Hello.

First time poster. I will try to be brief (but it never works like that for me). I have a 1991 240 auto sedan 183K.

I bought the car a couple of weeks ago and I am beginning to think it was a mistake. I bought it thinking I could solve a cold start problem. I should have read this forum first and I probably wouldn't have purchased the car. I have been searching and reading the forums diligently and working on the car after work when I can.

Problem I have and I see it is rather common with many others. Cold starts are impossible without starting fluid. Warm or hot starts are fine. Car runs and drives okay after it is warmed up.

Check engine is on. In pin 2 I have a 1-2-3 code, coolant temp sens or ground error, and in pin 6 I have error 2-2-4. At least I thought I saw 2-2-4 but there doesn't appear to be a 2-2-4. It is snowing and icing out so I can't really double check it right now.

I did some basic tune up items because before I started investigating the codes because it seemed like it was running rich. I smells like an old 70's jaguar my Dad had ages ago. I replaced the spark plugs (looked brown and not wet on first time looking at them). Wires are new now. Coil wire was arcing to shock tower. Coil windings test in spec. Cap and rotor are new.

I tested the resistance of the coolant temp sensor and it was close to spec. I replaced it anyways and the readings for both units weren't conclusive. I have my doubts about the replacement part I installed. I tested them at the same time after letting the car sit overnight and the part was in the trunk chilling off too.I have misplaced what my readings were but it was 30F out and i think they were 7.4K ohms for the installed sensor and 13K ohms for the replacement.

I have a question about the engine grounds. I cleaned the ground from the battery to the body. I also cleaned the ground at the valve cover to firewall. There was a ground wire that looked misplaced and was run from the drivers side shock tower to a bolt on the intake manifold. It is a braided copper? wire with a total of three eyes on it. Is this a factory part/location? I guessed it wasn't and moved one end to the firewall and put two of the eyes on the bolts for the fuel rail.

One other ground question and I will shut up and await replies. My ground wires (brown jacket) that come out by the injectors and are screwed into the bolts for the injector rail only have one wire. It seems like there is more wire in the black protective sleeve but I don't want to cut it open without probable cause. I think I saw a photo somewhere where there were two brown ground wires per black sleeve. I am trying to get a picture off my camera but I'm having issues. Could this possibly cause the 1-2-3 error if the fuel injectors don't have grounds? I am speculating.

I am trying to do this on a budget. If I had more money to burn on this I would have bought a newer cleaner and better running car.

I eagerly await any replies with suggestions. I have more I have read about on these forums but if I bring up any other issues I think it could confuse this current issue.

thanks in advance.

rpm

 

Just went through the 1-2-3 code issue with my 1990 240 wagon. Long story short, after a new ECT sensor install didn't fix the problem I ended up cleaning the wire connector really well with some contact cleaner spray and it fixed the problem. That 2-2-4 code is also an ECT signal failure for the ignition system (it has it's own set of codes, separate from the fuel injection codes), so it looks like fixing the one problem should clear both codes. I would try cleaning the connection and double checking for a loose or broken wire/connector.
After a quick check of my engine bay it looks like the two single brown ground wires are normal, one on each bolt holding the fuel rail in place. It does seem like there are more wires in that harness, but just the one protruding brown wire with the eye connector on each side.
The only braided ground wire I could find was a braided steel one that goes from the Valve cover to the firewall, just to the passenger side of center of the firewall. Couldn't find anything going from the drivers side strut tower to the intake manifold, but if you don't have the one I described then it may be something they changed from the '90 model year to the '91?

 

Nonsense! I love these cars, you can make them run forever! Well almost.

So there are two temp sensors in this car, which one did you replace? One is for the gauge and the other is for the fuel injection system. It on the head still but back a little further, under the intake manifold near cylinder 3. I think it's just a little further past the knock sensor. The two plugs (knock sensor and temp sensor) are interchangeable, so don't get them mixed up. The knock sensor should have green wires, the coolant should have yellow and black.

