Missing Under Load and at Idle

[NewGen]

Ok, I've been fighting this issue since I bought this engine and I'm turning to the forum for more help because I've run out of ideas once again :3d_frown:. The car is a 2jzgte MK III supra. The title pretty much explains everything. When I start the car up it misses and wont even try to idle. Under load it starts missing at about 6psi and 4000 rpm. It runs fine in cruise (a/rs are a little rich but no missing). There aren't any engine codes. The A/R's on my wide band read around 13.0 in cruise and 11.0 under wot. Also I've attempted to determine which cylinder my engines missing on. It seems to be missing on all cylinders intermittently at idle.

Things I've tried replacing.
-Coils
-Ignitor
-New ECU (mines re tuned for higher boost, 7200 rev limit, no fuel cut)
-Several map sensors.
-Engines been rebuilt (450miles on new engine).
-Crank sensor
-Cam sensors
-2 different sets of plugs both copper core both gaped to .28
Mods:
Engine Rebuild
-Stock rebuild aside from upgraded arp head studs, arp rod bolts and acl race bearings.
USDM Cams
Master Power T70
12X24X3 1/2 inter cooler
3" exhaust
Mines ECU
and a lot of other stuff that wouldn't affect anything
here's my build thread if your curious
http://www.supramania.com/forums/showthread.php?94869-Newgen-s-2jzgte-Swap

My ideas on what it could still be:
-When I did my battery relocation kit I ran the negative to the bumper support and there's one ground on the engine plus my solid engine mounts (not sure if that would make a difference). I don't no if maybe I don't have a good enough of a engine ground. I plan on buying enough welding power wire tomorrow to make a permanent ground to the engine from the battery.

-The only other thing I can thing of is I extend my wiring harness longer then I should of. I believe I extended mine 26 inches instead of the typical 18 inches. Could there be enough of a signal drop off from the ecu to the ignitor or the coils or even for that matter the cam angle sensors or crank sensor that they may not be firing on time or the timing may be off?

Any ideas would be excellent. I've run out of ideas .

 

[nick88]

Put more grounds on the engine, if I remember right there was valve cover to fire wall, block to frame rail, intake mani to somewhere by my shock tower on mine.

 

[87supraguy]

only real way to see if the extension is affecting the sensors and harness is to literally check every wire from the ecu and sensors....

so in other words... check how signal is leaving the batter and see if the same amount is reaching the ecu
then check the wires from the ecu to the ignitor and injectors and other sensors the same way... my $.2

 

[NewGen]

I'm going to check on that tonight. Were going to test the ground theory also.

 

[mkiiichip]

Why are you boosting an engine, that wont idle?:nono:

 

[nick88]

Can something like this be done to a jz igniter?

http://www.supramania.com/forums/showthread.php?52217-IGNITER-GROUND...-crispics

 

[NewGen]

Why are you boosting an engine, that wont idle?:nono:

Thanks for your useless rant in my thread. If you don't have anything productive to say or an idea to fix the solution please GTFO. I understand were your coming from but don't you think I may of already thought that through. The car hasn't been boosting while I've been working towards this issue.
---------- Post added at 01:18 AM ---------- Previous post was at 01:13 AM ----------

[/COLOR]

Can something like this be done to a jz igniter?

http://www.supramania.com/forums/showthread.php?52217-IGNITER-GROUND...-crispics

I always wondered about that. I'll put it on the list of things to check. I tested to make sure I was receiving a good enough body ground today. Seems to be fine there. I have another lead though. I'm going to fix it tomorrow and get back to you. To bad you had school today. You should head down this next weekend.

 

[Dirgle]

Can something like this be done to a jz igniter?

http://www.supramania.com/forums/showthread.php?52217-IGNITER-GROUND...-crispics

Unfortunately no. The inside of a JZ igniter is hermetically sealed, and even if you broke into the black case, you would find the delicate circuitry (and i mean delicate, unenclosed silicon) covered by a soft gel. Not something you want to open.

And I doubt the harness length itself would cause a problem. Mine has 24 inches added to it with no issues. Now the quality of the splice points could affect the signal. If solder was used, a cold solder joint could distort a signal. If a crimp splice was used, check to make sure the actual wire was crimped and not a part of the insulation by accident.

Now concerning ground points. If this is an Aristo, or a Supra 2JZ will matter. On a Supra 2JZ the primary ground point for the igniter will be located forward on the intake manifold. Make sure this connection has a quality ground. Also check the rear ground connection as this also houses the ECU ground, Another important ground. This is all assuming you harness has remained fairly factory.

 

[NewGen]

Unfortunately no. The inside of a JZ igniter is hermetically sealed, and even if you broke into the black case, you would find the delicate circuitry (and i mean delicate, unenclosed silicon) covered by a soft gel. Not something you want to open.

And I doubt the harness length itself would cause a problem. Mine has 24 inches added to it with no issues. Now the quality of the splice points could affect the signal. If solder was used, a cold solder joint could distort a signal. If a crimp splice was used, check to make sure the actual wire was crimped and not a part of the insulation by accident.

Now concerning ground points. If this is an Aristo, or a Supra 2JZ will matter. On a Supra 2JZ the primary ground point for the igniter will be located forward on the intake manifold. Make sure this connection has a quality ground. Also check the rear ground connection as this also houses the ECU ground, Another important ground. This is all assuming you harness has remained fairly factory.

^Thanks for the input i'm glad I didnt tear the ignitor apart lol. I have the front ground hooked up to my oil cooler underneath and the rear ground is hooked up to the lower intake manifold. I just recently replaced the wires going to my coil packs and one of the solders I was alittle sketchy about. I'm going to fix that issue tonight and see were I stand. If that doesn't fix it then I will probably pull the harness and check my solder extensions. Thanks for the input.

 

[T701jz]

^Thanks for the input i'm glad I didnt tear the ignitor apart lol. I have the front ground hooked up to my oil cooler underneath and the rear ground is hooked up to the lower intake manifold. I just recently replaced the wires going to my coil packs and one of the solders I was alittle sketchy about. I'm going to fix that issue tonight and see were I stand. If that doesn't fix it then I will probably pull the harness and check my solder extensions. Thanks for the input.

Stock injectors? What's the difference with the usdm cams (duration)? Have you tried advancing the cam gears? What are ur spark plugs look like? I'm to the point that I have to go to stand alone. I could adjust the cams (264) to where I can run with out missing but the plugs don't last long (rich).

 

[92TealSupra]

just curious was the check connector box wired into your car correctly? I know you said you don't have any codes, but have you tested to see if you " can " make the CEL come on?

 

[NewGen]

Ya stock injectors, I dont know the duration on the usdm cams. I was always curious if that would effect anything or not. The plugs look like there burning very clean.

The CEL comes on when the key is turned to ignition. As soon as the car is running it shuts off. I've never seen a check engine light come on. I guess I could check and verify that there isnt any codes. Do you have to plug an obd1 tester into it or can I just jumper the wires over similar to the 7m?