Tools Needed :
Harmonic Balancer Puller with 3 each 1/4-28 x 3” Hex head bolts, grade 8
Floor Jack and Jack stands
Vice Grips, Heavy Duty kind
3/8” Ratchet
4 – 6” ratchet extension
10mm socket
13mm deep socket
15mm socket
1/2” Breaker Bar, Long Kind, 3' or so with a 15/16” socket

Symptoms of a bad or failed Crankshaft Position Sensor :
No spark at plugs
Engine will run and suddenly die without warning
Engine will not or not easily restart
Tachometer may drop to zero but the car will continue to run, may also result in the TCS light coming on

The two big symptoms are the loss of spark after the engines dies and the loss of a tachometer signal, both of which are controlled by the Crankshaft Position Sensor. The engine being difficult if not impossible to start are a result of no signal being sent to the Ignition Control Module from the Crankshaft Position Sensor.

In examining my bad Crankshaft Position Sensor I saw no marks on it that would have indicated the vanes of the harmonic balancer had come in contact with the device and damaged it. So I can only surmise that the device fails as a result of heat or poor manufacturing quality.

Information about the Harmonic Balancer Puller :

The harmonic balancer puller for the 3800 engine is nothing unusual with respect to the puller itself. The oddity with the GM harmonic balancer is the bolts used to pull the balancer off, not the center threaded forcing screw (the screw that goes in the center of the harmonic balancer puller yoke that pushes against the crank). The puller bolts are of a very uncommon thread pitch, 1/4-28. A very fine thread to say the least. M6 x 1.0mm may also work since the thread pitch is very close but you would definitely risk messing up the threads in the harmonic balancer. I experimented with a set of M6 bolts and was able to get two or three turns on the bolt before it got to the point of tightening up to where it would screw in no more. Whether that is enough to pull the balancer off I don't know.

The second oddity with respect to getting the balancer off is the thread length of the puller bolts (Again, not the center forcing screw). The commercially available kits all have very short thread lengths. I can only imagine to keep from damaging the Crankshaft Position Sensor. However, if you know the sensor to be bad, then this probably matters little. The next issue would be making sure that all the bolts go in at equal depths. This is one feature of the commercially available and after market pullers. However, again, you have some wiggle room here. I took some measurements and eyeballed a few things when I had my puller off. The thread depth of the threads on the balancer itself are about ¼ – 3/8”. Then there is another 3/8” behind that (the depth of the vanes on the harmonic balancer). So as long as you keep the thread length on the puller bolts to 1/2” to 3/4” you should have no trouble with this.

The last thing to be aware of is the overall length of the bolt. There is not a lot of room between the balancer and the frame of the car. For this reason I would not recommend a bolt length of 3”. I used 4” bolts (all I could find) and just barely got the balancer off only because I was able to screw the bolts into the balancer deeper, otherwise I would not have been able to pull it off.

Removal Process

Step 1:
Remove the Accessory and supercharger belts. You can do this now or you can pull them off before you pull the balancer off. I removed mine just before pulling the balancer. Obviously you will have to move some stuff out of the way to get tot he accessory belt tensioner, like the coolant overflow bottle.

Step 2:
Jack up the vehicle and put it on a set of jack stands. I would highly recommend using the jack stands as well since you may have to get a little violent with the harmonic balancer retainer bolt to break it loose. I would jack up the passenger side (obviously) and put the jack stands at the two cradle mounting points on that side for stability. Also, I always leave the floor jack just partially supporting the weight where possible for added security.

Step 3:
Remove the plastic splash shield to expose the harmonic balancer. There are three push pin retainers that hold it in place. They can be very difficult to get out if they have been exposed to a lot of dirt and grime. So I would either have a tool to remove them (they do make one, I have it, just didn't take a picture of it) or have some spares to replace them with if they get tore up.

Step 4:
Before you get too far into this I would try out the bolts that came with your puller or the ones you bought for it just to make sure everything is good. The GM balancer (3300 & 3800 engines I believe) uses a non-standard thread pitch. In my research I came up two sizes, 1/4-28 and M6 x 1.0mm. The M6 will screw in partially but perhaps not enough to pull the balancer off and if you force it, you will likely booger up the threads and I don't think you will find a tap long enough to clean up the threads. Once you get the balancer off, you could retap the threads and personally if one could do that I would drill and tap them for 1/4-20. If I had had the time I would have done just that. 1/4-20 grade 8 bolts are a whole lot easier to find than 1/4-28.

Step 5:
Remove the flywheel inspection cover. It is held on with two (2) 10mm bolts.

Step 6:
Clamp a pair of good heavy duty vice grips on the flywheel towards the front side of the engine.

Step 7:
Using a 1/2” breaker bar with a 15/16” socket give it all you got. My balancer has been off before to replace the Crankshaft Position Sensor so I don't know if that made it easier or if it was the leverage offered by the breaker bar, but getting my 'harmonic balancer retainer bolt' out was not that difficult. In all fairness, though, the last time my balancer was pulled the person that did the work used an impact wrench to get the bolt out and put it back in.

Basically prepare for at least a little strain, but it will break loose. I do highly recommend using a decently long breaker bar. As Chris likes to say, leverage rules. I did spray a little penetrating fluid around the bolt. Don't know if it helped or not, but I didn't see how it could hurt.

Step 8:
Next set up the harmonic balancer puller. Now if you have a good harmonic balancer puller kit your forcing screw (the center screw) will be hollow and there will be a couple different lengths of smooth cylindrical rods. Those rods go in the center of the forcing screw to keep the screw from going in too far and damaging the crankshaft threads.

