks components for operation inputs.
I doubt the 3.1 is any different.
The code “ missing signal from LH” probably means a signal from the speedometer cluster for road speed on many vehicles!
In about 1991, 92 or Even 93 models, I have read about the speedometers were effecting idle speed too!
So if the speedometer isn’t for that cars ECU, well right there, it could be a problem all by itself!
Another Research hunt may find something.
Art Benstein has brought that up in my readings.
You might contact David Samuels on his site of Wagonmeister.com.
They both have shared information on speedometers repairs and differences over the years. He knows numbers and such!
If you can get the number off the speedometer back and check the connection anyways back there, it might be worth a shot for shutting down the CEL!
The L plug socket can go faulty on those cars I mentioned.

Side note:
When talking about the SHOTGUN blast, I was referring that analogy, because the diagnostic part was not invented to be in there for any great detail.
That stuff was aimed as being an auxiliary sale to wanting shops! I imagine that never took off very well!
OBD II was on or coming off the drawing boards!
That left service bulletins and at best for factory training on the dealerships. That waned a lot as more models came and went and mechanics retiring!
It was all a scramble and still is today with all of the car manufacturers!
Fine if it works, but junk, if it doesn’t! Crushers are working full time to keep up!
Today’s cars are terrible investments.
Lease or rent sales moved more cars than one would think and to own a vehicle in the future, is passing away, since they are overly complicated to maintain.

It doesn’t take a Sherlock to see, We are witnessing a new age to be coming a foot!
Not jumping, so far, but moving!

Phil

On the issue of speedometers and idle control I can throw this in:

I have a 1991 945 with the Yazaki instrument cluster - well known for leaky capacitors and failing Speedos. A while ago I finally ran out of usable speedometers and had to install a GPS Speedo, so no speed signal going to the ECU.
What happens now is that he idle speed is fine unless I go over about 65mph. After that the idle speed sits at about 1500rpm and will do so until I switch off and on again - then the idle speed is back to normal.
I can never understand why the system is designed this way, and no-one has been able to provide an explanation. What function could that serve??

Ian F

Hi again,

Here is the sheet that Kitty is talking about in his post as not being all that accurate.

www.nuceng.ca/bill/volvo/database/ecu.htm


I do not have all that much experience in dealing with all the various models either.
I will that it was a great attempt to put down some “form of order” to all the chaos created by Volvo, Bosch and Chrysler dinking around over the years!

Prototyping and experiments were abound in those years and it got worse with the 7&900’s.
Customer hunting was the issue. A Turbo scramble for comparable performance with the emissions spy glass on them!
Even with Volvo saying “No Front Wheel drives for them back then, Ha!
Up jumps the 850 with a 5 cylinder Porsche designed engine!
Hello, it was the times of changing and playing catch up!

Volvo is going to an all electric platform and is cutting to the chase, nowadays.
Don’t look around but it’s still happening at a consumers expense with frustrations of not having standards nail down Just to having only ONE cross charging platform of compatibility!

Cords with various plugs are slowly getting done all the while Ignoring inductive coils.
No standard on how or where to connect underneath. This either in the home or on the road is a fiasco!
Exchange packaging of batteries is not a set to a standard for removal and replacement.
It would be nice to have it set in stone “as in” working with an overall design to allow for the “inevitable change” of the type of a battery as the chemistry changes to increase capacity.
A Slide them in and out design like a hand held flashlight!

Don’t look around but it’s still happening today at consumer expenses.
It always will as we seem to learn very slowly for from our own man made chaos’s!
Remember or look into boxes of those “wall warts.” Those power transformers and their different voltage connector ends! Jeez .... and APPLE still pays a fine to keep theirs, every year! A FRAGILE inside out USB.

I’m not sure that I have read that there was any real gains made over the LH 2.4, unless its working to fine tune a turbo boosters emissions programs? Do you have a turbo?
The hot film over a fine wire maybe, but how the addition of a potentiometer that is reminiscent of an analog radio volume control was an improvement, gets me! When aged they made scratching sounds when moved.

Like Kitty is suggesting and you maybe thinking, it would be easier to roll the car over to a LH 2.4 system. It would not be a step backwards but a sideways one!

