Finally got my car back together, s14 with a non vvti 1jz. Motor is stock on a stock jzz30 ecu. At first we couldn't get the car to run but that was because we realized that a few pins on the ecu plugs were a little damaged and some of the ecu pins were bent a little bit. After fixing this the car finally idles but we still can't get it to stop misfiring when it revs. You can bring up the throttle gradually and it will be fine but if you tap the gas at all, it starts misfiring like crazy, then returns to its good idle. We checked everything, all the sensors (knock, cam, map, cps, etc.) seem ok. So does the ignitor, the coils, etc. The ecu doesn't show any codes. What could it be? Maybe some sensor wiring is reversed like the knock sensor so it thinks there is always knock and when the ecu sees any decent amount of throttle it retards the timing like crazy to not hurt the motor? I don't know. What could cause it to idle fine and the rpms can be brought up slowly, just with any real throttle it sputters.
1jz idles but will not rev
- Thread starter kas14slider
- Start date
I had nearly the same issue but it was a wiring issue. My friend that did my wiring ended up not deleting a certain connector that is located on the harness between the firewall and ECU and it just happened to fit a body side connector so I instinctively had it plugged in. When I finished the swap it had similar issues to what you are describing. I disconnected the plug and it ran perfect.
Well my friend did do my wiring but we eliminated all unnecessary plugs and wires. Basically anything having to do with abs, auto, traction control, a/c and diagnostics stuff. Do you know which plug it was that you had to disconnect?
It's always a smart thing to eliminate after you get it working and the check connector isn't something you want to eliminate when on a stock ECU...
Tried a different MAP sensor? What is the voltage it is putting out when the key is on and when car is idling?
Why would you think the knock sensors are wired wrong? It's only one wire.
Do you have any mods, list all of them. Fuel system? Anything different from stock?
Have you check the ECU caps?
Tried a different MAP sensor? What is the voltage it is putting out when the key is on and when car is idling?
Why would you think the knock sensors are wired wrong? It's only one wire.
Do you have any mods, list all of them. Fuel system? Anything different from stock?
Have you check the ECU caps?
Well the car ran perfect and had no problems before we redid the wiring. We decided to pull the motor to clean up the engine bay and redo some of the crappy and unnecessary wiring. We only removed connectors that were just sitting in the engine bay not plugged into anything. The diagnostics check connector was just one of those that was sitting there not doing anything.
As for map sensor, have not tried another one or checked its voltage. I just assumed that it would be too big of a coincidence for it to just suddenly break, I think the problem lies somewhere in my friend's wiring. Even though all he did was remove wires/connectors and shorten other wires because they were way too long from the previous guy who wired the car. But who knows, maybe the map sensor did just go bad. We will have to check it.
And I had driftmotion recap the ecu a few months ago and the car ran great with this ecu before we took the car apart.
As far as mods, it is a stock non-vvti 1j. Jzz30 ecu, greddy bcc, fmic, 3" exhaust, stock fuel rail and injectors with a 255 walbro pump.
As for map sensor, have not tried another one or checked its voltage. I just assumed that it would be too big of a coincidence for it to just suddenly break, I think the problem lies somewhere in my friend's wiring. Even though all he did was remove wires/connectors and shorten other wires because they were way too long from the previous guy who wired the car. But who knows, maybe the map sensor did just go bad. We will have to check it.
And I had driftmotion recap the ecu a few months ago and the car ran great with this ecu before we took the car apart.
As far as mods, it is a stock non-vvti 1j. Jzz30 ecu, greddy bcc, fmic, 3" exhaust, stock fuel rail and injectors with a 255 walbro pump.
IBoughtASupra;1816538 said:
I just wanted to see if anyone know had the same problem where the car idled good and you could bring up the rpm's slowly all the way up to redline but it fell on its face if you gave it any decent amount of throttle. It seems that something (probably some sensor) is not happy when it sees some throttle or maybe some sensor is just not seeing the fact that throttle is being applied.
Yeah, i figured that much, its just that the ecu is not throwing anymore codes and all the sensors seem to check out fine so I'm just wondering what sensor could be responsible for this? Because even though everything seems good, something is still messed up. Could it be tps wiring? But I read in another thread that tps doesn't affect that car that much. Just trying to figure out what it could be.
