Difficulty: Impossible: Crank, No spark. Pulling my hair out. 1995 850 Turbo

[SakuraSky]

Okay so. I'm officially out of idea's and I don't know what to do anymore with my car. This is my first time very posting on a forum so plz go easy!

My car cranks but has NO spark. Sometimes the car will spark randomly and sometimes absolutely NOTHING. I bought the car with a bad manual transmission. It ran fine before transmission swapped. Replaced transmission and now nothing?! .

I got it started twice after replacing the transmission. First time it started it took like 3 min of cranking. Second time it fired right up with no hesitation. Ran and idled just for for 30min. Shut it off, then I immediately tried to start it. Nothing. Wouldn't start. I am testing spark to a known good ground. I have tried it with spark plug light and that showed nothing either other than a random fart here and there.

Here's the process so far.

Coil wire removed from distributor to know good ground: No spark. All readings were taken back probed from the connector.

Ignition coil terminal 15 (red wire) to ground (key position 2): 12 volts! (Great!)
Ignition coil terminal 1 (blue wire) to ground (Cranking): 12 volts? (What? I think this is suppose to be 0.7-1.3v?)
Coil power stage connector terminal 1 (BLK) (resistance to ground): 0 ohms (Good)
Coil power stage connector terminal 3 (BLU/RED) (key position 2): 12 volts (Amazing!)
Coil power stage connector terminal 4 (YEL/WHT) (Cranking): 0.4. SOMETIMES ~0.6-1 volts but only for a moment. Oscilloscope shows a pretty messy signal but it could be just I'm bad at using it. (Should be 0.7 to 1.3 volts?)

Okay so here's the thing. Cam sensor shows a square 12v signal on pin 2. FSM says 5v but people argue about what its suppose to be. Point is, it's being pulled to 0v when cranking so I'm not exactly sure if that's an issue. I fired the damn parts cannon at it; New OEM = Crank (Continental), Cam (Bosch) and Coil (Also Bosch). The readings taken above did not change in anyway after replacing the parts. My Autel shows crank sensor reading 180 RPM when trying to start. Confirmed crank output.

So that leaves me where I am now... You might be wondering, Maybe the ECU is bad? Maybe! But here's the thing... It's a 4.4 ECU that was tuned by VAST by the previous owner. If I get a new ECU its going to set me back a cool $800+ from VAST. I want to make sure I'm absolutely sure the ECU is toast.

Here's my questions.

1. Ignition coil terminal 1. Why is this showing 12v while cranking AND in key position 2? How exactly does the coil work? Why would coil power stage terminal 2 show 0.4-0.6 but the blue terminal 1 show 12V? What is going on exactly? My assumption is that something is shorted to positive and or the signal is too weak to the terminal 2. How can I test this further?
2. Does the grey fuel pump relay have ANYTHING to do with spark? I have heard some people say it does but then I've heard other say to unplug it to test spark. The harness is pretty deteriorated.
3. There was a jump back hooked up backwards to test the reverse light switch on the new transmission. It went into safety mode but... Could is have damaged the ECU? No blown fuses. ECU communicates just fine it seems. If the ECU is bad I still need to go through the steps to verify it so please don't think on this too hard like I did.
4. Can a bad ignition switch cause this in anyway? If so, how should I test it.
5. Can any confirm if on a 1995 850 Turbo that pin 2 supply to the cam sensor is suppose to be 5v? Alldata says 12v but chiltons and FSM seems to think 5v?

Am I testing anything wrong? Is there anything else I'm missing? This is my girlfriends car. I'm sorry for such a long post but... It's sat now for 7 months and I can't do anything other than pull my hair out. Please help!

[scot850]

A bad ignition switch could do that (the electrical part).

There is a rare issue that can happen with these cars that I have only heard a couple of times. When the trans and the engine are separated, there has been a couple of cases where the cars had issues starting. It was caused by an oxide layer between the trans and the engine preventing a ground between the 2 items. Weird I know, but the solution was to connect a ground cable between the engine and trans.

Jump starting the car the wrong way around can damage stuff, including the alternator.

If you have been doing a lot of moving stuff around, make sure the crank and cam sensor wires have not been routed too close to the distributor. I had an issue with this and the distributor signal killed the crank sensor signal. Re-routing the wire away from the distributor as far as I could and the issue went away.

No spark can also be the immobiliser gone rogue. Try the manual locking/unlocking of the door slowly a few times. People think I am (more) crazy saying this. Not a Volvo but a friend recently had an issue with a GMC Yukon Hybrid. I suggested that as an option as I was no where near home and he had his 2 large dogs in the car. He did what I suggested while thinking I was nuts (his words). Then he got in and the car started up immediately!

Neil.

[abscate]

There was a jump back hooked up backwards to test the reverse light switch on the new transmission. It went into safety mode but... Could is have damaged the ECU? No blown fuses. ECU communicates just fine it seems. If the ECU is bad I still need to go through the steps to verify it so please don't think on this too hard like I did.

That’s really bad and likely the source of your problems.

I will search for the thread on reversed polarity jumping and what typically blows when you do this. It’s ugly.

[SakuraSky]

A bad ignition switch could do that (the electrical part).

There is a rare issue that can happen with these cars that I have only heard a couple of times. When the trans and the engine are separated, there has been a couple of cases where the cars had issues starting. It was caused by an oxide layer between the trans and the engine preventing a ground between the 2 items. Weird I know, but the solution was to connect a ground cable between the engine and trans.

Jump starting the car the wrong way around can damage stuff, including the alternator.

If you have been doing a lot of moving stuff around, make sure the crank and cam sensor wires have not been routed too close to the distributor. I had an issue with this and the distributor signal killed the crank sensor signal. Re-routing the wire away from the distributor as far as I could and the issue went away.

No spark can also be the immobiliser gone rogue. Try the manual locking/unlocking of the door slowly a few times. People think I am (more) crazy saying this. Not a Volvo but a friend recently had an issue with a GMC Yukon Hybrid. I suggested that as an option as I was no where near home and he had his 2 large dogs in the car. He did what I suggested while thinking I was nuts (his words). Then he got in and the car started up immediately!

Neil.

Hi Neil. I have bypassed the distributor and am testing the spark directly to ground. Hopefully this will eliminate any weird grounding issues the car could be having. As for the immobilizer, I’m having a hard time confirming if my car was equipped with one. Are they all equipped with one?

[SakuraSky]

There was a jump back hooked up backwards to test the reverse light switch on the new transmission. It went into safety mode but... Could is have damaged the ECU? No blown fuses. ECU communicates just fine it seems. If the ECU is bad I still need to go through the steps to verify it so please don't think on this too hard like I did.

That’s really bad and likely the source of your problems.

I will search for the thread on reversed polarity jumping and what typically blows when you do this. It’s ugly.

This is where I’m leaning. The issue I’m having is that 7/21 pin no.2 has 12v sign wave. My understanding is this should be a 5v sign wave. Microcontroller for pin B11 puts out only 0.4v instead of the required 0.7-1.3v. As a result, terminal .4 on the coil does not get enough volts to fire. Coil fires when manually jumper is installed at Ubat. Could the 12v on 7/21 no.2 be pulling the voltage down for the coil trigger I wonder?