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Misfire, tach not working or jumps around

nyTalonTsi

Proven Member
518
0
Sep 5, 2008
Buffalo, New_York
Posting at work.

Well just when i got my car to run 100%, i ran into another problem.

Im not gonna jump the gun and say its crankwalk but it sure seems like it.

I was going to work sunday, when all of a sudden the car starting backfiring and then the tach just quit. CEL came on and then the tach started jumping around like crazy, it spun like a clock. I have never seen that before, it went past 9k. I wasn't even going 20mph.

I pulled up the code on dsmlink and its a random misfire, car runs okish till it reaches full temp then it runs on 2cylinders. I haven't driven it since sunday, i had to limp it home.


Im wanna pick up another ptu and i have a set of different coils. Having a busy schedule, i haven't been able to check for the problem.


Just fyi, back in September my car died and i had to replace a faulty crank sensor. Crank endplay was .007. A month later end play was at .0075. Not out of spec but close and seems like the thrust bearing is wearing quickly.

Its been since October since the last test.

Both tests were done using different dial indicators.
 

skatershawn

Proven Member
1,271
11
Feb 27, 2009
Austin, Texas
crankwalk??

That doesn't cause misfire does it??

Well im not really sure how the 2g work but id say its your Power Transistor.... You say you misfire, you run on two cylinders (most likely 1-3 or 2-4), and your tach is wacked out......
All things the the PT are partners with!!
or coil pack... but that doesnt run you tach, the reason why im guessing the PT

hope this helps you some,
good luck man!
 

nyTalonTsi

Proven Member
518
0
Sep 5, 2008
Buffalo, New_York
Yeah, with crankwalk you can have misfires. Because the crank would be hitting the crank sensor.

Its just im familar with the misfires, my last 2g would misfire and run like crap, turned out to be a walker. Just the whole tach going crazy is new.
 

rstchris

Proven Member
448
0
Oct 5, 2008
kingman, Arizona
Yeah, with crankwalk you can have misfires. Because the crank would be hitting the crank sensor.

Its just im familar with the misfires, my last 2g would misfire and run like crap, turned out to be a walker. Just the whole tach going crazy is new.

If you are deathly afraid of crankwalk you can unplug the pedal switch so when you start up you don't have to push in the clutch and mash the thrust bearing. If the tach is doing the dance then the is an issue with the crank signal or primary ignition. Start by checking the CKP sensor and work your way up to the PTR and all wire conections. I had an issue like this where the CKP got water in the conector when I washed the engine, cleaned it and a glob of dielectric grease in it was the fix.
 

nyTalonTsi

Proven Member
518
0
Sep 5, 2008
Buffalo, New_York
If you are deathly afraid of crankwalk you can unplug the pedal switch so when you start up you don't have to push in the clutch and mash the thrust bearing. If the tach is doing the dance then the is an issue with the crank signal or primary ignition. Start by checking the CKP sensor and work your way up to the PTR and all wire conections. I had an issue like this where the CKP got water in the conector when I washed the engine, cleaned it and a glob of dielectric grease in it was the fix.


Disabling the clutch safety switch was my first mod, before i even put the car on the road.

The crank sensor went bad in September, not from crank walk but just an old sensor. Replaced it with a new crank sensor from Mitsu.

And i doubt water reached the sensor, i havent washed my car in over a month, and its been rather dry weather wise just cold. I'll check that out when i get a chance though. Thanks.



+1 for power transistor,ive had that happen 3 different times and its been that every time.Your not walking bro dont jump to worst case scenarios:p

As soon as the car started misfiring, bucking and the rpms jumping around like the tac was on crack, i was hoping it would be the ignition module. I just have to get a known working one.

Why i jumped to crankwalk, was because this is my 2nd dsm where the car would backfire and sound like a wrx. My first being also a '95, after digging through it was crankwalk. Its just ive been here before with a 7bolt that misfired wasn't a minor issue. And no problem has been minor with this car since ive had it.



So would a faulty PTU cause the car to misfire after the motor was fully warm? Because it runs ok when its cold. But the tach hasn't worked since.
 

kp116

Proven Member
620
2
Mar 25, 2009
Janesville, Wisconsin
I would also throw a power transistor in there. When they go bad I thought they're affected by heat... Kinda sounds like your problem.
 
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