1JZ Bogs when touch the throttle at all

[Untouchable7mgte]

hey guys,

just got my 1JZ into my 240. it starts up and idle perfect but as soon as i touch the throttle it just bogs out and stumbles until comes back to normal idle. ive already check crank sensor, cam sensors, test and adjust my TPS. After adjusting my TPS it would even start until i loosen it and turn it until it started. Fuel is right at 40psi and when i can rev it go to about 43ish. i dont want to just start throwing TPS or MAP sensors at it because there are about $100 a piece. OH and there is a brand new ecu coolant sensor. let me know is there is anything im missing.

Heres a video to explain more of what im saying

[video=youtube_share;x9qR-QiTh_8]https://youtu.be/x9qR-QiTh_8[/video]

 

[hvyman]

Map sensor. Or map sensor plumbing.

 

[Untouchable7mgte]

MAP sensor is plumbed into filter on intake manifold with 1in vac line and im going voltage at plug and voltage on the output as well. i even tried unplugging the MAP and it acted the same.

 

[Untouchable7mgte]

Ordered a TPS today to see if thats it, im leaning toward that more since i had that in spec and still didnt work

 

[Guyana00]

No codes stored? Check plug/coil boots as well and check gaps.

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[Untouchable7mgte]

well guys just installed that new tps and calibrated it as per shims. still would not start when it was within spec. loosen it, backed it off a bit and fired up to idle fine. still doing the same exact thing. checked all 6 plugs, all were very black. found cylinder 1 and 2 ceramic was cracked so i replaced them with others i had. checked all gaps and coils. didnt see anything wrong there. even opened the ecu up and checked the caps and there was zero sign of leakage/swollen. im running out of ideas and patience now

 

[RacerXJ220]

Is the harness modified?

 

[Untouchable7mgte]

wiring specialties brand new harness

 

[Untouchable7mgte]

forgot to mention that when i really try to rev it up, getting some serious black smoke out the exhaust. i tried listening to the injector while revving it to cut off and they seem to keep working

 

[RacerXJ220]

I'd double check the TPS wiring. Continuity meter, check each of the TPS wires to make sure they are wired right.

Sounds like overkill, right?

When I ran out of ideas on my "Dr.Tweak" harness, I found out two of the TPS wires were backwards, and he didn't even put a ground wire in for the sensors to the ECU. I had to fix those mistakes, but it took me a week to suspect the wiring. I went through the entire harness, and matched each wire to the corresponding pinout on the ECU.

I'm sure Wiring Specialties does good work, and am not trying to send you on wild goose chases. I just don't know what else to suggest at this point. Could possibly be an ECU issue...

 

[Guyana00]

Black plugs and black exhaust smoke seems like overly rich conditions. Do you have any logging or wideband?

Other than ruling things out that you've checked or tested, the smoke is all I'm going on.

I don't think you'll be able to hear out the injectors. But if one is leaking or you put some huge ones in that could contribute to the black smoke or rich condition, but not the stumble.

Was it always like this since you started it? If not, try pulling the battery for a while.

It could be the oxygen sensor. Have you tried unplugging it, free to check. To be honest, most things that come to mind should throw a code or store one. Is the CEL working?

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[Untouchable7mgte]

as far as i know everything is stock on the engine. not mods done at all. unfortunately my cluster isn't working so i cant pull a CEL if there was one. i dont have the exhaust hooked up yet either so i have no wideband yet but i did unplug the O2 sensor and it kept doing the same thing. i pull the battery every time im done working on it too

 

[f00g00]

did you verify the vacuum is ok to the MAP sensor? Also do a pin to pin check from the ECU to the MAP. It sounds like the MAP input isn't working.

 

[Untouchable7mgte]

when the engine was idling i pulled the vac line and engine stumbled so there was sucking from the line. i even tried different vac source other then the filtered spot where the MAP should be. i back probed the MAP while idling, had 5v on one and 1-2v while idling. voltage did change the little bit i was about the rev it. when car is on ACC MAP voltage is about 2.36v which i believe is normal with no vacuum. im going to buy a better multi-meter tonight to check continuity from sensor to ECU

 

[Untouchable7mgte]

hey guys well i fixed it. after doing some continuity tests i found that the outputs for TPS and the MAP were reversed on the harness. car idles fine now at adjusted TPS and revs up good. now to take it all apart cause valve lash is way out because i hear bad tapping on top.

 

[Guyana00]

Awesome glad to hear. Wiring issues can be the worst to find. Glad you posted the solution too good luck.

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[Untouchable7mgte]

indeed! thanks everyone for all the pointers!