Limp mode question
 

I am having a problem with my car with what i think is the limp mode everyone is talking about. At about 5000 rpm, the car feels like it hits rev limit. If i keep the gas down, it just stays there and wont move. Its been doing this for about a week now, but it worked fine for about half a day within that week. I can usually reproduce it everytime i try, but that one time it worked? i dont knwo whats wrong, if there is a fix, please help!

Have you done any tuning with the R4 lately ? Sounds like your aux. fuel pump isnt coming on .If you have done some tuning , I would say...your settings got changed . If not , you may have blown fuse , wire loose, thats where I would start to look for problems

Can you go above 5000 rpms even at low or no boost?

It's unlikely that you are maxing out your MAF at 4700 rpms with the supercharger. Also, when you hit limp mode and then slow down, the car will not rev above about 1500 rpms and it runs extemely rich until you restart the car.

Have you verified that the fuel pump is coming on? What are your R4 settings for the fuel pump? What is the A/F ratio at the point the rev limit is hit?

--Steve

I havent tuned it since i installed the vortech, and i checked the aux pump and all of the connections already. And the fuse is fine if you are talking about the one that goes to the aux pump...

I have a similiar problem that starts around 3500rpm, I have taken it to two dealers, the first one deamed it to be just the VDC kicking in, they didn't know sh!t. When I went to the second one, I couldn't reproduce the problem because the engine was already warmed up(that is when it stops doing it, but give it a cold start in the morning and I will get it everytime in every gear!) So I still have to get my car to dealer when it is cold to see if they can figure out the problem..... It sucks but I can live with it for now.

I cant go above 5000 in any gear. I thought my boost was the same no matter what with a supercharger since it runs off the belt?
I guess its not limp mode then because my car can still rev above about 1500 rpm after it slows down. And i havent verified that my aux pump is coming on, but i have checked all of its connections. And about the A/F, i would have to get it on the dyno again to tell you

Does this only happen at wide-open throttle or does it happen even if you gradually apply the throttle to reach 5000 rpms?

It sounds like a wiring problem. The first thing I would check is to see if any of the ECU wires have come disconnected. Did you solder or just crimp?

--Steve

This happens even if i gradually apply the throttle, and everytime at about 5000, it happens. The wires were soldered to the ecu when i installed it....

Definately NOT a textbook limp mode. The classic F/I induced limp-mode occurs when the MAF voltage maxes out at a realatively low point in the RPM band...around 4800rpm. This usuallly only occurs with the TT kits...havent seen it yet on the SC's, since they produce airlflow in a more linear fashion.

Could it be that one of the coils is burned? I had almost the same thing happen to me and then when the car stopped working :( I realized that I had three coils burned.

Do you have a semi rough idle? If yes then I would suggest that you check the coils.

Az

I would recheck your ECU harness wiring to make sure that all the SS box wiring is correct and that all solder joints are good. I've heard of this before and it was either an SS box problem or an SS box wiring problem.

--Steve

One more thing... Here's a link I remembered that might help.

MAF Error Code causes limp mode

--Steve

I just changed my plugs about a week ago and i checked the coils too. My idle isnt rough at all.

The weird thing is, today when i was driving it, on the way to the store, it did the rev limit thing. But, on the way back, it pulled all the way to redline. And then, on my way to class earlier tonight, it had the rev limit again.???
I wonder why its not consistent????

Same issue
 

I currently have a 2003 350z that has a jdm motor. The error code a it gave me was for my cam sensors, crank sensor, then o2 sensors bank 1&2. I changed the cam sensors and the crank sensor it cranks for about 3 seconds then turns on with a rough idle. What's weird is with the crank sensor unplugged it turns over with it plugged it doesnt. Other issue it doesn't go above 45-4700 rpm feels like it's stalling. Got a new throttle body and did the throttle body relearn. I'm also stuck and don't want to go to just any 👨*🔧 especially in nyc. Plz help

Same issue can we bring back this thread?
 

Hopefully this thread can come back to help. I am experiencing the same issue with my 2003. Did anyone figure out a fix by chance? I will add once I hit 5k RPMs and it goes into limp mode, if i shut off and restart the vehicle the issue clears itself and runs fine again. No CEL. I am reaching out to Split Second to see if this might be an overboost protection but it would be sweet if this might have been resolved by someone else already.

I have already replaced all plugs, coil packs, cam sensors, cleaned the maf, and checked all vacuum lines. I loaded the base tune from split second. I removed the cheap boost gauge the last owner had installed. I’m at a loss at this point.

Found the fix it seems
 

So for anyone that comes across this post with the same issue, turn your VDC off and try to do a pull. Has worked for me every time. Hope this helps!