Note: If you damage the crankshaft threads and you could run into real trouble so take all the necessary precautions to make sure that doesn't happen.

If you don't have a complete kit, then you may have to get creative. Ultimately I put in a 3/8” socket wrench extension with the square end facing out so the forcing screw could push off that without damaging the crank threads. Make sure your puller bolts (the three that go into the crows foot) do not have too long of thread length. I don't know how it could occur, but in my research there was concern of damaging the harmonic balancer vanes on the back side of the balancer if the bolts went in to far. I took some pictures and personally I just don't see how it could happen. The worse that I saw could happen is that the bolts go in too far and damage the plastic shield behind it, officially called a foreign object deflector.

Once you have the puller set up, start turning the forcing screw to pull the balancer off. It wont take much to get it off, but you will probably have to dismantle the puller so that you can get room to get the balancer out.

You can see in the picture below how I used the 3/8” ratchet extension so that the forcing screw of the balancer puller would not go in too deep and damage the threads of the crankshaft. The square recessed end facing out gives the forcing screw to settle in and push off on without slipping.

Here you can see how the puller looks and how the 3/8” ratchet extension helps. Notice also that I put some electrical tape around the threads of the forcing screw. Probably overkill, but I didn't want to take any chances.

If you have a good quality harmonic balancer puller kit, the forcing screw will be hollow so that smooth rods will fit up in it so that the threads of the forcing screw wont come in contact with the threads of the crank and damage them. In the picture below you can see that the rod would serve the same purpose as the 3/8” ratchet extension.

Here is another view.

Step 9:
Unplug the Crankshaft Position Sensor electrical connector. NOW would be a REALLY good time to inspect the wiring and connections here.

I know the pictures are backwards, cut me some slack. It was 30 degrees outside with a 20mph wind. My brain was kinda slow firing. You cant take off the Foreign Object Shield unless you unplug the Crankshaft Position Sensor.

Step 10:
Remove the plastic shield, called the foreign object shield that is around the crankshaft. It takes a little tug but it just pulls off, its not bolted on. You may need a small flat blade screwdriver to get it started.

Step 11:
Using a 13mm deep socket with a long extension with a long extension, remove the bolts for the Crankshaft Position Sensor. They are threaded studs of some sort and were not in there particularly tight.

Note: My bolts had thread sealant on them so I would suggest they are put back in with the same. So, with that in mind, I would take the time to clean the threads really good.

Step 12:
Now would be a very good time to check and inspect the camshaft position sensor and wiring. To replace it, it appears you would have to pull the balancer to replace that sensor anyway. I was tempted to replace mine but decided against it because I wanted to know exactly whether or not it was the Crankshaft Position Sensor that was the source of my issue.

Re-Install Process

Step 13:
Apply thread sealant to the Crankshaft Position Sensor mounting bolts and mount the new Crankshaft Position Sensor. I do not know the torque speck for those bolts. I used Permatex PX #59214.

Step 14:
Re-install the foreign object shield. Be sure you press it on all the way or it will rub against the Harmonic Balancer.

Note: The Foreign Object Shield also serves as a wiring guide/protector for the camshaft position sensor harness. Be sure the harness is secured to the shield with the hook that is on the shield.

Step 15:
Now put back on the harmonic balancer. The balancer is keyed and will only go on one way. Nonetheless, I would ensure you have it on the key way by slowly slipping on the balancer and twisting it slightly while pushing it on to the crankshaft. When it is on the key way you will no longer be able to twist it.

Here is the Key on the crankshaft itself.

Here is a view of the key way on the Harmonic Balancer.

Step 16:
Now start the Harmonic Balancer Retainer Bolt. What I did was tighten the bolt all the way down until the crank started to turn. Once that occurred I took the bolt back out. The reason for this is so I could apply some blue thread locker to the threads of the bolt. Remember, you will have to move the vice grips to do the final tightening of the bolt, so it does no good for the thread locker to be drying while your cranking (ha ha, get it) down on the bolt then move the vice grips and try to tighten down the bolt more. I used Permatex Thread Locker Blue Gel, PX #24010.

Once you have the vice grips re-positioned to the back side of the flywheel, put the thread locker on the bolt and start the final tightening of the bolt. If you have a breaker bar, give it all you got. I believe the torque spec for that bolt is around 200 ft/lbs or a little less. Even if I had an impact wrench I think I would still get on it with a good breaker bar just to be sure.

Notice how the vice grips are now on the backside of the flywheel vs. earlier when they were on the front side.

Here is the thread locker I used. Very easy to work with and only takes a dab. Whatever you do DO NOT use the red thread locker.

Step 17:
Once you have the Harmonic Balancer Retainer bolt tightened as much as you can, remove the vice grips from the flywheel and re-install the flywheel inspection cover.

Step 18:
At this point I would take the 1/2” breaker bar with the 15/16” socket and rotate the crank. Make sure nothing is hitting. My foreign object shield was rubbing a little when I checked and I had to push down the shield more to get the shield to clear properly.

Step 19:
Re-install your accessory and supercharger belts.

Step 20:
Re-install the lower splash shield.

Step 21:
Put the tire back on and remove the jack stands and lower the car.

Step 22:
At this point I personally clean up making sure every tool and supply is accounted for. No sense in doing all this and forget something in the engine bay only for it to get caught on something and do untold damage.

Step 23:
At this point, start the car for only a second or two and re-check the accessory and supercharger belts to make sure they are lined up and on properly. After that, let the car idle for a good long time (20 – 30 minutes) to make sure the car will not die during idle. If all is good there, then take it out on a road test. If all goes well you will have confirmation of a good fix and your car will be running properly again.

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