Code 224 is also an engine coolant temp code. Check this site out: Engine and OBD Diagnostic Codes

It's got Bosch LH2.4 and Motronic 1.8 Fuel Injection Fault Codes and after it,
EZK 116 and Regina Rex Ignition Fault Codes

The LH2.4 is your car's fuel injection system. It's uses socket 2. The EZK 116 is your car's ignition system. It uses socket 6. Use the first one for socket 2 codes and the second for socket 6 code. That should make using that system a little easier.

If it's not the sensor, then it's the the wires. Also, when you tested the sensor, I'm not sure how you went about testing it. The resistance varies depending on the temp. So at 14F it is 8k to 10k ohms. At 68F it's 2-3K ohms. At 175F it's 300 to 350 ohms. As far as the ground, the sensor grounds through the head. The wires head to each computer.

I'd go make sure you found the right sensor.

 

re those two grounds on the fuel rail, one of them is the ground for the 'power' circuits like the injectors, while the other is the ground for the control circuits.

 

Wow. Thanks for the quick replies!

norcal, I will try cleaning the connector. It is a bit tight to see down in there with the intake manifold in place and I recall now that it was greasy on the inside of the connector. As a matter of fact the whole engine has a fine layer of oil residue on it. I did buy a spare wiring harness, 2 pin for the ECT but I didn't put it on because I didn't want to pull the intake manifold just yet, and I didn't see that there was any way to splice it in without pulling intake manifold. I will probably have to pull it some day, but I need to try these repairs and keep it running to get my son to school in the mornings.

Titan Joe,

I am sure I have the right sensor, the one towards the rear of the block. Not the single pin for the gauge, which works. I was using the uk site info for looking up the codes. I wasn't sure if the 224 code in the regina section was for my engine.Thanks for clarifying that. I am learning more every day. I do like the car and want to keep it. I am very stubborn as well and I won't let this car get the best of me.
When I tested the sensor I was testing the installed sensor still in the block with my voltmeter probes directly on the two pins of the sensor. I tested the new part by the same method but it wasn't installed. It was at the same ambient temp though. It was 30 degrees F that morning last weekend.

There was a post by Pierce that mentioned testing ECT wires at the ecu. I was going to ask about that in my initial post but it was getting long and diluted. In that post #12 https://volvoforums.com/forum/volvo-...d-69897/page2/
Pierce mentions "measure the resistance from pin 13 (ECT) to pin 5 (ground) of the socket" is that on the wire harness end? I had the harness off the ECU briefly but I wasn't looking for numbers and there was some old die-electric grease on it that looked pretty gross. Are there numbers on the harness where you probe or do you count the wires? Also, is the ICU the black box back behind the fuel pump relay? If so are the pins/connectors numbered there?

I also replaced the fuel pump relay since I was putting in a parts order. First I re-soldered all the connections inside, one looked like it was cracked (relay stamped 2004). That didn't change anything and swapping the relay didn't change anything.

Pierce,
Thank you as well for the confirmation of grounds. Thank you as well for sharing you wealth of knowledge in all your posts. I have learned a lot about the intricacies of the 240 from your posts. I think I am going to replace my fuses as well. I had some old mercedes diesels a couple years ago and have some fuses sitting around. One time when I cleaned the fuse holders, with pencil erasers, and started the car warm, the check engine went out briefly and re-lit. Sensitive little beasts these things are.

I will post back with an update in a day or so.

Thanks again,
rpm

 

So I bought a can of CRC contact cleaner. It cleaned the heck out of the connectors for the coolant temp sensor. I also cleaned the idle air control valve connectors. That wasn't a silver bullet.

I thought I would check my idle air control valve. It activates with 12v applied. It also works when performing the engine diagnostics from the swedishbricks.net link someone posted. I believe it is Diagnostic Test Mode 3. The test where you press the button three times for one second each. I can hear fuel injectors clicking, IAC activating but not the cold start valve or fuel pumps. I am pretty sure my fuel pumps work. A while back I jumpered them at the solenoid and I could hear them running. At least the primary. I have not listened in the filler pipe for the in tank pump yet. I need to run the fuel down.

Does any one have any tips for running the Diagnostic Test Mode 2 all the way through? I could get confirmations 3-3-4, 3-3-2 and 3-3-1. I couldn't get the 3-3-3 to appear for TPS OK in full load position (when throttle is moved). I also couldn't get the 1-2-4 to appear. It is the Engine idle speed compensation for automatic trans. I tried it a couple of times and maybe don't have the sequence quite right, but the light just kept blinking.

