I've been reading about your car and it seems as if your problems is more complicated that most. My car throws misfire codes, but other than that it drives fine. My motor is fully built with rods, pistons, cams, and headwork also. Other than your case, I have never heard of anyone with these codes where the car runs bad. Good luck!

 

I'm with Gman. I throw the code at part throttle 3-8psi situations. Full throttle it doesn't do it. Just as long as you aren't having any individual sensor misfires it's no big deal.

 

Huh?

How do they know how far you've driven it since your last code? Is that in the computer?

According to the service manual that code doesn't throw on 1 missfire... It has to detect some serious misfires over a length of time before it pops it out.

Hell with my racelogic (causes misfires ALL THE TIME with my launch control) I have to get a good 2 or 3 seconds of constant misfires to throw the code. How does the stock computer detect a misfire anyway??? The knock sensor??

There must be a way of jury rigging it so it can't throw that code.

 

man i get this freking code everytime i drive the car,i wish we could figure out whats causing this

 

So this only happens with a return fuel system then?

 

I have a return fuel system. The whole CJM fuel sys, and I rarely get this code. I have only gotten it 3 times since I put the turbos on in the spring. Its been over 5500 miles, and only 3 times.

 

I have a return system, and I haven't got this code since the 1st day i installed.

I think people who built their blocks are seeing it more then people without... But there are a lot who see it without.

I can FORCE my car to misfire and it takes a LOT of misfires before this code pops.

I was getting this code when I wired my injector loom backwards... Amazingly the car drove and felt mostly fine. I'd love to get to the bottom of this... I don't have the problem... but I love information!

 

No, I am running with the T-netics kit and nothing else(no fuel return) and I have the problem,

 

hmm, not sure, cause I don't have fuel return yet and don't have it either

 

thanks, i think i need it now. unfortuneately havn't had much extra time at all for like a month now to work on thew car at all, so not much progress. my prob seems to be when i hold the accel. in one position for more than a few seconds in the cruise range. if i accel, coast, accel, coast it is fine and runs great, with tons of power if i give it more gas. my a/f also goes either to 19/1 or 9/1 during this condition too first then if i keep my foot at the same position it will through the po300 code. i have a feeling it will be something simple though. i sent my eu files and about 20 mins of datalogging to sharif to make sure i have my parameters set correct. waiting to hear back from him. main problem is no body around here has dealt with my combination or the eu and i don't want to pay the $150 an hour to have them learn on mine. and me not having extra time right now sucks, so i look at it in the garage and think of how fun it would be to drive it, ahahha.

 

Well...Good news today. After making 4 hours trip on the highway to see some friends. I found out that the code comes back on around every 150 miles. Becuase on the way, everytime the CEL is on...I pulled over and reset the ECU. So on the way back...I reset the ECU when I'm about 100 miles away from home. Then pull right in the inspection place and guess what??? I PASSED TODAY! So Happy.

 

Congrats!!!! Now you know the secret to passing in NY!!!

 

I'm getting the p0300 SES code and I don't have FI. Just hooked up the greedy emanage ultimate. Gonna do a little more research though to see whats going on.

 

I get it occassionally (at idle usually).

 

OK I found my source of the p0300 code. It does have something to do with the EU. Well more percisely, the harness. Position 2 and 5 ignition was not stripped (the end that greedy crimped on the harness), and injector connections 3 and 6 were not stripped as well. I guess that would cause miss fire's, now wouldn't?

So this goes to show, it always pays to double check every connection. Even if it is not your own.

 

I get the P0300 regularly. I don't even bother resetting the ECU anymore, though like others, I can do the pedal-push reset without a stop watch and get it right every time. It's time to invest in a scan-tool. What's a good one that can do real time data output, like timing retard, etc?

 

Damn I had no idea so many boosted cars were getting this code. I just got this code, but because the grounding strap on one of my spark plugs melted to the electrode. Id hate to put my turbo kit on and have a damn SES light on all the time when I drive. Subscribing to this thread I hope one of you smart Z owners comes up with a fix....cough:Sharif:cough

 

I have never gotten the code, thank god. The scan tool that I use is the Digi-Moto 3.7, ehichconnects to my PC for data logging. It works pretty well and only cost about $100, or so.

 

I think most of the F/I are getting it . It has to be one of the three things I changed all at once when we did the rebuild . CAS wire , bigger RC injectors , and the return fuel system with in tank pump upgrade

 

I believe it has to do with maf scaling and the af reading when it reads a richer af than it should. It is the only thing that makes sense. It tends to happen more to the people running bigger injectors and cams. The lower I run the static pressure the less it happens. The only problem with that is I am still running high impedance injectors so I run out of head room.