No More High Idle on Cold Start

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harrydunn said:
Interesting and thanks for posting. Has it every had the high cold idle?
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When I start it, it revs to 1200 or so and immediately drops down to ~600.
I haven't seen it sustain high idle, but as I stated before, it runs smooth, and takes throttle without hesitation.
 
PM'd you a local club member's info that lives in your area with an LX450. He's a great guy and might be willing to swap parts with you to help diagnose.
 
FZJ80 in KC said:
PM'd you a local club member's info that lives in your area with an LX450. He's a great guy and might be willing to swap parts with you to help diagnose.
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Thanks again for the PM. Not many Land Cruiser's around here, especially 80's.
 
My 94 does same thing so cleaned throttle body, and changed the iac, no difference really, next adjusted both throttle cables got her back now seems to high idle slowly drop and when in gear is at 650 700, I also increased my timing too 7, I live high altitude at 9000 ft
 
Well, ECU may have moved into first place. Got one code 12 today which I've never received in 6 years of ownership and on 5 separate occasions got codes 83, 84, 85. Typically, I get 5 83-83-85 per YEAR not per day. Glad I haven't purchased a VAF meter yet. It tested good today with my multimeter. I hate throwing parts at things but probably time to buy the "new" ECU.
 
so, what are those error codes for ?

how can you know it's the ECU ?

I don't get a "high" idle in the LX450, either - but then, that lives in Southern Arizona, where it's just about the same temperature as in Baton Rouge
 
83-84-85 are your typical codes for a "bad" ECU in early production '93 80's. I'm sure it can point to other issues as well, such as a maladjusted TPS, for example. Most '93 guys upgrade to the mid-'93 and '94 ECUs.
 
Got the same ecu codes on my 1993. Upgraded to the 1994 ecu and codes sent away. Take your time and source a good used 94 Ecu. That will solve one of your issues and hopefully the others as well
 
Good to hear. I'm assuming you mean find a low mileage unit? Not sure how else to ascertain quality of an ECU. CEL is kicking on every 5-10 minutes now.
 
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Had the first "cold" morning here in quite some time and I had the same startup as the last "cold" morning as depicted in my video several weeks ago. "New" ECU is on it's way. Found a good deal on a TPS as well, so what the heck. Ugh. Wish me luck. Happy Holidays!

wrestling-raw-dolph-ziggler-vs-santa-claas1_zps9ofwlxj1.jpg~original
 
Let's say hypothetically ;) I unplugged the IAC valve harness and started the truck on a whim after it was fully warmed up? What "SHOULD" happen?
 
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Well, crap. Updated ECU is in. No change. I'm back to square one. It seems like it just can't figure out that it's cold in the mornings but I replaced the ECT sensor. I did not use OEM, however. I don't know how big of a problem that could be. I suppose I could have received a bad ECT sensor from NAPA. Bad ECT sensor wiring? If I keep it in the garage overnight where it's warm it will not stumble like in the video below but it still will not kick into high idle.

To recap:

Cleaned TB three times (wasn't dirty)
Cleaned IAC (wasn't dirty)
Swapped IAC's
New fusible links
New spark plugs
New ECT ECU sensor
Updated to '94 ECU
Replaced intake pipe
Replaced PCV valve and hose
Checked for vacuum leaks
Disabled EGR system
Motorvac carbon cleaning
My reputable shop had it for two days and could not figure it out but it was warm while it was there so started okay.

New TPS arrives today. I don't know where to go from there. How would I go about checking the wiring to the ECT sensor? This morning's video below.

 
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So I had no cold start this morning after sitting all week, changed out throttle position sensor and now back to normal has cold start slowly drops down and also has good idle when in drive.
 
harrydunn said:
Well, crap. Updated ECU is in. No change. I'm back to square one. It seems like it just can't figure out that it's cold in the mornings but I replaced the ECT sensor. I did not use OEM, however. I don't know how big of a problem that could be. I suppose I could have received a bad ECT sensor from NAPA. Bad ECT sensor wiring? If I keep it in the garage overnight where it's warm it will not stumble like in the video below but it still will not kick into high idle.

To recap:

Cleaned TB three times (wasn't dirty)
Cleaned IAC (wasn't dirty)
Swapped IAC's
New fusible links
New spark plugs
New ECT ECU sensor
Updated to '94 ECU
Replaced intake pipe
Replaced PCV valve and hose
Checked for vacuum leaks
Disabled EGR system
Motorvac carbon cleaning
My reputable shop had it for two days and could not figure it out but it was warm while it was there so started okay.

New TPS arrives today. I don't know where to go from there. How would I go about checking the wiring to the ECT sensor? This morning's video below.

Click to expand...

300 rpm idle? So, again, this may not be applicable here, but our '93 had a no/very low idle after a power outage related to a fusible links exchange; ~ 200 rpm at best. What helped was resetting the IAC; the procedure was turnng the key to ignition on (but not starting) and then off, repeat 14 times within 20 seconds. In my case, I had to do thise twice, but that restored normal idle conditions.
 
Swapped a different TPS in. No change. Man, I'm so stumped here. I feel that it has to be something small that I'm overlooking. Again, runs great when fully warm. Smooth as silk and good idle.
 
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