I thought I would try to run some tests to see if anything obvious came up.
I pulled off the ECU connector and probed the connections there per a post by fochs. I probed for continuity:

5 and ground
17 and ground
19 and ground
29 and ground
5 and 19
5 and 29
all were good.

I probed anti-knock 28 and ground, .719v
I probed ECU power from ignition 35 and ground with ign on 12.35v
ECU power supply from battery 4 to ground with ign. off was 12.5v

I am starting to think it is my AMM. The previous owner that dumped this thing on me had a shop install a used AMM and it looks pretty bad, but I know looks aren't everything. I also think that at this point all the starting fluid has probably taken it's toll on the AMM. I have started to apply starting fluid to a vacuum intake now. The airbox valve was also stuck open in the warm position. I have wired it up for cold air only now.

I don't have a spare and $150 for a rebuild off brand unit is hard to swallow if it isn't going to solve my problem. Is there a test to confirm a bad ECU? If I search ECU on volvoforums it is discarded in my search since ECU is too short or some nonsense.

Are there any other tests someone can recommend? It is getting old having to pop the hood in 20 degree morning temps and spraying starting fluid to get her running.

***To recap the things done to this car already that are not listed above.
New cap and rotor, spark plugs, wires, coil. (it runs smoother now when it is running). Main fuel pump (not installed by me, but I hear it run for a couple of seconds when I turn the key. O2 sensor (not by me). ECT sensor replaced. Fuel pump relay replaced. Cleaned throttle body. Timing belt (not by me). Timing belt tensioner looks worn. Confirmed timing marks lining up at TDC. Chinese water torture/Seafoam procedure. I can hear the throttle position sensor click when barely moving throttle cable.

Things I want to know if I should look into.

Is there a main ground by the fuse panel that could be causing a problem?
Clogged catalytic converter
Compression test
Test for bad ECU (mentioned above)

Thank you so much anyone who can offer advice.

rpm

 

in addition to the grounds on the fuel rail, the other important grounds on a LH2.4 240 are...

the one on the back end of the relay bar on the left finder is used for the left headlight, left direction/parking lights (and an ignition controller not found on US models, and/or diesel-only stuff)

theres one on the right fender by the right headlight, which is for the right headlight and lights

the center console just forward of the left side of the shifter bezel, and near the bottom of hte console on that side has: fuel pump relay, headlight relay, bulb failure sensor, instrument lights, and most of the rest of the console/dashboard stuff.

behind the center console right support (just below the 'coin tray' on the center console) has: AC relay, electric window relay and switches, overdrive relay, central locking relay, and heater van.

the fuel rail grounds: front ground is 'signal', has the ECU pins 5, 19,29, ICU pin 20, MAF, and diag terminal, while the rear ground is 'power' and has ECU pin 17, throttle idle/max switch, O2 heater, ICU pin 14, and ignition power module.

beneath the left front seat near hte parking brake, a ground has the power door mirrors, heated seats, and seatbelt lock light.

beneath the rear seat, a dground has the fuel pump, sedan 3rd brake light, adn sedan electric antenna, and the wagon's tailgate wiper interval relay.

near the battery and left wheel housing, is the battery ground and ABS braking controller ground.

in the trunk is the ground for the tank pump, and other grounds near each tail light.

 

Many thanks Pierce!

Hopefully tomorrow evening I can get started on looking at that list of ground connections. Probably will take me until the weekend to complete.

Will post findings after ground cleaning expedition.

rpm

 

I use rubber pencil erasers to clean plated contacts and such, as they wont remove the plating but will remove the oxide, then put a drop of DeOxit D100 on them. if the oxide is particularly bad, I'll use the deoxit as a cleaner, too (put a drop of deoxit on it, then use a bit of the eraser to rub it in/off, it helps loosen the oxides). this is an old trick I learned in the computer business long long ago, far far away.

 

I still haven't had a chance to check the grounds per Pierce's suggestion, but I did try something else.

