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No spark

Maybe it's that BOV put your hand over it and see what happens. Or air leaks. Sounded like it was idling high in one video.

I use a smoke machine to locate air leaks.
 
Soo close. No -10 would mean 10 after top dead center. +10 is before top dead center. Try +10 if you didn't set it there. The turbo engines are usually +12 before top dead center.
 
So it ran good enough to take it for a drive. Got gas and on the way home it just died without warning. Waiting on a tow... Fuel pump is running, no blown fuses, fpr clicks.. pretty sure I lost spark.
 
So, once again, I have no injector pulse. But this time I have power at the injectors. If I put the meter across the two pins in an injector connector it just shows battery voltage while cranking.
 
I saw butt connectors in your video. No good. Solder and heat shrink is our policy at the shop.

You should also spend the $5 on a noid light. A meter averages the voltage and isn't the proper tool. 12v steady isn't good. That means shorted/always on injectors possibly. A test lamp or noid light would be better. Just make a test light or noid light!



Does it run on brake cleaner?
 
The injectors are grounding out through the smaller black manifold ground ring, regardless of the ECU being connected.

My oil is nice and gassy again..
 
Your explanation doesn't make sense to me. Good move unplugging the ECU, but do you have the ground rings unplugged also when you're making this measurement?

You have also stated you intermittently DON'T have power to one or more injectors. You may have a short internal to the harness. LH2.2 wiring harnesses commonly degrade.

Unplug the injectors, clear flood, and see if it runs on brake cleaner. And stays running. If so, shake down the fuel system.
 
Yeah, taking off the ground ring results in the injectors not being grounded out. But still no injector pulse, cause that's where they should normally be grounded by the ecu. Harness is only a couple years old.
 
Are you measuring between pin 1 and 2 of an UNPLUGGED injector? They should ALL be unplugged for a valid test.
 
So I'm seeing about 320kohms between white/green injector wire and ground. Goes down a bit if I connect the ECU. Still shows battery voltage across the two injector pins with ignition on. Ignition system works fine but it wouldn't run on brake clean so I took out a plug.

LGM5PSah.jpg
 
I suggest circuit verification. You should NOT measure 12v, key on, between the injectors pin 1 and 2.

A meter set on dwell or Hertz would be a legitimate test. Just measuring voltage and looking for "switching" on a cheap meter isn't the best way to look for a pulsed signal.

I've got a car right now in the shop with a bad injector circuit code. I will do some practice tests and see what I come up with on the Fluke meter, test lamp, noid light, and may put a scope on the circuit too. For science...
 
So I pulled and sanded/cleaned each plug and it still won't run on brake clean.. I used a timing light to check every plug wire and verified timing at 10 BTDC.

Edit So the injector ground wire goes to ecu pin 13 and nothing else if I'm correct. Between injector and ecu 13 there's no resistance, but clearly it's grounding somewhere on something. The harness jiggle tactic revealed nothing. Anything to try before I either hack into my harness willy nilly or run a bypass wire? Like I said the only damage to the harness was on the ignition side, so I don't really see why or how this could happen..
 
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Made a test harness for the injector ground pins (with actual soldering and heatshrink and everything, if you can believe it) which doesn't seem to have made a difference. Since it didn't run on brake clean I'm not gonna call it a failure yet. I'll replace the spark plugs and probably the plug wires too. (I've never actually bought plug wires for any of my Volvos..) What's weird is that the new temporary harness still has a connection to ground with injectors and ECU unplugged, though a lot more resistance than before. 2.3Mohms vs ~300Kohms

7aR29O9h.jpg


EDIT: Forgot to mention, with the new harness I'm no longer seeing 12v without cranking. Can't really tell if it's pulsing with the meter tho.
 
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Try putting a test lamp between battery positive and the injector ground and cranking. I did several tests yesterday and was having issues with noid lights and my meter. I was successful with the incandescent test lamp
I had a dim blink on all my injector circuits except for one cylinder that's throwing an injector circuit code (non volvo).
 
Blue go fast plug wires and new plugs did the trick. Fired right up. Also I did finally spend fifteen of my hard earned dollarydoos on a test light which showed injector pulse and should make things easier next time I break something.

54ScAX9h.jpg
 
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