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Any LH2.4 conversion experts in Dallas want $?

One more update for the day. I just went out and used the noid lite. The injectors are powered constantly with the ignition on and while cranking, no pulse. Just solid bright white light. To make sure, I went out and tested my 87 760t that's my girfriend's current daily, and it pulsated a dim light.

So does this pretty much point to a bad ECU? Apologies if other possibilities were already mentioned in this thread. It's been a month, and I'm still repeatedly reading back through all of this.

Edit: Actually it just hit me that I tried swapping the ECU before and nothing changed. ARRGH.
 
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Another thing that hit me, and I feel very, very stupid for it. So stupid that I wouldn't share it, except that I don't want this to be another one of those threads that someone looks through years from now wondering what happened because the solution was never posted. Not to say that I've figured it out. But anyway, my ignition switch has been rigged for years and I completely forgot that this could potentially cause an issue that it didn't cause with LH 2.2. My ignition switch crapped out a long time ago and I used a high-amp 2-position switch to bypass it and power everything up. Now I'm wondering if 2-position vs. 3-position and/ or the particular wires I'm powering constantly with the switch on, are causing this constant 12v thing to the injectors. I will have to look very closely at this after work tomorrow, and maybe reference my other 85 240's original ignition switch. That's one good thing about having a million Volvo's sitting around.

I'm curious to know if anyone agrees with me that an ignition wire that's wired differently than factory could cause this problem or not...
 
I really am truly hopeless. So I cannot figure out the ignition now. I removed my aftermarket switch and the wires I have are thick red (12v constant), thick yellow (wipers andother electronics work when this one is connected to 12v), thick yellow/blue (when connected to 12v, injector noid lite comes on constant and fuel relay clicks, pumps prime), thin red/black (fuel pumps prime when connected to 12v). And that's it, that's all I have for ignition wires. I'm not sure why the injectors are powered constantly like that when the thick yellow/blue wire is powered. And I'm not sure what to do differently. Without this wire connected, there's no injector power, no fuel relay, etc. But with it connected the injectors are powered constantly.
 
So there's 12vdc constant that should come from the radio suppression relay, through the ballast resistors, into all 4 injectors, and then into pin #18 (http://ipdown.net/jetronic.info/tiki-index.php?page=LH2.4+Pinouts+and+Diagrams) on the fuel injection ECU. The fuel injection ECU of course momentarily grounds that circuit to fire off the injectors in bank. If the ecu is hard shorted to ground you'd see this. How about disconnecting that pin @ the ecu and first see if the injectors are solid on still (short somewhere between ecu pin and injectors) and also test the pin on the ecu itself with everything powered off for ground continuity? I wouldn't expect it to be grounded with everything turned off but it sounds like it is grounded all the time?
 
GolfClapperX said:
I really am truly hopeless. So I cannot figure out the ignition now. I removed my aftermarket switch and the wires I have are thick red (12v constant), thick yellow (wipers andother electronics work when this one is connected to 12v), thick yellow/blue (when connected to 12v, injector noid lite comes on constant and fuel relay clicks, pumps prime), thin red/black (fuel pumps prime when connected to 12v). And that's it, that's all I have for ignition wires. I'm not sure why the injectors are powered constantly like that when the thick yellow/blue wire is powered. And I'm not sure what to do differently. Without this wire connected, there's no injector power, no fuel relay, etc. But with it connected the injectors are powered constantly.
Click to expand...

The thick yellow/blue wire is basically the fuel system. It will switch on the radio suppression relay which sends 12vdc to the injectors. The switching of the injectors is handled by the ECU momentarily grounding all 4 at once. So BL/YEL is totally doing its job.

You do have a wiring diagram for LH2.4 right?
 
From the '85 240 Wiring Greenbook, the ignition switch wires are:
- big Red: Battery +12v (ign sw pin 30)
- big Yellow: Accessories position, to fuses 1,2,3 (ign sw pin X)
- big Blue/Yellow: Run position, to fuses 11,12,13,etc. (ign sw pin 15)
- small Red/Black: Run position, to ECU and main relay coil (ign sw pin 15)
- small Blue: to Starter, through P/N interlock or jumpered (ign sw pin 50)

I assume you have the DB harness with the resistor pack installed???

Which wires did you connect from the new harness to your cabin wires???

Sounds like the injector driver in your ECU is damagaged. Do you have access to a spare ECU that you could try? There's still a possibility that something else in your wiring is causing the problem, or damaging the ECU.
 
