SES P0300 code
#21
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Originally Posted by overZealous1
the po300 code is for random multiple misfire. it is caused by the crank pos sensor signal to vary in relationship to rpm. it actually is a serious problem for f/i. i won't hardly drive my car till i get it figured out. mine is pretty bad though as i get an audible misfire, and drive around clearing codes when they pop up. but usually once it starts mine won't go away. i have gotten a bunch of military grade communications shielded wire and plan to do the crank pos wire and both cam wires too to see if it eliminates it.
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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.
Originally Posted by Gman2004
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!
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Originally Posted by Z PHAT Z
It's not that easy to get your car inspect in NY anymore. You have to clear the code then have to drive the car for more than 60 miles or couple days for the system to recycle and ready. You just can't clear and drive it up to inspect, it will failed right away. My inspection will expired at the end of this month. Don't know what to do now.
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.
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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.
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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!
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!
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Originally Posted by 002-M-P
So this only happens with a return fuel system then?
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#30
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Originally Posted by Gman2004
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!
#31
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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.
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Originally Posted by Z PHAT Z
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.
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Originally Posted by punish_her
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.
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So this goes to show, it always pays to double check every connection. Even if it is not your own.
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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?
#37
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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
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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.
#39
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Originally Posted by Alberto
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
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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.
Originally Posted by booger
It has to be one of the three things I changed all at once when we did the rebuild...bigger RC injectors....