Good evening all
1991 Chevrolet camero rs 305 tbi 700r4

I am relatively unexperienced when it comes to engine work. Last week I replaced my harmonic balancer but I did not use a guard at the end of the puller which stripped my crankshaft threads which I then had to re thread using a tap. The balancer and pulley went on smoothly, and match up with all other pulleys and have the right torque on the crank bolt. Yesterday I was going up hill, and the engine completely lost power and jumps from 0 rpms to about 700 within around every second. Removed harmonic balancer and re torqued it down to no avail. It also has an aging fuel pump which left me out of gas the other day, but this seems unrelated. Ideas would be very much appreciated.

 

If all you did was replaced the balancer then that should not be the cause of your loss of power issue.

You already have the balancer on however you never install a balancer by trying to pull it onto the crank with the crank bolt as you have already discovered. There is a special tool but you can easily make one with some threaded rod, washers and a nut. Thread the rod into the crank and press the balancer onto the shaft with the nut/washers. The threaded rod should not turn in the crank.

You'll need to do more diagnostics to determine the loss of power. TBI doesn't have a lot of fuel pressure anywhere from 9-13 psi is normal. Installing a mechanical test pressure gauge and try to recreate the fault to see what the fuel pressure does.

 

The loss of power is not intermittent. Since yesterday, the engine constantly switches between barely revving above idle and completely dying. I was wondering if I could have tapped the crankshaft at an angle causing the balancer to not sit flush.

 

No. If the balancer is installed to where the serpentine belt is perfectly lined up with all of the pulleys, there is no way it could be cocked off at a wrong angle.

You've got something else beyond the balancer causing your problem.

Two questions come to mind here, Are you 100% sure the ignition timing is correct, and, what caused you to replace the balancer ?

 

​​​​​​Dude....

 

The timing could be off, I am not sure exactly what could throw it off suddenly. I replaced the harmonic balancer because I was already replacing the crank seal and the rubber rings around the balancer were cracked. The fuel pump has only given me a problem the one time, where it misread my fuel Guage by about a quarter of a tank.

 

The timing won't be off unless you touched it (or your timing chain jumped, which isn't likely here). Yes the rubber can fail and allow the outer ring to slip (it's two parts held together by that rubber), so since you had to take it off for the seal just as well to have replaced it. And lastly, your fuel pump and your fuel gauge's sending unit live in the same general neighborhood, but other than sharing the same ground, are separate electrical circuits and your fuel pump can in no way "trick" your gauge out of a 1/4 tank of fuel.

Start with the basics, fuel pressure check, ignition system check (coil, cap, rotor, wires, plugs) and don't turn the distributor unless your 101% sure the "base timing" is off. It shouldn't be, but learning how to check (without adjusting, simply checking) such things will serve you well in fixing this .

PS, here's what happens when the two parts of the damper decide they ain't playin nice with each other anymore, now aren't ya happy you replaced yours ?.......

(Note, this is a six cylinder damper, but they all fail the same)

 

During your repair procedure, did you ever have the spark plug wires removed?

 

Thank you very much, this eases my mind a little that my sole daily driving car did no tear itself apart from the inside out. I will get the fuel pressure tester and maybe a compression tester as well and update after.

 

I did not, I removed the water pump pulley, radiator fan and housing and that is all.

 

Lol. I thought the same thing when I read that.

Hmmm, what could possibly cause loss of power and very rough idle......

 

Replace fuel filter?

 

Update: I tested the fuel pressure and it was normal. I had someone start the car and stopod under the hood when I noticed a very prominent hiss coming from the tbi. I cleaned the injectors which helped, it no longer stalled but had a semi consistent idle with a miss. Naturally I replaced the injectors, fuel pressure regulator, gaskets, pcv valve and all vacuum lines running to the tbi. The engine will now not start at all, not even with starter fluid. I re checked everything multiple times, going through 2 different manuals and several videos for each part, even replacing the IAC and MAP as well with no success. I can see the injectors spraying fuel and the pattern looks correct. I'm at somewhat of a loss, I'm not sure what could have caused this.

 

Check for spark.

 

Maybe broke or knocked loose a wire around the distributor or coil?

 

if you've got any ideas better than anyone else's I'd love to hear them.

 

Any voltage to the injectors? With the key on, the injectors get a constant 12v. The ECM modulates the ground to fire the injectors.