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Volvo 940 turbo not starting only backfires

T

that_guy

New member
Joined
May 6, 2024
Hello,

I’ve been experiencing some issues with my Volvo 940 1991 Turbo. Recently, the car has been shutting off unexpectedly while driving. On two occasions, it shut off and wouldn’t crank for a few hours. Another time, it turned off while idling as I was warming up the car. Since that day, it hasn’t been able to turn over at all.

We’ve tried using starter fluid among other things, but all it does is backfire. It sounds like it’s going to crank, but it never does. I’ve checked the codes on the diagnostic board, and it keeps displaying 1-1-1. I’ve read that this could be related to the crankshaft position sensor. Is it possible for it to fail suddenly? Additionally, I’ve replaced the fuel pump relay, but that didn’t resolve the issue. However, I can hear both fuel pumps activating.

Any insights or suggestions would be greatly appreciated!

Would love any pictures of any advice you give!
 
So are you saying that the engine is not spinning(turning over) at all? Or do you mean that it is turning over but not firing?
 
oh sorry, I did mean the engine is spinning over but just not firing for the car to fully start and turn on. I checked the spark plugs and the injectors. I got spark but sometimes the injectors wouldn't shoot that could just be user error though, we took off the fuel rail and checked it out
 
^^^ agreed, CPS is the top guess for intermittent, then permanent, died while running (and the fuel pumps are still OK). 2nd guess would be the ignition powerstage (aka ignition amplifier).
 
Backfire thru the intake means the ignition timing is off.

I once burned my eyebrows off from a backfire thru the carburetor on my boat engine while spinning the distributor to set the ignition timing.

Why is your ignition timing off!? Possible dying crank sensor could do it...
 
These are the typical symptoms of a failing/failed crank position sensor as said above. Don't over think it. So many of these cars are running around with their original CPS it is mind boggling. Get a Bougicord CPS. Nothing else. You can likely find a better deal than IPD. That is just a reference to what you are looking for.

Crank Speed Sensor - Bougicord 146404 - Volvo 271949

>106845 146404 271949 Bougicord Crank Sensor Speed Volvo
www.ipdusa.com www.ipdusa.com
 
My car was doing the same thing buddy, Swapped to New EVERYTHING and it didnt solve the issue and I KNEW it had to be in the Wiring...Sure enough, as I ripped out the wiring for my Maxxecu swap and New Wiring, the old Wiring had corrosion (Green Creep) in several places, wiring got HOT in several places and some wire had BURNT with the copper wiring protruding in some areas...GLAD to be done with LH 2.4 and that 30yr old wiring, Ive got a 1994 940 turbo...Check carefully or else you WILL spend alot as I did...
 
Also CHECK your Injector RESISTOR Wiring, mines was very corrosive and 1 of the wires on the Resistor itself was barely attached by maybe 5 copper strands...Hope this helps..
 
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