The Experiment

I gave this ‘01 engine one more shot. The guys on the Volvo forum seemed to believe that if I swapped the orientation of the wires on the crank sensor, it would send an opposite signal to the ECU, which is what it would need with this flywheel. I dragged everything back into the shop and tried it again.

I got it running with the flex plate and the CPS wires in standard orientation. Runs well.

With the flex plate still in place, I swapped the wires on the CPS... and it runs... the same?!

I swapped the flywheel in place of the flex plate, with the wires still reversed, and it runs the same! Sounds great! (But wait... there’s a ‘but’.)

I swapped the wires back to standard orientation just for science, and it runs, but it doesn’t like to be revved. It stumbles, then the idle hangs high.

I swapped the wires back to reverse orientation, and this time it ran with high idle, I bumped the pedal to see if it would adjust itself down, and it did somewhat, then it died. It did that from this point on, no matter what I tried with the flywheel on.

At this point, I grabbed my cheap scanner. At first it was just a trans position code and a (810) clutch position control malfunction. (??) Odd, since it’s automatic. I cleared the codes, ran it again until it died (8 seconds?), and this time I got 4 codes. 446 (EVAP), 1500 (my code book doesn’t even go that high), 453 (EVAP), and 73 (ambient air temperature sensor circuit high).

I swapped the flex plate back on, and it runs fine again. I’m now convinced that this system needs a flywheel with the gaps, rather than an earlier flywheel with the holes. Time wasted, but it answered some questions.

NOW this thread is done.

 

The flywheel that is supposed to go with this engine has teeth, not holes. The holes are foreign to it. The flywheel is from an era when the flex plate used a solid (rather than a gap) for location. Everything is backwards, and I was just trying to trick the ECU into reading opposite.

‘01 flex plate vs ‘93 flywheel....



...and the flywheel that’s supposed to go with this engine...


There is no clearance in the bell to add anything to the outside of the flywheel. There are some really tight clearances there.

My only option in that regard would be to weld the holes shut, turn it smooth, then mill 57 small and one large slots into it, then properly balancing it. I’m not in love with this engine enough to put the work into it. The level of computerization and wiring from ‘95 to ‘01 was a ten-fold increase. I’ll try to be patient and wait to use my DD in the spring.

 

Will a 93 cps bolt on? Just thinking out loud but maybe with the other sensor it might work.

 

No, after around ‘98/99, everything changed. It’s an entirely different engine management system.

These things were in their prime from around ‘94-96

 

Not that it's really worth the effort, but it seems like you could machine the flywheel down past the holes and weld the ring from the flex plate onto it (in the right orientation). And by "machine", I mean find some way to spin it true and use an angle grinder. Unless you have access to a big lathe.

 

This.

 

That goddamned Magnetti-Marelli Throttlebody.....

Whoever it was in Stockholm that decided to go to the bloody ITALIANS for reliable engine management electronics ought to have their head examined.

 

What about cutting a ring with the right amount and orientation and putting it up front on the crank? Then mount the sensor up front also?

 

Maybe? But it would have to go on the outside of the pulley. The pulley/belt is up against the timing belt cover. And getting 58 teeth and a gap to read properly on a ring that small would probably need a smaller sensor, like an ABS sensor. This one’s the diameter of a quarter.

I appreciate the input, but quite frankly, I don’t care enough. If I was determined to use this engine, I’d just grab a used (proper) flywheel before I did anything too drastic.

Like Kenny Rogers, I know when to fold’em....
and know when to run.

 

.....Or you can Build it the way you know will work for you & then have a chip burned for your ECM . That's what all the sensor's respond too...... the Chip. One Cannot " trick" an ECM , but one can tell it how to behave.
BTW, your saidmark is very profound . & Cool. ( Hear, Here )