bad 1jz problem that we cant figure out

Boostage

New Member
Oct 4, 2006
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Florida
Specs:
1jz
Blitz ecu
Sard 620cc
SAFC II

Problem:

Car was done 3 weeks ago, and Dyno tuned Last week. everything was 100% perfect. but had a weird oil pan leak. we drained the oil, removed the pan, and resealed it. added fresh oil. then cranked it up. then all of a sudden the car was dumping fuel bad, and would stall. it now does this everyday until the car is completely warm then the problem seems to go away.

Parts that were replaced over the next few days:
IACV
MAP sensor
Coolant temp sensor

TPS reads fine on the safc so its not TPS. every sensor including Air temp was tested. Opened up the ECU. no leaky caps or discoloration anywhere.

When cold the car runs so rich that it fouls out the spark plugs and you can smell gas in the oil. if you try to drive like this the car bucks badly and will die every time you come to a stop once warmed up the problem eventually goes away. what is causing the car to run super rich and die when cold?
 

OneJSupra

I'm a sleeper ...
Feb 9, 2007
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Supraland
Have you tried running it with the stock ecu just to rule out if it's the blitz. When I tried my friend's blitz ecu my cold idle speed was so aggressive (smells fuel everywhere) till it's warmed up then idles fine drives normal. Werd.

Are you running stock 02 sensor? Not sure but I think the blitz don't like my mustang sensor. I read in the mr2 forum someone who had a blitz that have the same problem but when he switched back to stock 02 sensor his car idles/drives fine cold and hot.
 
Last edited:

Boostage

New Member
Oct 4, 2006
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Florida
OneJSupra;1295625 said:
Have you tried running it with the stock ecu just to rule out if it's the blitz. When I tried my friend's blitz ecu my cold idle speed was so aggressive (smells fuel everywhere) till it's warmed up then idles fine drives normal. Werd.

Are you running stock 02 sensor? Not sure but I think the blitz don't like my mustang sensor. I read in the mr2 forum someone who had a blitz that have the same problem but when he switched back to stock 02 sensor his car idles/drives fine cold and hot.

Stock ecu will not idle with a safc plugged in as its intercepting the MAP signals. and if u unplug the safc the stock ecu will not idle 620 injectors. there is no way to use a stock ecu to rule out the blitz unless it gets dyno tuned all over again. but as I said I went inside the ecu and it looks fine. also O2 is brand new
 

OneJSupra

I'm a sleeper ...
Feb 9, 2007
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My car idles fine (14.7 afr) stock ecu with the 540cc with only -12 fuel correction in the safc. If I zero it out it would stall. I can't imagine even with the 620cc the safc can't control it at idle speed. I guess every car is different. There has to be something else causing it to run pig rich. Maybe it's your safc, just throwing some ideas here ... g/l.
 

JonoTurbo

Going for broke
Mar 30, 2005
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Even though you opened the ECU and looked, unless the caps have been replaced I'm still gonna say ECU. Usually when you get a problem that comes out of nowhere it's the cause, and the caps can be bad without looking bad.
 

Boostage

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Oct 4, 2006
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Florida
JonoTurbo;1295656 said:
Even though you opened the ECU and looked, unless the caps have been replaced I'm still gonna say ECU. Usually when you get a problem that comes out of nowhere it's the cause, and the caps can be bad without looking bad.

Ok but why would it run perfect again after its warmed?
 

JonoTurbo

Going for broke
Mar 30, 2005
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Boostage;1295669 said:
Ok but why would it run perfect again after its warmed?

Because only the open loop portion of the fuel circuit is damaged.

I'm not saying this is definitely the case, but the 1jz ecu's fail all the time and I wouldn't rule it out.
 

Boostage

New Member
Oct 4, 2006
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Florida
JonoTurbo;1295701 said:
Because only the open loop portion of the fuel circuit is damaged.

I'm not saying this is definitely the case, but the 1jz ecu's fail all the time and I wouldn't rule it out.

Tonight I tried my blitz in an sc300 with a 1jz and the idle was PERFECT, put the Lexus ecu in my car and the problem was still there. so we know its not the ecu
 

JonoTurbo

Going for broke
Mar 30, 2005
670
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Boostage;1296039 said:
Tonight I tried my blitz in an sc300 with a 1jz and the idle was PERFECT, put the Lexus ecu in my car and the problem was still there. so we know its not the ecu

Well that's one way to rule it out. :)

I'm just throwing these out there as things to check: the ISC, and the cam sensors. You seem to have covered everything else.
 

OneJArpus

Supramania Contributor
Jul 1, 2005
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Newark, New Jersey, United States
when i did my 1j swap i had a sard ecu, i finished everything and it wouldn't start, it would stumble for a few seconds and crank but would never fully fire. I sent the ECU to DM and Aaron said that the board was perfect but the blitz board added was screwed up and he couldn't fix it cause he didnt know the specs of what was on the board. I ended up borrowing an ECU and it started right away. i took my wiring apart 4 times thinking it was that but i did ti perfect the first time to find out the ECU was shit.