so i drive my car to my friends the other night then left it there and went out and then when i get back i start it up and the a/f are reading 17.x so i think its a leak or something. i get to my friends check for leaks. tighten the coupler on the tb and clean the maf. now the a/f are normal but its misfiring and i keep getting p0300. so i go get new plugs lfr6a-11 check the coil packs everything seems fine then put the plugs in and its even worse now

anyone have any idea?

i have a 04 g35 sts kit utec

 

P0300 is normal on a turbo car

 

its bad you can hear it and if i go more then 20% throttle the engine light flashes so its parked until i can figure it out

 

if your check engine light is flashing.. you have bigger issues than P0300... that some serious problems

 

p0300 is random misfire.... the light flashes during heavy misfire

what i dont get is why would it get worse after cleaning a maf and putting in new plugs

that should make things better

 

are you sure the maf is plugged back in secure?

 

clogged injectors
bad coil pack(s)
intake manifold leaks

all can cause the above issues

 

after we put the new plugs in it was still misfiring so we went through and pulled the clips to see if it was a certain cyl and none made a difference but my friend didnt slip cyl 4 back in so i cleared the codes and plugged it in and now its fine


but what would cause it to act like that? lean then good a/f then misfiring? is that all product of bad plugs?

 

alright i figured out whats making it go lean... something with the utec because if i run it on map 0 ecu controlled fully it runs i just cant boost. if i put it on map 1 it runs supppperrrr lean. so im gonna check to make sure the girl i was with dindt kicked anything with the utec and check the map sensor then do some logs

 

I am having the exact same problems with the UTEC on my car right now. My previous maps don't work and no matter what I do I can't seem to fix it.

Do you smell fuel coming out of the tail pipe even though it reads lean?

From what I gathered from the guys at Turbo XS, if you are in map 0, the car uses the stock ecu's injector and ignition drivers. If you are in any other map other than 0, and this includes any of the load sites with ECU in them, the UTEC is using its own drivers for both ignition and injectors.

I have raw unburnt fuel coming out my exhaust and my air fuel gauge further supports that because it is always lean. In my case, I wasted the $200 to send my injectors out and get them tested, cleaned and inspected. No problems what so ever. I replaced the crank angle sensor. I have tried lean and I have tried rich, all with no success of getting rid of the same misfire you are having.

The more and more I look at it I am starting to think my UTEC has bad drivers of some sort. My motor is a freshly built motor and three cylinders look clean as day after 80 miles, like they are being washed down. The other three look like they have been running pig rich and are darker than they should be.

Hope you find out what is wrong and hopefully it is not the UTEC.

 

I've had 2 issues with the UTEC. First one was the ECU went bad... somehow.. or my cousin kicked it.

Second one was the map selector switch was set on 0 and I had no idea and had to take it to my tuner because I thought something was seriously wrong.. or somehow my cousin kicked it again. OR.. vibration caused the switch to go to 0.

Conclusion: Cousin stays out of the car.

 

/\ lol..

OP, You have to do some logging to really see if it is Utec related. Make sure you are on the right MAP, see if what load cell you are hitting and what A/F. You can do a short trouble shooting like adding more fuel on that load and see if it makes a difference. If not then have your injector check first. Make sure temp compensation is setup right too or didnt change. If you dont want to make adjustment on the Fuel Map, you can always use the Temp Compensation to subtract/add Fuel. Check or log your IAT and add 2% - 4% on the temp compensation table and see if it makes a difference.

 

Did you check your wiring? I had this exact symptoms(smelling fuel but lean, missing....but no codes) after my engine rebuild and couldn't find a solution. Luckily found on another site something similar which turned out to be mine as well, i had #4 and #6 cyl wire/clip switched....they fit either way and could be mixed up easy.

 

after i posted that last night i went and did some logs and went over the maps and nothing seemed weird so i just started tuning a little and added fuel and its good now while cruising but as soon as my boost gauge reads -2 it just starts leaning out i guess thats where it transitions from maf to map. any tips on what to adjust to smoothen that

 

maybe somethign with your maf.. can you swap it with someone elses to see? well then again if it was the maf you would be getting that code and it wouldn't let you pass 2500 rpms ..

 

yea thats what i figured id be getting a code and when i used dashboard on the utec the voltage seemed to be right

 

I already triple checked my wiring and everything appears to be in the correct location. I am going to check it again this weekend though.

 

just got off the phone with turbo xs and the tech guy is telling me that i had a leak when the car was tuned... and when it say for 3 hrs it magically fixed itself and thats why its lean... lmao that was boost leak tested to 12psi no leaks

 

So have you been able to fix your problem or is it still going on?

 

What load are you hitting at -2psi? Post the log so we can dissect it. Which part of your fuel map did you add the fuel? Are you using UTI to log your A/F? If so what version? The new version can log the IPW instead of the IDC which will tell us the injector pulse width at a certain load. I assume you are using a 440cc injector. Do you have a dual WB? It is going to be handy if you have both so you can monitor both bank. This will help us figure out if the problem is happening in 1 bank.


As far as tip, if you are just leaning out at the transition level then this mean you need to add more fuel on column 10. If you are still leaning after that then do what I suggested before. look at your Air Intake Temp and go to your temp compensation table and add 2-4 on that range. This will add a % on the entire fuel map. Post some log first so we can figure out what is going on.