94 850 - No spark after engine swap to 97 engine

[soulvoid21]

Most Volvo connectors have ridges that prevent you from plugging them into the wrong item. Also, harness is usually tightly positioned to prevent that as well, hard to mess up, unless someone tries very hard.

A few weeks ago I replaced my cylinder head for a burnt valve. After all was back together the car would not start at all. Key wouldn't even crank also would not push start. Had a bad wire in the manual swap harness. If you are cranking and have no spark, must have another issue. Maybe a bad ground somewhere.

Cam sensor plug is a known weak link, the connector falls apart. Do check to make sure 7 things are connected...
1. Cam sensor
2. Crank sensor
3. Throttle position sensor
4. Idle air control valve
5. Turbo BCS
6. MAF
7. Fuel injector relay.

You may also find a connector for the EGR valve if still installed.

Most of the connections did have propitiatory key slots making it easy, you're correct. But a few on the drivers side of the engine bay are the same key slot. A lot of the plastic trim and clips that keep the cables in route are missing as well, so there was a lot of slack in most of the cables.

I've confirmed that my fuel injectors are not pulsing, but I have good pressure at the rail with a full tank of good gas. So my guess is the crank sensor isn't in the right connection, since I was able to confirm I have the cam sensor correct.

Problem is I have no way to confirm if I have things in the correct connection. I managed to figure most of them out just by judging cable length, and checking the key slot, and what diagrams I found online. A full harness diagram would be my best bet at this point, then I can confirm every connection.

Also, grounds are good. All the braided grounds were replaced by the PO and I cleaned up the ground harness next to the battery, behind the headlight.

I see in Robert video that the EGR has the red 2pin connector on. So once I get this sorted out and it's running, I'll go through and remove that so it's not just hanging there. The video didn't show the actual connection if he were to remove the air box, so I could get much else from it.

[soulvoid21]

Pretty sure the red one is for EGR, which your 94 harness has but your 97 engine probably doesn't have.

Yep, was able to confirm with Roberts video above, thank you. One more to go

[wizechatmgr]

Small suggestion for future teardowns, use these https://www.bradyid.com/en-us/product/w ... VwQAvD_BwE to mark all your connections as you take them off. I use these in data centers when the fiber or copper hasn't been adequately marked. No one likes playing 768+ connection roulette...

A cheap brother labeller could work as well. I suggest at least 3/8" tape.

The best part is that there is nothing saying you need to remove the markers. It makes it that much easier the next time... And there will always be a next time.

[soulvoid21]

Small suggestion for future teardowns, use these https://www.bradyid.com/en-us/product/w ... VwQAvD_BwE to mark all your connections as you take them off. I use these in data centers when the fiber or copper hasn't been adequately marked. No one likes playing 768+ connection roulette...

A cheap brother labeller could work as well. I suggest at least 3/8" tape.

The best part is that there is nothing saying you need to remove the markers. It makes it that much easier the next time... And there will always be a next time.

Absolutely, lol. I knew I should have, but didn't have the money at the time to get anything. But in hindsight, I could have even just used masking tape. I've definitely learned a lot in the three years that it sat, some more do's and don't's, even that I've applied in my field of work that I could have used. I actually manage servers myself. Nothing in a large data center setting, but just some small racks for a local potato chip company.

[rspi]

Have you checked the fuel injector relay on top of the fan? Sometimes the connection goes bad and it stops the injectors from working.

[soulvoid21]

Have you checked the fuel injector relay on top of the fan? Sometimes the connection goes bad and it stops the injectors from working.

I didn't test the relay, no, but it seems Ok and the connections are clean. Doesn't look like a very old relay either, looks newer.

Haven't touched the car since my last post, this weather has been insane in my area as far as heat. Over 110 in the sun. Changing the starter in my S60, then getting back on the 850.