97 850 turbo, fuel injector pulses, no spark, no start

davefishsound · Post by **davefishsound** » 09 May 2020, 15:48

Greetings from the Big Island of Hawaii. I'm a bit frustrated with my current project, 97 850 with bits and pieces from a 98 v70 and 99 v70 cc, all of which were abandoned in various stages of disrepair following the 2018 eruption of Kilauea which devastated vast swaths of the Island.But to the point:
The 97 850 selected to be the alpha Volvo, has fresh top end rebuild, rings, valves, on up to plugs and injectors. Good compression,j fuel delivery to injectors which pulse appropriately but after a brief period of sporadic spark initially, now no spark.
Tried 3 different coil/igniter sets, all Bosch. Swapped out both the cam and crank sensors using the best set of meter readings, which are by the book correct, but still no fire.
Other than engine build, also swapped 99 v70xc interior to the 850 to get a nice black and blue scheme.
Wondering if there is something in this interior that might be causing this spark dilemma?
Living on an Island routinely covered in fiery creation but can't seem to get a little fire going in the combustion chamber.
All ideas and options are open for consideration at this point. Mahalo in advance for taking the time to read this. Fish

Post by **misha** » 09 May 2020, 16:05

In what shape are cap & rotor?
Are fuses ok?
Does the IAC buzzing when key is in pos.II?

davefishsound · Post by **davefishsound** » 11 May 2020, 00:42

I have been testing for spark directly from the coil via plug wire placed near one of the strut mount bolts, with 3 different coil wires. But cap and rotor were harvested from a 4th vehicle that ended up in salvage yard, same year as the 850 but a sedan. Both are Bosch, nice and clean, good continuity.. Idle air purring soon as key in 2nd position, went through the entire fuse panel, all 3 layers of them and that rainbow of essential relays most forget about as well.

The area I am currently in is one of the wettest on the planet, mix that with sea air nearby and high humidity, climate is brutal to the electrics, some days you can see the rust develop hour by hour.
Add in high UV and old plastics, and the connectors are all potential suspects. I'm getting ready to trace both the cam and crank sensors back to the computer.
I was getting good readings from cam yesterday for a couple of hours, briefly had sporadic spark from coil nut it stopped arcing, I took new readings and went from 0_5_13v respectively to 0_12_12v so I don't see much alternative.

Post by **misha** » 11 May 2020, 05:03

Are spark plug wires routed correctly...correct firing order?

Post by **rspi** » 11 May 2020, 07:13

My guess would be that you installed the exhaust cam sensor ring 180 degrees off. Happens a lot.

Post by **rspi** » 11 May 2020, 07:40

davefishsound · Post by **davefishsound** » 11 May 2020, 14:41

I hardwired and soldered the cam sensor directly to the computer. I have a clear understanding of the term "offset" and can visually confirm such when aligning sensor disc, but I have extra part I can sacrifice in the name of mechanical science. And I poured both regular multivis and Lucas additive down each jug prior to even attempting to get one rotation from crankshaft. Added more after rotating 10x by hand with a socket and ratchet. For good measure, I added a few more caps full prior to engaging the electric motor starter.

Again, the question is how can I be getting injector control pulse 5v but not coil control pulse 5v.

Perhaps I am mistaken, but I thought that it was the same sensor that pulses both actions. It keeps leading back to cam sensor, which I have tried 3 of, and then I checked for continuity from yellow/red and blue yellow, the 12v and 5v control wires to cam sensor, through the ECU connectors and everything tested ok.

Is there a bench test for cam sensor? Can Hall effect sensor be rebuilt, cleaned, renewed? Will a cam sensor from the 70 series, a different type altogether but far more common it seems, work as a replacement if I modified the sensor housing?

Thanks for the feedback on this island mystery. Aloha and mahalo.

Post by **misha** » 11 May 2020, 15:03

Crankshaft (TDC) sensor ok and connected?

Nevermind....i just read the 1st post where you said that it's within spec.

Post by **erikv11** » 11 May 2020, 17:05

davefishsound wrote: 11 May 2020, 14:41 ... Is there a bench test for cam sensor? Can Hall effect sensor be rebuilt, cleaned, renewed? Will a cam sensor from the 70 series, a different type altogether but far more common it seems, work as a replacement if I modified the sensor housing?...

98 70 series uses the exact same cam sensor as an 850. But like you refer to your 00 V70 cam sensor; probably not.

You can test a cam sensor in the car by back probing it, search this site for instructions. Also you could try sending PM to MVS member RickHaleParker, answering the kind of questions you pose here is in his wheelhouse.