... how'z it bayou?

You can test the RPM or crank position sensor (CPS) by pulling the connector and testing two of the three pins for continuity. I forget what two pins. Wiggle at the CPS sensor. Easy access in 700 / 900 (versus 240 with EZK116!).

If the CPS sheathing has failed and you see a shiny foil like stuff, the CPS may be failing. The threshold for the EZK116 ICU (ignition control unit, or box, or computer) is rather high to lodge a fault code as initial faults in the CPS as it begins to fail are not recorded and relayed as a fault code. You will know the failing CPS symptoms before the CHECK ENGINE light illuminates. Much like a failing or dirty throttle position switch.

Yet on 700 / 900 series you have the behind the ashtray relay and fuse platform. That white greasy corrosion stuff forms and heat forms, and fuse and relay sockets deform and melt like the climate control. Yet before this you'll get circuit connection interrupts that behave as the symptoms you are encountering.

By now, you have probably replaced the CPS sensor at least once if not more. Also, for all 700 / 900 owners, the (usually) under the dash and behind the ashtray relay board could use an inspect and service. Inspect and pull relay and fuses. Any melting plastic around the relay and fuse mounts? Got some of Caig's DeoxIT-D spray, salve, grease, concentrate with 90% Isopropanol or isopropyl (as 90% Walmart rubbing alcohol) in a spray bottle. Use this on all low volt connector ends like at the AMM, the computer boxes in the US market passenger foot well (boning tool to get under the plastic interior pieces so you can pull up carpet), switches, and stuff. Deoxit D displaces the corrosion and prevents a return of the corrosion for maybe a decade or so.

Else, please refer to all other's reply to your post.

Yet we want to know the outcome of your fault diagnosis (using the OBD-1) and resolution. That your son's 1992 900-series Wagon is okay. You worked through the vacuum and turbo piping for leaks.

Bougicord is or was OEM for the CPS. There is an thread where Arty B and folks discuss two CPS brands. I've had problems with the CPS sensor end fit into the plate at the top of the bell housing. Be gentle! These CPS mount plates may be frail, yet by 1992, they are a little more durable. I had to file the hole the retaining bolts passes through on a Bougicord CPS replacement so it would fit.

FCP lists three. OEM Volvo is the same as Bougicord, I guess?

https://www.fcpeuro.com/Volvo-parts/940/Crankshaft-Position-Sensor/?year=1992&m=208&e=914&t=5&b=6&d=42&v=11

Not heard of Bremi brand CPS. Brami Made in Germany versus France (Bougicord). Like an AMM, keep a spare on the shelf and in the Volvo.

Questions?

Hope that helps.

MacDuffy's Buttermilk Tavern


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