I do have the DB harness with the resistor pack connector, and I'm using a resistor pack. I don't have a radio suppression relay though. Isn't that only needed on the 7-series? I don't think there's a connector for one on the DB harness.

Interior wires I have connected from the DB harness:
A1. Blue- switched power from ign pin 15 (tapped into fuse panel number 11)
A2. Blue (fat)- switched power from ign pin 15 (also tapped into fuse panel 11 - DB's instructions state that fuses 11,12,or 13 are acceptable)
B2. Red/yel (fat) (although it's not really very fat like the old one was which confuses me)- fuse panel number 4
B7. Pink- wired to starter solenoid

Wires NOT being used:
B1. red/gray- ECU pin 15- A/C relay
B3. green- ECU pin 14- A/C clutch
B4. black/blue- ECU pin 34- Speedo pulse
B5. Violet- ECU pin 26- shift light
B6. pink/white (x2) ECU pin 22, ICU pin3- check engine light
B8. red/white- powerstage pin 1- output to tach

So the way I was just switching 12v to the three ignition wires before (big yel, big yel/blue, small red/black) has been working fine for a couple years with LH 2.2. Is there really a reason this wouldn't work with LH 2.4? It does seem like it's blown injector drivers, but I do remember trying the ECU out of a 92 940t that I had sitting around a while back, and the symptoms remained identical. The only thing is that 92 940t also barely ran and was running really rich and billowing black smoke, so it's possible it also had blown injector drivers. I didn't think it would be that common though. Besides, that one did start and idle so it's symptoms were a little different. I have one more ECU to try, it's on a 94 940t that runs fine. It's being stored 25 miles from me though so I'll have to try and make time to go get it.

rallydallas, I'll try your suggestion. It's a brand new harness so I doubt there's a short in it, but I'll try it anyway...what else am I going to do.
 
rallydallas said:
The thick yellow/blue wire is basically the fuel system. It will switch on the radio suppression relay which sends 12vdc to the injectors. The switching of the injectors is handled by the ECU momentarily grounding all 4 at once. So BL/YEL is totally doing its job.

You do have a wiring diagram for LH2.4 right?
Click to expand...

The grounding is supposed to be momentary though right? Because the injectors will just stay powered until the yel/blue wire is disconnected from the red 12v wire again.

I have a few different diagrams I found online, but none are perfect. Wire colors changed on Volvo's about 10 times per year for no reason, so I've found it impossible to find just the right diagram. I have the diagram for my new Dave Barton harness, which should be almost all I need...
 
Also, anyone know if there would be visible damage to the ECU circuit board if the injector drivers had died? I assume there would at least be that fried-electrical smell up close. Maybe I'll open it up.

Edit: Opened up the ECU, looks perfect, smells perfect...I don't know.
 
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So, testing pin 18 on the ECU for a short to ground:

Testing with injectors unplugged and a noid lite on an injector wire. I'm running the positive lead of my multimeter to the big red wires on the fuel relay for a 12v source.

-ECU connected, all pins still in, ignition off, - wire on multimeter to pin 18 = approx. 14v.

-ECU connected, pin/wire 18 removed, ignition off, multimeter - to wire 18 = 14v.

So there's definitely a constant ground through wire 18 even with ignition off. With ign off, the noid lite on the injectors is off. Only when ign is turned on does the noid lite come on, and constant. I also don't know why it's 14v and not more like 12v. I do have a charger on it but still.
 
IT RUNS! Albeit not well, and I have no idea why it started running. I just plugged ECU 18 back in and plugged the injectors back in and tried cranking it to watch the noid lite, and it started up and idled! It's a choppy idle, it does have an IPD cam but it's choppier than it should be still. Also lots of exhaust smoke and a 224 code. 224 is ECT right? Thing is this ECT is the same one that was working fine in the car I pulled it from, so I don't know why it would be bad now.

Seems like I'm getting closer (famous last words), I'm pretty happy at the moment.
 
GolfClapperX said:
I do have the DB harness with the resistor pack connector...
Interior wires I have connected from the DB harness:
A1. Blue- switched power from ign pin 15 (tapped into fuse panel number 11)
A2. Blue (fat)- switched power from ign pin 15 (also tapped into fuse panel 11 - DB's instructions state that fuses 11,12,or 13 are acceptable)
B2. Red/yel (fat) (although it's not really very fat like the old one was which confuses me)- fuse panel number 4
B7. Pink- wired to starter solenoid

Wires NOT being used:
B1. red/gray- ECU pin 15- A/C relay
B3. green- ECU pin 14- A/C clutch
B4. black/blue- ECU pin 34- Speedo pulse
B5. Violet- ECU pin 26- shift light
B6. pink/white (x2) ECU pin 22, ICU pin3- check engine light
B8. red/white- powerstage pin 1- output to tach
Click to expand...
Looks OK. The DB harness has a fuse and a big red wire to the battery in the engine compartment, correct? Some years of the Volvo harnesses have that, and others route the main battery red wires through the cabin connector.