Using another wiring harness to the properly fit up between the four components or two to be changed, is what you are looking for.
You might find it all off one car, of a later year, with or without the EGR differences.

You didn’t say anything about having an EGR, so I assume not?
A thought, the rough idle might be that or a hole in the accordion hose behind the AMM.
Loose clamping fit ups can cause idle rise and fall and stop light faults.
Any vacuum leaks behind the AMM is always a cause.

Keep us posted

Phil

Ok yes no egr and I do have a 001 air flow sensor.The silver accordian tube has always been disconnected but until recently I put a new air box thermostat in,which was stuck sucking hot air anyway but the tube was never hooked up ever so I changed it and still left the tube disconnected until it's dialed in for sure.The air flow sensor accordian snorkel is new from ipd and is leak free.Im trying to remember all the questions from machine man and kitty🤔🤔🤔oh the 25 amp fuse is still fender mounted and the fuse is good and has continuity,don't know how weather proof it is tho.I haven't looked into where to find the part number on my FI harness so I don't have that info right now.I didn't try clearing the codes yet manually with the diagnostic port as I drove the car to Philly today,but it ripped 310 miles out of a full tank of gas with the cruise on 70 most of the trip.which isn't terrible but I feel it could get a lil better and I don't wanna look at the check engine light.I.do have a complete 2.4 harness so I could make it 2.4 but I don't even think i could call that a can of worms that's a pallet of worms😂I will try to manually clear the codes tommorow am and see what happens

Yea everything on Dave's wire harness page has listings for 2.4 no 3.1 there's not one wire harness on there that has a 4 pin air flow sensor connector😤and that would have been awesome to get a new one with new connectors and shit but clear the codes tommarrow and see what happens

Is that really it? I scared you guys away that quick😂nobody has any more input from working on these cars as to why the check engine light won't go off despite using new OEM parts on the only thing that reads engine rpm?

3.1 Handed of Left,

Please forgive my terrible earlier response. Wastes time for everyone. Sorry. I had too much strong caffeinated beverage and too little sleep.

In new browser window or tab, navigate to:

http://www.v8volvo.se/mekartips/volvo/index.html

Mitchel Service wiring diagrams for 240. Includes the LH-Jetronic 3.1 and 2.4 wire harness diagrams on separate pages in the 1992 240 version.

The 1993 PDF does not include the LH-Jetronic 3.1 harness diagram.

Navigate to the "Files 140-240-260". See File "Volvo 240 1992.pdf". The engine control wire harness for both LH-Jetronic 3.1 / EZK116 by pinout and wire harness color. Unsure if wire insulation color varies for 1993 with LH-Jetronic 3.1.

I thought the 1992 240 green book wiring diagrams were here as were books on the EZK116 and LH-Jetronic 2.4 / 3.1. I'm forgetting where these diagrams are if they were here.

Unsure if Mitchell diagrams are 100% accurate. Art has the green books. The 1993 green book available at the Oz Volvo Archived excludes the LH-Jetronic 3.1 wire harness.

What Art indicates for wire color.
https://www.brickboard.com/RWD/volvo/1672519/220/240/260/280/verify_wire_harness_pn_1990_240.html

I'll try to find the 1992 green book 240 system wiring diagram.

Oz Volvo Archive:
https://ozvolvo.org/archive/

On this page find the PDF file "TALIESSIN PENFOUND - TP32352-1 1993 240 WIRING DIAGRAMS.PDF".

Hope that halps.
--
Jonathan Harshman Winters III: The Mightiest, Greatest, & Most Powerful North American Comedian & Comedic Actor in Perpetuity!

What is inconclusive to me is whether you have a 1990 Volvo 240 with M47 II manual transmission equipped or not equipped with ????:
- LH-Jetronic 3.1 or 2.4 fuel control
- EGR or not with the LJ-Jetronic 2.4 Bosch PN 0280000556 (same as came on my 1991 German Market 240 with M47 II YES EGR).
- Wire harness part number. See Dave Barton's Wire Harness Page info.

Resolve these ambiguities and we'll get someplace to resolve your issues.

The engine does start and run as you say, the CPS works, unless an intermittent fault. Reset (clear) DTC codes in socket 2 and 4.