I did the AMM test where you unplug the sensor and start the car. I had to do it after the car was warm due to the cold start issues, but it ran when it was unplugged. It didn't smell that much different than it does when it is plugged in. It was a richer smelling exhaust so it was definitely not right. So it looks like I will be visiting the pick and pull tomorrow.

Will update again on progress if I am successful finding a working AMM to sub in.

rpm

 

just make sure its an -016 AMM, which is what you'll find on any LH2.4 240/740/940 (1989+ non-turbo or 1990+ turbo) ... if the car is Regina based (some 7/9's), it won't have a MAF at all.

 

I had a reply all ready and then my browser took a dump and wiped it out.

So... this weekend I pulled a bunch of parts off of every kind of Volvo but a 240. I ended up with two good looking 016 AMM's off various 740/940. I cleaned them up tonight and they seem to work. I haven't had an extended test drive yet.

I also had a nice problem happen tonight that may help solve my no cold start condition. I had found a loose vacuum line on the line that runs through the firewall. On the opposite end by the 90 degree elbow there was a longitudinal crack in the line. I cleaned up the line and reassembled. Here is the good part. I was about to leave and I couldn't get the car started at all. It wouldn't start with a shot of starting fluid so I retraced my steps and started looking for things that would keep it from making spark.

After a good amount of time I remembered that I touched the connector for the crankshaft position sensor. I am assuming that is what the part is. It has a three pronged connector, same style as the injector connectors. Anyways, the spring clip is broken and hanging off. So I pushed that together and she fired up.

I am wondering if there is a ground in there that could be causing the ECU code 123 error if the connector is loose.

I am hoping that the car wants to start in the morning without starting fluid.

Thanks,
rpm

 

that vacuum line through the firewall is for the heating/ventilation system, the vacuum is used to open/close the air flaps when you push the buttons.

code 123 is the engine coolant temperature sensor...

you've reset that code and it keeps coming back?

thats one of the 3 sensors on the head immediately under the intake manifold, its the 2 pin connector there... in the middle I think. the flat one on its side is a knock sensor, the 2 round ones, one has a singel connector, and thats just the dashboard temp gauge, the other one has a double connector, one pin is for the ECU and the other pin is for the ICU. its a frequent culprit in hard-to-start-when-cold problems (or runs-crappy-when-warmed-up, depending on the failure mode).

I'd locate the sensor, and pull the connector and reseat it a couple times. I know its tough to get in there, but if you can clean the connector, all the better. reset the codes, see fi they recur...

if they keep recurring, then....

its about as likely to be a wiring or connector issue as a sensor issue. the best test is to pop the passenger under-dash felt panel off, then the plastic side panel thats forward of the passenger door to expose the ECU, which is mounted just forward of the passenger side door hinge... car off, and disconnect the battery ground cable to be safe. remove the connector from the ECU, and shine a flashlight into that connector, and you should be able to see the pin numbers next to each pin... use a digital volt meter in OHMS mode, one probe on pin 13 (the ECT), the other on pin 5 (which is ground), and the resistance shoudl be something like...

32F (0C)-- about 6000 ohms within a range of +/- 10%
68F(20C) -- about 2300 ohms
104F(40C) -- about 1300 ohms
140F(60C) -- about 600 ohms
176F(80C) -- about 300 ohms
212F -- about 190 ohms

based on the engine block temperature. it doesn't ahve to be exact, just more or less consistent with that table. higher resistance if COLD, lower if HOT. ideally, get the car hot before you unplug it and do this test (take off the panels, do a nice long drive to warm things up, THEN switch the car off, pull that battery ground, and pull the connector and check the resistance before it can cool down too much), then wait a few hours for things to get cold and measure it again.

if it measures way off, then its time to figure out of its the wiring or what... I think I'd pull the ECT connector at the engine, and ground both pins with a cliplead or something, then measure it at the ECU connector, you shoudl see 0 ohms, if you DONT then the wire is funky. if you DO see 0 ohms, remove the clip-lead, and measure again, it should be infinite resistance (or at least several megohms), if thats also the case, then I suspect the sensor itself.


here's a whole lot more detail on the ECT.
Engine Sensors

 

Pierce,

I did replace the ECT a couple of weeks ago. That was the first thing I replaced back when I looked up the code. I also cleaned up all the grounds I could find. I tested the ECT itself and it wasn't that out of spec. I still need to check the harness at the ECU as you prescribed. I cleaned the fuse holder in the car and replaced some fuses with new brass style ceramic fuses.
It is still resetting the 123 code. So I will have to check the wiring at the ECU.

