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99 GST Bad Crankshaft Position Sensor, or did she Crankwalk?

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Oakley792

Probationary Member
18
0
Dec 8, 2012
Wichita, Kansas
Hello!

I recently bought a 99 GST two months ago with 145,000 miles. Long story short the other night me and a buddy made a trip to get some food, on the way there I was having loppy idle. Sounded like a big cam in the car, very rough when we hit the 2500-3500rpm. We ended up limping it home to his house, left it there. We were thinking a boost leak and would inspect the next morning as it was dark and raining. The next morning we got in the car, started fined. We let her warm up and went for a drive. All was fine, we were going down a residental area, I pushed in the clutch, put in 2nd and made a left dirt down a dirt road. The whole car shutoff and we could not get it started, luckly his house was only a block away so we pushed it home. Check engine light was on, the code was Crankshaft Position Sensor.

So my question is, do I just replace the sensor. I already saw it is going to be a $$#% to get the timing cover off. Or did the car offically crank walk and should I just pull the engine. I can't afford a new 6 bolt engine but if it did crank walk and there is no fix I guess I have no choice.

Thanks!
 

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Buy a dial indicator and metal base and measure your crank play. Use a pry bar on the crankshaft bolt to push the crank to the passenger side, set the indicator, then push the clutch all the way in. You'll see the play there. I think the stock service limit is .009"? I forget exactly.

Replacing the crankshaft position sensor if you know what you're doing would probably take you 2-3 hours. There's a lot of stuff to get out of the way and you need to move the engine up and down to be able to get at all the pullies.

edit - that should have said "magnetic base", not "metal".
 
Check the crank for play as stated , but it also sounds like the timing belt skipped a tooth , happened to me on the freeway . When you open It up get the timing belt to line up with the timing marks before removing the belt and you'll see if it skipped or not.
 
Thanks guys, so should I just go ahead and pull the whole engine out of the car. Then check the Crankshaft play? and go from there. Because if it is bad I will have to go to a 6 bolt engine correct? No fix for the crankwalk in 7 bolt? Correct or wrong?
 
Thanks guys, so should I just go ahead and pull the whole engine out of the car. Then check the Crankshaft play? and go from there.

:confused: There's no reason to pull the engine yet. You just need to remove the front driver's side wheel & splash shield to get access to the crank pulley so you can measure.

Read what 666 posted again.

Buy a dial indicator and metal base and measure your crank play. Use a pry bar on the crankshaft bolt to push the crank to the passenger side, set the indicator, then push the clutch all the way in. You'll see the play there. I think the stock service limit is .009
 
Pull the whole engine? You haven't even checked anything. Check the play if you're concerned, and if it's ok replace the sensor. You're a bit premature for an engine pull.
 
Ok so if I measure the crank play and it is past the .009 service limit. Then what?, but if the crank play is OK do I just replace the sensor and look at my belt and timing marks to see if it jumped?
 
Correct me if im wrong, i read somewhere that you can check crankwalk either by method above or start up the car until operating temperature, then turn the wheel to right or left while depressing the clutch, watch if the idle RPM Drop. Variance should not be more than 400RPM drop

Again, im not sure if this work, i read it somewhere, i just couldnt find the source.
 
The chance of a '99 block crankwalking is very, very slim. I love how any time ANYTHING happens to a 2G, it's instantly crankwalk. :ohdamn:

Agreed. It's like developing a cough and saying you have cancer. OP check the small stuff first. There are A LOT of things that can cause similiar symptoms to crankwalk that aren't even close to being crankwalk. Check for play just in case, check the sensor. Then you'll have a better idea.
 
BEFORE you change your sensor you should use a multi meter on your CAS wires to make sure that the ECU is not receiving information from the CAS. I am assuming that the blue signal wire is not outputting the correct voltage. (crank the car while testing the wire with a multimeter.)
 
My 98gst was freshly rebuilt, on a block that never walked before. Less than 500 miles on a full build and my car died one day. Luckily I was backing it into it's parking spot for the winter. Long story short after checking everything with a multi meter I discovered it was my crank sensor. Checked end play it was .062. You could visibly see it move and you could see on the brand new cps where the trigger plate chewed it up. The whole time I blamed my TOB for sketchy engagement and a weird noise when in fact my crank walked all the way through the park. I know it is a long shot but it is an issue of concern. Look at your sensor when u pull it, assuming the checks point to it and see if it looks chewed up as well as check end play. Good Luck.
 
^ Sounds like whoever assembled the engine didn't align the thrust bearing properly upon installation. Regardless, yours happened to a fresh build....it's extremely unlikely that a running engine with 145K would suddenly develop rapid thrust wear unless the car was driven without oil- at which point a worn thrust bearing is the least of your worries.
 
This sounds like exactly what happened to me. I replaced the sensor and it worked. For like 4 days until it broke again. Found metal in the oil pan. But who knows, maybe your crank position sensor is toast. Like someone else said, when you take off the old one, inspect it and see if it has damage. If it does, your wallet is going to be very mad at you LOL
 
Check the timming and change the sensor, clean all and be sure that all be good, check the metal disc...
 
Check your timing belt alignment first.
You may not need a sensor at all if the engine is out of time, since the ECU looks for alignment between the CAS and CPS in order to trigger the injectors in proper sequence.

Sounds like a big cam? That's usually caused by the cams going out of phase with the crank.
When the car shut off, were you engine braking?

Unless someone has been into that engine and didn't know what they were doing, the chances of your split-thrust 97.5+ block developing crankwalk is extremely rare. How often do you hear about an Evo 8-9 having crankwalk? -They use the same thrust design.
 
^ Sounds like whoever assembled the engine didn't align the thrust bearing properly upon installation. Regardless, yours happened to a fresh build....it's extremely unlikely that a running engine with 145K would suddenly develop rapid thrust wear unless the car was driven without oil- at which point a worn thrust bearing is the least of your worries.

I won't go into that. But obviously something was a miss when it was built.
 
The chance of a '99 block crankwalking is very, very slim. I love how any time ANYTHING happens to a 2G, it's instantly crankwalk. :ohdamn:
I second this. The 97.5-99 engines have had the thrust bearing redesigned to combat the crank walk issue. Even the Evo 4g63 uses the same thrust bearing design. Perfect opportunity to catch up on your vehicle maintenance and replace the timing belt and balance shaft belt, don't forget the components. We need pics once you take the timing covers off.
 
Sorry this thread is technically a year old now, but is it necessary/appropriate to check the endplay whenever replacing the CPS?





I thought this was ontopic enough to belong in this thread instead of creating a new one and getting flamed for not searching.
 
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