I hope by now the 25-AMP engine control fuse holder in the engine bay secured to the inner fender car left side aft of the battery is a new 25-AMP holder that is weather proof and secured. You can pull this fuse, wait 30-seconds, and reinstall to clear store codes / corresponding check engine light.

I'll guess you have seen this page. A grain of salt, take with you, to this FAQ. (Copy and Paste into new browser tab or window):
https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm

LH-Jetronic 3.1 ECU (Bosch PN 0280000572) does not use EGR, and so, neither does the EZK116 ignition ECU (or I [ignition] CU). The EZK ignition computer controls EGR.

On my 1992 240 with Bosch LH-Jetronic 3.1 ECU (White Label Bosch PN 0280000572) has the Bosch EZK116 ECU (White Label Bosch PN 0227400169 / NON EGR).

Of the Bosch EZK116 ICUs PN 0227400169, All are NON EGR and NON Turbo. Oldest uses a pink label and newest uses a white label. All are known to be durable so far as I know, yet Art Benstein and others have the final word on such details.

My 1991 240 German Market sedan uses the LH-Jetronic 2.4 Bosch PN 0280000556 ECU and EZK116 ICU PN 0227400140. EZK116 YES EGR is used on CA-state 240s as CA-state mandated EGR.

Earlier Bosch LH-Jetronic 3.1 ECU used a Magenta Label (Bosch PN 0280000572) and may have been problematic. I have one of these as a spare and it is no spare!

The AMM / MAF used with LH-Jetronic 3.1 is Bosch PN 0280217001.

The information here:
https://www.brickboard.com/FAQ/700-900/EngineFIComputer.htm

and Here:
http://www.nuceng.ca/bill/volvo/database/ecu.htm

Leads one to make an incorrect conclusion by abbreviating the part number for the 4-pin AMM / MAF.

Both these LH-Jetronic ECU ID tables are wholly incomplete and omit the ignition control computer information such as what paring of these two go into what model year and market and model option.

I understand the information is for 700/900, yet used by 240 owners, and contains information identified as used only on 240, so should include the Chrysler / MPG ignition control information as used on 240. Also, no Bendix Rex / Regina information here either for those ECU / ICU.

ZJZ quit updating this information years ago. The information was incomplete at the start.


So what is the Bosch and Volvo Part Number for the Bosch EZK116 Ignition Control Unit on your 1990 240 secured to the bulkhead / firewall below the glove box?

What is the part number on the AMM / MAF current installed? IF the LH-Jetronic 3.1 AMM / MAF:



Is the silver accordion hose between the exhaust manifold heat shroud and the air filter box connected? If you do not know the state of the preheater flap valve control inside the air filter box, disconnect the silver hose. The silver hose unscrews from the air filter box.

Are you certain your 1990 240 with M47 II manual transmission is fitted with LH-Jetronic 3.1 fuel injection wire harness?

Many 1989+ 240s in USA with M47 II NON EGR were fitted with LH-Jetronic 2.4 (Bosch 0280000561 / NON EGR) and NON EGR EZK116 ECU (Bosch PN 0227400169).

Use these Mitchell Service Wiring Diagrams at this site to determine wire harness details.

http://www.v8volvo.se/mekartips/volvo/index.html

Have you resolved what version wire harness you have installed in your 1990 Volvo 240 with M47 II manual transmission?

On Dave Barton's Wire harness page (copy and paste URL into new browser tab or window).

https://www.240turbo.com/volvoharnesses.html

On that page, find: Volvo Wire Harness Part Number Collection

Also Find on that Page:

Where can you find Part Numbers on engine harnesses? CLICK HERE

Information is on the same web page.

The socket 6 1-4-4 DTC fault indicating the load signal missing that is sent or shared between the fuel control and ignition ECUs. A wrong computer either side, more so the LH-Jet ECU side, may mean a different pinout connection at the LH-Jet pinout ECU.


The socket 2 1-3-1 DTC fault The Bougicourd crank position sensor, in article mentioned on this board, suggest sometimes faulty new CPS cable. Of the three conductor / pins in the cable, Volvo 240 uses only twp of the three pins. I forget what number pins.

Maybe clear the codes? ECUs may not clear the codes on their own.