For B7 Pink to starter solenoid: is the car an automatic? If so, where exactly is this connected? It should be on the ignition switch side of the P/N interlock, not on the other side that goes to the solenoid. [This wire isn't critical, but the ECU uses this for idle adjustment on the automatics when going between park and drive.]

GolfClapperX said:
So the way I was just switching 12v to the three ignition wires before (big yel, big yel/blue, small red/black) has been working fine for a couple years with LH 2.2. Is there really a reason this wouldn't work with LH 2.4?
Click to expand...
Should be fine.

GolfClapperX said:
It does seem like it's blown injector drivers, but I do remember trying the ECU out of a 92 940t that I had sitting around a while back, and the symptoms remained identical. ...
Click to expand...
How good was your original resistor pack wiring - are you sure that nothing was mis-wired or shorted out before you tried starting it for the first time? If you tried to start it and the ECU side of the injectors was shorted to +12, or the resistor pack wasn't correct, you may have damaged the ECU. I'm not sure how quickly the damage occurs -- I don't know if it would have started and fried in minutes or only a few seconds.

GolfClapperX said:
Also, anyone know if there would be visible damage to the ECU circuit board if the injector drivers had died?
Click to expand...
The injector driver is the power transistor on the heatsink closest to the main connector. They usually fry without smelling, but the plastic transistor body may bulge out or discolor.

For repair instructions, see:
http://ipdown.net/jetronic.info/tiki-index.php?page=HOWTO%3A+LH2.4+Injector+Driver+Replacement

You'll need a TIP122 ($0.55) [the original is an ON823, or similar darlington transistor, and the TIP122 is generic substitute]:
https://www.jameco.com/z/TIP122--Major-Brands-Transistor-Darlington-NPN-100-Volt-5-Amp-3-Pin3-Tab-TO-220-Bulk_120416.html
 
bobxyz, you've been amazingly helpful all throughout my ordeal and I really appreciate it. You even linked me to the transistor I'd need, that's awesome.

My pink wire actually right now is going to the momentary switch I use for my starter (an old 240 defrost switch mounted on the console). I had it running all the way to the solenoid earlier but I changed that. This car is auto. It was an M46 car but I made it auto a long time ago for my girlfriend...can't win every battle.

As for how good my wiring was before the DB harness, well, the wiring condition itself was pretty good. But I definitely could have hooked something up wrong and fried stuff.

Nice instructions on replacing the transistor too. The first sentence on that page still concerns me a bit since it says the symptoms would be a car that doesn't run, or only runs briefly with the injectors unplugged, and crankcase full of gas. All those things did 100% apply to me until about 30 minutes ago. Now it runs but I guess maybe it's still running rich. Since the code is 224 I guess I have to look closely at the ECT and it's wiring...
 
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Knew I spoke too soon. I changed the ECT and went start it again, and after it turned over a few times and didn't start I noticed the pumps and injectors were powered even when not cranking. It wasn't doing that earlier. I quickly unhooked the injectors and tried to crank it again but it was hydrolocked. I'll try again tomorrow afternoon.

Also, it's not nice of me to post this publicly but on the other hand it's not nice to charge someone $417 for garbage... the new wiring harness is actually crap as it turns out. The wires pull out of the pins every time you try and unplug a connector, and you have to unclip/remove the pins and re-crimp them. Both wires just loosely fell out of the ECT connector, and earlier while removing pin 18 on the ECU, I noticed that wire didn't look crimped tight and gave it a light tug and out it came. It's not like I'm just tugging on wires either, I'm pulling on the connectors at their base. And I've never had this happen on an OE Volvo harness. Plastic connectors disintegrating with age, of course. This harness is going to be a basketcase later down the road or maybe right now. I might just switch it back to an OE harness that doesn't probably have 150+ loose connections.
 
