Odd Miss @ Wot

[KB240RB]

First id like to say ive read the threads about the coilpack issues and i dont believe thats the problem. The problem is the car misses only when going WOT. At part throttle under boost its perfectly fine and pulls hard but once at 100% it misses and feels like it pulls timing. I dont understand whats causing it. I have timing set to 15*. Checked boost leaks to 20psi and found none. Fuel pressure is at 43psi w/o vacuum. New SS Performance Coilpacks. Ive tried BKR7EIX plugs and BCPR6ES-11 plugs both gapped at .030" and didnt make a difference. Just for the hell of it i disconnected the battery to try and reset the ecu. Everything is properly grounded. TPS is set to .45 volts closed. Anybody have any idea or suggestions what this WOT miss is caused from?

[nikr33turb]

First id like to say ive read the threads about the coilpack issues and i dont believe thats the problem. The problem is the car misses only when going WOT. At part throttle under boost its perfectly fine and pulls hard but once at 100% it misses and feels like it pulls timing. I dont understand whats causing it. I have timing set to 15*. Checked boost leaks to 20psi and found none. Fuel pressure is at 43psi w/o vacuum. New SS Performance Coilpacks. Ive tried BKR7EIX plugs and BCPR6ES-11 plugs both gapped at .030" and didnt make a difference. Just for the hell of it i disconnected the battery to try and reset the ecu. Everything is properly grounded. TPS is set to .45 volts closed. Anybody have any idea or suggestions what this WOT miss is caused from?

Whats your boost set to bud?

[KB240RB]

It does it at stock 7psi, 10psi, or 13psi. What i found the other day is if i set the TPS to .45 volts with the engine off, the voltage drops to .35 volts when its running, and then voltage drops to .15 volts when the e-fans turn on. Its also not reading WOT. With throttle plate fully open, the ecu is only seeing 90% throttle at best using my AVCR. To get it to read 100% throttle, i have to turn the voltage up to .70 at idle and then when the e-fans turn on the voltage drops down to around .55 volts and then it wont go to 100% throttle. Im thinking the TPS is messed up. Has anyone else had this problem?

[DanShirts]

It does it at stock 7psi, 10psi, or 13psi. What i found the other day is if i set the TPS to .45 volts with the engine off, the voltage drops to .35 volts when its running, and then voltage drops to .15 volts when the e-fans turn on. Its also not reading WOT. With throttle plate fully open, the ecu is only seeing 90% throttle at best using my AVCR. To get it to read 100% throttle, i have to turn the voltage up to .70 at idle and then when the e-fans turn on the voltage drops down to around .55 volts and then it wont go to 100% throttle. Im thinking the TPS is messed up. Has anyone else had this problem?

I'm having the exact same problem. Runs perfectly at 95% throttle. But when I mash the pedal, it coughs and dies.

My TPS had the same readings as yours. I took my TPS apart and cleaned it. It isn't hard, but you can break it if your not extremely careful. I can adjust it correctly now (0.47 ~ 4.09), but I still have the miss.

I'm running BKR7E plugs gapped at 0.8 (0.030"). I've also run BCPR7ES plugs, they run the same. My coils are good.

I also have a bad turbo and a boost leak.. so that is likely my problem. Do you have a boost leak?

[KB240RB]

No boost leaks. I can go half throttle and it's fine but if I go over 80% then it starts to miss.

[mad082]

the missfire is going to be either a spark or fuel issue. i see that you have a rb25 in a 240sx. do you happen to know what series motor it is (series 1 or 2)? there are a few ways to tell if you don't happen to know. the plug on the TPS and the presence/lack of an ignitor pack at the rear of the rocker cover. if the TPS is a black rectangle and there is an ignitor pack on the rocker cover then it is series 1. if the TPS is more rounded with 2 plugs on it and there is no ignitor then it is series 2 (they have the ignitor built into the coils).

back to the missfire, what is most likely happening (what happens with most missfire issues) is that the spark plug isn't able to ignite the fuel. the reason it happens at WOT and not lesser throttle is because the further you put your foot down the richer the air/fuel mixtures get as well as the more fuel that is in the combustion chamber. the cause of the missfire can be caused by a few things.

1: over fueling.

2: weak spark plugs.

3: weak coils.

4: weak ignitor.

now you have changed the plugs, so that rules that out. the overfueling can be caused by a few things. can be fouled injectors not shutting properly, dirty/damaged AFM or a boost leak (you have also ruled that out). you could try taping up the coils with electrical tape to reduce the chance of them arcing out. if your car has the ignitor pack then they can also strat to fail at higher load due to the fact that they are getting old now and don't perform like they used to.

[KB240RB]

Its a series 1. Have already put brand new coilpacks in it. I pulled the plugs and they do appear to be more on the darker side of a caramel/tanish color. Im gonna get a new set of bcpr6es-11 plugs and gap them down to .030" and try them. Ill see what i can do about getting another ignitor to try and ill clean my MAF as well.