When I replaced my rear main seal, could I have miss aligned my flywheel?

Tiny
STUPEDMONKY
  • MEMBER
  • 1991 VOLVO 940
  • 20,000 MILES
I had reacently pulled the motor out to replace all the seals due to leaking, when I put the engine back in, it does not run right. Looked everything over and everything was right. Then it dawned on me. The Impulse sensor reades off the flywheel, if I did not set the flywheel right could that cause ignition problems?
Monday, May 14th, 2012 AT 4:42 PM

16 Replies

Tiny
RASMATAZ
  • MECHANIC
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Check the ignition timing-you could be correct on the impulse sensor
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Monday, May 14th, 2012 AT 4:48 PM
Tiny
KHLOW2008
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There is no way you can set the flywheel wrong. There is a possibility of the flywheel sensor gears being damaged or the sensor itself or its wiring is faulty.

What do you mean by not running right?
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Monday, May 14th, 2012 AT 4:49 PM
Tiny
STUPEDMONKY
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Its hard to start, idles very ruff, it pings like crazy under any boost, and will randomly stall
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Monday, May 14th, 2012 AT 5:41 PM
Tiny
STUPEDMONKY
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Also when I went to re install the flywheel it was able to be bolted in any way, there were no bolts off center like most other flywheels, and based on that theory, thats whats got me wondering
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Monday, May 14th, 2012 AT 5:44 PM
Tiny
KHLOW2008
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I believe yours is turbo which means the crankshaft position sensor is in the distributor therefore the ignition timing is not from the flywheel, which is for sensing engine cranking only. If you had removed the timing belt and/or distributor, I would suggest rechecking those.
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Monday, May 14th, 2012 AT 5:56 PM
Tiny
STUPEDMONKY
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It has to be from the crank. There is no sensor in the distributor, and my timing is correct.
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Monday, May 14th, 2012 AT 6:05 PM
Tiny
STUPEDMONKY
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SIGNAL (B)
The frequency (7) of the signal is used to determine the engine speed.

To provide a reference signal for the crankshaft position, one "window" on the flywheel circumference is longer than the others. The ignition ECU detects the crankshaft position by sensing the interruption in the signal (8) which occurs as the long "window" passes the sensor (90° BTDC). This referance is used to determine the top dead center (TDC) position.
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Monday, May 14th, 2012 AT 6:07 PM
Tiny
KHLOW2008
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Is your vehicle with or without turbo?

Which engine do you have?

ELECTRONIC IGNITION

The electronic ignition ECU controls primary windings of ignition coil using signals from fuel injection ECU based on crankshaft position, engine speed and vehicle speed. Turbo models use a Hall Effect sensor, located in distributor, to determine crankshaft position and engine speed. Non-turbo models use a flywheel sensing permanent magnet generator to determine crankshaft position and engine speed.
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Monday, May 14th, 2012 AT 7:45 PM
Tiny
STUPEDMONKY
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2.3 T, but if there were a sensor in the distributor, would there not be a connector going in to it? Because mine has the coil wire gong in and 4 plug wires goin out and that's it
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Monday, May 14th, 2012 AT 8:50 PM
Tiny
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Seems our database has conflicting information. Upon checking the wiring diagram, you are correct, the distributor is a stand alone and does not have any sensors within it.

The repair manual does not place any special note on the flywheel installation and from my personal experience, it is not the main point. If the flywheel had not been torqued correctly, you could have a problem. The other thing is that the impulse sensor wires tends to get brittle over time and since you meddeled with it during removal and installation of the engine, the wires could have been damaged.

Btw, have you checked the ignition timing?
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Tuesday, May 15th, 2012 AT 1:46 PM
Tiny
STUPEDMONKY
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I have checked the timing. I cant get a clear reading on just what the degree its at sins it jumps around so much.
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Tuesday, May 15th, 2012 AT 1:55 PM
Tiny
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That could indicate a loose timing belt.
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Tuesday, May 15th, 2012 AT 4:50 PM
Tiny
STUPEDMONKY
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So me coworker and I did a little research on alldata today, there is a cretin degree that the plate has to be set at for all timing to be correct,

Installation:
1. Install flywheel (manual transmission) or drive plate (automatic transmission).
2. Turn crankshaft to top dead centre position for cylinder No. 1.
3. Position flywheel/drive plate on crankshaft so that pin A is 15° below horizontal position, see illustration.
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+1
Wednesday, May 16th, 2012 AT 8:25 PM
Tiny
KHLOW2008
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Thanks for the info. Does not have this information.
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Wednesday, May 16th, 2012 AT 8:59 PM
Tiny
STUPEDMONKY
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Lol no problem. I guess I just answered my own question
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Thursday, May 17th, 2012 AT 2:05 PM
Tiny
KHLOW2008
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Sometimes we just need to go around in a circle to get something done though the answer is there.

Have a nice day.
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Thursday, May 17th, 2012 AT 3:33 PM

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