6 bolt swap now this...

[streetsoldier60]

going down the road while cruising the motor just kind of drops a cylinder kind of at random I shut the car off and restart it, it runs fine for a while then drops out again. could it be a bad ECU or bad injectors!? any help would be appriciated! thanks guys.

 

[eeeewidner]

sounds like the mpi relay or coils....

 

[Colt4G63 also]

By random, do you mean always the same one cylinder, and constant missfire until you restart the engine. Or just totally random.

 

[streetsoldier60]

basically its random it does it until i shut the car off and start it again. i have no idea which cylinder it is because it doesn't throw a cel. also if I take my battery out for a lil while then start it up again it runs okay for a lil longer then does it again...so i have no idea my buddy was thinking the ECU but i duno. its a 95 talon with 6 bolt swap with EPROM...

 

[DSM_PWR]

Very common problem, my friends car did that after his 6 bolt swap and i couldnt figure it out, even after we changed the spark plugs, wires, CAS, coil packs, power transistor...

He has DSMLink and i was recommended to try and uncheck one of the boxes "random misfire" and bam, after that never happened again

I see you dont have dsmlink so its not much help, although.. when we tried a different CAS, it stopped happening for a while, might wanna try that

 

[Colt4G63 also]

Does it make a difference if you are boosting or just criusing, or does it just keep misfiring no matter what?

 

[streetsoldier60]

could it be that i need to dial in base timing and set it to like 3 degrees and go from there becaue i have the CAS installed and I know its close but never got a base timing set any thoughts to that? but then again it is 2g so it wouldn't be quite the same would it?! i dunno I'm just at a loss and really can't afford dsmlink so thats why i have safc set to 0% correction accross the board...i dunno this car is all F***ed up and I'm at a loss haha. me chasing my tail on this one...

 

[streetsoldier60]

if I'm boosting its fine if under slight load sometimes it does it sometimes not a lot of times its just when cruising....

 

[DSM_PWR]

Yes definetly make sure your base timing is correct.

The misfire happends because there is no longer a crank trigger sensor which the CAS alone becomes inaccurate

 

[Colt4G63 also]

It sounds like you may have "lean miss". When you restart the car, it resets to open loop and begins all over again. I could be wrong, but it's just a guess. Do you have a wideband?

 

[streetsoldier60]

no only narrow band for now which i know doesn't do shit...i'm working on the money to get wideband. think if i reset the computer and turned boost back down to like ten instead of 15-18 it would work better since i am running a 16g with stock fuel system? just a thought?

 

[DSM_PWR]

Doubt it, best bet is if you have another dsm friend near by, try swapping your Spark Wires (Change your plugs since their cheap) , CAS, Coil Packs, Power Transistor with his/hers to see if that solves your problem.

But im willing to bet its the CAS since its the only thing that shoulda changed during the 6 bolt swap.

 

[RyAn007]

I had ta similar problem and it ended up being a spark plug, but I would check all that DSM PWR said to check because those weould be your most likely suspects in this problem.

 

[T is for TURBO]

Random Multiple Misfire. Anyone who does a 6bolt swap will have this problem. It's because you are running a 1g style CAS. There are several band aids to this problem. Best is through DSMlink, but that might be out of your price range for the moment. However you can minimize the occurance by using a black lid CAS off of a 94 7 bolt head. Another way is to use a potentiometer (just do a search for pot mod) Also get a data logger. You can clear the engine code without turning the car off, and it will run fine after the CEL is cleared

Good luck!

 

[ArticNemesis]

The fact that it's throwing the random misfire while cruising or under slight load makes it look like the common random misfire 2g's get when they eliminate the crank sensor after installing a 6bolt.

http://www.magnusmotorsports.com/tech/1gina2g.pdf

Scroll down to page 10. It'll give you ways of trying to fix it, short of buying dsmlink or a chip to eliminate the code.

[edit] ^^ T is for turbo beat me by a minute. =P

 

[streetsoldier60]

I got a buddy with a dsm junk yard bout 30 mins from here I will try swapping some stuff with him and see what happens. yea I am running I think a green top so i will try that black and swap everything else. i just put brand new plugs in and 30 seconds later did same things so i dunno. will try everyting everyone mentioned and see what happens...guess i might just have to ask for DSMlink as realy really early or late b-day present hahaaha! sigh

 

[streetsoldier60]

straight off of magnus...Make sure the ignition key is off and the ECU fuse is pulled. At this time make changes to your plug wires
and injector wires if necessary. Connect your custom wiring harness to the 1G CAS. Route the harness away
from extreme heat possible noise generators, (spark plugs, coil's, alternators etc.) Behind/under the intake
manifold works fine.


my wires from the CAS are right on top of my manifold by all my injectors and plug wires this could be the simple fix ... move my CAS wires to behind manifold like it says think that should probably help huh!? haha

 

[ArticNemesis]

move my CAS wires to behind manifold like it says think that should probably help huh!? haha

Doubt it, they were just providing advice to keep the signal from degrading. You have all the symptoms of the random misfire. Try the 10K potentiometer fix.

 

[streetsoldier60]

wont that just tell the computer not to look for the misfire but wont the misfire still hapen!?? or because the computer is looking for the misfire thats why it keeps popping up!? I mean some days it doesn't do it at all an I can travel like couple hundred miles and nothing then other days it doesnt matter it just misses!? i will try the potentiometer fix and see what happens i read on that before but didn't understand why i should do that so i haven't yet...i'll give it a try...thanks for all the help and advice everyone i do apriciate it.

 

[T is for TURBO]

wont that just tell the computer not to look for the misfire but wont the misfire still hapen!?? or because the computer is looking for the misfire thats why it keeps popping up!? I mean some days it doesn't do it at all an I can travel like couple hundred miles and nothing then other days it doesnt matter it just misses!? i will try the potentiometer fix and see what happens i read on that before but didn't understand why i should do that so i haven't yet...i'll give it a try...thanks for all the help and advice everyone i do apriciate it.

If I'm not mistaking, the the engine isn't actually misfiring. I believe that the sensor is just detecting a misfire when there really isn't one... but I could be totally wrong.

 

[ArticNemesis]

Correct, the engine isn't actually misfiring. The 2g ecu just thinks it is.

If you don't understand why they suggest it, then you need to actually read the link i provided. The ECU looks at four criteria before searching for random misfires. The potentiometer takes one of the four (baro sensor) basically out of the criteria, so the ECU won't look for random misfires. An effect of doing this is a slightly leaner effect, so they also suggest at higher elevations and/or already lean tunes (car specific) you may have to richen up the band.

Read the magnus page in it's entirety, so you completely understand what's going on and why you are doing this.