Buried in my last rambling post I asked about the connector to what I think is the crankshaft position sensor. It wasn't aimed at you , but I have a feeling you may know the answer. Is a wire that looks like it goes down behind the rear of the block towards the transmission that has a 3 lead connector the crankshaft position sensor wire/connector? Reason I was asking is that it is way loose. The wire spring lock is falling off and it was basically just sitting there. It was what caused my no start debacle last night. I pushed it together and the car fired right up. They had some electrical tape around it too, but it was 11:30 and I wasn't in the mood to investigate that, I just wanted to get home.

Any chance that one of the three wires is a ground and causing a problem?

thanks!
rpm

 

yeah, the CPS is three wires, there's a shield (black, pin 3) and a signal pair (blue-yellow & red-yellow, on pins 1,2), and yes, the CPS is behind the head, stuck into the top of the bell housing, reading notches on the flywheel or flexplate. the sensor itself is pretty robust, most problems with iCPS seem to be wiring related.

 

I just finished up checking the ECT resistance at the ECU. I have 0 continuity across pins 5 and 13. Then I unplugged the connector from the ECT and jump the plug and got 0 continuity across 5 and 13. I guess it is the wiring. I think I will be running new wires from a new plug end to the ECU. I sure hope this works. It really is the last straw for this car. I can't take much more.

On the Crankshaft position sensor side of things the wire clip is broken and there is a bare spot in the wire jacket were I can see the foil shield. There are a couple of spots where there is electrical tape covering some future disaster up that I couldn't bear to look at.

I am ready to drive this to the junk yard collect my money and ask to pull the levers on the crusher.

thanks for your help Pierce.

I will report back after rewiring the ECT plug.

ugh...

rpm

 

note, the ECT is just connected to ECU pin 5 and engine ground(the threads), NOT to the other pin. the other pin goes to the ICU (and is a separate thermistor, also wired to engine ground).

so, to do the continuity test, you'd need to take both pins on the plug that goes onto the ECT and connect them to chassis ground, not just to each other. I probably should have made that clearer earlier.

 

I spent a good portion of last evening splicing in a new connector for the ECT. I ran through the test as I posted previously I had no continuity at the ECU on pins 5 and 13.

I pulled the plug from the ECT and then worked the boot back and there was a wire broken. That was a relief, really, I was expecting to have to run a new wire through the firewall. So I spliced the connector in and it made no difference once I got to running the car. I had installed a uro brand ECT a couple of weeks ago and the part was defective out of the box. I figured that out by heating the car up and taking the temp and measuring resistance as it cooled down.

The gory details are here.

Degrees F and Ohms
177 1.84k
173 1.7k
168 4.01k
145 4.33k
125 4.85k
113 5.32k
102 5.86k
93 6.59k

 

I didn't finish and posted that last one prematurely.

Degrees F and Ohms
177 1.84k
173 1.7k
168 4.01k
145 4.33k
125 4.85k
113 5.32k
102 5.86k
93 6.59k
85 7.36k
75 9.02k
66 10.33k

At this point I put the old Bosch ECT back in. Then I had at 64F 3.25k ohms.

Then I plugged the harness back in and gave it a go and it fired up and for the first time since I have owned the car the check engine light went out.

It seems to be behaving so far. It is about 30 degrees out and it starts up on the first try. If I did that this morning it would have been 4 or 5 crank cycles to get it to start.

Pierce and the others back in the beginning of the thread, thank you very much for your help.

Moral of the story. Don't just throw parts at it. Check the grounds and wire connections thoroughly

 

Not to say "throw parts at it" but from the sounds of it you will need a crank position sensor. These tend to fail intermittently prior to a hard failure. Flaking insulation, etc. generally indicates a need for replacement.