Ahh, reading comprehension fail on my part. Sorry, been really worn out lately. So you're doing a B230FT / LH 2.4 into a 245? Is this the harness you got? https://www.240turbo.com/volvoharnesses.html#240lhconvharness2
https://www.davebarton.com/pdf/HarnessLH2.4EZKconvHi-LoZ.pdf

Anyways check here, this is what I was referencing --> https://www.myvolvolibrary.info/Tech_files2_ficheiros/940MY95_EN_Wiring_Diagrams_section-3-39.pdf Page "48"

See the power going into the injectors and being grounded by the ECU at pin 18? Power to the injectors is always on if the ignition is switched on, but the ECU toggles the ground to fire them. I'm suggesting there's a short-to-ground somewhere between the injectors and that pin #18 that's forcing the injectors open.

You need to get a proper voltmeter and test the pin on the ECU itself for continuity / resistance to real ground and also the wire leading to pin #18 itself for a short to ground. I think.

Check this one too, 1993 240 wiring diagram http://turbosti.com/volvo-manuals-01/volvo_240__1993.pdf Page 22. It lacks the signaling in/out that the one up above shows.
 
Oh my, sorry to hear that it was almost working and then misbehaved again. At least you're not paying a shop $100/hour for them to have the same problems, and to eventually return it to you un-fixed but with a big bill.

GolfClapperX said:
...The wires pull out of the pins every time you try and unplug a connector, and you have to unclip/remove the pins and re-crimp them. Both wires just loosely fell out of the ECT connector, and earlier while removing pin 18 on the ECU, I noticed that wire didn't look crimped tight and gave it a light tug and out it came.
Click to expand...

Contact DB and explain the wires pulling out. Sure sounds like it the harness was not manufactured correctly. For good quality crimps, you should be able to pull mighty hard on them without the wire pulling out. (Don't do this with the crimp still in the connector -- the little wings that hold it in the connector are not rated for high pulling forces.) Here's a link to the Molex Industrial Crimp Quality Handobook. Page 24 has a table of minimum wire pull forces versus wire size. For the harness, the smaller wires are probably 18ga or 16ga, so 20 or 30 pounds of force min (which feels like you're going to snap the wire first). http://www.molex.com/pdm_docs/ats/TM-640160065.pdf

I still think your ECU is suspect. I'd swap it for a different one if you can, just to get it out of the picture for now.
 
That's true. I've been unable to fathom letting a shop touch any of my cars for at least 10 years now, so at least I'm experienced enough to make that work. With about 8 cars that I'm unable to part with until I die, newest one being an '87, I do need experience and patience. Wiring has always been my weak point, obviously.

Yeah I contacted him. I'm trying not to be too irritated over spending a week's pay on a harness that sucks worse than the original one and installing it, etc. I don't think I'll get another new one, even if the loose crimps are fixed. This is because right after I swapped this engine in, I now remember that this is exactly how it ran. It would start and idle really choppy with black smoke, but it would idle. Ridiculously enough, that was with a harness I had pieced together from the 940 donor. Since then I installed that Picknpull 89 240 harness, and now the DB one. And I'm back to square one...
 
rallydallas said:
Ahh, reading comprehension fail on my part. Sorry, been really worn out lately. So you're doing a B230FT / LH 2.4 into a 245? Is this the harness you got? https://www.240turbo.com/volvoharnesses.html#240lhconvharness2
https://www.davebarton.com/pdf/HarnessLH2.4EZKconvHi-LoZ.pdf

Anyways check here, this is what I was referencing --> https://www.myvolvolibrary.info/Tech_files2_ficheiros/940MY95_EN_Wiring_Diagrams_section-3-39.pdf Page "48"

See the power going into the injectors and being grounded by the ECU at pin 18? Power to the injectors is always on if the ignition is switched on, but the ECU toggles the ground to fire them. I'm suggesting there's a short-to-ground somewhere between the injectors and that pin #18 that's forcing the injectors open.

You need to get a proper voltmeter and test the pin on the ECU itself for continuity / resistance to real ground and also the wire leading to pin #18 itself for a short to ground. I think.

Check this one too, 1993 240 wiring diagram http://turbosti.com/volvo-manuals-01/volvo_240__1993.pdf Page 22. It lacks the signaling in/out that the one up above shows.
Click to expand...

Yep, that's the harness I got. It did seem like the wire going to pin 18 was grounded even with the ignition off. But since it has basically the same symptoms it did with the last harness, I guess both harnesses would have to be shorted similarly. I'm pretty sure (?) I tested everything the way you suggested...

I don't like to say this out loud but I am using one of those $4 Harbor Freight multimeters. I know everyone will say they won't do the job but I think for very basic stuff they do. It's a glorified test light.

Thanks for the links!
 
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