6bolt swap, Random misfires...

[seth98es]

Well I completed the swap in my Galant back in May or so and never did get the p0300 CEL once. Im running a complete JDM motor, 1g CAS, 2g 98 GSX ECU. My timing jumped about a month ago and I just bought a used head off a friend who had a JDM 4g63t sitting in his garage. Well I put the new head on and its been running good for about a week and yesterday I get the p0300 CEL while slightly boosting up a hill in second gear.

Just curious as to why I get the misfire code now and not before? I drove it around again today and the car pulled the same CEL and would keep randomly misfiring untill I cleared it. I am using all the exact same electronics off my old head. Only thing new is the complete head, ARP headstuds, and headgasket.

Im going to go to RadioShack today and buy the potentiometer and see if that fixes it. But I was just curious as to why I get the CEL now and not before? Just weird if you ask me

 

[97GSX-509]

I am having this same problem in my 97 GSX w/ EPROM & KeyDiver Stage3. I chipped 2 exhaust valves for cyl #2. so i tore apart my head, replaced the valves, and put it back on. Now I am getting P0300 a lot too, and sometimes its actually giving a cylinder number (i.e. P0302, P0303).

 

[B005T3DT5i]

the random misfires is a common problem with 6 bolt swaps. a common theroy is that you get the code right when the motor is started for the first time. wrong. it could take acouple hundred miles or thousand for the ecu to truely see what you have replaced. but also in some cases you will throw the code right off the bat. it took me about 400 miles to start throwing the random misfire code. the reason it throws it is because the CAS in a 6 bolt is inverted. in 95-96, and 98-99 it is not . now 97 ecu seem to like the 1g CAS the best. because of changes made to it durring production. a 97 ecu might buy you some more time or even elminate the problem. some times it dose some times it dosent. my 2 recomended ways to deal with the code are to either A. buy dsmlink as i have done. it completely elminates/sloves the problem. or B. when you start to get misfires wile driving, push the clutch pedal down. quickly turn the key to ACC then to ON agian. NO NEED TO CRANK THE STARTER. it should stop the problem for acouple miles. i noticed also if you keep the trottle allways moving and dont keep it in one place (ex:giving gas then coasting and repeating) you tend not to throw the misfire code. hope that helps

JAke

 

[seth98es]

So you dont recommend the potentiometer mod for a quick fix? Id love to have DSMLink, but its not in the budget as of yet. Its been about 2,000 miles since I first started it btw.

 

[B005T3DT5i]

So you dont recommend the potentiometer mod for a quick fix? Id love to have DSMLink, but its not in the budget as of yet. Its been about 2,000 miles since I first started it btw.

the potentiometer mod is just bad for the car over all...it messes with the fuel maps to much. its sorta like diet soda....it has less calories but alot of olther bad chemicals that are worse for you.

 

[hellotbone]

the potentiometer mod is just bad for the car over all...it messes with the fuel maps to much. its sorta like diet soda....it has less calories but alot of olther bad chemicals that are worse for you.

I don't beleive your startement and you can ask another wiseman on here to vouch for how well my car runs with the pot mod with proper tuning. 1.5 seasons on the swap now and no random misfire at all no tuning issues and a fast car. What more could you ask for at 10 bucks for a pot at radio shack its worth a try on your car. I have no regrets running one thats forsure. I would like to have dsm link but can't justify the $$ when my car runs perfectly without.

 

[98RedGs]

I don't beleive your startement and you can ask another wiseman on here to vouch for how well my car runs with the pot mod with proper tuning. 1.5 seasons on the swap now and no random misfire at all no tuning issues and a fast car. What more could you ask for at 10 bucks for a pot at radio shack its worth a try on your car. I have no regrets running one thats forsure. I would like to have dsm link but can't justify the $$ when my car runs perfectly without.

I fully back this statement being as I know when I had my car that it was misfiring and I did the pot mod and for the time I had the car when the POT mod was connected it was working fine and never a problem with it. Granted my car had "other" problems but the pot mod wasn't the cause of them and didn't assist in causing any problems to my knowledge.

Thank you
john

 

[Michael Z.]

Well, some of you swapped your heads on your 6-bolts and you suddenly got a random misfire error. Same thing happened to me. That's when I realized that a damn plug wire wasn't on the plug properly (it didn't snap down), so my error was legit. Since I installed it properly, no CELs. It's a possibility that one of your wires is not seated properly, especially considering that you had to pull the wires to pull the head. Sometimes it's the simple things, too often it's not. Just another thing you may want to look at.

 

[B005T3DT5i]

I fully back this statement being as I know when I had my car that it was misfiring and I did the pot mod and for the time I had the car when the POT mod was connected it was working fine and never a problem with it. Granted my car had "other" problems but the pot mod wasn't the cause of them and didn't assist in causing any problems to my knowledge.

im not saying it wrong to do the mod. im saying that i just dont like it. hey if it works fine go for it. but in my mind your messing with the ecu too much. in my eyes at the time it didnt seem like a good idea to me. but hey i guess it works just fine.if i ever swap a 6 bolt agian ill give it a try for 10 bucks.
thanks for the info,
Jake