It's been a while since i used this forum, but now i need some serious help.

The car started producing some hesitation one day, it rapidly became worse, included stopping and now it does not even start. Car is a 850 -96 GLT 20V.

Situation:
-Starter runs fine, engine cranks OK
-No spark, checked with the plug out and also with strobe lamp.
-No gas on the plugs, they seem dry
-Fuel pump produces 3bar (have no idea how many psi, but is OK) when ignition key in II
-No error codes. At least there were none earlier in the troubleshooting stage when i borrowed a diag tool

What i have checked or changed:
-Ignition coil OK
-Fuel pump relay changed
-Pump runs fine if fed with 12V (3 bar)
-Battery changed
-Plugs+cap+rotor changed
-Cam shaft sensor replaced with one from my other car
-Relays with "J" marking changed
-Checked the gray 40A relay above the radiator
-Checked ECU connector visually
-Checked various other connectors in the engine compartment

Questions:
-Crankshaft sensor, is it possible to diagnose this? I measured resistance at still engine to 270ohm, when the starter is running it went up to 295ohm. Is this the correct procedure or behavior?
-Immobilizer, does it only affect the starter or does it cut power to the ECU?
-Is it possible to to check that you have power to the ECU? Lots of pins...
-Is it possible to check the ECU stand-alone, i.e. out of the car?
-Is it possible to check the ignition module and/or feed to the ignition coil?


Any ideas?

Have tried without MAF, still no joy.

Also tried changing the crankshaft sensor, since old ones casing was broken.

I think the main problem is that i have no contact with the ECU, using a real Volvo diagnostic tool. I think either the ECU is shot or it does not get power. Does anyone have a pinout of the ECU connector or a schematic of the cabling for the ECU and surrounding equipment. Also i get error codes from the immobilizer, saying that it does not get a init signal from the ECU.

Urgent help is appreciated! I need to get this brick running again.

There was a recent service bulletin on the ignition key ring (the part that lights up when you stick your key in the ignition, I believe) that is part of the immobilizer system. Replacement of this has sovled problems like you describe (from reading from posters on www.matthewsvolvosite.com). Ask the dealer about it...not suppose to be very expensive at all. Good luck!
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.

Had similar problem with 92 245 a few years ago. The independent mechanic was sure it was the igniton module. The car fried three ignition modules that he installed, before also replacing the MAF. It has been fine since.

Is it possible to substitute the ignition module from your other car?


Hugh

Sounds like there's no 12 volts in your fuel & ignition system

with ignition key in position II: check if there's 12V present on the fuel injectors,on the MAF and on the Idle Air Control valve and let me know

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Ken

Just to be sure it's not the MAF, unplug it and see if your car cranks.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.