Well there was in my case, you should have seen how long those wires were in comparison to where they needed to plug in. But from what I understood about googling shortening shielded wires, its not that bad to shorten them. The ones people really are concerned about shortening are in non car applications, things like coaxial quad shielded cables. Of course I could be wrong. Is there a proper procedure for shortening these wires? And could that be why the car runs bad?
kas14slider;1816524 said:
I don't recall exactly what it looks like, but I do remember that it was one of only a few thats between the firewall and ECU that is a connector with between 3 and 7 pins. I just disconnected one at a time and tried the motor each time and then it magically ran perfect after I disconnected a certain one.
Hmm, I'm pretty sure we eliminated all not needed connectors. Guess we will just have to go over the wiring again.
propper tps calibration is vital.. if you messed with the idle screw at all you will have to adjust the tps.. on my car if the tps is out at all it runs like crap misfires if you rev it , and flat runs like shit under any load at allkas14slider;1817396 said:
Well we could try calibrating it again but we calibrated it with a multimeter and made sure it is in spec. We used 2jz tps volt specs to do it. I think they are the same.
Well here is a list of everything we eliminated. Do any of these things seem like they would need to be there for the car to run properly? The only ones that I can think of that sound important are at the bottom of the list, M-Rel (main relay) and FPC and D1 (both are fuel pump control relay) Does a 1j ecu need to see the fuel pump? Because my pump has always been on a switch but I can't remember if these pins on the ecu were wired in before we messed with it. I don't think they were since my pump has always just been on a switch. As for the rest of the pins, I doubt they are important
EVP - Charcoal Canister Purge Solenoid Valve
NSW, STA - Neutral Start Switch (A/T Indicator switch)
VF - Diagnostics plug in engine bay
S1, S2 - Auto Solenoids
SL - Lock up auto solenoids
IDL 2 - Sub Throttle (traction)
SP2-,SP2+ - Speed Sensor
NCO-,NCO+ - Speed Sensor (overdrive lock up clutch)
VTA 2 - sub throttle for traction control
EGW - exhaust gas warning light
OD1 - Cruise control
OD2 - O/Drive switch
ACMG - A/C magnetic clutch
P - Pattern select switch
L - A/T indicator switch (located on tranny)
TT, TE2 - Test plug (kick panel)
CCo - exhaust sensor
SP1 - speed sensor 1
S - A/T indicator switch
A/C - AC idle up
ELS - External load input
STP - Stop light switch
FPC - Fuel pump control relay
M-REL - Main relay
NEO, VTO 1, TR - Traction control
TE1 - Diagnostics plug in engine bay
VTO 2 - Traction control
D1 - Fuel pump control relay
E1 - Diagnostics plug in engine bay
ABS - Abs computer
EVP - Charcoal Canister Purge Solenoid Valve
NSW, STA - Neutral Start Switch (A/T Indicator switch)
VF - Diagnostics plug in engine bay
S1, S2 - Auto Solenoids
SL - Lock up auto solenoids
IDL 2 - Sub Throttle (traction)
SP2-,SP2+ - Speed Sensor
NCO-,NCO+ - Speed Sensor (overdrive lock up clutch)
VTA 2 - sub throttle for traction control
EGW - exhaust gas warning light
OD1 - Cruise control
OD2 - O/Drive switch
ACMG - A/C magnetic clutch
P - Pattern select switch
L - A/T indicator switch (located on tranny)
TT, TE2 - Test plug (kick panel)
CCo - exhaust sensor
SP1 - speed sensor 1
S - A/T indicator switch
A/C - AC idle up
ELS - External load input
STP - Stop light switch
FPC - Fuel pump control relay
M-REL - Main relay
NEO, VTO 1, TR - Traction control
TE1 - Diagnostics plug in engine bay
VTO 2 - Traction control
D1 - Fuel pump control relay
E1 - Diagnostics plug in engine bay
ABS - Abs computer
Also, after looking over wiring diagrams some more, my friend saw that the stock wiring uses separate power for the coil and injector circuits but he just has it all wired into one power source. So he thinks that maybe the car idles fine but when you rev it it does not give enough power to properly power the coils/injectors. Could this be the cause?
So one last question. This may be a dumb question but do you think something could be wrong because we crimped our connections and didn't solder them? We used good quality open ended parallel crimp connectors (not crappy walmart crimp connectors) and heatshrinked around them. Do you think crimping and not soldering them can cause weird problems like with wire resistances?