Thread: Crank but no start after replacing balancer and crank sensor

Hello,

2007 Grand Prix GT stalled then died and wouldn't start. Found out it was the balancer digging into the crank sensor. Replaced the sensor and straightened out the pins on the balancer, and after that, she ran like a dream for a while. While driving, car started to stall every time it got to around 2500rpm, nearly undriveable; would still crank and start though. Got a new sensor, a new balancer, and now it will crank but not start. Replaced ignition control module too, nothing changed. Please help, what is wrong with my car???

Replacing the balancer and sensor didn't really solve the original problem: Why did the balancer/reluctor contact the sensor.

The only way I can see the balancer/reluctor coming into contact with the crank sensor is if there is too much crankshaft end play.
Drain your engine oil into something clean and look for metal particles/flakes in the oil (crank thrust bearing material).
Or, gently pry the balancer away, and/or toward the engine, there should only be a tiny bit of play, say .010 at the most, remove all acc. belts first.

Also note: when I had to replace the balancer on my 2000 GTP, I got a new one from RA, it was made in INDIA, (closeout/wholesale, only 30 day warranty) and after installation
I had belts squealing and chirping, took me a month to notice that the belt grooves in the new balancer were off an 1/8 of an inch.
So I got another new one from O'rielly's (made in Australia) it worked fine, no more belt sequel/chirps.

The sensor was cracked at one of the bolts and was floppy, probably why it was able to contact. I'm a bit confused because behind the sensor there were some spacer nuts, and after watching a video of someone replacing the sensor, those nuts weren't there. So I put the new sensor on without the nuts and that's when it ran fine for a while until it started stalling again. Sorry for the confusion.

The replacement balancer is made by Dorman, lifetime warranty. It seems to be the correct balancer, and when I crank the engine, it shows RPM, so I don't think it's the sensor or balancer. If trying to crank it or drive it while the balancer was ****ed up could **** something else up good enough to stop the car from starting, that could be an issue, but I'm stumped.

So the sensor is reading rpm, but even if the sensor is good, could the balancer itself prevent the car from starting if it was somehow faulty? Or maybe the timing chain jumped a tooth or something and now it will crank but not start? The original problem had to have been the sensor because it was visibly broken as **** and replacing it worked. The stalling that came after it started driving fine again was way different from the original stalling and it would still idle fine until I put on the new balancer. At this point I think I will try putting on the old balancer and see if it will start again.

Highly unlikely it jumped a tooth on the timing, these engines are known to run for many miles on a stock chain with no issues.

Dumb question, but when you installed the new balancer did you make sure you aligned the key in the crankshaft with the balancer before you tightened the bolt down?

Other than that have you checked the basics such as fuses? Was the wire harness that connects to the crank sensor damaged at all? If it got rubbed through somewhere it may be grounding out.

Originally Posted by FordMan77

Highly unlikely it jumped a tooth on the timing, these engines are known to run for many miles on a stock chain with no issues.

Dumb question, but when you installed the new balancer did you make sure you aligned the key in the crankshaft with the balancer before you tightened the bolt down?

Other than that have you checked the basics such as fuses? Was the wire harness that connects to the crank sensor damaged at all? If it got rubbed through somewhere it may be grounding out.

Yeah the key was aligned.

Fuses, yeah, the cps fuse is working. I'm not sure if it could be the wire harness since the sensor is reading rpm.

I have an update though. Got it running using starting fluid. Makes me think fuel issue so checked to see fuel pressure. There is fuel pressure getting to the fuel rail while cranking and while its running on starting fluid, so probably not fuel. While running on starting fluid it is running like **** though, need to give it gas to keep it alive.

Never took the balancer off either but I don't really know what that would solve. I'm beyond confused now, I have no idea what the problem could even possibly be.

Checked the plug on one of the injectors and it was fine, but another update: it started up on its own. Ran at 1500rpm then dipped to 500 for a second then back to 1500. Did that twice or three times before falling to normal idle <1000rpm. Gave it a little gas and it ran like **** and sounded scary so I cut it off. It was reading rpm like normal, I have fuel pressure getting to the fuel rail, I am getting spark, maybe blocked airflow or vacuum leak? Can it still even be the sensor at this point?

I've had this issue before. If you have a spare ICM laying around try swapping it out. I've also had a bad coil do this. Turns out that one of my coils cracked and apparently messed with the ICM underneath it enough to kill it. My test was to pull the working ICM/coil assembly from my other 3800 powered car and swap it in. Ran like a champ with that one and after figuring out how to test the coils I found one was bad and the ICM went with it.

A good ICM/coil pack setup from the JY later and all is well.