Search this forum for Art Benstein's comments and check out the wire harness diagrams.

Resolving the cause for the fault does not clear the fault code / on-dash check engine light. Reset codes listed here.

Questions?

Hope that helps.
--
Jonathan Harshman Winters III: The Mightiest, Greatest, & Most Powerful North American Comedian & Comedic Actor in Perpetuity!

Ok more input,the ICU in the car now is in fact a 0227400169 and the air flow sensor is a 001 4pin.i have cleared the 131 code from Port 2 and the 144 code from Port 6 manually by pressing the button for more than five seconds and all that jazz,only to have it come back on again in 30 miles,this time just a 131 code again from Port 2 check engine light on.And another thing I would like to clarify because once again I think I have bogus information 😤how big the capacity of my gas tank? Is it 12.8 or 15.8? Because as the saga continues I drove the car to Philly yesterday and pumped it full to the brim,and it got 310 miles until it showed empty,cruise on 70 most of the way.so if it's a 12.8 gallon tank that means I got 24.2 miles per gallon which is right an par🤔🤔??so what load isn't it sensing??the car is acting like it's lying😂if the ECU that it was at full load wouldn't my MPG suffer? I'm sorry if I'm pissing some people off cuz I'm getting 24 mpg in a 30 year old car and still unhappy but I don't want that check engine light on.

Hi,

You haven't scared anyone off, it's just sometimes we are just off OR doing other things to keep us from in being bored! (:)

I would like to comment on the gas gauge in these cars.
The orange zone, on the nineties cars, covers at least two gallons of fuel. I say at least, because it's more like three but don't count on it! The tilt of the tank can get really thin right where the pickup is.

I give the orange zone about a fifty mile range in my cars and I plan on 25 miles to the gallon, in either town or highway driving for the whole tank. It's easier to go 25 divided into any given A to B distance in my head for approximation and if I get more than 25 it's a plus factor in my favor.
I try to set it that way for my wife also as she's not super good using math because it was not her favorite class in school, she tells me? I have learned to believe her too!

The tanks have always been listed as 15.8 but again, what good is the .8, if you can't suck it up reliably?
You "probably"0 have three gallons there when you just touch on the orange reserve limit. That's the reason for confusion.
YIt comes down to of what's relative on how much the needle is touching orange or a white line?
If the car runs below orange it dies add something as a comfort factor if you are on the level. If not, you don't want to think about the alternative!

You'll notice that the top end is not measured as it don't matter how full the tank is as empty has its consequences in lots of ways!
Same goes for the temperature gauge too, when it's at the very top, except you don't want to know how far it can go past it! (:(

Phil

Interesting. I've been driving a 91 240 wagon M47 LH3.1 for the last 13 years, save those gas receipts & do the math. Yes, I did have to toss the Purple 572 in favor of the white...
It's been pretty consistent. Around town 23-24mpg. Open road at about 70mph, around 30mpg. With 185/65/14 tires the figure would be about 31+, so realistically more like 30. Now with 195/65/14. just above 30.
I would think that seeing only 24mpg for highway miles, and "LH3.1", something's rotten in Denmark.
File under "of little use dept":
I can drive that gas gauge down to under the white line at the bottom of the orange, and still show 1.5 left at the pump. FWIW
chow - S

Yes, the tank is 15.8 gallons, unless it has been dented. More often than dented, I think, a bit of fuel leaked into the float ball will change the fuel gauge behavior after 30 years. MPG is measured by writing the mileage on your gas receipts, collecting a few, and then doing the math.
--
Art Benstein near Baltimore

The check engine light is wire-ored, meaning either ECU could be responsible. Be sure it isn't your precious 3.1 fuel ECU setting the light by checking with one of the two not plugged in. Or if it doesn't set until you're driving, release the pin in the connector. Best if you're not making assumptions.

While you're down there, check the wire colors on the fuel ECU pins. Should have a yellow into 8 which goes to ICU-7. On a 2.4 harness ECU-8 would be a white wire headed for the AMM. The blue/white should be in 10, not 3 in the 3.1 cable.

Having a 30-year-old car that you didn't buy new might fill you with doubt as to how much of it is the way Volvo intended.
--
Art Benstein near Baltimore