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Old 06-16-2012, 07:23 AM   #2
cre

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Unless you are failing emissions due to the idle richness or the idle is irregular then you are best off dismissing that as a means of performing any form of diagnosis. When the engine is in open loop the ECU does not try to maintain a stoichiometric mixture and the mixture will always be on the rich side. Open loop mode is entered under the following conditions: Engine cold, defective ECU temp sensor, invalid or no OX signal, >70% throttle, RPM >6000 (I can't remember the exact number but it was fairly high... There are other conditions but I can't recall all of them and I haven't the time to look it up (my 10mo puppy broke her leg today and requires constant supervision so I'm just checking in).

You've done as mentioned in your previous thread and downloaded the manual for the wideband sensor, verified the wiring is all correct and sound, made sure the narrow band and wideband are not both connected to the ECU and have performed a sensor calibration?

It's best that you not start a new thread half way into a diagnosis which you started in another thread. Newcomers and even people who've been trying to help will often get lost and miss things which you've already tried or fail to mention things which they expected you to have already done.

I seldom say this about diagnostic hardware, but if you don't know how to use it and what conditions will cause a given reading then you probably shouldn't be using it until you've done more research.

Quote:
Originally Posted by 1989toyotasupraandpickup
a/f ratio goes to 17+ until i press the throttle down.
It should go to about 22 when you're coasting above fuel cut RPM. The ECU does not inject fuel when coasting unless the engine speed is around 1K or less.
Quote:
Originally Posted by 1989toyotasupraandpickup
while boosting the a/f ratio goes to 10-11.2
This is appropriate as you're in open loop operation and if it were too much leaner when boosting and you'll melt pistons.

Timing is controlled by the ECU and will always vary. You put in the jumper to lock it to its base advance where the ECU cannot adjust it. It's fine.

EGR... No. The gasses introduced into the cylinders are inert. They contain neither fuel nor oxygen and shouldn't affect your mixture at all.

An intake leak can cause mixture problems. An exhaust leak can cause your sensors to misread the data. Personally, I'd look at the intake, exhaust, vacuum hoses, test the ECU temp sensor, TPS and AFM. Don't bother with ANY of this until you've checked all of the wideband's wiring (ESPECIALLY THE POWER AND GROUNDS!!!!!), read the manual cover to cover, and calibrated it.

I don't have time to look at the video, I've got a whimpering puppy to take to bed now... Hopefully someone else will chime in if I missed something of note. Good luck with it.
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