New CAS random misfire problem

[VergeTSi]

So after searching for weeks on what the mysterious freeway misfire is, I decided that its the CAS. I have a 2g with 6 bolts swap. So I got the crank angle sensor mounted. Before I thought it was CAS related I changed the plugs, wires, tested coils, changed fuel filter, tested fuel pump, even changed the CAS toa brand new black top one, no boost leaks at all. Still having the random misfire on freeway between 50-70 mph. I read upon a bunch of threads that 2g with 6 bolt swaps are having this problem and its a 50/50 thing that even with the black top some users will have same RM's. So I read that to clear the code and prevent it from popping up is to get a ecu prom and dsmlink? I just want to get some facts on this topic and to see what have others have done to get this damn RM out of the way so I can drive my car over 60 mph. Is there any other inexpensive way to fix this? Thanks

 

[MilitaryTalon]

I had kinda the same problem on my car about a month ago and mine was being caused by a loose wire close to the ECU. It's worth a look around, I found mine by shaking looms of wire until I saw an arc. Not recomended but that the liquored up test. Also many people told me to check the power transistor unit. Dont know if 6 bolts are the same but if so I have 2 good ones.

 

[VergeTSi]

I havent checked those out yet. I will def check that out. Where is the power transistor located? I've never messed with the ecu, where is that located so I can check the wires? Thanks.

 

[MilitaryTalon]

ECU: under console behind radio
PTU: long thin connector right in the middle of your intake manifold. I think there is a test in a Chiltons manual. But like I said if you can find out if it is the same as a 7 bolt then I have a couple if you wanna come up and try one out.

 

[VergeTSi]

So its a possibility that, that same exact misfire could be due the ECU wires or the PTU? RRE is guessing that its still the CAS. But its a brand new one and its still misfiring. It did all start when my first black top CAS went out on me. Another question is, how do I test to see if the CAS is working correctly?> Thanks

 

[vanilla gorilla]

Have you done a clutch job lately? I had the same problem after installing a lightweight flywheel. Come to find out the lightweight flywheel, started making my old, weak CRANK POSITION sensor go bad. New crank position sensor, no more problems.

 

[Ceddy]

Is this a stock car? What are you using for tuning? you should give more info.

If its a stock setup you can try putting 97-99 ecu in, they have a normal CAS signal like the 1Gs. The 95-96 have a inverted CAS setup.

To reduce confusion CAS = Cam Angle Sensor, mounts on end of Cams.
The Crank Trigger Sensor mounts down by the Crank Sprocket.

 

[PieEyedPiper]

http://www.dsmtuners.com/forums/pro...p0300-isc-coil-results.html?highlight=misfire
http://www.dsmtuners.com/forums/pro...tiple-misfire-detected.html?highlight=misfire
http://www.dsmtuners.com/forums/new...tiple-cylinder-misfire.html?highlight=misfire
http://www.dsmtuners.com/forums/newbie-forum/260269-multiple-cylinder-misfire-p0300.html


Here's just a couple more threads for you to cruise through, ALL the information available on this topic has been discussed at some point on DSMtuners. Happy hunting! Oh and do let us know what solves this for you. That particular list is getting kinda long.

 

[Nofear20]

I had the misfire problem as well. It started a while after I had my 6 bolt swap done. It was easily fixed by installing DSMlink and just setting it to ignore all misfire codes. Theres also some trick you can do with a potentiometer without even needing DSMlink

 

[VergeTSi]

No I have the crank angle sensor so I can run the 6 bolt. It's moderately modded. Got ic piping. Fmic. Big 16 g. 1g bov. 1g tb. Evo 3 exhaust manifold ported. 3 inch exhaust. Ngk wires and plugs. New crank angle sensor. I have a 97 ecu.

 

[VergeTSi]

Thanks for the info. I will do more diagnoses soon and hopefully I can fix the problem soon. I'm really getting tired of driving my car 60 mph without boosting. Everyones passing. It sucks.

 

[snowborder714]

I also cured my random misfire (1g 7 bolt) by installing DSMlink. When I bought the car, it had the pot mod done, but still had issues some of the time. It did make it much better than without it, but not nearly as nice as DSMlink.

 

[jeffo]

DSMChips also fix Random Misfire MIL's.

 

[vanilla gorilla]

http://www.dsmtuners.com/forums/pro...p0300-isc-coil-results.html?highlight=misfire
http://www.dsmtuners.com/forums/pro...tiple-misfire-detected.html?highlight=misfire
http://www.dsmtuners.com/forums/new...tiple-cylinder-misfire.html?highlight=misfire
http://www.dsmtuners.com/forums/newbie-forum/260269-multiple-cylinder-misfire-p0300.html


Here's just a couple more threads for you to cruise through, ALL the information available on this topic has been discussed at some point on DSMtuners. Happy hunting! Oh and do let us know what solves this for you. That particular list is getting kinda long.

Just curious, do you still suffer from speed dependent P0300? Because I remember back when I was having that problem, you were too, so I was just wondering if you got to the root of your problem?

 

[VergeTSi]

I'm going to check out the ecu and ptu today and install my friends eprom and dsmlink to see if it is the infamous 2g 6 bolt swap cas rm problem. I DO remember when I had the a fuse blown and was driving for 2 days untill i get another fuse, the cel was off and I can drive 80 moh without ever hesistating. So I'm really hoping its the cas problem. After i put in the fuse, drove 70 mph fine and then boom, the cel pops up and misfire again.

 

[VergeTSi]

DSMChips also fix Random Misfire MIL's.

In order to get dsmchip do i have to tell you exactly all the mods I have and have to have no boost leaks? I have all intake and exhaust bolt ons, but have stock fuel, how much whp can i put down with a big 16 g with stock fuel? how much psi? thanks

 

[MilitaryTalon]

In order to get dsmchip do i have to tell you exactly all the mods I have and have to have no boost leaks? I have all intake and exhaust bolt ons, but have stock fuel, how much whp can i put down with a big 16 g with stock fuel? how much psi? thanks

I just installed an upgraded DSMChip today. I do have the old fuel setup if interested PM me
then I'll give you details. I you want a new one you need to go to the website and the order form will walk you through what you need to do.

As far as how much power with stock fuel depends on what you have to control it.

 

[PieEyedPiper]

Just curious, do you still suffer from speed dependent P0300? Because I remember back when I was having that problem, you were too, so I was just wondering if you got to the root of your problem?

Thanks for pointing that out to me, I never did document my solution. I'll find time to do it but essentially the stock, cut flywheel was the problem. I replaced it with a 11lbs Competition Clutch flywheel (which is awesome, btw) and I've not seen the code since December '08.

I noticed that when I pulled off the stock flywheel (again, it had been cut) the shop not only resurfaced it but they attempted some sort of balancing as there were holes present all over the outer edge. There were no such holes in a stock un-cut flywheel I had access to. I guess the shop messed up the balancing?