Harmonic balancer

[iceman2]

I just replaced the harmonic balancer and I've lost the tachometer and an error code says crankshaft position sensor needs attention.

[paul19691969]

i have 97 3.4 i just replaced the crank sensor. you have to take the balancer back off to get the bolts all the way out. but i was told that if a crank sensor goes bad it wont start? mine still starts but it wont stay running. i had it tested and they said it was bad.

[Scrapper]

yah you need to reguage cps when replacing harmonic
they got a tool for that or you can use brass guages always take neg battery cable off...
good luck....

[iceman2]

Originally Posted by Scrapper

yah you need to reguage cps when replacing harmonic
they got a tool for that or you can use brass guages always take neg battery cable off...
good luck....

Scrapper, how, exactly do you regauge cps?

[Scrapper]

the gruves in cps with the right tool you can guage it with balancer off then put harmonic balancer.but if you use brass feeler guage you have to crawl under car but if i was you i get the right tool so you know it's gapped right or it'll hit the back of balancer...hope i exsplained it right so you can understand...like i say get you a hanes manual...
good luck....

[iceman2]

Thanks, by the way, it runs great, only problem is my average mpg is 17, when it should be over 20, based on my driving conditions. My check engine light is on, and the error code reported, "Check crankshaft position sensor."

[LMP]

Which car is this related to?..I suggest you update your profile to include the Transport year and engine type.

[iceman2]

Originally Posted by LMP

Which car is this related to?..I suggest you update your profile to include the Transport year and engine type.

It's a 1997 Trans Sport, 3.4L. I replaced the head gaskets, got it all back together, started beautifully, serpentine belt burned off, turned out balancer was pushed out about an inch, replaced it, now get the check engine light, went to AZ, code reader said to check crankshaft position sensor. Engine runs well, gas mileage is poor.

The following is from the manual, all Greek to me:

3.4L Engine

3X reference PCM input

From the ignition control module, the PCM uses this signal to calculate engine Rpm and crankshaft position at engine speeds above 1200 RPM .The PCM also uses the pulses on this circuit to initiate injector pulses. If the PCM receives no pulses on this circuit, it will use the 24X reference signal circuit for fuel and ignition control. The engine will continue to start and run using the 24X reference signal only.

24X reference PCM input

From the ignition control module, the DPCM uses this signal to calculate engine RPM and crankshaft position at engine speeds below 1200 RPM. The PCM also uses the pulses on this circuit to initiate injector pulses. If the PCM receives no pulses on this circuit, the PCM will use the 3X reference signal circuit at all times for fuel and ignition control. The engine will continue to start and run using the 3X reference signal only.

7X Crankshaft Position (CKP) Sensor

The 7X crankshaft position sensor provides a signal used by the ignition control module to calculate ignition sequence. The ignition control module also uses the crankshaft position sensor signals to initiate 3X reference pulses that the PCM uses as reference to calculate RPM and crankshaft position.

Ignition timing is not adjustable.-The firing order is 1-2-3-4-5-6.

TESTING

3.4L Engine

*

Incorrect harness routing near secondary ignition components.
*

Ignition coil arcing to the wiring harness or to the Ignition Control Module. Check the ignition coils for cracks, carbon tracking, or other signs of damage.
*

Secondary ignition wire(s) arcing to the wiring harness.
*

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation.
*

Check for a poor connection or damaged harness: Inspect the PCM harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connections and damaged harnesses.
*

If harness appears to be OK, disconnect the PCM, turn the ignition ON and observe a voltmeter connected to the 24X reference circuit at the PCM harness connector while moving connectors and wiring harnesses related to the 24X Crankshaft Position Sensor and Camshaft Position Sensor. The 24X and Camshaft Position sensors share the same sensor feed from the PCM. A change in voltage will indicate the location of the fault.
*

If the 24X sensor feed is open, the tachometer on the dash (if vehicle is equipped) will not operate.

1.

If necessary to perform a test on the crankshaft sensor, use the diagnostic repair chart and the wire and connector diagram given here for the 3.4L Engine.

[iceman2]

I believe I isolated the problem, it's the crankshaft position sensor behind the balancer, AZ actually has one in stock, I really don't want to have to pull the balancer off again, anyone out there have any advice? I must've damaged the sensor or wires, when I replaced the balancer.

[paul19691969]

when i replaced mine i had to pull it all the way off to get the bolts out.mine came came right off with the puller, that you can rent from autozone.

[iceman2]

Originally Posted by paul19691969

when i replaced mine i had to pull it all the way off to get the bolts out.mine came came right off with the puller, that you can rent from autozone.

Did this do the trick? How did you know your sensor was bad? Like i"ve said, my gas mileage ain't right, other than that, she runs fine.

[paul19691969]

mine is still not running right. autozone tested it and said it was bad. i changed it and it wasnt a bad job to do.i still cant figure mine out.good luck paul

[iceman2]

Solved the problem! I finally realized when I replaced the head and intake gaskets, got it all back together, started the engine, the serpentine belt sheered off and took out the crankshaft position sensor. Thanks for all the posts on this one.